Novel mutation leading to splice donor loss in a conserved site ofDMDcauses cryptorchidism

Abstract

BackgroundAs one of the most common congenital abnormalities in male births, cryptorchidism has been found to have a polygenic etiology 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.MethodsIn this study, a cohort of 115 Chinese probands with cryptorchidism was analyzed using whole-genome sequencing (WGS), 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 utilized to observe the phenotype.ResultsIn 30 of 115 patients (26.1%), we identified four novel genes (ARSH,DMD,MAGEA4, andSHROOM2) affecting at least five unrelated patients and four known genes (USP9Y,UBA1,BCORL1, andKDM6A) 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 from X chromosome (seven on X and one on Y) and all rare X-chromosomal segregating variants exhibited a maternal inheritance rather thande novoorigin. CRISPR-Cas9 mouse modeling of a splice donor loss variant inDMD(NC_000023.11:g.32454661C>G), which resides in a conserved site across vertebrates, replicated bilateral cryptorchidism phenotypes, confirmed by Magnetic resonance imaging (MRI) at 4 and 10 weeks.ConclusionOur results revealed the role of theDMDgene 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.