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Baumann AA, Knol LI, Arlt M, Hutschenreiter T, Richter A, Widmann TJ, Franke M, Hackmann K, Winkler S, Richter D, Spier I, Aretz S, Aust D, Porrmann J, William D, Schröck E, Glimm H, Jahn A. Long-read genome and RNA sequencing resolve a pathogenic intronic germline LINE-1 insertion in APC. NPJ Genom Med 2025; 10:30. [PMID: 40180948 PMCID: PMC11968988 DOI: 10.1038/s41525-025-00485-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2024] [Accepted: 02/28/2025] [Indexed: 04/05/2025] Open
Abstract
Familial adenomatous polyposis (FAP) is caused by pathogenic germline variants in the tumor suppressor gene APC. Confirmation of diagnosis was not achieved by cancer gene panel and exome sequencing or custom array-CGH in a family with suspected FAP across five generations. Long-read genome sequencing (PacBio), short-read genome sequencing (Illumina), short-read RNA sequencing, and further validations were performed in different tissues of multiple family members. Long-read genome sequencing resolved a 6 kb full-length intronic insertion of a heterozygous LINE-1 element between exons 7 and 8 of APC that could be detected but not fully resolved by short-read genome sequencing. Targeted RNA analysis revealed aberrant splicing resulting in the formation of a pseudo-exon with a premature stop codon. The variant segregated with the phenotype in several family members allowing its evaluation as likely pathogenic. This study supports the utility of long-read DNA sequencing and complementary RNA approaches to tackle unsolved cases of hereditary disease.
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Affiliation(s)
- Alexandra A Baumann
- Institute for Clinical Genetics, University Hospital Carl Gustav Carus at TUD Dresden University of Technology and Faculty of Medicine of TUD Dresden University of Technology, Dresden, Germany
- National Center for Tumor Diseases (NCT), NCT/UCC Dresden,, a partnership between DKFZ, Faculty of Medicine and University Hospital Carl Gustav Carus, TUD Dresden University of Technology, and Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Dresden, Germany
- ERN GENTURIS, Hereditary Cancer Syndrome Center Dresden, Dresden, Germany
| | - Lisanne I Knol
- National Center for Tumor Diseases (NCT), NCT/UCC Dresden,, a partnership between DKFZ, Faculty of Medicine and University Hospital Carl Gustav Carus, TUD Dresden University of Technology, and Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Dresden, Germany
- Department of Translational Medical Oncology, NCT Dresden and DKFZ, Dresden, Germany
- Translational Medical Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, TUD Dresden University of Technology, Dresden, Germany
| | - Marie Arlt
- Institute for Clinical Genetics, University Hospital Carl Gustav Carus at TUD Dresden University of Technology and Faculty of Medicine of TUD Dresden University of Technology, Dresden, Germany
- ERN GENTURIS, Hereditary Cancer Syndrome Center Dresden, Dresden, Germany
| | - Tim Hutschenreiter
- Institute for Clinical Genetics, University Hospital Carl Gustav Carus at TUD Dresden University of Technology and Faculty of Medicine of TUD Dresden University of Technology, Dresden, Germany
- ERN GENTURIS, Hereditary Cancer Syndrome Center Dresden, Dresden, Germany
| | - Anja Richter
- Institute for Clinical Genetics, University Hospital Carl Gustav Carus at TUD Dresden University of Technology and Faculty of Medicine of TUD Dresden University of Technology, Dresden, Germany
- National Center for Tumor Diseases (NCT), NCT/UCC Dresden,, a partnership between DKFZ, Faculty of Medicine and University Hospital Carl Gustav Carus, TUD Dresden University of Technology, and Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Dresden, Germany
- ERN GENTURIS, Hereditary Cancer Syndrome Center Dresden, Dresden, Germany
| | - Thomas J Widmann
- National Center for Tumor Diseases (NCT), NCT/UCC Dresden,, a partnership between DKFZ, Faculty of Medicine and University Hospital Carl Gustav Carus, TUD Dresden University of Technology, and Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Dresden, Germany
- Pfizer-University of Granada-Junta de Andalucía Centre for Genomics and Oncological Research (GENYO), PTS Granada, managed by Fundación Pública Andaluza Progreso y Salud (FPS), Granada, Spain
| | - Marcus Franke
- Institute for Clinical Genetics, University Hospital Carl Gustav Carus at TUD Dresden University of Technology and Faculty of Medicine of TUD Dresden University of Technology, Dresden, Germany
- ERN GENTURIS, Hereditary Cancer Syndrome Center Dresden, Dresden, Germany
| | - Karl Hackmann
- Institute for Clinical Genetics, University Hospital Carl Gustav Carus at TUD Dresden University of Technology and Faculty of Medicine of TUD Dresden University of Technology, Dresden, Germany
- ERN GENTURIS, Hereditary Cancer Syndrome Center Dresden, Dresden, Germany
| | - Sylke Winkler
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
| | - Daniela Richter
- National Center for Tumor Diseases (NCT), NCT/UCC Dresden,, a partnership between DKFZ, Faculty of Medicine and University Hospital Carl Gustav Carus, TUD Dresden University of Technology, and Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Dresden, Germany
- Department of Translational Medical Oncology, NCT Dresden and DKFZ, Dresden, Germany
- Translational Medical Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, TUD Dresden University of Technology, Dresden, Germany
- German Cancer Consortium (DKTK), Dresden, Germany
- German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Isabel Spier
- Institute of Human Genetics, Medical Faculty, University of Bonn, Bonn, Germany
- National Center for Hereditary Tumor Syndromes, University Hospital Bonn, Bonn, Germany
| | - Stefan Aretz
- Institute of Human Genetics, Medical Faculty, University of Bonn, Bonn, Germany
- National Center for Hereditary Tumor Syndromes, University Hospital Bonn, Bonn, Germany
| | - Daniela Aust
- Institute of Pathology, University Hospital Carl Gustav Carus at TUD Dresden University, Dresden, Germany
- Tumor- and Normal Tissue Bank of the University Cancer Center (UCC), University Hospital Carl Gustav Carus, Medical Faculty, TUD Dresden University of Technology, Dresden, Germany
| | - Joseph Porrmann
- Institute for Clinical Genetics, University Hospital Carl Gustav Carus at TUD Dresden University of Technology and Faculty of Medicine of TUD Dresden University of Technology, Dresden, Germany
- ERN GENTURIS, Hereditary Cancer Syndrome Center Dresden, Dresden, Germany
| | - Doreen William
- Institute for Clinical Genetics, University Hospital Carl Gustav Carus at TUD Dresden University of Technology and Faculty of Medicine of TUD Dresden University of Technology, Dresden, Germany
- ERN GENTURIS, Hereditary Cancer Syndrome Center Dresden, Dresden, Germany
| | - Evelin Schröck
- Institute for Clinical Genetics, University Hospital Carl Gustav Carus at TUD Dresden University of Technology and Faculty of Medicine of TUD Dresden University of Technology, Dresden, Germany
- National Center for Tumor Diseases (NCT), NCT/UCC Dresden,, a partnership between DKFZ, Faculty of Medicine and University Hospital Carl Gustav Carus, TUD Dresden University of Technology, and Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Dresden, Germany
- ERN GENTURIS, Hereditary Cancer Syndrome Center Dresden, Dresden, Germany
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
- German Cancer Consortium (DKTK), Dresden, Germany
- German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Hanno Glimm
- National Center for Tumor Diseases (NCT), NCT/UCC Dresden,, a partnership between DKFZ, Faculty of Medicine and University Hospital Carl Gustav Carus, TUD Dresden University of Technology, and Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Dresden, Germany
- Department of Translational Medical Oncology, NCT Dresden and DKFZ, Dresden, Germany
- Translational Medical Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, TUD Dresden University of Technology, Dresden, Germany
- German Cancer Consortium (DKTK), Dresden, Germany
- German Cancer Research Center (DKFZ), Heidelberg, Germany
- Center for Personalized Oncology, NCT Dresden and University Hospital Carl Gustav Carus, Faculty of Medicine and TUD Dresden University of Technology, Dresden, Germany
- Translational Functional Cancer Genomics, NCT Heidelberg and DKFZ, Heidelberg, Germany
| | - Arne Jahn
- Institute for Clinical Genetics, University Hospital Carl Gustav Carus at TUD Dresden University of Technology and Faculty of Medicine of TUD Dresden University of Technology, Dresden, Germany.
- National Center for Tumor Diseases (NCT), NCT/UCC Dresden,, a partnership between DKFZ, Faculty of Medicine and University Hospital Carl Gustav Carus, TUD Dresden University of Technology, and Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Dresden, Germany.
- ERN GENTURIS, Hereditary Cancer Syndrome Center Dresden, Dresden, Germany.
- German Cancer Consortium (DKTK), Dresden, Germany.
- German Cancer Research Center (DKFZ), Heidelberg, Germany.
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Zhang TQ, Cai JD, Li C, Xu Y, Xu Y. De novo familial adenomatous polyposis with germline double heterozygosity of APC/BRCA2: a case report and literature review. Hered Cancer Clin Pract 2025; 23:6. [PMID: 39985003 PMCID: PMC11843810 DOI: 10.1186/s13053-025-00306-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2023] [Accepted: 02/05/2025] [Indexed: 02/23/2025] Open
Abstract
BACKGROUND The widespread application of colonoscopy screening and genetic testing in colorectal cancer (CRC) treatment has led to the identification of a subset of familial adenomatous polyposis (FAP) patients who lack a family history of the disease but harbor germline gene mutations. Moreover, distinct genotypes may be associated with varied clinical presentations and therapeutic options. This case report describes a male patient with de novo FAP who harbored germline double heterozygosity (GDH) for APC and BRCA2 mutations. The patient underwent total colectomy, and genetic testing enabled personalized surveillance and management strategies for his family members. CASE PRESENTATION A 43-year-old male with no family history of cancer presented to the outpatient clinic of the Colorectal Surgery Department with complaints of constipation and hematochezia. Colonoscopy revealed hundreds of polyps throughout the colon and a rectal adenocarcinoma located 5 cm from the anal verge. Gastroduodenal endoscopy did not detect any upper gastrointestinal adenomas. The patient underwent laparoscopic total colectomy with abdominoperineal resection of the rectum and end ileostomy. With the consent of the patient and his family, genetic testing was performed. The index patient was found to carry an APC splicing site mutation (exon 15: c.1744-1G > A) and a BRCA2 missense mutation (exon 17: c.7976G > A: p.R2659K). His daughter was found to have inherited the same germline BRCA2 variant. Additionally, the rectal cancer exhibited proficient DNA mismatch repair (pMMR) status, ERBB2 copy number amplification, and a missense mutation, while the KRAS, NRAS, and BRAF genes were wild-type. Based on the genetic testing results and clinical manifestations, the index patient was diagnosed with familial adenomatous polyposis (FAP) and rectal cancer. Personalized surveillance and management strategies were implemented for the patient and his family, focusing on the risks of extra-colonic diseases and potential malignancies in the prostate, pancreas, breast, and ovaries. CONCLUSION De novo FAP with double germline mutations in APC and BRCA2, along with somatic ERBB2 mutations, is exceptionally rare among hereditary cancer cases. With the rapid advancements in genomics, the detection of multiple gene variants in individuals or families has become increasingly common. Additionally, the application of artificial intelligence (AI) in medical research may provide powerful tools for genetic analysis and clinical decision-making. Consequently, a comprehensive evaluation of family history, a deep understanding of hereditary cancer syndromes, and precise interpretation of genetic mutations are essential for personalized clinical management in the era of precision medicine. However, these tasks pose significant challenges for clinicians and genetic counselors alike.
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Affiliation(s)
- Tian-Qi Zhang
- Department of Pathology, Fudan University Shanghai Cancer Center, Shanghai, China
| | - Ji-Dong Cai
- Department of Endoscopy, Fudan University Shanghai Cancer Center, Shanghai, China
| | - Cong Li
- Department of Colorectal Surgery, Fudan University Shanghai Cancer Center, Shanghai, China
| | - Yun Xu
- Department of Colorectal Surgery, Fudan University Shanghai Cancer Center, Shanghai, China
| | - Ye Xu
- Department of Colorectal Surgery, Fudan University Shanghai Cancer Center, Shanghai, China.
- Department of Colorectal Surgery, Fudan University, Shanghai Cancer Center, Dong'an Road, 270, Shanghai, 200032, China.
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Yin X, Richardson M, Laner A, Shi X, Ognedal E, Vasta V, Hansen TVO, Pineda M, Ritter D, de Dunnen J, Hassanin E, Lin WL, Borras E, Krahn K, Nordling M, Martins A, Mahmood K, Nadeau E, Beshay V, Tops C, Genuardi M, Pesaran T, Frayling IM, Capellá G, Latchford A, Tavtigian SV, Maj C, Plon SE, Greenblatt MS, Macrae FA, Spier I, Aretz S. Large-scale application of ClinGen-InSiGHT APC-specific ACMG/AMP variant classification criteria leads to substantial reduction in VUS. Am J Hum Genet 2024; 111:2427-2443. [PMID: 39357517 PMCID: PMC11568752 DOI: 10.1016/j.ajhg.2024.09.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2024] [Revised: 09/05/2024] [Accepted: 09/06/2024] [Indexed: 10/04/2024] Open
Abstract
Pathogenic constitutional APC variants underlie familial adenomatous polyposis, the most common hereditary gastrointestinal polyposis syndrome. To improve variant classification and resolve the interpretative challenges of variants of uncertain significance (VUSs), APC-specific variant classification criteria were developed by the ClinGen-InSiGHT Hereditary Colorectal Cancer/Polyposis Variant Curation Expert Panel (VCEP) based on the criteria of the American College of Medical Genetics and Genomics and the Association for Molecular Pathology (ACMG/AMP). A streamlined algorithm using the APC-specific criteria was developed and applied to assess all APC variants in ClinVar and the International Society for Gastrointestinal Hereditary Tumours (InSiGHT) international reference APC Leiden Open Variation Database (LOVD) variant database, which included a total of 10,228 unique APC variants. Among the ClinVar and LOVD variants with an initial classification of (likely) benign or (likely) pathogenic, 94% and 96% remained in their original categories, respectively. In contrast, 41% ClinVar and 61% LOVD VUSs were reclassified into clinically meaningful classes, the vast majority as (likely) benign. The total number of VUSs was reduced by 37%. In 24 out of 37 (65%) promising APC variants that remained VUS despite evidence for pathogenicity, a data-mining-driven work-up allowed their reclassification as (likely) pathogenic. These results demonstrated that the application of APC-specific criteria substantially reduced the number of VUSs in ClinVar and LOVD. The study also demonstrated the feasibility of a systematic approach to variant classification in large datasets, which might serve as a generalizable model for other gene- or disease-specific variant interpretation initiatives. It also allowed for the prioritization of VUSs that will benefit from in-depth evidence collection. This subset of APC variants was approved by the VCEP and made publicly available through ClinVar and LOVD for widespread clinical use.
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Affiliation(s)
- Xiaoyu Yin
- Department of Colorectal Medicine and Genetics, Royal Melbourne Hospital, Parkville, VIC, Australia; Department of Medicine, University of Melbourne, Parkville, VIC, Australia; Institute of Human Genetics, Medical Faculty, University of Bonn, Bonn, Germany
| | | | | | - Xuemei Shi
- Greenwood Genetic Center, Greenwood, SC, USA
| | - Elisabet Ognedal
- Western Norway Familial Cancer Center, Haukeland University Hospital, Bergen, Norway
| | - Valeria Vasta
- Northwest Genomics Center, Department of Genome Sciences, University of Washington, Seattle, WA, USA
| | - Thomas V O Hansen
- Department of Clinical Genetics, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark; Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Marta Pineda
- European Reference Network on Genetic Tumour Risk Syndromes (ERN GENTURIS), Nijmegen, the Netherlands; Hereditary Cancer Program, Catalan Institute of Oncology - ONCOBELL, IDIBELL, Barcelona, Spain; Centro de Investigación Biomédica en Red de Cáncer (CIBERONC), Instituto Salud Carlos III, Madrid, Spain
| | - Deborah Ritter
- Baylor College of Medicine, Houston, TX, USA; Texas Children's Cancer Center, Texas Children's Hospital, Houston, TX, USA
| | - Johan de Dunnen
- Departments of Human Genetics & Clinical Genetics, Leiden University Medical Center, Leiden, the Netherlands
| | - Emadeldin Hassanin
- Institute for Genomic Statistics and Bioinformatics, University Hospital Bonn, Bonn, Germany; Luxembourg Centre for Systems Biomedicine, University of Luxembourg, Esch-sur-Alzette, Luxembourg
| | | | | | | | - Margareta Nordling
- Department of Biomedical and Clinical Sciences, Linköping University, Linköping, Sweden; Department of Clinical Genetics, Linköping University Hospital, Linköping, Sweden
| | | | - Khalid Mahmood
- Colorectal Oncogenomics Group, Department of Clinical Pathology, University of Melbourne, Melbourne, VIC, Australia
| | - Emily Nadeau
- Department of Medicine, Larner College of Medicine, University of Vermont, Burlington, VT, USA
| | | | - Carli Tops
- Departments of Human Genetics & Clinical Genetics, Leiden University Medical Center, Leiden, the Netherlands
| | - Maurizio Genuardi
- Fondazione Policlinico Universitario A. Gemelli IRCCS, and Dipartimento di Scienze della Vita e Sanità Pubblica, Università Cattolica del Sacro Cuore, Rome, Italy
| | | | - Ian M Frayling
- Polyposis Registry, St Mark's Hospital, London, UK; Inherited Tumour Syndromes Research Group, Institute of Cancer & Genetics, Cardiff University, Cardiff, UK; National Centre for Colorectal Disease, St Vincent's University Hospital, Dublin, Ireland
| | - Gabriel Capellá
- European Reference Network on Genetic Tumour Risk Syndromes (ERN GENTURIS), Nijmegen, the Netherlands; Hereditary Cancer Program, Catalan Institute of Oncology - ONCOBELL, IDIBELL, Barcelona, Spain; Centro de Investigación Biomédica en Red de Cáncer (CIBERONC), Instituto Salud Carlos III, Madrid, Spain
| | - Andrew Latchford
- Polyposis Registry, St Mark's Hospital, London, UK; Department of Surgery and Cancer, Imperial College, London, UK
| | - Sean V Tavtigian
- Huntsman Cancer Institute, University of Utah, Salt Lake City, UT, USA; Department of Oncological Sciences, School of Medicine, University of Utah, Salt Lake City, UT, USA
| | - Carlo Maj
- Institute for Genomic Statistics and Bioinformatics, University Hospital Bonn, Bonn, Germany; Centre for Human Genetics, University of Marburg, Marburg, Germany
| | - Sharon E Plon
- Baylor College of Medicine, Houston, TX, USA; Texas Children's Cancer Center, Texas Children's Hospital, Houston, TX, USA
| | - Marc S Greenblatt
- Department of Medicine, Larner College of Medicine, University of Vermont, Burlington, VT, USA
| | - Finlay A Macrae
- Department of Colorectal Medicine and Genetics, Royal Melbourne Hospital, Parkville, VIC, Australia; Department of Medicine, University of Melbourne, Parkville, VIC, Australia
| | - Isabel Spier
- Institute of Human Genetics, Medical Faculty, University of Bonn, Bonn, Germany; European Reference Network on Genetic Tumour Risk Syndromes (ERN GENTURIS), Nijmegen, the Netherlands; National Center for Hereditary Tumor Syndromes, University Hospital Bonn, Bonn, Germany
| | - Stefan Aretz
- Institute of Human Genetics, Medical Faculty, University of Bonn, Bonn, Germany; European Reference Network on Genetic Tumour Risk Syndromes (ERN GENTURIS), Nijmegen, the Netherlands; National Center for Hereditary Tumor Syndromes, University Hospital Bonn, Bonn, Germany.
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He M, Hu M, Zhang Q, Yao K. A novel splice-altering TNC variant (c.5247A > T, p.Gly1749Gly) in an Chinese family with autosomal dominant non-syndromic hearing loss. BMC Med Genomics 2024; 17:189. [PMID: 39020321 PMCID: PMC11256465 DOI: 10.1186/s12920-024-01964-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2024] [Accepted: 07/15/2024] [Indexed: 07/19/2024] Open
Abstract
BACKGROUND This study aims to analyze the pathogenic gene in a Chinese family with non-syndromic hearing loss and identify a novel mutation site in the TNC gene. METHODS A five-generation Chinese family from Anhui Province, presenting with autosomal dominant non-syndromic hearing loss, was recruited for this study. By analyzing the family history, conducting clinical examinations, and performing genetic analysis, we have thoroughly investigated potential pathogenic factors in this family. The peripheral blood samples were obtained from 20 family members, and the pathogenic genes were identified through whole exome sequencing. Subsequently, the mutation of gene locus was confirmed using Sanger sequencing. The conservation of TNC mutation sites was assessed using Clustal Omega software. We utilized functional prediction software including dbscSNV_AdaBoost, dbscSNV_RandomForest, NNSplice, NetGene2, and Mutation Taster to accurately predict the pathogenicity of these mutations. Furthermore, exon deletions were validated through RT-PCR analysis. RESULTS The family exhibited autosomal dominant, progressive, post-lingual, non-syndromic hearing loss. A novel synonymous variant (c.5247A > T, p.Gly1749Gly) in TNC was identified in affected members. This variant is situated at the exon-intron junction boundary towards the end of exon 18. Notably, glycine residue at position 1749 is highly conserved across various species. Bioinformatics analysis indicates that this synonymous mutation leads to the disruption of the 5' end donor splicing site in the 18th intron of the TNC gene. Meanwhile, verification experiments have demonstrated that this synonymous mutation disrupts the splicing process of exon 18, leading to complete exon 18 skipping and direct splicing between exons 17 and 19. CONCLUSION This novel splice-altering variant (c.5247A > T, p.Gly1749Gly) in exon 18 of the TNC gene disrupts normal gene splicing and causes hearing loss among HBD families.
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Affiliation(s)
- Min He
- Department of Neurology, The First People's Hospital of Wuhu, Chizhu Shandong Road, Jiujiang District, Wuhu, 241000, Anhui Province, China.
| | - Miaomiao Hu
- Key Laboratory of Digital Technology in Medical Diagnostics of Zhejiang Province, Dian Diagnostics Group Co., Ltd., Hangzhou, 310030, Zhejiang Province, China
| | - Qiang Zhang
- Department of Neurology, The First People's Hospital of Wuhu, Chizhu Shandong Road, Jiujiang District, Wuhu, 241000, Anhui Province, China
| | - Kai Yao
- Department of Neurology, The First People's Hospital of Wuhu, Chizhu Shandong Road, Jiujiang District, Wuhu, 241000, Anhui Province, China
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Yin X, Richardson M, Laner A, Shi X, Ognedal E, Vasta V, Hansen TVO, Pineda M, Ritter D, den Dunnen JT, Hassanin E, Lyman Lin W, Borras E, Krahn K, Nordling M, Martins A, Mahmood K, Nadeau EAW, Beshay V, Tops C, Genuardi M, Pesaran T, Frayling IM, Capellá G, Latchford A, Tavtigian SV, Maj C, Plon SE, Greenblatt MS, Macrae FA, Spier I, Aretz S. Systematic large-scale application of ClinGen InSiGHT APC -specific ACMG/AMP variant classification criteria substantially alleviates the burden of variants of uncertain significance in ClinVar and LOVD databases. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2024:2024.05.03.24306761. [PMID: 38746299 PMCID: PMC11092726 DOI: 10.1101/2024.05.03.24306761] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2024]
Abstract
Background Pathogenic constitutional APC variants underlie familial adenomatous polyposis, the most common hereditary gastrointestinal polyposis syndrome. To improve variant classification and resolve the interpretative challenges of variants of uncertain significance (VUS), APC-specific ACMG/AMP variant classification criteria were developed by the ClinGen-InSiGHT Hereditary Colorectal Cancer/Polyposis Variant Curation Expert Panel (VCEP). Methods A streamlined algorithm using the APC -specific criteria was developed and applied to assess all APC variants in ClinVar and the InSiGHT international reference APC LOVD variant database. Results A total of 10,228 unique APC variants were analysed. Among the ClinVar and LOVD variants with an initial classification of (Likely) Benign or (Likely) Pathogenic, 94% and 96% remained in their original categories, respectively. In contrast, 41% ClinVar and 61% LOVD VUS were reclassified into clinically actionable classes, the vast majority as (Likely) Benign. The total number of VUS was reduced by 37%. In 21 out of 36 (58%) promising APC variants that remained VUS despite evidence for pathogenicity, a data mining-driven work-up allowed their reclassification as (Likely) Pathogenic. Conclusions The application of APC -specific criteria substantially reduced the number of VUS in ClinVar and LOVD. The study also demonstrated the feasibility of a systematic approach to variant classification in large datasets, which might serve as a generalisable model for other gene-/disease-specific variant interpretation initiatives. It also allowed for the prioritization of VUS that will benefit from in-depth evidence collection. This subset of APC variants was approved by the VCEP and made publicly available through ClinVar and LOVD for widespread clinical use.
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Xie Z, Liu C, Yu H, Xie Z, Sun C, Zhu Y, Hu X, Bai L, Wei L, Sun P, Lu Y, Lu Y, Zhao Y, Zhang W, Wang Z, Meng L, Yuan Y. Clinical and genetic interpretation of uncertain DMD missense variants: evidence from mRNA and protein studies. Orphanet J Rare Dis 2024; 19:123. [PMID: 38486238 PMCID: PMC10941385 DOI: 10.1186/s13023-024-03128-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Accepted: 03/03/2024] [Indexed: 03/17/2024] Open
Abstract
BACKGROUND Pathogenic missense variants in the dystrophin (DMD) gene are rarely reported in dystrophinopathies. Most DMD missense variants are of uncertain significance and their pathogenicity interpretation remains complicated. We aimed to investigate whether DMD missense variants would cause aberrant splicing and re-interpret their pathogenicity based on mRNA and protein studies. METHODS Nine unrelated patients who had an elevated serum creatine kinase level with or without muscle weakness were enrolled. They underwent a detailed clinical, imaging, and pathological assessment. Routine genetic testing and muscle-derived mRNA and protein studies of dystrophin and sarcoglycan genes were performed in them. RESULTS Three of the 9 patients presented with a Duchenne muscular dystrophy (DMD) phenotype and the remaining 6 patients had a suspected diagnosis of Becker muscular dystrophy (BMD) or sarcoglycanopathy based on their clinical and pathological characteristics. Routine genetic testing detected only 9 predicted DMD missense variants in them, of which 6 were novel and interpreted as uncertain significance. Muscle-derived mRNA studies of sarcoglycan genes didn't reveal any aberrant transcripts in them. Dystrophin mRNA studies confirmed that 3 predicted DMD missense variants (c.2380G > C, c.4977C > G, and c.5444A > G) were in fact splicing and frameshift variants due to aberrant splicing. The 9 DMD variants were re-interpreted as pathogenic or likely pathogenic based on mRNA and protein studies. Therefore, 3 patients with DMD splicing variants and 6 patients with confirmed DMD missense variants were diagnosed with DMD and BMD, respectively. CONCLUSION Our study highlights the importance of muscle biopsy and aberrant splicing for clinical and genetic interpretation of uncertain DMD missense variants.
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Affiliation(s)
- Zhiying Xie
- Department of Neurology, Peking University First Hospital, No. 8 Xishiku Street, Xicheng District, Beijing, 100034, China
| | - Chang Liu
- Department of Neurology, Peking University First Hospital, No. 8 Xishiku Street, Xicheng District, Beijing, 100034, China
| | - Haiyan Yu
- Department of Clinical Laboratory, Peking University First Hospital, Beijing, 100034, China
| | - Zhihao Xie
- Department of Epidemiology and Biostatistics, West China School of Public Health and West China Fourth Hospital, Sichuan University, Chengdu, 610041, China
| | - Chengyue Sun
- Department of Neurology, Peking University People's Hospital, Beijing, 100044, China
| | - Ying Zhu
- Department of Radiology, Peking University First Hospital, Beijing, 100034, China
| | - Xiaoyu Hu
- Department of Radiology, Peking University First Hospital, Beijing, 100034, China
| | - Li Bai
- Department of Neurology, Peking University First Hospital, No. 8 Xishiku Street, Xicheng District, Beijing, 100034, China
| | - Luhua Wei
- Department of Neurology, Peking University First Hospital, No. 8 Xishiku Street, Xicheng District, Beijing, 100034, China
| | - Peng Sun
- Department of Neurology, Peking University First Hospital, No. 8 Xishiku Street, Xicheng District, Beijing, 100034, China
| | - Yanyu Lu
- Department of Neurology, Peking University First Hospital, No. 8 Xishiku Street, Xicheng District, Beijing, 100034, China
| | - Yunlong Lu
- Department of Neurology, Peking University First Hospital, No. 8 Xishiku Street, Xicheng District, Beijing, 100034, China
| | - Yawen Zhao
- Department of Neurology, Peking University First Hospital, No. 8 Xishiku Street, Xicheng District, Beijing, 100034, China
| | - Wei Zhang
- Department of Neurology, Peking University First Hospital, No. 8 Xishiku Street, Xicheng District, Beijing, 100034, China
| | - Zhaoxia Wang
- Department of Neurology, Peking University First Hospital, No. 8 Xishiku Street, Xicheng District, Beijing, 100034, China
| | - Lingchao Meng
- Department of Neurology, Peking University First Hospital, No. 8 Xishiku Street, Xicheng District, Beijing, 100034, China.
| | - Yun Yuan
- Department of Neurology, Peking University First Hospital, No. 8 Xishiku Street, Xicheng District, Beijing, 100034, China.
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7
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Wang P, Li W, Liu Z, He X, Hong Q, Lan R, Liu Y, Chu M. Identification of WNT4 alternative splicing patterns and effects on proliferation of granulosa cells in goat. Int J Biol Macromol 2022; 223:1230-1242. [PMID: 36395931 DOI: 10.1016/j.ijbiomac.2022.11.083] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Revised: 09/29/2022] [Accepted: 11/05/2022] [Indexed: 11/16/2022]
Abstract
Increasing ovulation numbers is one of the most important ways to promote reproduction in mammals, and follicular granulosa cells (GCs) provide the necessary nutrients and microenvironment for oocytes to ovulate. WNT4 has been shown to be a key factor in regulating the proliferation of GCs in mammalian ovarian tissues. Our previous transcriptome sequencing (RNA-seq) results have identified two alternatively spliced products of WNT4;however, little is known about the splicing mechanism and its effect on GC proliferation. In this study, two alternatively spliced products of WNT4, designated WNT4-α and WNT4-β, were identified by cloning and analyzed for their function by bioinformatics. The RT-qPCR and Western blot results showed that the expression of WNT4-α was significantly higher than that of WNT4-β in the ovary tissues and GCs of Yunshang black goats. We therefore hypothesized that WNT4-α was the main isoform affecting the proliferation of goat GCs. Subsequently, goat GC proliferation assays showed that overexpression of WNT4-α significantly promoted GC proliferation, and the opposite was true after WNT4-α inhibition. The expression of marker genes of the Wnt signaling pathway was also examined and WNT4-α was found to affect the proliferation and hormone secretion of goat GCs by regulating the Wnt signaling pathway. In addition, a series of splicing factors were involved in in the alternative splicing; in this study, SRSF6 was found to be involved as a splicing factor in the generation of WNT4 alternative splicing. In summary, WNT4 alternative splicing was mediated by the splicing factor SRSF6, and WNT4-α alternative splicing played an important role in follicle development and had a significant effect on the proliferation of goat GCs. The results of this study provide a theoretical foundation for further understanding the molecular regulatory mechanisms of the WNT4 in follicle development in goats.
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Affiliation(s)
- Peng Wang
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Ministry of Agriculture and Rural Affairs, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Wentao Li
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Ministry of Agriculture and Rural Affairs, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Ziyi Liu
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Ministry of Agriculture and Rural Affairs, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Xiaoyun He
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Ministry of Agriculture and Rural Affairs, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Qionghua Hong
- Yunnan Animal Science and Veterinary Institute, Kunming 650224, China
| | - Rong Lan
- Yunnan Animal Science and Veterinary Institute, Kunming 650224, China
| | - Yufang Liu
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Ministry of Agriculture and Rural Affairs, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing 100193, China.
| | - Mingxing Chu
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Ministry of Agriculture and Rural Affairs, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing 100193, China.
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8
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Hereditary Colorectal Cancer: State of the Art in Lynch Syndrome. Cancers (Basel) 2022; 15:cancers15010075. [PMID: 36612072 PMCID: PMC9817772 DOI: 10.3390/cancers15010075] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Revised: 12/13/2022] [Accepted: 12/18/2022] [Indexed: 12/24/2022] Open
Abstract
Hereditary non-polyposis colorectal cancer is also known as Lynch syndrome. Lynch syndrome is associated with pathogenetic variants in one of the mismatch repair (MMR) genes. In addition to colorectal cancer, the inefficiency of the MMR system leads to a greater predisposition to cancer of the endometrium and other cancers of the abdominal sphere. Molecular diagnosis is performed to identify pathogenetic variants in MMR genes. However, for many patients with clinically suspected Lynch syndrome, it is not possible to identify a pathogenic variant in MMR genes. Molecular diagnosis is essential for referring patients to specific surveillance to prevent the development of tumors related to Lynch syndrome. This review summarizes the main aspects of Lynch syndrome and recent advances in the field and, in particular, emphasizes the factors that can lead to the loss of expression of MMR genes.
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9
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Kaissarian NM, Meyer D, Kimchi-Sarfaty C. Synonymous Variants: Necessary Nuance in our Understanding of Cancer Drivers and Treatment Outcomes. J Natl Cancer Inst 2022; 114:1072-1094. [PMID: 35477782 PMCID: PMC9360466 DOI: 10.1093/jnci/djac090] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Revised: 03/24/2022] [Accepted: 04/18/2022] [Indexed: 11/13/2022] Open
Abstract
Once called "silent mutations" and assumed to have no effect on protein structure and function, synonymous variants are now recognized to be drivers for some cancers. There have been significant advances in our understanding of the numerous mechanisms by which synonymous single nucleotide variants (sSNVs) can affect protein structure and function by affecting pre-mRNA splicing, mRNA expression, stability, folding, miRNA binding, translation kinetics, and co-translational folding. This review highlights the need for considering sSNVs in cancer biology to gain a better understanding of the genetic determinants of human cancers and to improve their diagnosis and treatment. We surveyed the literature for reports of sSNVs in cancer and found numerous studies on the consequences of sSNVs on gene function with supporting in vitro evidence. We also found reports of sSNVs that have statistically significant associations with specific cancer types but for which in vitro studies are lacking to support the reported associations. Additionally, we found reports of germline and somatic sSNVs that were observed in numerous clinical studies and for which in silico analysis predicts possible effects on gene function. We provide a review of these investigations and discuss necessary future studies to elucidate the mechanisms by which sSNVs disrupt protein function and are play a role in tumorigeneses, cancer progression, and treatment efficacy. As splicing dysregulation is one of the most well recognized mechanisms by which sSNVs impact protein function, we also include our own in silico analysis for predicting which sSNVs may disrupt pre-mRNA splicing.
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Affiliation(s)
- Nayiri M Kaissarian
- Hemostasis Branch, Division of Plasma Protein Therapeutics, Office of Tissues and Advanced Therapies, Center for Biologics Evaluation & Research, US Food and Drug Administration, Silver Spring, MD, USA
| | - Douglas Meyer
- Hemostasis Branch, Division of Plasma Protein Therapeutics, Office of Tissues and Advanced Therapies, Center for Biologics Evaluation & Research, US Food and Drug Administration, Silver Spring, MD, USA
| | - Chava Kimchi-Sarfaty
- Hemostasis Branch, Division of Plasma Protein Therapeutics, Office of Tissues and Advanced Therapies, Center for Biologics Evaluation & Research, US Food and Drug Administration, Silver Spring, MD, USA
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10
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Kudchadkar S, Ahmed S, Mukherjee T, Sagar J. Current guidelines in the surgical management of hereditary colorectal cancers. World J Gastrointest Oncol 2022; 14:833-841. [PMID: 35582097 PMCID: PMC9048527 DOI: 10.4251/wjgo.v14.i4.833] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/25/2021] [Revised: 10/16/2021] [Accepted: 03/04/2022] [Indexed: 02/06/2023] Open
Abstract
Incidence of colorectal cancer (CRC) is on rise. While approximately 70% of all CRC cases are sporadic in nature, 20%-25% have familial aggregation and only < 5% is hereditary in origin. Identification of individuals with hereditary predilection for CRC is critical, as it has an impact on their overall surgical management including surgical timing, approach & technique and determines the role of prophylactic surgery and outcome. This review highlights the concept of hereditary CRC, provides insight into its molecular basis, possibility of its application into clinical practice and emphasizes the current treatment strategies with surgical management, based on the available international guidelines.
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Affiliation(s)
- Shantata Kudchadkar
- Department of Colorectal Surgery, Luton & Dunstable University Hospital NHS Foundation Trust, Luton LU4 0DZ, United Kingdom
| | - Safia Ahmed
- Department of Colorectal Surgery, Luton & Dunstable University Hospital NHS Foundation Trust, Luton LU4 0DZ, United Kingdom
| | - Tanmoy Mukherjee
- Department of Colorectal Surgery, Luton & Dunstable University Hospital NHS Foundation Trust, Luton LU4 0DZ, United Kingdom
| | - Jayesh Sagar
- Department of Colorectal Surgery, Luton & Dunstable University Hospital NHS Foundation Trust, Luton LU4 0DZ, United Kingdom
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11
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Lejman J, Zieliński G, Gawda P, Lejman M. Alternative Splicing Role in New Therapies of Spinal Muscular Atrophy. Genes (Basel) 2021; 12:1346. [PMID: 34573328 PMCID: PMC8468182 DOI: 10.3390/genes12091346] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Revised: 08/24/2021] [Accepted: 08/25/2021] [Indexed: 11/17/2022] Open
Abstract
It has been estimated that 80% of the pre-mRNA undergoes alternative splicing, which exponentially increases the flow of biological information in cellular processes and can be an attractive therapeutic target. It is a crucial mechanism to increase genetic diversity. Disturbed alternative splicing is observed in many disorders, including neuromuscular diseases and carcinomas. Spinal Muscular Atrophy (SMA) is an autosomal recessive neurodegenerative disease. Homozygous deletion in 5q13 (the region coding for the motor neuron survival gene (SMN1)) is responsible for 95% of SMA cases. The nearly identical SMN2 gene does not compensate for SMN loss caused by SMN1 gene mutation due to different splicing of exon 7. A pathologically low level of survival motor neuron protein (SMN) causes degeneration of the anterior horn cells in the spinal cord with associated destruction of α-motor cells and manifested by muscle weakness and loss. Understanding the regulation of the SMN2 pre-mRNA splicing process has allowed for innovative treatment and the introduction of new medicines for SMA. After describing the concept of splicing modulation, this review will cover the progress achieved in this field, by highlighting the breakthrough accomplished recently for the treatment of SMA using the mechanism of alternative splicing.
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Affiliation(s)
- Jan Lejman
- Student Scientific Society, Laboratory of Genetic Diagnostics, Medical University of Lublin, 20-093 Lublin, Poland;
| | - Grzegorz Zieliński
- Department of Sports Medicine, Medical University of Lublin, 20-093 Lublin, Poland; (G.Z.); (P.G.)
| | - Piotr Gawda
- Department of Sports Medicine, Medical University of Lublin, 20-093 Lublin, Poland; (G.Z.); (P.G.)
| | - Monika Lejman
- Laboratory of Genetic Diagnostics, Medical University of Lublin, 20-093 Lublin, Poland
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12
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Wanitsuwan W, Vijasika S, Jirarattanasopa P, Horpaopan S. A distinct APC pathogenic germline variant identified in a southern Thai family with familial adenomatous polyposis. BMC Med Genomics 2021; 14:87. [PMID: 33740971 PMCID: PMC7980625 DOI: 10.1186/s12920-021-00933-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Accepted: 03/08/2021] [Indexed: 11/28/2022] Open
Abstract
BACKGROUND Familial adenomatous polyposis (FAP) is caused by pathogenic germline variants in the APC gene. To date, multiple pathogenic variants in coding regions, splice sites, and deep intronic regions have been revealed. However, there are still pathogenic variants that remain unidentified. METHODS Twenty-nine primer pairs flanking exons 2-16 (i.e., coding exons 1-15) of APC and their exon-intron junctions were used for germline pathogenic variant screening in Southern Thai patients with familial adenomatous polyposis (FAP). Transcription analysis was performed to confirm the pathogenicity of a splice site deletion of intron 10. Family members were interviewed for clinical histories. Blood samples were collected from 18 family members for a segregation study. Subsequently, clinical data of affected members were collected from the hospital databases. RESULTS We found a distinct heterozygous 16-bp deletion at the splice donor site of intron 10 leading to a skipping of exon 10 which was confirmed by transcript analysis (APC: c 1312 + 4_1312 + 19del, r.934_1312del). Predictive testing for the pathogenic APC variant in 18 of the proband's family members (ten healthy and eight affected) from three generations showed the same heterozygous germline pathogenic variant in eight affected adult members (15-62 years old) and two children (7 and 10 years old). Seven of the ten carriers of the disease-causing variant had undergone colonoscopy, and colonic polyps were found in all cases, which confirmed the segregation of the inherited pathogenic variant. The phenotypic spectrum was found to vary within the family; and some affected family members exhibited extracolonic manifestations. CONCLUSIONS To our knowledge, the pathogenic APC variant, c.1312 + 4_1312 + 19del, r.934_1312del, has not previously been reported. This study is one of the few reports describing the phenotypic consequences of a pathogenic APC variant in a high number of affected family members.
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Affiliation(s)
- Worrawit Wanitsuwan
- Department of Surgery, Faculty of Medicine, Prince of Songkla University, Songkhla, 90110, Thailand
| | - Sukanya Vijasika
- Department of Surgery, Faculty of Medicine, Prince of Songkla University, Songkhla, 90110, Thailand
| | - Pichai Jirarattanasopa
- Department of Ophthalmology, Faculty of Medicine, Prince of Songkla University, Songkhla, 90110, Thailand
| | - Sukanya Horpaopan
- Department of Anatomy, Faculty of Medical Science, Naresuan University, Phitsanulok, 65000, Thailand.
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Disciglio V, Forte G, Fasano C, Sanese P, Lepore Signorile M, De Marco K, Grossi V, Cariola F, Simone C. APC Splicing Mutations Leading to In-Frame Exon 12 or Exon 13 Skipping Are Rare Events in FAP Pathogenesis and Define the Clinical Outcome. Genes (Basel) 2021; 12:353. [PMID: 33670833 PMCID: PMC7997234 DOI: 10.3390/genes12030353] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Revised: 02/22/2021] [Accepted: 02/22/2021] [Indexed: 11/16/2022] Open
Abstract
Familial adenomatous polyposis (FAP) is caused by germline mutations in the tumor suppressor gene APC. To date, nearly 2000 APC mutations have been described in FAP, most of which are predicted to result in truncated protein products. Mutations leading to aberrant APC splicing have rarely been reported. Here, we characterized a novel germline heterozygous splice donor site mutation in APC exon 12 (NM_000038.5: c.1621_1626+7del) leading to exon 12 skipping in an Italian family with the attenuated FAP (AFAP) phenotype. Moreover, we performed a literature meta-analysis of APC splicing mutations. We found that 119 unique APC splicing mutations, including the one described here, have been reported in FAP patients, 69 of which have been characterized at the mRNA level. Among these, only a small proportion (9/69) results in an in-frame protein, with four mutations causing skipping of exon 12 or 13 with loss of armadillo repeat 2 (ARM2) and 3 (ARM3), and five mutations leading to skipping of exon 5, 7, 8, or (partially) 9 with loss of regions not encompassing known functional domains. The APC splicing mutations causing skipping of exon 12 or 13 considered in this study cluster with the AFAP phenotype and reveal a potential molecular mechanism of pathogenesis in FAP disease.
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Affiliation(s)
- Vittoria Disciglio
- Medical Genetics, National Institute of Gastroenterology “S. de Bellis” Research Hospital, Castellana Grotte, 70013 Bari, Italy; (G.F.); (C.F.); (P.S.); (M.L.S.); (K.D.M.); (V.G.); (F.C.)
| | - Giovanna Forte
- Medical Genetics, National Institute of Gastroenterology “S. de Bellis” Research Hospital, Castellana Grotte, 70013 Bari, Italy; (G.F.); (C.F.); (P.S.); (M.L.S.); (K.D.M.); (V.G.); (F.C.)
| | - Candida Fasano
- Medical Genetics, National Institute of Gastroenterology “S. de Bellis” Research Hospital, Castellana Grotte, 70013 Bari, Italy; (G.F.); (C.F.); (P.S.); (M.L.S.); (K.D.M.); (V.G.); (F.C.)
| | - Paola Sanese
- Medical Genetics, National Institute of Gastroenterology “S. de Bellis” Research Hospital, Castellana Grotte, 70013 Bari, Italy; (G.F.); (C.F.); (P.S.); (M.L.S.); (K.D.M.); (V.G.); (F.C.)
| | - Martina Lepore Signorile
- Medical Genetics, National Institute of Gastroenterology “S. de Bellis” Research Hospital, Castellana Grotte, 70013 Bari, Italy; (G.F.); (C.F.); (P.S.); (M.L.S.); (K.D.M.); (V.G.); (F.C.)
| | - Katia De Marco
- Medical Genetics, National Institute of Gastroenterology “S. de Bellis” Research Hospital, Castellana Grotte, 70013 Bari, Italy; (G.F.); (C.F.); (P.S.); (M.L.S.); (K.D.M.); (V.G.); (F.C.)
| | - Valentina Grossi
- Medical Genetics, National Institute of Gastroenterology “S. de Bellis” Research Hospital, Castellana Grotte, 70013 Bari, Italy; (G.F.); (C.F.); (P.S.); (M.L.S.); (K.D.M.); (V.G.); (F.C.)
| | - Filomena Cariola
- Medical Genetics, National Institute of Gastroenterology “S. de Bellis” Research Hospital, Castellana Grotte, 70013 Bari, Italy; (G.F.); (C.F.); (P.S.); (M.L.S.); (K.D.M.); (V.G.); (F.C.)
| | - Cristiano Simone
- Medical Genetics, National Institute of Gastroenterology “S. de Bellis” Research Hospital, Castellana Grotte, 70013 Bari, Italy; (G.F.); (C.F.); (P.S.); (M.L.S.); (K.D.M.); (V.G.); (F.C.)
- Department of Biomedical Sciences and Human Oncology (DIMO), Medical Genetics, University of Bari Aldo Moro, 70124 Bari, Italy
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14
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Zou M, Guven A, BinEssa HA, Al-Rijjal RA, Meyer BF, Alzahrani AS, Shi Y. Molecular Analysis of CYP27B1 Mutations in Vitamin D-Dependent Rickets Type 1A: c.590G > A (p.G197D) Missense Mutation Causes a RNA Splicing Error. Front Genet 2020; 11:607517. [PMID: 33329754 PMCID: PMC7729158 DOI: 10.3389/fgene.2020.607517] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Accepted: 11/10/2020] [Indexed: 11/22/2022] Open
Abstract
Context Vitamin D-dependent rickets type 1A (VDDR1A) is a rare autosomal recessively inherited disorder due to loss-of-function mutations in the CYP27B1 gene. CYP27B1 encodes an enzyme of 25-hydroxyvitamin D-1α-hydroxylase for converting inactive 25-OHD to biologically active 1,25-(OH)2D. Objective To identify underlying genetic defects in patients with VDDR1A. Methods Twelve patients from 7 Turkish and 2 Saudi families were investigated. The coding exons and intron-exon boundaries of the CYP27B1 gene were amplified by Polymerase Chain Reaction (PCR) from peripheral lymphocyte DNA. PCR products were directly sequenced. The consequences of c.590G > A mutation were analyzed by in silico and functional analysis. Results CYP27B1 mutations were identified in all the patients. Two novel mutations were identified in two separate families: c.171delG (family 7) and c.398_400dupAAT (family 8). The intra-exon deletion of c.171delG resulted in a frameshift and premature stop codon 20 amino acids downstream from the mutation (p.L58Cfs∗20). The intra-exon duplication of c.398_400dupAAT generated a premature stop codon at the mutation site (p.W134∗). A missense c.590G > A (p.G197D) mutation was found in a patient from family 4 and caused a defect in pre-mRNA splicing. As a result, two populations of transcripts were detected: the majority of them with intron 3 retention (83%), and the minority (17%) being properly spliced transcripts with about 16% of wild-type enzymatic activity. The remaining nine patients from six families carried a previously reported c.1319_1325dupCCCACCC (F443Pfs∗24) mutation. Clinically, all the patients need continued calcitriol treatment, which was consistent with inactivation of 25-hydroxy vitamin D1α-hydroxylase activity. Conclusion Two novel frameshift CYP27B1 mutations were identified and predicted to inactivate 25-hydroxyvitamin D-1α-hydroxylase. The loss of enzymatic activity by c.590G > A missense mutation was mainly caused by aberrant pre-mRNA splicing.
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Affiliation(s)
- Minjing Zou
- Department of Genetics, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia
| | - Ayla Guven
- Pediatric Endocrinology Clinic, Zeynep Kamil Women and Children Hospital, University of Health Science, Istanbul, Turkey
| | - Huda A BinEssa
- Department of Genetics, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia
| | - Roua A Al-Rijjal
- Department of Genetics, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia
| | - Brian F Meyer
- Pediatric Endocrinology Clinic, Zeynep Kamil Women and Children Hospital, University of Health Science, Istanbul, Turkey
| | - Ali S Alzahrani
- Department of Medicine, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia
| | - Yufei Shi
- Department of Genetics, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia
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A cDNA analysis disclosed the discordance of genotype-phenotype correlation in a patient with attenuated MPS II and a 76-base deletion in the gene for iduronate-2-sulfatase. Mol Genet Metab Rep 2020; 25:100692. [PMID: 33335838 PMCID: PMC7734304 DOI: 10.1016/j.ymgmr.2020.100692] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2020] [Accepted: 11/27/2020] [Indexed: 11/22/2022] Open
Abstract
We previously showed that the genotype-phenotype correlation in MPS II is well-conserved in Japan (Kosuga et al., 2016). Almost all of our patients with attenuated MPS II have missense variants, which is expected to result in residual activity of iduronate-2-sulfatase. In contrast, our patients with severe MPS II have so-called null-type disease-associated variants, such as nonsense variants, frame-shifts, gene insertions, gene deletions and rearrangement with pseudogene (IDS2), none of which are expected to result in residual activity. However, we recently encountered a patient with attenuated MPS II who had a presumable null-type disease-associated variant and 76-base deletion located in exon 1 that extended into intron 1. To investigate this discordance, we extracted RNA from the leukocytes of the patient and performed reverse transcription polymerase chain reaction. One of the bands of the cDNA analysis was found to include a nucleotide sequence whose transcript was expected to generate an almost full-length IDS mature peptide lacking only part of its signal peptide as well as only one amino acid at the end of the N-terminus. This suggests that an alternative splicing donor site is generated in exon 1 upstream of the deleted region. Based on these observations, we concluded that the phenotype-genotype discordance in this patient with MPS II was due to the decreased amount of IDS protein induced by the low level of the alternatively spliced mRNA, lacking part of the region coding for the signal peptide but including the region coding almost the full mature IDS protein. The first 25 amino acids at the N-terminus of IDS protein are a signal peptide. The alternative splice transcript has only 13 (1 M-13 L) of those 25 amino acids; 14G-25G are missing, suggesting that the exclusively hydrophobic 1 M-13 L of the signal peptide of IDS might have a crucial role in the signal peptide.
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16
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Lee H, Kim HK, Yang DH, Hong YS, Lee W, Lim SB, Byeon JS, Chun S, Min WK. A Novel Splice Variant (c.438T>A) of APC, Suspected by Family History and Confirmed by RNA Sequencing. Ann Lab Med 2020; 41:123-125. [PMID: 32829589 PMCID: PMC7443526 DOI: 10.3343/alm.2021.41.1.123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Revised: 04/21/2020] [Accepted: 07/17/2020] [Indexed: 11/19/2022] Open
Affiliation(s)
- Heerah Lee
- Department of Laboratory Medicine, University of Ulsan College of Medicine and Asan Medical Center, Seoul, Korea
| | - Hyun-Ki Kim
- Department of Laboratory Medicine, University of Ulsan College of Medicine and Asan Medical Center, Seoul, Korea
| | - Dong-Hoon Yang
- Department of Gastroenterology, University of Ulsan College of Medicine and Asan Medical Center, Seoul, Korea
| | - Yong Sang Hong
- Department of Oncology, University of Ulsan College of Medicine and Asan Medical Center, Seoul, Korea
| | - Woochang Lee
- Department of Laboratory Medicine, University of Ulsan College of Medicine and Asan Medical Center, Seoul, Korea
| | - Seok-Byung Lim
- Department of Surgery, University of Ulsan College of Medicine and Asan Medical Center, Seoul, Korea
| | - Jeong-Sik Byeon
- Department of Gastroenterology, University of Ulsan College of Medicine and Asan Medical Center, Seoul, Korea
| | - Sail Chun
- Department of Laboratory Medicine, University of Ulsan College of Medicine and Asan Medical Center, Seoul, Korea
| | - Won-Ki Min
- Department of Laboratory Medicine, University of Ulsan College of Medicine and Asan Medical Center, Seoul, Korea
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Abstract
One of the mechanisms potentially explaining the discrepancy between the number of human genes and the functional complexity of organisms is generating alternative splice variants, an attribute of the vast majority of multi-exon genes. Members of the RAS family, such as NRAS, KRAS and HRAS, all of which are of significant importance in cancer biology, are no exception. The structural and functional differences of these splice variants, particularly if they contain the canonical (and therefore routinely targeted for diagnostic purposes) hot spot mutations, pose a significant challenge for targeted therapies. We must therefore consider whether these alternative splice variants constitute a minor component as originally thought and how therapies targeting the canonical isoforms affect these alternative splice variants and their overall functions.
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Affiliation(s)
- Erzsébet Rásó
- 2nd Department of Pathology, Semmelweis University, Budapest, Hungary.
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18
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Peltomäki P, Olkinuora A, Nieminen TT. Updates in the field of hereditary nonpolyposis colorectal cancer. Expert Rev Gastroenterol Hepatol 2020; 14:707-720. [PMID: 32755332 DOI: 10.1080/17474124.2020.1782187] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
INTRODUCTION Up to one third of colorectal cancers show familial clustering and 5% are hereditary single-gene disorders. Hereditary non-polyposis colorectal cancer comprises DNA mismatch repair-deficient and -proficient subsets, represented by Lynch syndrome (LS) and familial colorectal cancer type X (FCCTX), respectively. Accurate knowledge of molecular etiology and genotype-phenotype correlations are critical for tailored cancer prevention and treatment. AREAS COVERED The authors highlight advances in the molecular dissection of hereditary non-polyposis colorectal cancer, based on recent literature retrieved from PubMed. Future possibilities for novel gene discoveries are discussed. EXPERT COMMENTARY LS is molecularly well established, but new information is accumulating of the associated clinical and tumor phenotypes. FCCTX remains poorly defined, but several promising candidate genes have been discovered and share some preferential biological pathways. Multi-level characterization of specimens from large patient cohorts representing multiple populations, combined with proper bioinformatic and functional analyses, will be necessary to resolve the outstanding questions.
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Affiliation(s)
- Paivi Peltomäki
- Department of Medical and Clinical Genetics, University of Helsinki , Helsinki, Finland
| | - Alisa Olkinuora
- Department of Medical and Clinical Genetics, University of Helsinki , Helsinki, Finland
| | - Taina T Nieminen
- Department of Medical and Clinical Genetics, University of Helsinki , Helsinki, Finland
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Araujo LF, Molfetta GA, Vincenzi OC, Huber J, Teixeira LA, Ferraz VE, Silva WA. Molecular basis of familial adenomatous polyposis in the southeast of Brazil: identification of six novel mutations. Int J Biol Markers 2019; 34:80-89. [PMID: 30852976 DOI: 10.1177/1724600818814462] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
BACKGROUND The goal of this study was to screen point mutations and deletions in APC and MUTYH genes in patients suspected of familial adenomatous polyposis (FAP) in a Brazilian cohort. METHODS We used high-resolution melting, Sanger direct sequencing and multiplex ligation-dependent probe association (MLPA) assays to identify point mutations, and large genomic variations within the coding regions of APC and MUTYH genes. RESULTS We identified 19 causative mutations in 40 Brazilian patients from 20 different families. Four novel mutations were identified in the APC gene and two in the MUTYH gene. We also found a high intra- and inter-familial diversity regarding extracolonic manifestations, and gastric polyps were the most common manifestation found in our cohort. CONCLUSION We believe that the FAP mutational spectrum can be population-specific and screening FAP patients in different populations can improve pre-clinical diagnosis and improve clinical conduct.
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Affiliation(s)
- Luiza Ferreira Araujo
- 1 Departament of Genetics, Ribeirão Preto Medical School, University of São Paulo, Brazil.,3 Center for Cell-Based Therapy CEPID/FAPESP, and Regional Blood Center of Ribeirão Preto, Brazil.,5 Medical Genomics Laboratory, AC Camargo Cancer Center, Brazil
| | - Greice Andreotti Molfetta
- 1 Departament of Genetics, Ribeirão Preto Medical School, University of São Paulo, Brazil.,2 Center for Medical Genomics at Clinical Hospital of the Ribeirão Preto Medical School, University of São Paulo, Brazil.,3 Center for Cell-Based Therapy CEPID/FAPESP, and Regional Blood Center of Ribeirão Preto, Brazil
| | - Otavio Costa Vincenzi
- 2 Center for Medical Genomics at Clinical Hospital of the Ribeirão Preto Medical School, University of São Paulo, Brazil.,3 Center for Cell-Based Therapy CEPID/FAPESP, and Regional Blood Center of Ribeirão Preto, Brazil.,4 Medical Genetics Unit, Clinical Hospital of the Medical School of Ribeirão Preto, University of São Paulo, Brazil
| | - Jair Huber
- 4 Medical Genetics Unit, Clinical Hospital of the Medical School of Ribeirão Preto, University of São Paulo, Brazil
| | - Lorena Alves Teixeira
- 4 Medical Genetics Unit, Clinical Hospital of the Medical School of Ribeirão Preto, University of São Paulo, Brazil
| | - Victor Evangelista Ferraz
- 1 Departament of Genetics, Ribeirão Preto Medical School, University of São Paulo, Brazil.,2 Center for Medical Genomics at Clinical Hospital of the Ribeirão Preto Medical School, University of São Paulo, Brazil.,4 Medical Genetics Unit, Clinical Hospital of the Medical School of Ribeirão Preto, University of São Paulo, Brazil
| | - Wilson Araujo Silva
- 1 Departament of Genetics, Ribeirão Preto Medical School, University of São Paulo, Brazil.,2 Center for Medical Genomics at Clinical Hospital of the Ribeirão Preto Medical School, University of São Paulo, Brazil.,3 Center for Cell-Based Therapy CEPID/FAPESP, and Regional Blood Center of Ribeirão Preto, Brazil.,4 Medical Genetics Unit, Clinical Hospital of the Medical School of Ribeirão Preto, University of São Paulo, Brazil
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Understanding human DNA variants affecting pre-mRNA splicing in the NGS era. ADVANCES IN GENETICS 2019; 103:39-90. [PMID: 30904096 DOI: 10.1016/bs.adgen.2018.09.002] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Pre-mRNA splicing, an essential step in eukaryotic gene expression, relies on recognition of short sequences on the primary transcript intron ends and takes place along transcription by RNA polymerase II. Exonic and intronic auxiliary elements may modify the strength of exon definition and intron recognition. Splicing DNA variants (SV) have been associated with human genetic diseases at canonical intron sites, as well as exonic substitutions putatively classified as nonsense, missense or synonymous variants. Their effects on mRNA may be modulated by cryptic splice sites associated to the SV allele, comprehending exon skipping or shortening, and partial or complete intron retention. As splicing mRNA outputs result from combinatorial effects of both intrinsic and extrinsic factors, in vitro functional assays supported by computational analyses are recommended to assist SV pathogenicity assessment for human Mendelian inheritance diseases. The increasing use of next-generating sequencing (NGS) targeting full genomic gene sequence has raised awareness of the relevance of deep intronic SV in genetic diseases and inclusion of pseudo-exons into mRNA. Finally, we take advantage of recent advances in sequencing and computational technologies to analyze alternative splicing in cancer. We explore the Catalog of Somatic Mutations in Cancer (COSMIC) to describe the proportion of splice-site mutations in cis and trans regulatory elements. Genomic data from large cohorts of different cancer types are increasingly available, in addition to repositories of normal and somatic genetic variations. These are likely to bring new insights to understanding the genetic control of alternative splicing by mapping splicing quantitative trait loci in tumors.
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Liu Q, Tan YQ. Advances in Identification of Susceptibility Gene Defects of Hereditary Colorectal Cancer. J Cancer 2019; 10:643-653. [PMID: 30719162 PMCID: PMC6360424 DOI: 10.7150/jca.28542] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2018] [Accepted: 12/08/2018] [Indexed: 12/17/2022] Open
Abstract
Colorectal cancer (CRC) is a common malignant tumor of the digestive system worldwide, associated with hereditary genetic features. CRC with a Mendelian genetic predisposition accounts for approximately 5-10% of total CRC cases, mainly caused by a single germline mutation of a CRC susceptibility gene. The main subtypes of hereditary CRC are hereditary non-polyposis colorectal cancer (HNPCC) and familial adenomatous polyposis (FAP). With the rapid development of genetic testing methods, especially next-generation sequencing technology, multiple genes have now been confirmed to be pathogenic, including DNA repair or DNA mismatch repair genes such as APC, MLH1, and MSH2. Since familial CRC patients have poor clinical outcomes, timely clinical diagnosis and mutation screening of susceptibility genes will aid clinicians in establishing appropriate risk assessment and treatment interventions at a personal level. Here, we systematically summarize the susceptibility genes identified to date and the potential pathogenic mechanism of HNPCC and FAP development. Moreover, clinical recommendations for susceptibility gene screening, diagnosis, and treatment of HNPCC and FAP are discussed.
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Affiliation(s)
- Qiang Liu
- Hunan Key Laboratory of Translational Radiation Oncology, Hunan cancer Hospital and The Affiliated Cancer of Xiangya School of Medicine, Central South University, Changsha, China.,Institute of Reproductive and Stem Cell Engineering, School of Basic Medical Science, Central South University, Changsha, China.,Reproductive and Genetic Hospital of CITIC-Xiangya, Changsha, China
| | - Yue-Qiu Tan
- Institute of Reproductive and Stem Cell Engineering, School of Basic Medical Science, Central South University, Changsha, China.,Reproductive and Genetic Hospital of CITIC-Xiangya, Changsha, China
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Zhang Z, Liang S, Huang H, Wang D, Zhang X, Wu J, Chen H, Wang Y, Rong T, Zhou Y, Banerjee S. A novel pathogenic large germline deletion in adenomatous polyposis coli gene in a Chinese family with familial adenomatous polyposis. Oncotarget 2018; 7:50392-50400. [PMID: 27391059 PMCID: PMC5226590 DOI: 10.18632/oncotarget.10408] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Accepted: 06/14/2016] [Indexed: 12/26/2022] Open
Abstract
Germline mutations of the APC gene are associated with an autosomal dominant precancerous condition, termed familial adenomatous polyposis (FAP). FAP is clinically manifested by the presence of multiple colorectal adenomas or polyps. Gradually, these colorectal adenomas or polyps inevitably result in colorectal cancer by the third-to fourth decade of life. Surgical interventions or total proctocolectomy is the best possible treatment for FAP. Here, we present a clinical molecular study of a five generation Chinese family with FAP. Diagnosis of FAP was made on the basis of clinical manifestations, family history and medical (colonoscopy and histopathology) records. Blood samples were collected and genomic DNA was extracted. Genetic screening of the APC gene was performed by targeted next-generation sequencing and quantitative real-time PCR. Targeted next generation sequencing identified a novel heterozygous large deletion [exon5-exon16; c.423_8532del] of APC gene, which segregated with the FAP phenotypes in the proband and in all the affected family members. Unaffected family members and normal controls did not carry this deletion. In the Chinese population, most of the previously reported APC gene mutations are missense mutations. This is the first report describing the largest deletion of the APC gene in the Chinese population associated with FAP.
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Affiliation(s)
- Zhao Zhang
- Tianjin University of Traditional Chinese Medicine, Department of Colorectal Surgery, Tianjin Union Medical Center, Tianjin 300121, China
| | | | - Hui Huang
- BGI-Shenzhen, Shenzhen 518083, China
| | - Dan Wang
- Department of Pathology, Tianjin Medical University General Hospital, Tianjin 300000, China
| | - Xipeng Zhang
- Tianjin University of Traditional Chinese Medicine, Department of Colorectal Surgery, Tianjin Union Medical Center, Tianjin 300121, China
| | - Jing Wu
- BGI-Shenzhen, Shenzhen 518083, China
| | | | | | | | - Yulin Zhou
- Xiamen Prenatal Diagnosis Center, Xiamen Maternal and Child Health Care Hospital, Xiamen 361000, China
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A novel pathogenic splice acceptor site germline mutation in intron 14 of the APC gene in a Chinese family with familial adenomatous polyposis. Oncotarget 2017; 8:21327-21335. [PMID: 28423518 PMCID: PMC5400587 DOI: 10.18632/oncotarget.15570] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2016] [Accepted: 01/27/2017] [Indexed: 11/25/2022] Open
Abstract
Familial adenomatous polyposis (FAP) is an autosomal dominant precancerous condition, clinically characterized by the presence of multiple colorectal adenomas or polyps. Patients with FAP has a high risk of developing colorectal cancer (CRC) from these colorectal adenomatous polyps by the mean age of diagnosis at 40 years. Germline mutations of the APC gene cause familial adenomatous polyposis (FAP). Colectomy has recommended for the FAP patients with significant polyposis. Here, we present a clinical molecular study of a four generation Chinese family with FAP. Clinical diagnosis of FAP has been done according to the phenotype, family history and medical records. Patient's blood samples were collected and genomic DNA was extracted. In order to identify the pathogenic mutation underlying the disease phenotype targeted next-generation sequencing and confirmatory sanger sequencing has undertaken. Targeted next generation sequencing identified a novel heterozygous splice-acceptor site mutation [c.1744-1G>A] in intron 14 of APC gene, which is co-segregated with the FAP phenotypes in the proband and amongst all the affected family members. This mutation is not present in unaffected family members and in normal healthy controls of same ethnic origin. According to the LOVD database for Chinese colorectal cancer patients, in Chinese population, 60% of the previously reported APC gene mutations causes FAP, are missense mutations. This novel splice-acceptor site mutation causing FAP in this Chinese family expands the germline mutation spectrum of the APC gene in the Chinese population.
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Tsukanov AS, Pospekhova NI, Shubin VP, Kuzminov AM, Kashnikov VN, Frolov SA, Shelygin YA. Mutations in the APC gene in Russian patients with classic form of familial adenomatous polyposis. RUSS J GENET+ 2017. [DOI: 10.1134/s1022795417030139] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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Abstract
Familial adenomatous polyposis (FAP) is a colorectal cancer predisposition syndrome with considerable genetic and phenotypic heterogeneity, defined by the development of multiple adenomas throughout the colorectum. FAP is caused either by monoallelic mutations in the adenomatous polyposis coli gene APC, or by biallelic germline mutations of MUTYH, this latter usually presenting with milder phenotype. The aim of the present study was to characterize the genotype and phenotype of Hungarian FAP patients. Mutation screening of 87 unrelated probands from FAP families (21 of them presented as the attenuated variant of the disease, showing <100 polyps) was performed using DNA sequencing and multiplex ligation-dependent probe amplification. Twenty-four different pathogenic mutations in APC were identified in 65 patients (75 %), including nine cases (37.5 %) with large genomic alterations. Twelve of the point mutations were novel. In addition, APC-negative samples were also tested for MUTYH mutations and we were able to identify biallelic pathogenic mutations in 23 % of these cases (5/22). Correlations between the localization of APC mutations and the clinical manifestations of the disease were observed, cases with a mutation in the codon 1200-1400 region showing earlier age of disease onset (p < 0.003). There were only a few, but definitive dissimilarities between APC- and MUTYH-associated FAP in our cohort: the age at onset of polyposis was significantly delayed for biallelic MUTYH mutation carriers as compared to patients with an APC mutation. Our data represent the first comprehensive study delineating the mutation spectra of both APC and MUTYH in Hungarian FAP families, and underscore the overlap between the clinical characteristics of APC- and MUTYH-associated phenotypes, necessitating a more appropriate clinical characterization of FAP families.
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Alternative splicing within the Wnt signaling pathway: role in cancer development. Cell Oncol (Dordr) 2016; 39:1-13. [PMID: 26762488 DOI: 10.1007/s13402-015-0266-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/29/2015] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND The Wnt signaling cascade plays a fundamental role in embryonic development, adult tissue regeneration, homeostasis and stem cell maintenance. Abnormal Wnt signaling has been found to be prevalent in various human cancers. Also, a role of Wnt signaling in the regulation of alternative splicing of several cancer-related genes has been established. In addition, accumulating evidence suggests the existence of multiple splice isoforms of Wnt signaling cascade components, including Wnt ligands, receptors, components of the destruction complex and transcription activators/suppressors. The presence of multiple Wnt signaling-related isoforms may affect the functionality of the Wnt pathway, including its deregulation in cancer. As such, specific Wnt pathway isoform components may serve as therapeutic targets or as biomarkers for certain human cancers. Here, we review the role of alternative splicing of Wnt signaling components during the onset and progression of cancer. CONCLUSIONS Splice isoforms of components of the Wnt signaling pathway play distinct roles in cancer development. Isoforms of the same component may function in a tissue- and/or cancer-specific manner. Splice isoform expression analyses along with deregulated Wnt signaling pathway analyses may be of help to design efficient diagnostic and therapeutic strategies.
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27
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Whisper mutations: cryptic messages within the genetic code. Oncogene 2015; 35:3753-9. [PMID: 26657150 DOI: 10.1038/onc.2015.454] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Revised: 10/28/2015] [Accepted: 10/28/2015] [Indexed: 01/17/2023]
Abstract
Recent years have seen a great expansion in our understandings of how silent mutations can drive a disease and that mRNAs are not only mere messengers between the genome and the encoded proteins but also encompass regulatory activities. This review focuses on how silent mutations within open reading frames can affect the functional properties of the encoded protein. We describe how mRNAs exert control of cell biological processes governed by the encoded proteins via translation kinetics, protein folding, mRNA stability, spatio-temporal protein expression and by direct interactions with cellular factors. These examples illustrate how additional levels of information lie within the coding sequences and that the degenerative genetic code is not redundant and have co-evolved with the encoded proteins. Hence, so called synonymous mutations are not always silent but 'whisper'.
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Leoz ML, Carballal S, Moreira L, Ocaña T, Balaguer F. The genetic basis of familial adenomatous polyposis and its implications for clinical practice and risk management. APPLICATION OF CLINICAL GENETICS 2015; 8:95-107. [PMID: 25931827 PMCID: PMC4404874 DOI: 10.2147/tacg.s51484] [Citation(s) in RCA: 73] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Familial adenomatous polyposis (FAP) is an inherited disorder that represents the most common gastrointestinal polyposis syndrome. Germline mutations in the APC gene were initially identified as responsible for FAP, and later, several studies have also implicated the MUTYH gene as responsible for this disease, usually referred to as MUTYH-associated polyposis (MAP). FAP and MAP are characterized by the early onset of multiple adenomatous colorectal polyps, a high lifetime risk of colorectal cancer (CRC), and in some patients the development of extracolonic manifestations. The goal of colorectal management in these patients is to prevent CRC mortality through endoscopic and surgical approaches. Individuals with FAP and their relatives should receive appropriate genetic counseling and join surveillance programs when indicated. This review is focused on the description of the main clinical and genetic aspects of FAP associated with germline APC mutations and MAP.
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Affiliation(s)
- Maria Liz Leoz
- Department of Gastroenterology, Hospital Clínic, Centro de Investigación Biomédica en Red en Enfermedades Hepáticas y Digestivas (CIBERehd), Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Catalonia, Spain
| | - Sabela Carballal
- Department of Gastroenterology, Hospital Clínic, Centro de Investigación Biomédica en Red en Enfermedades Hepáticas y Digestivas (CIBERehd), Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Catalonia, Spain
| | - Leticia Moreira
- Department of Gastroenterology, Hospital Clínic, Centro de Investigación Biomédica en Red en Enfermedades Hepáticas y Digestivas (CIBERehd), Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Catalonia, Spain
| | - Teresa Ocaña
- Department of Gastroenterology, Hospital Clínic, Centro de Investigación Biomédica en Red en Enfermedades Hepáticas y Digestivas (CIBERehd), Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Catalonia, Spain
| | - Francesc Balaguer
- Department of Gastroenterology, Hospital Clínic, Centro de Investigación Biomédica en Red en Enfermedades Hepáticas y Digestivas (CIBERehd), Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Catalonia, Spain
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Esplin ED, Snyder MP. Genomic era diagnosis and management of hereditary and sporadic colon cancer. World J Clin Oncol 2014; 5:1036-1047. [PMID: 25493239 PMCID: PMC4259930 DOI: 10.5306/wjco.v5.i5.1036] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/27/2014] [Revised: 03/21/2014] [Accepted: 05/16/2014] [Indexed: 02/06/2023] Open
Abstract
The morbidity and mortality attributable to heritable and sporadic carcinomas of the colon are substantial and affect children and adults alike. Despite current colonoscopy screening recommendations colorectal adenocarcinoma (CRC) still accounts for almost 140000 cancer cases yearly. Familial adenomatous polyposis (FAP) is a colon cancer predisposition due to alterations in the adenomatous polyposis coli gene, which is mutated in most CRC. Since the beginning of the genomic era next-generation sequencing analyses of CRC continue to improve our understanding of the genetics of tumorigenesis and promise to expand our ability to identify and treat this disease. Advances in genome sequence analysis have facilitated the molecular diagnosis of individuals with FAP, which enables initiation of appropriate monitoring and timely intervention. Genome sequencing also has potential clinical impact for individuals with sporadic forms of CRC, providing means for molecular diagnosis of CRC tumor type, data guiding selection of tumor targeted therapies, and pharmacogenomic profiles specifying patient specific drug tolerances. There is even a potential role for genomic sequencing in surveillance for recurrence, and early detection, of CRC. We review strategies for diagnostic assessment and management of FAP and sporadic CRC in the current genomic era, with emphasis on the current, and potential for future, impact of genome sequencing on the clinical care of these conditions.
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Pavicic W, Nieminen TT, Gylling A, Pursiheimo JP, Laiho A, Gyenesei A, Järvinen HJ, Peltomäki P. Promoter-specific alterations of APC are a rare cause for mutation-negative familial adenomatous polyposis. Genes Chromosomes Cancer 2014; 53:857-64. [PMID: 24946964 DOI: 10.1002/gcc.22197] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2014] [Revised: 06/04/2014] [Accepted: 06/05/2014] [Indexed: 12/30/2022] Open
Abstract
n familial adenomatous polyposis (FAP), 20% of classical and 70% of attenuated/atypical (AFAP) cases remain mutation-negative after routine testing; yet, allelic expression imbalance may suggest an APC alteration. Our aim was to determine the proportion of families attributable to genetic or epigenetic changes in the APC promoter region. We studied 51 unrelated families/cases (26 with classical FAP and 25 with AFAP) with no point mutations in the exons and exon/intron borders and no rearrangements by multiplex ligation-dependent probe amplification (MLPA, P043-B1). Promoter-specific events of APC were addressed by targeted resequencing, MLPA (P043-C1), methylation-specific MLPA, and Sanger sequencing of promoter regions. A novel 132-kb deletion encompassing the APC promoter 1B and upstream sequence occurred in a classical FAP family with allele-specific APC expression. No promoter-specific point mutations or hypermethylation were present in any family. In conclusion, promoter-specific alterations are a rare cause for mutation-negative FAP (1/51, 2%). The frequency and clinical correlations of promoter 1B deletions are poorly defined. This investigation provides frequencies of 1/26 (4%) for classical FAP, 0/25 (0%) for AFAP, and 1/7 (14%) for families with allele-specific expression of APC. Clinically, promoter 1B deletions may associate with classical FAP without extracolonic manifestations.
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Affiliation(s)
- Walter Pavicic
- Department of Medical Genetics, Haartman Institute, University of Helsinki, Helsinki, Finland; Laboratorio de Citogenética y Mutagénesis, Instituto Multidisciplinario de Biología Celular (IMBICE-CONICET-CICPBA), La Plata, Argentina
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Taki K, Sato Y, Sato Y, Ashihara Y, Chino A, Igarashi M, Sato K, Kitagawa T, Maetani I, Nemoto C, Nasuno K, Sekine T, Arai M. A case of a child with an APC pathogenic mutation, aberrant expression of splice variants and positive family history of FAP. Jpn J Clin Oncol 2014; 44:602-6. [PMID: 24823678 DOI: 10.1093/jjco/hyu050] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Familial adenomatous polyposis is an autosomal dominant hereditary disease characterized by the appearance of hundreds to thousands of colorectal adenomatous polyps; if left untreated, there is nearly a 100% lifetime risk of colorectal cancer. In the present case, adenomatous polyps were observed at 6 years of age. Unlike our previous assumption, adenomatous polyps were detected by colonoscopy at <10 years of age. Considering the clinical importance of early diagnosis, we report this case involving germline adenomatous polyposis coli mutation (c.1958G > C, GenBank: M74088.1) that caused an increase in the isoform without exon 15. Although this isoform has been reported previously, it remains controversial whether the variant is pathogenic or not because it was observed both in patients with familial adenomatous polyposis and in normal controls. Nonetheless, due to quantitative distortion of splice variants in adenomatous polyposis coli transcripts and the early development of adenomatous polyps, we believe that this variant may be pathogenic.
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Affiliation(s)
- Keiko Taki
- Clinical Genetic Oncology, Cancer Institute Hospital of Japanese Foundation for Cancer Research, Tokyo
| | - Yasuyoshi Sato
- Clinical Genetic Oncology, Cancer Institute Hospital of Japanese Foundation for Cancer Research, Tokyo
| | - Yuri Sato
- Clinical Genetic Oncology, Cancer Institute Hospital of Japanese Foundation for Cancer Research, Tokyo
| | - Yuumi Ashihara
- Clinical Genetic Oncology, Cancer Institute Hospital of Japanese Foundation for Cancer Research, Tokyo
| | - Akiko Chino
- Division of Gastroenterology, Cancer Institute Hospital of Japanese Foundation for Cancer Research, Tokyo
| | - Masahiro Igarashi
- Division of Gastroenterology, Cancer Institute Hospital of Japanese Foundation for Cancer Research, Tokyo
| | - Koichiro Sato
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, Toho University Ohashi Medical Center, Tokyo
| | - Tomoyuki Kitagawa
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, Toho University Ohashi Medical Center, Tokyo
| | - Iruru Maetani
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, Toho University Ohashi Medical Center, Tokyo
| | - Chieko Nemoto
- Department of Pediatrics, Ohashi Hospital, Toho University School of Medicine, Tokyo, Japan
| | - Kiyoto Nasuno
- Department of Pediatrics, Ohashi Hospital, Toho University School of Medicine, Tokyo, Japan
| | - Takashi Sekine
- Department of Pediatrics, Ohashi Hospital, Toho University School of Medicine, Tokyo, Japan
| | - Masami Arai
- Clinical Genetic Oncology, Cancer Institute Hospital of Japanese Foundation for Cancer Research, Tokyo
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APC Germline Mutations in Individuals Being Evaluated for Familial Adenomatous Polyposis. J Mol Diagn 2013; 15:31-43. [DOI: 10.1016/j.jmoldx.2012.07.005] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2012] [Revised: 06/04/2012] [Accepted: 07/13/2012] [Indexed: 02/07/2023] Open
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Spraggon L, Cartegni L. Antisense Modulation of RNA Processing as a Therapeutic Approach in Cancer Therapy. ACTA ACUST UNITED AC 2013; 10:e139-e148. [PMID: 25589899 DOI: 10.1016/j.ddstr.2013.06.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Next-generation antisense technologies are re-emerging as viable and powerful approaches to the treatment of several genetic diseases. Similar strategies are also being applied to cancer therapy. Re-programming of the expression of endogenous oncogenic products to replace them with functional antagonists, by interfering with alternative splicing or polyadenylation, provides a promising novel approach to address acquired drug resistance and previously undruggable targets.
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Affiliation(s)
- Lee Spraggon
- Molecular Pharmacology and Chemistry Program, Memorial Sloan-Kettering Cancer Center, New York, USA
| | - Luca Cartegni
- Molecular Pharmacology and Chemistry Program, Memorial Sloan-Kettering Cancer Center, New York, USA
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Schwarzová L, Štekrová J, Florianová M, Novotný A, Schneiderová M, Lněnička P, Kebrdlová V, Kotlas J, Veselá K, Kohoutová M. Novel mutations of the APC gene and genetic consequences of splicing mutations in the Czech FAP families. Fam Cancer 2012; 12:35-42. [DOI: 10.1007/s10689-012-9569-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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Borràs E, Pineda M, Brieger A, Hinrichsen I, Gómez C, Navarro M, Balmaña J, Ramón y Cajal T, Torres A, Brunet J, Blanco I, Plotz G, Lázaro C, Capellá G. Comprehensive functional assessment of MLH1 variants of unknown significance. Hum Mutat 2012; 33:1576-88. [PMID: 22736432 DOI: 10.1002/humu.22142] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2012] [Accepted: 05/29/2012] [Indexed: 12/15/2022]
Abstract
Lynch syndrome is associated with germline mutations in DNA mismatch repair (MMR) genes. Up to 30% of DNA changes found are variants of unknown significance (VUS). Our aim was to assess the pathogenicity of eight MLH1 VUS identified in patients suspected of Lynch syndrome. All of them are novel or not previously characterized. For their classification, we followed a strategy that integrates family history, tumor pathology, and control frequency data with a variety of in silico and in vitro analyses at RNA and protein level, such as MMR assay, MLH1 and PMS2 expression, and subcellular localization. Five MLH1 VUS were classified as pathogenic: c.[248G>T(;)306G>C], c.[780C>G;788A>C], and c.791-7T>A affected mRNA processing, whereas c.218T>C (p.L73P) and c.244A>G [corrected] (p.T82A) impaired MMR activity. Two other VUS were considered likely neutral: the silent c.702G>A variant did not affect mRNA processing or stability, and c.974G>A (p.R325Q) did not influence MMR function. In contrast, variant c.25C>T (p.R9W) could not be classified, as it associated with intermediate levels of MMR activity. Comprehensive functional assessment of MLH1 variants was useful in their classification and became relevant in the diagnosis and genetic counseling of carrier families.
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Affiliation(s)
- Ester Borràs
- Hereditary Cancer Program, Catalan Institute of Oncology, ICO-IDIBELL, Hospitalet de Llobregat, Spain
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Pritchard CC, Smith C, Salipante SJ, Lee MK, Thornton AM, Nord AS, Gulden C, Kupfer SS, Swisher EM, Bennett RL, Novetsky AP, Jarvik GP, Olopade OI, Goodfellow PJ, King MC, Tait JF, Walsh T. ColoSeq provides comprehensive lynch and polyposis syndrome mutational analysis using massively parallel sequencing. J Mol Diagn 2012; 14:357-66. [PMID: 22658618 DOI: 10.1016/j.jmoldx.2012.03.002] [Citation(s) in RCA: 159] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2011] [Revised: 02/10/2012] [Accepted: 03/15/2012] [Indexed: 02/07/2023] Open
Abstract
Lynch syndrome (hereditary nonpolyposis colon cancer) and adenomatous polyposis syndromes frequently have overlapping clinical features. Current approaches for molecular genetic testing are often stepwise, taking a best-candidate gene approach with testing of additional genes if initial results are negative. We report a comprehensive assay called ColoSeq that detects all classes of mutations in Lynch and polyposis syndrome genes using targeted capture and massively parallel next-generation sequencing on the Illumina HiSeq2000 instrument. In blinded specimens and colon cancer cell lines with defined mutations, ColoSeq correctly identified 28/28 (100%) pathogenic mutations in MLH1, MSH2, MSH6, PMS2, EPCAM, APC, and MUTYH, including single nucleotide variants (SNVs), small insertions and deletions, and large copy number variants. There was 100% reproducibility of detection mutation between independent runs. The assay correctly identified 222 of 224 heterozygous SNVs (99.4%) in HapMap samples, demonstrating high sensitivity of calling all variants across each captured gene. Average coverage was greater than 320 reads per base pair when the maximum of 96 index samples with barcodes were pooled. In a specificity study of 19 control patients without cancer from different ethnic backgrounds, we did not find any pathogenic mutations but detected two variants of uncertain significance. ColoSeq offers a powerful, cost-effective means of genetic testing for Lynch and polyposis syndromes that eliminates the need for stepwise testing and multiple follow-up clinical visits.
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Affiliation(s)
- Colin C Pritchard
- Department of Laboratory Medicine, University of Washington, 1959 NE Pacific St, Seattle, WA 98195, USA.
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Spier I, Horpaopan S, Vogt S, Uhlhaas S, Morak M, Stienen D, Draaken M, Ludwig M, Holinski-Feder E, Nöthen MM, Hoffmann P, Aretz S. Deep intronic APC mutations explain a substantial proportion of patients with familial or early-onset adenomatous polyposis. Hum Mutat 2012; 33:1045-50. [PMID: 22431159 DOI: 10.1002/humu.22082] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2011] [Accepted: 03/05/2012] [Indexed: 01/13/2023]
Abstract
To uncover pathogenic deep intronic variants in patients with colorectal adenomatous polyposis, in whom no germline mutation in the APC or MUTYH genes can be identified by routine diagnostics, we performed a systematic APC messenger RNA analysis in 125 unrelated mutation-negative cases. Overall, we identified aberrant transcripts in 8% of the patients (familial cases 30%; early-onset manifestation 21%). In eight of them, two different out-of-frame pseudoexons were found consisting of a 167-bp insertion from intron 4 in five families with a shared founder haplotype and a 83-bp insertion from intron 10 in three patients. The pseudoexon formation was caused by three different heterozygous germline mutations, which are supposed to activate cryptic splice sites. In conclusion, a few deep intronic mutations contribute substantially to the APC mutation spectrum. Complementary DNA analysis and/or target sequencing of intronic regions should be considered as an additional mutation discovery approach in polyposis patients.
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Affiliation(s)
- Isabel Spier
- Institute of Human Genetics, University of Bonn, Sigmund-Freud-Strasse 25,Bonn, Germany.
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Palmirotta R, De Marchis ML, Ludovici G, Leone B, Valente MG, Alessandroni J, Spila A, Della-Morte D, Guadagni F. An AT-rich region in the APC gene may cause misinterpretation of familial adenomatous polyposis molecular screening. Hum Mutat 2012; 33:895-8. [PMID: 22447671 DOI: 10.1002/humu.22043] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2011] [Accepted: 01/20/2012] [Indexed: 11/09/2022]
Abstract
Familial adenomatous polyposis (FAP) is an autosomal-dominant condition mainly due to a mutation of the adenomatous polyposis coli (APC) gene. The present study reports evidence of a technical issue occurring during the mutational analysis of APC exon 4. Genetic conventional direct sequence analysis of a repetitive AT-rich region in the splice acceptor site of APC intron 3 could be misinterpreted as a pathogenetic frameshift result. However, this potential bias may be bypassed adopting a method for random mutagenesis of DNA based on the use of a triphosphate nucleoside analogues mixture. Using this method as a second-level analysis, we also demonstrated the nonpathogenic nature of the variant in the poly A trait in APC exon 4 region (c.423-4delA) that do not result in aberrant splicing of APC exons 3-4; conversely, we did not find a previously reported T deletion/insertion polymorphism.
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Affiliation(s)
- Raffaele Palmirotta
- Laboratory of Molecular Diagnostics, Department of Laboratory Medicine and Advanced Biotechnologies, IRCCS San Raffaele Pisana, via della Pisana 235, Rome, Italy.
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Pećina-Šlaus N, Nikuševa Martić T, Zeljko M, Bulat S. Brain metastases exhibit gross deletions of the APC gene. Brain Tumor Pathol 2011; 28:223-8. [PMID: 21442240 DOI: 10.1007/s10014-011-0030-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2010] [Accepted: 03/03/2011] [Indexed: 11/28/2022]
Abstract
Candidate genes involved in metastasis to the brain require investigation. In the present study, the adenomatous polyposis coli (APC) gene was analyzed in a set of human brain metastases. Gross deletions of the APC gene were tested by polymerase chain reaction/loss of heterozygosity (LOH) using the restriction fragment length polymorphism method performed by the use of MspI and RsaI genetic markers inside exon 15 and exon 11. Among 21 brain metastases analyzed, 58.8% of samples showed LOH of the APC gene. When assigning the genetic changes to a specific primary tumor type, 6 LOHs were found in metastases originated from lung and 4 LOHs in metastases from colon. The main effector of the wnt signaling, beta-catenin, was upregulated in 42.9% of cases and transferred to the nucleus in 28.6% of metastasis cases. Our findings suggest that genetic changes of the tumor suppressor gene APC, a component of the wnt pathway, represent a part of the brain metastasis genetic profile.
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Affiliation(s)
- Nives Pećina-Šlaus
- Laboratory of Neurooncology, Croatian Institute for Brain Research, School of Medicine, University of Zagreb, Šalata 12, 10000 Zagreb, Croatia.
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Chen S, Zhou J, Zhang X, Zhou X, Zhu M, Zhang Y, Ma G, Li J. Mutation Analysis of the APC Gene in a Chinese FAP Pedigree with Unusual Phenotype. ISRN GASTROENTEROLOGY 2011; 2011:909121. [PMID: 22164339 PMCID: PMC3226247 DOI: 10.5402/2011/909121] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/02/2011] [Accepted: 01/19/2011] [Indexed: 12/22/2022]
Abstract
Background and Aim. Germline mutations of the adenomatous polyposis coli (APC) gene cause familial adenomatous polyposis (FAP), an autosomal dominant inherited disease mainly characterized by colorectal adenomatous polyposis. Genetic studies of FAP have shown that somatic APC mutations are dependent on the position of the germline APC mutation. However, the molecular mechanism underlying these genotype-phenotype associations for APC in Chinese remain largely unknown. Patients and Methods. In this study, we investigated the APC gene mutation in a Chinese FAP family by systematic screening with multiplex ligation-dependent probe amplification (MLPA), denaturing high-performance liquid chromatography (dHPLC), and DNA sequencing. Promoter methylation was detected by methylation-specific PCR. Results. The identical germline mutation c.1999 C>T (Q667X) of APC was identified in 5 affected members, among which 2 members carried somatic mutations of APC, one with promoter hypermethylation and the other with loss of wild-type allele in their adenomas. The somatic mutations were shown connected with the disease severity, demonstrating a unique genotype-phenotype association in this FAP pedigree. Conclusion. The study revealed the existence of novel pathogenic mutations in Chinese patients with FAP. Somatic mutations are of particular interest because of the unusual phenotypic features shown by patients.
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Affiliation(s)
- S Chen
- Laboratory of Genetics and Molecular Biology, Jiangsu Institute of Cancer Research, Nanjing 210009, China
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Miura K, Fujibuchi W, Sasaki I. Alternative pre-mRNA splicing in digestive tract malignancy. Cancer Sci 2010; 102:309-16. [PMID: 21134075 DOI: 10.1111/j.1349-7006.2010.01797.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Alternative precursor messenger RNA (pre-mRNA) splicing plays an important role in the generation of functional diversity of the genome. The process of pre-mRNA splicing is regulated by cis- and trans-elements, and their deregulations result in aberrantly spliced individual variants and aberrant expression profiles. Accumulating evidence has revealed that aberrant splicing contributes to a number of diseases including human neoplasms. It is well known that germ line mutations in the cis-element of tumor suppressor genes such as mismatch repair (MMR) genes, the adenomatous polyposis coli (APC) gene and the E-cadherin (CDH1) gene are involved in Lynch syndrome, familial adenomatous polyposis and hereditary diffuse gastric cancer, respectively. In addition, somatic mutations in cis-elements also play a role in tumorigenesis. These genetic alterations including nonsense, missense or silent mutations in cis-elements led to aberrant transcripts by exon skipping, retention of the intron or introduction of a new splice site. The majority of erroneous transcripts with a premature termination codon are eliminated through nonsense-mediated mRNA decay. However, it is difficult to accurately predict the resulting transcripts with current in silico strategies. Correct interpretation of genetic alterations and the investigation of aberrant transcripts are crucial for genetic diagnosis of hereditary diseases and elucidation of the molecular characteristics of neoplasms from a clinical point of view. In this review we summarize the current knowledge of the regulatory mechanism underlying alternative pre-mRNA splicing and aberrant splicing, with particular focus on digestive tract malignancies.
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Affiliation(s)
- Koh Miura
- Department of Surgery, Tohoku University Graduate School of Medicine, Sendai Computational Biology Research Center, National Institute of Advanced Industrial Science and Technology, Tokyo, Japan.
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Tao H, Shinmura K, Yamada H, Maekawa M, Osawa S, Takayanagi Y, Okamoto K, Terai T, Mori H, Nakamura T, Sugimura H. Identification of 5 novel germline APC mutations and characterization of clinical phenotypes in Japanese patients with classical and attenuated familial adenomatous polyposis. BMC Res Notes 2010; 3:305. [PMID: 21078199 PMCID: PMC2994888 DOI: 10.1186/1756-0500-3-305] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2010] [Accepted: 11/16/2010] [Indexed: 12/29/2022] Open
Abstract
Background Familial adenomatous polyposis (FAP) is an autosomal dominant hereditary disease characterized by multiple colorectal adenomatous polyps and frequent extracolonic manifestations. An attenuated form of FAP (AFAP) is diagnosed based on a milder colorectal phenotype, and the colorectal phenotype of (A)FAP has been linked to germline APC mutations. The relationships between the spectrum of mutations and extracolonic manifestations are quite well known, but they need to be further defined. Findings Nine germline APC mutations, but no large deletions, were identified in the APC locus of 8 (A)FAP patients, and 5 of the mutations, c.446A > T (p.Asp149Val), c.448A > T (p.Lys150X), c.454_457insAGAA (p.Glu152ArgfsX17), c.497insA (p.Thr166AsnfsX2), and c.1958G > C (p.Arg653Ser), were novel mutations. In one patient the p.Asp149Val mutation and p.Lys150X mutation were detected in the same APC allele. The c.1958G > C mutation was located in the last nucleotide of exon 14, and RT-PCR analysis revealed that the mutation resulted in abnormal splicing. The above findings meant that a nonsense mutation, a frameshift mutation, or an exonic mutation leading to abnormal splicing was found in every patient. The following phenotypes, especially extracolonic manifestations, were observed in our (A)FAP patients: (1) multiple gastroduodenal adenomas and early-onset gastric carcinoma in AFAP patients with an exon 4 mutation; (2) a desmoid tumor in two FAP patients with a germline APC mutation outside the region between codons 1403 and 1578, which was previously reported to be associated with the development of desmoid tumors in FAP patients; (3) multiple myeloma in an AFAP patient with an exon 4 mutation. Conclusions Nine germline APC mutations, 5 of them were novel, were identified in 8 Japanese (A)FAP patients, and some associations between germline APC mutations and extracolonic manifestations were demonstrated. These findings should contribute to establishing relationships between germline APC mutations and the extracolonic manifestations of (A)FAP patients in the future.
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Affiliation(s)
- Hong Tao
- First Department of Pathology, Hamamatsu University School of Medicine, 1-20-1 Handayama, Higashi Ward, Hamamatsu, Shizuoka 431-3192, Japan.
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Castellsagué E, González S, Guinó E, Stevens KN, Borràs E, Raymond VM, Lázaro C, Blanco I, Gruber SB, Capellá G. Allele-specific expression of APC in adenomatous polyposis families. Gastroenterology 2010; 139:439-47, 447.e1. [PMID: 20434453 PMCID: PMC2910837 DOI: 10.1053/j.gastro.2010.04.047] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/01/2009] [Revised: 03/24/2010] [Accepted: 04/21/2010] [Indexed: 12/02/2022]
Abstract
BACKGROUND & AIMS Germline mutations in the APC gene cause of most cases of familial adenomatous polyposis (FAP) and a lesser proportion of attenuated FAP (AFAP). Systematic analysis of APC at the RNA level could provide insight into the pathogenicity of identified mutations and the molecular basis of FAP/AFAP in families without identifiable mutations. Here, we analyzed the prevalence of imbalances in the allelic expression of APC in polyposis families with germline mutations in the gene and without detectable mutations in APC and/or MUTYH. METHODS Allele-specific expression (ASE) was determined by single nucleotide primer extension using an exon 11 polymorphism as an allele-specific marker. In total, 52 APC-mutation-positive (36 families) and 24 APC/MUTYH-mutation-negative (23 families) informative patients were analyzed. Seventy-six controls also were included. RESULTS Of the APC-mutation-positive families, most of those in whom the mutation was located before the last exon of the gene (12 of 14) had ASE imbalance, which is consistent with a mechanism of nonsense-mediated decay. Of the APC/MUTYH-mutation-negative families, 2 (9%) had ASE imbalance, which might cause the disease. Normal allele expression was restored shortly after lymphocytes were cultured with puromycin, supporting a 'nonsense-mediated' hypothesis. CONCLUSIONS ASE analysis might be used to determine the pathogenesis of some cases of FAP and AFAP in which APC mutations are not found. ASE also might be used to prioritize the order in which different areas of APC are tested. RNA-level studies are important for the molecular diagnosis of FAP.
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Affiliation(s)
- Ester Castellsagué
- Translational Research Laboratory, IDIBELL-Institut Català d’Oncologia, Barcelona 08907, Spain
| | - Sara González
- Translational Research Laboratory, IDIBELL-Institut Català d’Oncologia, Barcelona 08907, Spain
| | - Elisabet Guinó
- Bioinformatics and Biostatistics Unit, Department of Epidemiology, IDIBELL-Institut Català d’Oncologia, Barcelona 08907, Spain
| | - Kristen N. Stevens
- Department of Epidemiology, University of Michigan, Ann Arbor MI 48109, Michigan, USA
| | - Ester Borràs
- Translational Research Laboratory, IDIBELL-Institut Català d’Oncologia, Barcelona 08907, Spain
| | - Victoria M. Raymond
- Department of Internal Medicine, University of Michigan Medical School, Ann Arbor MI 48109, Michigan, USA
| | - Conxi Lázaro
- Translational Research Laboratory, IDIBELL-Institut Català d’Oncologia, Barcelona 08907, Spain
| | - Ignacio Blanco
- Cancer Genetic Counseling Program, IDIBELL-Institut Català d’Oncologia, Barcelona, Spain
| | - Stephen B. Gruber
- Department of Internal Medicine, Epidemiology, and Human Genetics, Division of Molecular Medicine and Genetics, University of Michigan, Ann Arbor MI 48109, Michigan, USA
| | - Gabriel Capellá
- Translational Research Laboratory, IDIBELL-Institut Català d’Oncologia, Barcelona 08907, Spain
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Aretz S. The differential diagnosis and surveillance of hereditary gastrointestinal polyposis syndromes. DEUTSCHES ARZTEBLATT INTERNATIONAL 2010; 108:163-9. [PMID: 21475574 DOI: 10.3238/arztebl.2010.0163] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2010] [Accepted: 10/12/2010] [Indexed: 12/24/2022]
Abstract
BACKGROUND Hereditary gastrointestinal polyposis syndromes account for about 1% of all cases of colorectal cancer and are associated with a broad spectrum of extracolonic tumors. The early detection and accurate classification of these syndromes are essential, since effective methods for surveillance and treatment are available. METHODS This review article is based on a selective literature search, the author's own work, and evidence-based guidelines and recommendations. RESULTS AND CONCLUSIONS The diagnosis is initially suspected on the basis of the endoscopic findings and polyp histology. Because different syndromes can resemble each other phenotypically, e.g., autosomal dominant familial adenomatous polyposis and autosomal recessive MUTYH-associated polyposis, molecular genetic studies are important for differential diagnosis and for assessing the risk of recurrence. Identification of the familial mutation in an affected patient is a prerequisite for predictive testing in asymptomatic persons at risk and sometimes enables prognostication. In recent years, the rate of detection of mutations has risen by 10% to 30%, and clinically relevant genotype-phenotype correlations have been described for juvenile polyposis syndrome. Except in cases of mild adenomatous polyposis, phenotypic overlap among the hamartomatous polyposes often causes difficulties in differential diagnosis. Thus, in unclear cases, a pathologist with special expertise in gastrointestinal disorders should be consulted for the evaluation of polyp tissue. Aside from the monogenic polyposes, there are many other types of polyposis that are non-hereditary or of unknown cause, including the hyperplastic and mixed polyposis syndromes. Risk-adapted surveillance programs have been established for the more frequently occurring polyposes.
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Affiliation(s)
- Stefan Aretz
- Institut für Humangenetik, Biomedizinisches Zentrum (BMZ), Universitätsklinikum Bonn, Siegmund-Freud-Strasse 25, Bonn, Germany.
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Diosdado B, Buffart TE, Watkins R, Carvalho B, Ylstra B, Tijssen M, Bolijn AS, Lewis F, Maude K, Verbeke C, Nagtegaal ID, Grabsch H, Mulder CJJ, Quirke P, Howdle P, Meijer GA. High-resolution array comparative genomic hybridization in sporadic and celiac disease-related small bowel adenocarcinomas. Clin Cancer Res 2010; 16:1391-401. [PMID: 20179237 DOI: 10.1158/1078-0432.ccr-09-1773] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
PURPOSE The molecular pathogenesis of small intestinal adenocarcinomas is not well understood. Understanding the molecular characteristics of small bowel adenocarcinoma may lead to more effective patient treatment. EXPERIMENTAL DESIGN Forty-eight small bowel adenocarcinomas (33 non-celiac disease related and 15 celiac disease related) were characterized for chromosomal aberrations by high-resolution array comparative hybridization, microsatellite instability, and APC promoter methylation and mutation status. Findings were compared with clinicopathologic and survival data. Furthermore, molecular alterations were compared between celiac disease-related and non-celiac disease-related small bowel adenocarcinomas. RESULTS DNA copy number changes were observed in 77% small bowel adenocarcinomas. The most frequent DNA copy number changes found were gains on 5p15.33-5p12, 7p22.3-7q11.21, 7q21.2-7q21.3, 7q22.1-7q34, 7q36.1, 7q36.3, 8q11.21-8q24.3, 9q34.11-9q34.3, 13q11-13q34, 16p13.3, 16p11.2, 19q13.2, and 20p13-20q13.33, and losses on 4p13-4q35.2, 5q15-5q21.1, and 21p11.2-21q22.11. Seven highly amplified regions were identified on 6p21.1, 7q21.1, 8p23.1, 11p13, 16p11.2, 17q12-q21.1, and 19q13.2. Celiac disease-related and non-celiac disease-related small bowel adenocarcinomas displayed similar chromosomal aberrations. Promoter hypermethylation of the APC gene was found in 48% non-celiac disease-related and 73% celiac disease-related small bowel adenocarcinomas. No nonsense mutations were found. Thirty-three percent of non-celiac disease-related small bowel adenocarcinomas showed microsatellite instability, whereas 67% of celiac disease-related small bowel adenocarcinomas were microsatellite unstable. CONCLUSIONS Our study characterized chromosomal aberrations and amplifications involved in small bowel adenocarcinoma. At the chromosomal level, celiac disease-related and non-celiac disease-related small bowel adenocarcinomas did not differ. A defect in the mismatch repair pathways seems to be more common in celiac disease-related than in non-celiac disease-related small bowel adenocarcinomas. In contrast to colon and gastric cancers, no APC nonsense mutations were found in small bowel adenocarcinoma. However, APC promoter methylation seems to be a common event in celiac disease-related small bowel adenocarcinoma. Clin Cancer Res; 16(5); 1391-401.
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Affiliation(s)
- Begoña Diosdado
- Departments of Pathology and Gastroenterology, VU University Medical Center, Amsterdam, The Netherlands.
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Large intron 14 rearrangement in APC results in splice defect and attenuated FAP. Hum Genet 2009; 127:359-69. [PMID: 20033212 DOI: 10.1007/s00439-009-0776-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2009] [Accepted: 12/07/2009] [Indexed: 10/20/2022]
Abstract
Familial adenomatous polyposis [FAP (OMIM 175100)] is an autosomal dominant colorectal cancer predisposition syndrome characterized by hundreds to thousands of colonic polyps and, if untreated by a combination of screening and/or surgical intervention, an approximately 99% lifetime risk of colorectal cancer. A subset of FAP patients develop an attenuated form of the condition characterized by lower numbers of colonic polyps (highly variable, but generally less than 100) and a lower lifetime risk of colorectal cancer, on the order of 70%. We report the diagnosis of three attenuated FAP families due to a 1.4-kb deletion within intron 14 of APC, originally reported clinically as a variant of unknown significance (VUS). Sequence analysis suggests that this arose through an Alu-mediated recombination event with a locus on chromosome 6q22.1. This mutation is inherited by family members who presented with an attenuated FAP phenotype, with variable age of onset and severity. Sequence analysis of mRNA revealed an increase in the level of aberrant splicing of exon 14, resulting in the generation of an exon 13-exon 15 splice-form that is predicted to lead to a frameshift and protein truncation at codon 673. The relatively mild phenotypic presentation and the intra-familial variation are consistent with the leaky nature of exon 14 splicing in normal APC. The inferred founder of these three families may account for as yet undetected affected branches of this kindred. This and similar types of intronic mutations may account for a significant proportion of FAP cases where APC clinical analysis fails because of the current limitations of testing options.
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Filipe B, Baltazar C, Albuquerque C, Fragoso S, Lage P, Vitoriano I, Mão de Ferro S, Claro I, Rodrigues P, Fidalgo P, Chaves P, Cravo M, Nobre Leitão C. APCorMUTYHmutations account for the majority of clinically well-characterized families with FAP and AFAP phenotype and patients with more than 30 adenomas. Clin Genet 2009; 76:242-55. [DOI: 10.1111/j.1399-0004.2009.01241.x] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Guédard-Méreuze SL, Vaché C, Molinari N, Vaudaine J, Claustres M, Roux AF, Tuffery-Giraud S. Sequence contexts that determine the pathogenicity of base substitutions at position +3 of donor splice-sites. Hum Mutat 2009; 30:1329-39. [DOI: 10.1002/humu.21070] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Pećina-Slaus N, Majić Z, Musani V, Zeljko M, Cupić H. Report on mutation in exon 15 of the APC gene in a case of brain metastasis. J Neurooncol 2009; 97:143-8. [PMID: 19711014 DOI: 10.1007/s11060-009-0001-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2009] [Accepted: 08/10/2009] [Indexed: 11/29/2022]
Abstract
The study analyzes exon 15 of the adenomatous polyposis coli gene (APC) in a 49-year-old male patient with brain metastasis. The primary site was lung carcinoma. PCR method and direct DNA sequencing of the metastasis and autologous lymphocyte samples identified the presence of a somatic mutation. The substitution was at position 5883 G-A in the metastasis tissue. The mutation was confirmed by RFLP analysis using Msp I endonuclease, since the mutation strikes the Msp I restriction site. Immunohistochemical analysis revealed the lack of protein expression of this tumor suppressor gene. The main molecular activator of the wnt pathway, beta-catenin, was expressed, and located in the nucleus. The mutation is a silent mutation that might have consequences in the creation of a new splice site. Different single-base substitutions in APC exons need not only be evaluated by the predicted change in amino acid sequence, but rather at the nucleotide level itself. In our opinion, such silent mutations should also be incorporated in mutation detection rate and validation.
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Affiliation(s)
- Nives Pećina-Slaus
- Laboratory of Neurooncology, Croatian Institute for Brain Research, School of Medicine University of Zagreb, Zagreb, Croatia.
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Körner M, Miller LJ. Alternative splicing of pre-mRNA in cancer: focus on G protein-coupled peptide hormone receptors. THE AMERICAN JOURNAL OF PATHOLOGY 2009; 175:461-72. [PMID: 19574427 DOI: 10.2353/ajpath.2009.081135] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Through alternative splicing, multiple different transcripts can be generated from a single gene. Alternative splicing represents an important molecular mechanism of gene regulation in physiological processes such as developmental programming as well as in disease. In cancer, splicing is significantly altered. Tumors express a different collection of alternative spliceoforms than normal tissues. Many tumor-associated splice variants arise from genes with an established role in carcinogenesis or tumor progression, and their functions can be oncogenic. This raises the possibility that products of alternative splicing play a pathogenic role in cancer. Moreover, cancer-associated spliceoforms represent potential diagnostic biomarkers and therapeutic targets. G protein-coupled peptide hormone receptors provide a good illustration of alternative splicing in cancer. The wild-type forms of these receptors have long been known to be expressed in cancer and to modulate tumor cell functions. They are also recognized as attractive clinical targets. Recently, splice variants of these receptors have been increasingly identified in various types of cancer. In particular, alternative cholecystokinin type 2, secretin, and growth hormone-releasing hormone receptor spliceoforms are expressed in tumors. Peptide hormone receptor splice variants can fundamentally differ from their wild-type receptor counterparts in pharmacological and functional characteristics, in their distribution in normal and malignant tissues, and in their potential use for clinical applications.
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Affiliation(s)
- Meike Körner
- Institute of Pathology of the University of Berne, Murtenstrasse 31, CH-3010 Berne, Switzerland.
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