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Mutation spectrum of PRPF31, genotype-phenotype correlation in retinitis pigmentosa, and opportunities for therapy. Exp Eye Res 2020; 192:107950. [PMID: 32014492 PMCID: PMC7065041 DOI: 10.1016/j.exer.2020.107950] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Revised: 01/13/2020] [Accepted: 01/27/2020] [Indexed: 12/11/2022]
Abstract
Pathogenic variants in pre-messenger RNA (pre-mRNA) splicing factor 31, PRPF31, are the second most common genetic cause of autosomal dominant retinitis pigmentosa (adRP) in most populations. This remains a completely untreatable and incurable form of blindness, and it can be difficult to predict the clinical course of disease. In order to design appropriate targeted therapies, a thorough understanding of the genetics and molecular mechanism of this disease is required. Here, we present the structure of the PRPF31 gene and PRPF31 protein, current understanding of PRPF31 protein function and the full spectrum of all reported clinically relevant variants in PRPF31. We delineate the correlation between specific PRPF31 genotype and RP phenotype, suggesting that, except in cases of complete gene deletion or large-scale deletions, dominant negative effects contribute to phenotype as well as haploinsufficiency. This has important impacts on design of targeted therapies, particularly the feasibility of gene augmentation as a broad approach for treatment of PRPF31-associated RP. We discuss other opportunities for therapy, including antisense oligonucleotide therapy and gene-independent approaches and offer future perspectives on treatment of this form of RP.
PRPF31 is the second most common cause of autosomal dominant retinitis pigmentosa and a potential target for gene therapy. We present all reported pathogenic variants in PRPF31 as a resource for clinicians, diagnostic genetics labs, and researchers. Genotype-phenotype correlations suggest that, dominant negative effects contribute to disease in addition to haploinsufficiency. This finding has important impacts on the suitability of gene augmentation approaches across all mutation types. This finding may aid prognosis of disease in PRPF31-associated RP patients.
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Martin-Merida I, Aguilera-Garcia D, Fernandez-San JP, Blanco-Kelly F, Zurita O, Almoguera B, Garcia-Sandoval B, Avila-Fernandez A, Arteche A, Minguez P, Carballo M, Corton M, Ayuso C. Toward the Mutational Landscape of Autosomal Dominant Retinitis Pigmentosa: A Comprehensive Analysis of 258 Spanish Families. Invest Ophthalmol Vis Sci 2019; 59:2345-2354. [PMID: 29847639 DOI: 10.1167/iovs.18-23854] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose To provide a comprehensive overview of the molecular basis of autosomal dominant retinitis pigmentosa (adRP) in Spanish families. Thus, we established the molecular characterization rate, gene prevalence, and mutational spectrum in the largest European cohort reported to date. Methods A total of 258 unrelated Spanish families with a clinical diagnosis of RP and suspected autosomal dominant inheritance were included. Clinical diagnosis was based on complete ophthalmologic examination and family history. Retrospective and prospective analysis of Spanish adRP families was carried out using a combined strategy consisting of classic genetic techniques and next-generation sequencing (NGS) for single-nucleotide variants and copy number variation (CNV) screening. Results Overall, 60% of our families were genetically solved. Interestingly, 3.1% of the cohort carried pathogenic CNVs. Disease-causing variants were found in an autosomal dominant gene in 55% of the families; however, X-linked and autosomal recessive forms were also identified in 3% and 2%, respectively. Four genes (RHO, PRPF31, RP1, and PRPH2) explained up to 62% of the solved families. Missense changes were most frequently found in adRP-associated genes; however, CNVs represented a relevant disease cause in PRPF31- and CRX-associated forms. Conclusions Implementation of NGS technologies in the adRP study clearly increased the diagnostic yield compared with classic approaches. Our study outcome expands the spectrum of disease-causing variants, provides accurate data on mutation gene prevalence, and highlights the implication of CNVs as important contributors to adRP etiology.
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Affiliation(s)
- Inmaculada Martin-Merida
- Department of Genetics, Instituto de Investigación Sanitaria-Fundación Jiménez Díaz University Hospital-Universidad Autónoma de Madrid (IIS-FJD, UAM), Madrid, Spain.,Center for Biomedical Network Research on Rare Diseases (CIBERER), ISCIII, Madrid, Spain
| | - Domingo Aguilera-Garcia
- Department of Genetics, Instituto de Investigación Sanitaria-Fundación Jiménez Díaz University Hospital-Universidad Autónoma de Madrid (IIS-FJD, UAM), Madrid, Spain
| | - Jose P Fernandez-San
- Department of Genetics, Instituto de Investigación Sanitaria-Fundación Jiménez Díaz University Hospital-Universidad Autónoma de Madrid (IIS-FJD, UAM), Madrid, Spain.,Center for Biomedical Network Research on Rare Diseases (CIBERER), ISCIII, Madrid, Spain
| | - Fiona Blanco-Kelly
- Department of Genetics, Instituto de Investigación Sanitaria-Fundación Jiménez Díaz University Hospital-Universidad Autónoma de Madrid (IIS-FJD, UAM), Madrid, Spain.,Center for Biomedical Network Research on Rare Diseases (CIBERER), ISCIII, Madrid, Spain
| | - Olga Zurita
- Department of Genetics, Instituto de Investigación Sanitaria-Fundación Jiménez Díaz University Hospital-Universidad Autónoma de Madrid (IIS-FJD, UAM), Madrid, Spain.,Center for Biomedical Network Research on Rare Diseases (CIBERER), ISCIII, Madrid, Spain
| | - Berta Almoguera
- Department of Genetics, Instituto de Investigación Sanitaria-Fundación Jiménez Díaz University Hospital-Universidad Autónoma de Madrid (IIS-FJD, UAM), Madrid, Spain.,Center for Applied Genomics, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, United States
| | - Blanca Garcia-Sandoval
- Department of Ophthalmology, Instituto de Investigación Sanitaria-Fundación Jiménez Díaz University Hospital-Universidad Autónoma de Madrid (IIS-FJD, UAM), Madrid, Spain
| | - Almudena Avila-Fernandez
- Department of Genetics, Instituto de Investigación Sanitaria-Fundación Jiménez Díaz University Hospital-Universidad Autónoma de Madrid (IIS-FJD, UAM), Madrid, Spain.,Center for Biomedical Network Research on Rare Diseases (CIBERER), ISCIII, Madrid, Spain
| | - Ana Arteche
- Department of Genetics, Instituto de Investigación Sanitaria-Fundación Jiménez Díaz University Hospital-Universidad Autónoma de Madrid (IIS-FJD, UAM), Madrid, Spain
| | - Pablo Minguez
- Department of Genetics, Instituto de Investigación Sanitaria-Fundación Jiménez Díaz University Hospital-Universidad Autónoma de Madrid (IIS-FJD, UAM), Madrid, Spain
| | - Miguel Carballo
- Molecular Genetics Unit, Hospital de Terrassa, Terrassa, Barcelona, Spain
| | - Marta Corton
- Department of Genetics, Instituto de Investigación Sanitaria-Fundación Jiménez Díaz University Hospital-Universidad Autónoma de Madrid (IIS-FJD, UAM), Madrid, Spain.,Center for Biomedical Network Research on Rare Diseases (CIBERER), ISCIII, Madrid, Spain
| | - Carmen Ayuso
- Department of Genetics, Instituto de Investigación Sanitaria-Fundación Jiménez Díaz University Hospital-Universidad Autónoma de Madrid (IIS-FJD, UAM), Madrid, Spain.,Center for Biomedical Network Research on Rare Diseases (CIBERER), ISCIII, Madrid, Spain
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Moghadam AK, Vallian J, Vallian S. Molecular characterization of AIPL1 gene region in the Iranian population: application of novel informative haplotypes and detection of mutational founder effect. Genes Genomics 2017. [DOI: 10.1007/s13258-016-0467-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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4
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Van Cauwenbergh C, Coppieters F, Roels D, De Jaegere S, Flipts H, De Zaeytijd J, Walraedt S, Claes C, Fransen E, Van Camp G, Depasse F, Casteels I, de Ravel T, Leroy BP, De Baere E. Mutations in Splicing Factor Genes Are a Major Cause of Autosomal Dominant Retinitis Pigmentosa in Belgian Families. PLoS One 2017; 12:e0170038. [PMID: 28076437 PMCID: PMC5226823 DOI: 10.1371/journal.pone.0170038] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2016] [Accepted: 12/27/2016] [Indexed: 12/14/2022] Open
Abstract
Purpose Autosomal dominant retinitis pigmentosa (adRP) is characterized by an extensive genetic heterogeneity, implicating 27 genes, which account for 50 to 70% of cases. Here 86 Belgian probands with possible adRP underwent genetic testing to unravel the molecular basis and to assess the contribution of the genes underlying their condition. Methods Mutation detection methods evolved over the past ten years, including mutation specific methods (APEX chip analysis), linkage analysis, gene panel analysis (Sanger sequencing, targeted next-generation sequencing or whole exome sequencing), high-resolution copy number screening (customized microarray-based comparative genomic hybridization). Identified variants were classified following American College of Medical Genetics and Genomics (ACMG) recommendations. Results Molecular genetic screening revealed mutations in 48/86 cases (56%). In total, 17 novel pathogenic mutations were identified: four missense mutations in RHO, five frameshift mutations in RP1, six mutations in genes encoding spliceosome components (SNRNP200, PRPF8, and PRPF31), one frameshift mutation in PRPH2, and one frameshift mutation in TOPORS. The proportion of RHO mutations in our cohort (14%) is higher than reported in a French adRP population (10.3%), but lower than reported elsewhere (16.5–30%). The prevalence of RP1 mutations (10.5%) is comparable to other populations (3.5%-10%). The mutation frequency in genes encoding splicing factors is unexpectedly high (altogether 19.8%), with PRPF31 the second most prevalent mutated gene (10.5%). PRPH2 mutations were found in 4.7% of the Belgian cohort. Two families (2.3%) have the recurrent NR2E3 mutation p.(Gly56Arg). The prevalence of the recurrent PROM1 mutation p.(Arg373Cys) was higher than anticipated (3.5%). Conclusions Overall, we identified mutations in 48 of 86 Belgian adRP cases (56%), with the highest prevalence in RHO (14%), RP1 (10.5%) and PRPF31 (10.5%). Finally, we expanded the molecular spectrum of PRPH2, PRPF8, RHO, RP1, SNRNP200, and TOPORS-associated adRP by the identification of 17 novel mutations.
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Affiliation(s)
- Caroline Van Cauwenbergh
- Center for Medical Genetics Ghent, Ghent University and Ghent University Hospital, Ghent, Belgium
| | - Frauke Coppieters
- Center for Medical Genetics Ghent, Ghent University and Ghent University Hospital, Ghent, Belgium
| | - Dimitri Roels
- Department of Ophthalmology, Ghent University and Ghent University Hospital, Ghent, Belgium
| | - Sarah De Jaegere
- Center for Medical Genetics Ghent, Ghent University and Ghent University Hospital, Ghent, Belgium
| | - Helena Flipts
- Center for Medical Genetics Ghent, Ghent University and Ghent University Hospital, Ghent, Belgium
- Center for Human Genetics, University Hospitals Leuven, Louvain, Belgium
| | - Julie De Zaeytijd
- Department of Ophthalmology, Ghent University and Ghent University Hospital, Ghent, Belgium
| | - Sophie Walraedt
- Department of Ophthalmology, Ghent University and Ghent University Hospital, Ghent, Belgium
| | - Charlotte Claes
- Center for Medical Genetics Antwerp, Antwerp University, Antwerp, Belgium
| | - Erik Fransen
- Center for Medical Genetics Antwerp, Antwerp University, Antwerp, Belgium
| | - Guy Van Camp
- Center for Medical Genetics Antwerp, Antwerp University, Antwerp, Belgium
| | - Fanny Depasse
- Department of Ophthalmology, Hôpital Erasme-ULB, Brussels, Belgium
| | - Ingele Casteels
- Department of Ophthalmology, University Hospitals Leuven, Louvain, Belgium
| | - Thomy de Ravel
- Center for Human Genetics, University Hospitals Leuven, Louvain, Belgium
| | - Bart P. Leroy
- Center for Medical Genetics Ghent, Ghent University and Ghent University Hospital, Ghent, Belgium
- Department of Ophthalmology, Ghent University and Ghent University Hospital, Ghent, Belgium
- Division of Ophthalmology & Center for Cellular & Molecular Therapy, The Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, United States of America
| | - Elfride De Baere
- Center for Medical Genetics Ghent, Ghent University and Ghent University Hospital, Ghent, Belgium
- * E-mail:
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Marfany G, Gonzàlez-Duarte R. Clinical applications of high-throughput genetic diagnosis in inherited retinal dystrophies: Present challenges and future directions. World J Med Genet 2015; 5:14-22. [DOI: 10.5496/wjmg.v5.i2.14] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2014] [Revised: 12/30/2014] [Accepted: 02/09/2015] [Indexed: 02/06/2023] Open
Abstract
The advent of next generation sequencing (NGS) techniques has greatly simplified the molecular diagnosis and gene identification in very rare and highly heterogeneous Mendelian disorders. Over the last two years, these approaches, especially whole exome sequencing (WES), alone or combined with homozygosity mapping and linkage analysis, have proved to be successful in the identification of more than 25 new causative retinal dystrophy genes. NGS-approaches have also identified a wealth of new mutations in previously reported genes and have provided more comprehensive information concerning the landscape of genotype-phenotype correlations and the genetic complexity/diversity of human control populations. Although whole genome sequencing is far more informative than WES, the functional meaning of the genetic variants identified by the latter can be more easily interpreted, and final diagnosis of inherited retinal dystrophies is extremely successful, reaching 80%, particularly for recessive cases. Even considering the present limitations of WES, the reductions in costs and time, the continual technical improvements, the implementation of refined bioinformatic tools and the unbiased comprehensive genetic information it provides, make WES a very promising diagnostic tool for routine clinical and genetic diagnosis in the future.
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Villanueva A, Willer JR, Bryois J, Dermitzakis ET, Katsanis N, Davis EE. Whole exome sequencing of a dominant retinitis pigmentosa family identifies a novel deletion in PRPF31. Invest Ophthalmol Vis Sci 2014; 55:2121-9. [PMID: 24595387 DOI: 10.1167/iovs.13-13827] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE Mutations at some retinitis pigmentosa (RP) loci are associated with variable penetrance and expressivity, exacerbating diagnostic challenges. The purpose of this study was to dissect the genetic underpinnings of nonsyndromic RP with variable age of onset in a large Mexican family. METHODS We ascertained members of a large, multigenerational pedigree using a complete ophthalmic examination. We performed whole exome sequencing on two affected first cousins, an obligate carrier, and a married-in spouse. Confirmatory sequencing of candidate variants was performed in the entire pedigree, as well as genotyping and mRNA studies to investigate expression changes in the causal locus. RESULTS We identified a 14-base pair (bp) deletion in PRPF31, a gene implicated previously in autosomal dominant (ad) RP. The mutation segregated with the phenotype of all 10 affected females, but also was present in six asymptomatics (two females and four males). Studies in patient cells showed that the penetrance/expressivity of the PRPF31 deletion allele was concordant with the expression levels of wild-type message. However, neither the known PRPF31 modulators nor cis-eQTLs within 1 Mb of the locus could account for the variable expression of message or the clinical phenotype. CONCLUSIONS We have identified a novel 14-bp deletion in PRPF31 as the genetic driver of adRP in a large Mexican family that exhibits nonpenetrance and variable expressivity, known properties of this locus. However, our studies intimate the presence of additional loci that can modify PRPF31 expression.
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de Castro-Miró M, Pomares E, Lorés-Motta L, Tonda R, Dopazo J, Marfany G, Gonzàlez-Duarte R. Combined genetic and high-throughput strategies for molecular diagnosis of inherited retinal dystrophies. PLoS One 2014; 9:e88410. [PMID: 24516651 PMCID: PMC3917917 DOI: 10.1371/journal.pone.0088410] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2013] [Accepted: 01/06/2014] [Indexed: 12/30/2022] Open
Abstract
Most diagnostic laboratories are confronted with the increasing demand for molecular diagnosis from patients and families and the ever-increasing genetic heterogeneity of visual disorders. Concerning Retinal Dystrophies (RD), almost 200 causative genes have been reported to date, and most families carry private mutations. We aimed to approach RD genetic diagnosis using all the available genetic information to prioritize candidates for mutational screening, and then restrict the number of cases to be analyzed by massive sequencing. We constructed and optimized a comprehensive cosegregation RD-chip based on SNP genotyping and haplotype analysis. The RD-chip allows to genotype 768 selected SNPs (closely linked to 100 RD causative genes) in a single cost-, time-effective step. Full diagnosis was attained in 17/36 Spanish pedigrees, yielding 12 new and 12 previously reported mutations in 9 RD genes. The most frequently mutated genes were USH2A and CRB1. Notably, RD3–up to now only associated to Leber Congenital Amaurosis– was identified as causative of Retinitis Pigmentosa. The main assets of the RD-chip are: i) the robustness of the genetic information that underscores the most probable candidates, ii) the invaluable clues in cases of shared haplotypes, which are indicative of a common founder effect, and iii) the detection of extended haplotypes over closely mapping genes, which substantiates cosegregation, although the assumptions in which the genetic analysis is based could exceptionally lead astray. The combination of the genetic approach with whole exome sequencing (WES) greatly increases the diagnosis efficiency, and revealed novel mutations in USH2A and GUCY2D. Overall, the RD-chip diagnosis efficiency ranges from 16% in dominant, to 80% in consanguineous recessive pedigrees, with an average of 47%, well within the upper range of massive sequencing approaches, highlighting the validity of this time- and cost-effective approach whilst high-throughput methodologies become amenable for routine diagnosis in medium sized labs.
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Affiliation(s)
- Marta de Castro-Miró
- Departament de Genètica, Facultat de Biologia, Universitat de Barcelona, Barcelona, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Instituto de Salud Carlos III, Barcelona, Spain
- Institut de Biomedicina (IBUB), Universitat de Barcelona, Barcelona, Spain
| | - Esther Pomares
- Departament de Genètica, Facultat de Biologia, Universitat de Barcelona, Barcelona, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Instituto de Salud Carlos III, Barcelona, Spain
| | - Laura Lorés-Motta
- Departament de Genètica, Facultat de Biologia, Universitat de Barcelona, Barcelona, Spain
| | - Raul Tonda
- Centre Nacional d’Anàlisi Genòmica, PCB, Barcelona, Spain
| | - Joaquín Dopazo
- Department of Computational Genomics, Centro de Investigación Príncipe Felipe, Valencia, Spain
- BIER, Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Valencia, Spain
| | - Gemma Marfany
- Departament de Genètica, Facultat de Biologia, Universitat de Barcelona, Barcelona, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Instituto de Salud Carlos III, Barcelona, Spain
- Institut de Biomedicina (IBUB), Universitat de Barcelona, Barcelona, Spain
| | - Roser Gonzàlez-Duarte
- Departament de Genètica, Facultat de Biologia, Universitat de Barcelona, Barcelona, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Instituto de Salud Carlos III, Barcelona, Spain
- Institut de Biomedicina (IBUB), Universitat de Barcelona, Barcelona, Spain
- * E-mail:
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Shukla R, Kannabiran C, Jalali S. Genetics of Leber congenital amaurosis: an update. EXPERT REVIEW OF OPHTHALMOLOGY 2014. [DOI: 10.1586/eop.12.14] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Abu-Safieh L, Alrashed M, Anazi S, Alkuraya H, Khan AO, Al-Owain M, Al-Zahrani J, Al-Abdi L, Hashem M, Al-Tarimi S, Sebai MA, Shamia A, Ray-Zack MD, Nassan M, Al-Hassnan ZN, Rahbeeni Z, Waheeb S, Alkharashi A, Abboud E, Al-Hazzaa SAF, Alkuraya FS. Autozygome-guided exome sequencing in retinal dystrophy patients reveals pathogenetic mutations and novel candidate disease genes. Genome Res 2012; 23:236-47. [PMID: 23105016 PMCID: PMC3561865 DOI: 10.1101/gr.144105.112] [Citation(s) in RCA: 220] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Retinal dystrophy (RD) is a heterogeneous group of hereditary diseases caused by loss of photoreceptor function and contributes significantly to the etiology of blindness globally but especially in the industrialized world. The extreme locus and allelic heterogeneity of these disorders poses a major diagnostic challenge and often impedes the ability to provide a molecular diagnosis that can inform counseling and gene-specific treatment strategies. In a large cohort of nearly 150 RD families, we used genomic approaches in the form of autozygome-guided mutation analysis and exome sequencing to identify the likely causative genetic lesion in the majority of cases. Additionally, our study revealed six novel candidate disease genes (C21orf2, EMC1, KIAA1549, GPR125, ACBD5, and DTHD1), two of which (ACBD5 and DTHD1) were observed in the context of syndromic forms of RD that are described for the first time.
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Affiliation(s)
- Leen Abu-Safieh
- Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh 11211, Saudi Arabia
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Anasagasti A, Irigoyen C, Barandika O, López de Munain A, Ruiz-Ederra J. Current mutation discovery approaches in Retinitis Pigmentosa. Vision Res 2012; 75:117-29. [PMID: 23022136 DOI: 10.1016/j.visres.2012.09.012] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2012] [Revised: 09/08/2012] [Accepted: 09/13/2012] [Indexed: 12/22/2022]
Abstract
With a worldwide prevalence of about 1 in 3500-5000 individuals, Retinitis Pigmentosa (RP) is the most common form of hereditary retinal degeneration. It is an extremely heterogeneous group of genetically determined retinal diseases leading to progressive loss of vision due to impairment of rod and cone photoreceptors. RP can be inherited as an autosomal-recessive, autosomal-dominant, or X-linked trait. Non-Mendelian inheritance patterns such as digenic, maternal (mitochondrial) or compound heterozygosity have also been reported. To date, more than 65 genes have been implicated in syndromic and non-syndromic forms of RP, which account for only about 60% of all RP cases. Due to this high heterogeneity and diversity of inheritance patterns, the molecular diagnosis of syndromic and non-syndromic RP is very challenging, and the heritability of 40% of total RP cases worldwide remains unknown. However new sequencing methodologies, boosted by the human genome project, have contributed to exponential plummeting in sequencing costs, thereby making it feasible to include molecular testing for RP patients in routine clinical practice within the coming years. Here, we summarize the most widely used state-of-the-art technologies currently applied for the molecular diagnosis of RP, and address their strengths and weaknesses for the molecular diagnosis of such a complex genetic disease.
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Affiliation(s)
- Ander Anasagasti
- Division of Neurosciences, Instituto Biodonostia, San Sebastián, Gipuzkoa, Spain
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Rabbani B, Mahdieh N, Hosomichi K, Nakaoka H, Inoue I. Next-generation sequencing: impact of exome sequencing in characterizing Mendelian disorders. J Hum Genet 2012; 57:621-32. [DOI: 10.1038/jhg.2012.91] [Citation(s) in RCA: 151] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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12
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Paterson RL, De Roach JN, McLaren TL, Hewitt AW, Hoffmann L, Lamey TM. Application of a high-throughput genotyping method for loci exclusion in non-consanguineous Australian pedigrees with autosomal recessive retinitis pigmentosa. Mol Vis 2012; 18:2043-52. [PMID: 22876132 PMCID: PMC3413434] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2012] [Accepted: 07/20/2012] [Indexed: 11/03/2022] Open
Abstract
PURPOSE Retinitis pigmentosa (RP) is the most common form of inherited blindness, caused by progressive degeneration of photoreceptor cells in the retina, and affects approximately 1 in 3,000 people. Over the past decade, significant progress has been made in gene therapy for RP and related diseases, making genetic characterization increasingly important. Recently, high-throughput technologies have provided an option for reasonably fast, cost-effective genetic characterization of autosomal recessive RP (arRP). The current study used a single nucleotide polymorphism (SNP) genotyping method to exclude up to 28 possible disease-causing genes in 31 non-consanguineous Australian families affected by arRP. METHODS DNA samples were collected from 59 individuals affected with arRP and 74 unaffected family members from 31 Australian families. Five to six SNPs were genotyped for 28 genes known to cause arRP or the related disease Leber congenital amaurosis (LCA). Cosegregation analyses were used to exclude possible causative genes from each of the 31 families. Bidirectional sequencing was used to identify disease-causing mutations in prioritized genes that were not excluded with cosegregation analyses. RESULTS Two families were excluded from analysis due to identification of false paternity. An average of 28.9% of genes were excluded per family when only one affected individual was available, in contrast to an average of 71.4% or 89.8% of genes when either two, or three or more affected individuals were analyzed, respectively. A statistically significant relationship between the proportion of genes excluded and the number of affected individuals analyzed was identified using a multivariate regression model (p<0.0001). Subsequent DNA sequencing resulted in identification of the likely disease-causing gene as CRB1 in one family (c.2548 G>A) and USH2A in two families (c.2276 G>T). CONCLUSIONS This study has shown that SNP genotyping cosegregation analysis can be successfully used to refine and expedite the genetic characterization of arRP in a non-consanguineous population; however, this method is effective only when DNA samples are available from more than one affected individual.
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Affiliation(s)
- Rachel L. Paterson
- Australian Inherited Retinal Disease Register & DNA Bank, Department of Medical Technology and Physics, Sir Charles Gairdner Hospital, Perth, Western Australia, Australia
| | - John N. De Roach
- Australian Inherited Retinal Disease Register & DNA Bank, Department of Medical Technology and Physics, Sir Charles Gairdner Hospital, Perth, Western Australia, Australia
| | - Terri L. McLaren
- Australian Inherited Retinal Disease Register & DNA Bank, Department of Medical Technology and Physics, Sir Charles Gairdner Hospital, Perth, Western Australia, Australia
| | - Alex W. Hewitt
- Lions Eye Institute, Centre for Ophthalmology and Visual Science, University of Western Australia, Perth, Western Australia, Australia
| | - Ling Hoffmann
- Australian Inherited Retinal Disease Register & DNA Bank, Department of Medical Technology and Physics, Sir Charles Gairdner Hospital, Perth, Western Australia, Australia
| | - Tina M. Lamey
- Australian Inherited Retinal Disease Register & DNA Bank, Department of Medical Technology and Physics, Sir Charles Gairdner Hospital, Perth, Western Australia, Australia
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Maubaret C, Kosmaoglou M, Low S, Chakarova CF, Bidot S, Thauvin-Robinet C, Robson AG, Waseem N, Cheetham ME, Bhattacharya SS. Functional characterization of a novel c.614-622del rhodopsin mutation in a French pedigree with retinitis pigmentosa. Mol Vis 2012; 18:581-7. [PMID: 22419850 PMCID: PMC3298422] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2011] [Accepted: 02/28/2012] [Indexed: 10/28/2022] Open
Abstract
PURPOSE To identify and functionally characterize the mutation responsible for autosomal dominant retinitis pigmentosa (adRP) in a large, six-generation French family. METHODS Twenty individuals from this family participated in the genetic investigation. Six affected and 14 unaffected individuals from three-generations were available for linkage analysis using microsatellite markers flanking the rhodopsin (RHO) gene. A two-point logarithm of odds (LOD) score calculation was undertaken using GENEMARKER and MLINK software. Sanger sequencing of RHO was performed. Cellular localization of the mutant protein was performed by transforming SK-N-SH cells with pEGFP-N1-Rho, pEGFP-N1-Rho(P23H), and pEGFP-N1-Rho(c.614-622del). RESULTS The proband had nyctalopia, visual field constriction, peripheral bone spicule pigmentation of the fundus, central acuity (6/24 RE; 6/12 LE) at 55 years of age. Linkage analysis of this family suggested RHO as a possible candidate since the flanking marker D3S1292 yielded a LOD score of 2.43 at θ=0. Cloning of an exon 3 PCR product and direct sequencing of single clones identified a novel deletion in the third exon of RHO, c.614-622del (p.Y206-F208del). The deleted mutant protein localized to the endoplasmic reticulum and formed inclusion bodies. CONCLUSIONS This novel deletion in exon 3 of the RHO gene, c.614-622del results in a classical form of adRP in a multi-generation French family. Protein expression analyses confirmed that the deletion led to protein misfolding and suggest this is a class II mutation, similar to P23H, the most common class II mutation seen in North America.
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Affiliation(s)
| | | | - Sancy Low
- UCL Institute of Ophthalmology, London, United Kingdom,Moorfields Eye Hospital, London, United Kingdom
| | | | | | | | - Anthony G. Robson
- UCL Institute of Ophthalmology, London, United Kingdom,Moorfields Eye Hospital, London, United Kingdom
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High-throughput approaches for the genetic diagnosis of retinal dystrophies. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2012; 723:329-35. [PMID: 22183350 DOI: 10.1007/978-1-4614-0631-0_43] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
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Yang HC, Lin HC, Kang M, Chen CH, Lin CW, Li LH, Wu JY, Chen YT, Pan WH. SAQC: SNP array quality control. BMC Bioinformatics 2011; 12:100. [PMID: 21501472 PMCID: PMC3101186 DOI: 10.1186/1471-2105-12-100] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2010] [Accepted: 04/18/2011] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Genome-wide single-nucleotide polymorphism (SNP) arrays containing hundreds of thousands of SNPs from the human genome have proven useful for studying important human genome questions. Data quality of SNP arrays plays a key role in the accuracy and precision of downstream data analyses. However, good indices for assessing data quality of SNP arrays have not yet been developed. RESULTS We developed new quality indices to measure the quality of SNP arrays and/or DNA samples and investigated their statistical properties. The indices quantify a departure of estimated individual-level allele frequencies (AFs) from expected frequencies via standardized distances. The proposed quality indices followed lognormal distributions in several large genomic studies that we empirically evaluated. AF reference data and quality index reference data for different SNP array platforms were established based on samples from various reference populations. Furthermore, a confidence interval method based on the underlying empirical distributions of quality indices was developed to identify poor-quality SNP arrays and/or DNA samples. Analyses of authentic biological data and simulated data show that this new method is sensitive and specific for the detection of poor-quality SNP arrays and/or DNA samples. CONCLUSIONS This study introduces new quality indices, establishes references for AFs and quality indices, and develops a detection method for poor-quality SNP arrays and/or DNA samples. We have developed a new computer program that utilizes these methods called SNP Array Quality Control (SAQC). SAQC software is written in R and R-GUI and was developed as a user-friendly tool for the visualization and evaluation of data quality of genome-wide SNP arrays. The program is available online (http://www.stat.sinica.edu.tw/hsinchou/genetics/quality/SAQC.htm).
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Affiliation(s)
- Hsin-Chou Yang
- Institute of Statistical Science, Academia Sinica, Taipei, Taiwan.
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Khan MI, Collin RW, Arimadyo K, Micheal S, Azam M, Qureshi N, Faradz SM, den Hollander AI, Qamar R, Cremers FP. Missense mutations at homologous positions in the fourth and fifth laminin A G-like domains of eyes shut homolog cause autosomal recessive retinitis pigmentosa. Mol Vis 2010; 16:2753-9. [PMID: 21179430 PMCID: PMC3003713] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2010] [Accepted: 12/09/2010] [Indexed: 11/03/2022] Open
Abstract
PURPOSE To describe two novel mutations in the eyes shut homolog (EYS) gene in two families with autosomal recessive retinitis pigmentosa (arRP) from Pakistan and Indonesia. METHODS Genome-wide linkage and homozygosity mapping were performed using single nucleotide polymorphism microarray analysis in affected members of the two arRP families. Sequence analysis was performed to identify genetic changes in protein coding exons of EYS. RESULTS In the Indonesian and Pakistani families, homozygous regions encompassing the EYS gene at 6q12 were identified, with maximum LOD scores of 1.8 and 3.6, respectively. Novel missense variants in the EYS gene (p.D2767Y and p.D3028Y) were found in the Pakistani and Indonesian families, respectively, that co-segregate with the disease phenotype. Interestingly, the missense variants are located at the same homologous position within the fourth and fifth laminin A G-like domains of EYS. CONCLUSIONS To date, mostly protein-truncating mutations have been described in EYS, while only few patients have been described with pathogenic compound heterozygous missense mutations. The mutations p.D2767Y and p.D3028Y described in this study affect highly conserved residues at homologous positions in laminin A G-like domains and support the notion that missense mutations in EYS can cause arRP.
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Affiliation(s)
- Muhammad Imran Khan
- Department of Biosciences, COMSATS Institute of Information Technology, Islamabad, Pakistan,Department of Human Genetics, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Rob W.J. Collin
- Department of Human Genetics, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands,Department of Ophthalmology, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands,Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Kentar Arimadyo
- Department of Human Genetics, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands,Division of Human Genetics, Center for Biomedical Research,
Faculty of Medicine, Diponegoro University, Semarang, Indonesia
| | - Shazia Micheal
- Department of Biosciences, COMSATS Institute of Information Technology, Islamabad, Pakistan
| | - Maleeha Azam
- Department of Biosciences, COMSATS Institute of Information Technology, Islamabad, Pakistan
| | - Nadeem Qureshi
- Vitreoretina Services, Al-Shifa Trust Eye Hospital, Rawalpindi, Pakistan
| | - Sultana M.H. Faradz
- Division of Human Genetics, Center for Biomedical Research,
Faculty of Medicine, Diponegoro University, Semarang, Indonesia
| | - Anneke I. den Hollander
- Department of Human Genetics, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands,Department of Ophthalmology, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands,Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Raheel Qamar
- Department of Biosciences, COMSATS Institute of Information Technology, Islamabad, Pakistan,Shifa College of Medicine, Islamabad, Pakistan
| | - Frans P.M. Cremers
- Department of Biosciences, COMSATS Institute of Information Technology, Islamabad, Pakistan,Department of Human Genetics, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands,Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
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Wang Z, Liu Y, Liu J, Liu K, Wen J, Wen S, Wu Z. HSG/Mfn2 gene polymorphism and essential hypertension: a case-control association study in Chinese. J Atheroscler Thromb 2010; 18:24-31. [PMID: 20940517 DOI: 10.5551/jat.5611] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
AIM Hyperplasia suppressor gene/mitofusion-2 (HSG/Mfn2) is a hyperplasia suppressor gene and an essential component of mitochondrial fusion machinery; however, the association between the single nucleotide polymorphism (SNP) of HSG/Mfn2 and hypertension is unclear. METHODS In this study, 542 normotensive subjects (NT group) and 539 hypertensive patients (EH group) were screened for an association study between HSG/Mfn2 and hypertension. RESULTS The results showed that the genotype distribution and allelic frequency of rs873457, rs2336384, rs1474868, rs4846085 and rs2236055 were significantly different (p lt; 0.05 for all) between EH and NT groups, although those of rs4240897 and rs873458 were not. When comparing the dominant model, significant differences still existed (p lt; 0.05 for all). The allelic frequency of rs4240897 was also slightly different between EH and NT groups (P = 0.047). When subgrouped by sex, the genotype distribution and allelic frequency of all the SNPs (except rs873458) were significantly different in male (p lt; 0.05 for all) but not in female groups. For all the SNPs, only the allelic frequency of rs4240897 was obviously different in female NT and EH groups (p lt; 0.01). Logistic regression showed that body mass index and rs873457 were closely associated with BP after adjusting for age. The frequency of the C-G-A-A-A-C-C haplotype was significantly higher in essential hypertensive patients versus control individuals, both in the entire population, in male or female groups (p lt; 0.01 for all). As for other haplotypes, most were only significantly different in the entire population and male subjects. CONCLUSION The genetic variations of HSG/Mfn2 may be associated with hypertension in male Chinese.
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Affiliation(s)
- Zuoguang Wang
- Department of Hypertension, Beijing Anzhen Hospital, Attached to Capital University of Medical Sciences, Beijing Institute of Heart, Lung, Blood Vessel Diseases, Chaoyang District, Beijing, PR China.
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Ayuso C, Millan JM. Retinitis pigmentosa and allied conditions today: a paradigm of translational research. Genome Med 2010; 2:34. [PMID: 20519033 PMCID: PMC2887078 DOI: 10.1186/gm155] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Monogenic human retinal dystrophies are a group of disorders characterized by progressive loss of photoreceptor cells leading to visual handicap. Retinitis pigmentosa is a type of retinal dystrophy where degeneration of rod photoreceptors occurs at the early stages. At present, there are no available effective therapies to maintain or improve vision in patients affected with retinitis pigmentosa, but post-genomic studies are allowing the development of potential therapeutic approaches. This review summarizes current knowledge on genes that have been identified to be responsible for retinitis pigmentosa, the involvement of these genes in the different forms of the disorder, the role of the proteins encoded by these genes in retinal function, the utility of genotyping, and current efforts to develop novel therapies.
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Affiliation(s)
- Carmen Ayuso
- Department of Medical Genetics, IIS-Fundación Jiménez Díaz/CIBERER, Av/Reyes Católicos no, 2; 28040, Madrid, Spain.
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Permanyer J, Navarro R, Friedman J, Pomares E, Castro-Navarro J, Marfany G, Swaroop A, Gonzàlez-Duarte R. Autosomal recessive retinitis pigmentosa with early macular affectation caused by premature truncation in PROM1. Invest Ophthalmol Vis Sci 2009; 51:2656-63. [PMID: 20042663 DOI: 10.1167/iovs.09-4857] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE To identify the genetic basis of a large consanguineous Spanish pedigree affected with autosomal recessive retinitis pigmentosa (arRP) with premature macular atrophy and myopia. METHODS After a high-throughput cosegregation gene chip was used to exclude all known RP and Leber congenital amaurosis (LCA) candidates, genome-wide screening and linkage analysis were performed. Direct mutational screening identified the pathogenic mutation, and primers were designed to obtain the RT-PCR products for isoform characterization. RESULTS Mutational analysis detected a novel homozygous PROM1 mutation, c.869delG in exon 8 cosegregating with the disease. This variant causes a frameshift that introduces a premature stop codon, producing truncation of approximately two-thirds of the protein. Analysis of PROM1 expression in the lymphocytes of patients, carriers, and control subjects revealed an aberrant transcript that is degraded by the nonsense-mediated decay pathway, suggesting that the disease is caused by the absence of the PROM1 protein. Three (s2, s11 and s12) of the seven alternatively spliced isoforms reported in humans, accounted for 98% of the transcripts in the retina. Given that these three contained exon 8, no PROM1 isoform is expected in the affected retinas. CONCLUSIONS A remarkable clinical finding in the affected family is early macular atrophy with concentric spared areas. The authors propose that the hallmark of PROM1 truncating mutations is early and severe progressive degeneration of both rods and cones and highlight this gene as a candidate of choice to prioritize in the molecular genetic study of patients with noncanonical clinical peripheral and macular affectation.
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Affiliation(s)
- Jon Permanyer
- Departament de Genètica, Facultat de Biologia, Universitat de Barcelona, Barcelona, Spain
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