Jiang Y, Tang S, He F, Yuan JX, Zhang Z. New mechanism of partial duplication and deletion of chromosome 8: A case report. World J Clin Cases 2021; 9(24): 7139-7145 [PMID: 34540970 DOI: 10.12998/wjcc.v9.i24.7139]
This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
World J Clin Cases. Aug 26, 2021; 9(24): 7139-7145 Published online Aug 26, 2021. doi: 10.12998/wjcc.v9.i24.7139
New mechanism of partial duplication and deletion of chromosome 8: A case report
Yan Jiang, Shuang Tang, Fang He, Jue-Xin Yuan, Zhu Zhang
Yan Jiang, Shuang Tang, Jue-Xin Yuan, Office of Prenatal Diagnosis, Mianyang People’s Hospital, Mianyang 621000, Sichuan Province, China
Fang He, Department of Obstetrics, Mianyang People’s Hospital, Mianyang 621000, Sichuan Province, China
Zhu Zhang, Office of Prenatal Diagnosis, West China Second University Hospital, Sichuan University, Chengdu 610000, Sichuan Province, China
Author contributions: Jiang Y and He F reviewed the literature and contributed to manuscript drafting; Yuan JX performed the G-banding chromosome analyses and contributed to manuscript drafting; Tang S performed the genetic counseling and contributed to manuscript drafting; Zhang Z performed the chromosome microarray analysis and contributed to manuscript drafting; Jiang Y and Tang S were responsible for revision of the manuscript for important intellectual content; all authors issued final approval for the version to be submitted.
Informed consent statement: The patient provided informed written consent prior to study enrollment.
Conflict-of-interest statement: The authors declare that they have no conflict of interest.
CARE Checklist (2016) statement: The authors have read the CARE Checklist (2016), and the manuscript was prepared and revised according to the CARE Checklist (2016).
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/Licenses/by-nc/4.0/
Received: February 21, 2021 Peer-review started: February 21, 2021 First decision: May 6, 2021 Revised: May 23, 2021 Accepted: June 7, 2021 Article in press: June 7, 2021 Published online: August 26, 2021
Abstract
BACKGROUND
During meiosis, the recombination of homologous chromosomes produces some new heritable mutations, which are the basis of biological evolution and diversity. However, when there is pericentric inversion of chromosomes, unbalanced gametes will be formed in the process of germ cell meiosis.
CASE SUMMARY
A 23-year-old pregnant woman at 25 wk of gestation wanted to terminate her pregnancy due to fetal chromosomal abnormalities. She had no exposure to toxic or hazardous substances before and during pregnancy, no history of medication usage during pregnancy, and she underwent cystectomy of ovarian cysts in 2017. On the second day of the 16th week of gestation, non-invasive prenatal testing showed chromosome 8 copy number variation. Following genetic counseling, her pregnancy was terminated.
CONCLUSION
Recombinant offspring chromosome is rarely seen when the inversion segment is shorter than one-third of the chromosome length. In terms of the mechanism of chromosome 8 duplication/deletion occurrence, attention should be paid to the production of unbalanced gametes by the pairing of homologous chromosome during meiosis, and the possibility of mitotic recombination exchange as well.
Core Tip: The mechanism of partial deletion/duplication at the end of chromosome 8 involves two prevailing theories: Parental chromosome 8 inversion producing unbalanced gametes, and a recombination hot spot of chromosome 8p. Although the recombination hot spot of chromosome 8q occurring during mitosis is rarely reported, it was confirmed in the present case. Non-invasive prenatal testing (NIPT) for copy number variation has been used, but 40% or less mosaic abnormalities cannot be detected by NIPT. When chromosome 8 partial deletion/duplication occurs, in addition to the unbalanced gamete production caused by parental chromosome 8 inversion, attention should be paid to the mechanism of spontaneous recombination in meiosis or mitosis.
