尿道下裂是一种最常见的泌尿生殖系统先天性复杂畸形，遗传度约为57–77%。但通过人群队列的GWAS分析仅解释了约9.5%的遗传方差，对尿道下裂的遗传基础还不清楚。申请人过去通过基因组测序发现影响蛋白功能的大效应稀有突变可以用于衡量出生缺陷的遗传风险，且会通过网络互作影响疾病发生。据此本项目假设：稀有突变可能可以解释尿道下裂中GWAS分析所导致的遗传度缺失，同时稀有突变可能会通过网络调控影响尿道下裂的发生。基于以上科学假设，本项目拟通过对家系和散发病例进行全外显组测序技术挖掘尿道下裂中的稀有致病突变，用于解释GWAS分析在尿道下裂中所导致的遗传度缺失。同时该申请将通过RNA-seq界定突变导致尿道下裂中基因的差异表达，并基于网络互作评估多遗传位点可能导致的尿道下裂风险，从基因变异和遗传突变导致的网络调控失衡两个层面研究外生殖器发育异常导致尿道下裂的分子遗传机制，完善尿道下裂发生的理论基础。

Hypospadias is among the most common congenital diseases in the male reproductive system. The current literatures demonstrated that a variety of genes and pathways are known to contribute the etiology of hypospadias, and the heritability of hypospadias is around 57–77%. However, the genome-wide association studies (GWAS) by hypospadias cohort only explained about 9.5% of the genetic variance, and the genetic etiology of hypospadias is still unclear. Our previous studies also demonstrated that the genetic basis for human birth defect risk can be measured by vary rare damaging variants, which affect the risk of disease via protein-protein interactions (PPIs). This project proposes that rare mutations may explain the “missing heritability” caused by GWAS analysis in hypospadias, and that these rare mutations may affect hypospadias through PPIs. Based on the above scientific hypothesis, this study intends to explore rare pathogenic mutations in hypospadias by performing whole exome sequencing (WES) using trios and sporadic cases to explain the heritability of GWAS analysis in the hypospadias. We will also evaluate the differential expression of genes caused by mutations in hypospadias using RNA-seq, and evaluate the risk of hypospadias caused by combined genetic variants and network regulation. This project investigates the molecular genetic mechanism of hypospadias caused by rare functional variants and network regulation in the development of external genitalia. This study will complement the theoretical basis for molecular genetic mechanism and regulation mechanism of early diagnosis of hypospadias.