Case Report
Copyright ©The Author(s) 2021. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Clin Cases. Aug 16, 2021; 9(23): 6789-6797
Published online Aug 16, 2021. doi: 10.12998/wjcc.v9.i23.6789
2+0 CYP21A2 deletion carrier — a limitation of the genetic testing and counseling: A case report
Na Xi, Xiao Song, Xue-Yan Wang, Sheng-Fang Qin, Guan-Nan He, Ling-Ling Sun, Xi-Min Chen
Na Xi, Xiao Song, Xue-Yan Wang, Sheng-Fang Qin, Ling-Ling Sun, Xi-Min Chen, Department of Medical Genetics and Prenatal Diagnosis, Sichuan Provincial Hospital for Women and Children, Chengdu 610045, Sichuan Province, China
Guan-Nan He, Department of Ultrasound, Sichuan Provincial Hospital for Women and Children, Chengdu 610045, Sichuan Province, China
Author contributions: Xi N is responsible for the study conception and design, definition of intellectual content, literature research, clinical studies, data acquisition and analysis, statistical analysis, manuscript preparation and editing; Song X and He GN are responsible for the clinical studies, data acquisition; Wang XY is responsible for the integrity of the entire study, study conception and design, definition of intellectual content, clinical studies, data acquisition and manuscript review; Qin SF and Chen XM are responsible for the experimental studies; Sun LL is responsible for the clinical studies; all authors read and approved the final manuscript.
Supported by the Fundamental Research Funds of Health Commission of Sichuan Province, No. 17ZD035.
Informed consent statement: Informed consent was obtained.
Conflict-of-interest statement: There are no potential conflicts of interest to disclose.
CARE Checklist (2016) statement: The article was revised according to the journal guide.
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/
Corresponding author: Xue-Yan Wang, MD, Department of Medical Genetics and Prenatal Diagnosis, Sichuan Provincial Hospital for Women and Children, No. 290 Shayanxi Er Street, Wuhou District, Chengdu 610045, Sichuan Province, China. wang_xueyan20@21cn.com
Received: January 7, 2021
Peer-review started: January 7, 2021
First decision: February 12, 2021
Revised: March 4, 2021
Accepted: June 28, 2021
Article in press: June 28, 2021
Published online: August 16, 2021
Abstract
BACKGROUND

CYP21A2 gene mutations may all cause reduction or loss of 21-hydroxylase activity, leading to development of congenital adrenal hyperplasia (CAH) with different clinical phenotypes. For families with CAH children, genetic testing of the parents and genetic counseling are recommended to assess the risk of recurrence.

CASE SUMMARY

We report a case of CAH with a high suspicion before delivery. The risk of the child suffering from CAH during the pregnancy had been underestimated due to the deviation of genetic counseling and genetic testing results. Our report confirmed a CYP21A2 homozygous deletion in this case, CYP21A2 heterozygous deletion in the mother, and a rare 2+0 CYP21A2 deletion in the father.

CONCLUSION

It is important to analyze the distribution of CYP21A2 gene in the two alleles of parents of children with CAH.

Keywords: CYP21A2 gene mutations, Congenital adrenal hyperplasia, Pregnancy, Genetic counseling, Genetic testing, Pathogenic point mutations, Alleles

Core Tip: This study suggests that carriers of type 2+0 are likely to be a trap in genetic testing and genetic counseling.