Novel mutation leading to splice donor loss in a conserved site of DMD gene causes Duchenne muscular dystrophy with cryptorchidism

Jianhai Chen; Yangying Jia; Jie Zhong; Kun Zhang; Hongzheng Dai; Guanglin He; Fuping Li; Li Zeng; Chuanzhu Fan; Huayan Xu

doi:10.1136/jmg-2024-109896

Novel mutation leading to splice donor loss in a conserved site of DMD gene causes Duchenne muscular dystrophy with cryptorchidism

J Med Genet. 2024 May 10:jmg-2024-109896. doi: 10.1136/jmg-2024-109896. Online ahead of print.

Authors

Jianhai Chen^{1

2}, Yangying Jia^{1

3}, Jie Zhong⁴, Kun Zhang⁵, Hongzheng Dai⁶, Guanglin He⁴, Fuping Li⁷, Li Zeng⁸, Chuanzhu Fan⁹, Huayan Xu¹⁰

Affiliations

¹ Institutes for Systems Genetics, Frontiers Science Center for Disease-related Molecular Network, West China Hospital, Sichuan University, Chengdu, Sichuan, People's Republic of China.
² Department of Ecology and Evolution, The University of Chicago, Chicago, Illinois, USA.
³ Department of Chemistry, The University of Chicago, Chicago, Illinois, USA.
⁴ Institute of Rare Diseases, West China Hospital, Sichuan University, Chengdu, Sichuan, People's Republic of China.
⁵ Department of Radiology, Key Laboratory of Birth Defects and Related Diseases of Women and Children of Ministry of Education, West China Second University Hospital, Sichuan University, Chengdu, Sichuan, China.
⁶ Department of Human and Molecular Genetics, Baylor College of Medicine, Houston, Texas, USA.
⁷ Laboratory of Molecular Translational Medicine, Center for Translational Medicine, Key Laboratory of Birth Defects and Related Diseases of Women and Children (Sichuan University), Ministry of Education, Clinical Research Center for Birth Defects of Sichuan Province, West China Second University Hospital, Sichuan University, Chengdu, Sichuan, China.
⁸ Department of Pediatric Surgery, West China Hospital, Sichuan University, Chengdu, Sichuan, China.
⁹ Department of Biological Sciences, Wayne State University, Detroit, Michigan, USA.
¹⁰ Department of Radiology, Key Laboratory of Birth Defects and Related Diseases of Women and Children of Ministry of Education, West China Second University Hospital, Sichuan University, Chengdu, Sichuan, China xuhuayan89@sina.com.

PMID: 38621993
DOI: 10.1136/jmg-2024-109896

Abstract

Background: As one of the most common congenital abnormalities in male births, cryptorchidism has been found to have a polygenic aetiology according to previous studies of common variants. However, little is known about genetic predisposition of rare variants for cryptorchidism, since rare variants have larger effective size on diseases than common variants.

Methods: In this study, a cohort of 115 Chinese probands with cryptorchidism was analysed using whole-genome sequencing, alongside 19 parental controls and 2136 unaffected men. Additionally, CRISPR-Cas9 editing of a conserved variant was performed in a mouse model, with MRI screening used to observe the phenotype.

Results: In 30 of 115 patients (26.1%), we identified four novel genes (ARSH, DMD, MAGEA4 and SHROOM2) affecting at least five unrelated patients and four known genes (USP9Y, UBA1, BCORL1 and KDM6A) with the candidate rare pathogenic variants affecting at least two cases. Burden tests of rare variants revealed the genome-wide significances for newly identified genes (p<2.5×10^-6) under the Bonferroni correction. Surprisingly, novel and known genes were mainly found on X chromosome (seven on X and one on Y) and all rare X-chromosomal segregating variants exhibited a maternal inheritance rather than de novo origin. CRISPR-Cas9 mouse modelling of a splice donor loss variant in DMD (NC_000023.11:g.32454661C>G), which resides in a conserved site across vertebrates, replicated bilateral cryptorchidism phenotypes, confirmed by MRI at 4 and 10 weeks. The movement tests further revealed symptoms of Duchenne muscular dystrophy (DMD) in transgenic mice.

Conclusion: Our results revealed the role of the DMD gene mutation in causing cryptorchidism. The results also suggest that maternal-X inheritance of pathogenic defects could have a predominant role in the development of cryptorchidism.

Keywords: Child Health; Genetic Diseases, X-Linked; Genetics, Medical; Genomics; Reproductive Health.