Copy Number Variation in Patients with Disorders of Sex Development Due to 46,XY Gonadal Dysgenesis

Disorders of sex development (DSD), ranging in severity from mild genital abnormalities to complete sex reversal, represent a major concern for patients and their families. DSD are often due to disruption of the genetic programs that regulate gonad development. Although some genes have been identified in these developmental pathways, the causative mutations have not been identified in more than 50% 46,XY DSD cases. We used the Affymetrix Genome-Wide Human SNP Array 6.0 to analyse copy number variation in 23 individuals with unexplained 46,XY DSD due to gonadal dysgenesis (GD). Here we describe three discrete changes in copy number that are the likely cause of the GD. Firstly, we identified a large duplication on the X chromosome that included DAX1 (NR0B1). Secondly, we identified a rearrangement that appears to affect a novel gonad-specific regulatory region in a known testis gene, SOX9. Surprisingly this patient lacked any signs of campomelic dysplasia, suggesting that the deletion affected expression of SOX9 only in the gonad. Functional analysis of potential SRY binding sites within this deleted region identified five putative enhancers, suggesting that sequences additional to the known SRY-binding TES enhancer influence human testis-specific SOX9 expression. Thirdly, we identified a small deletion immediately downstream of GATA4, supporting a role for GATA4 in gonad development in humans. These CNV analyses give new insights into the pathways involved in human gonad development and dysfunction, and suggest that rearrangements of non-coding sequences disturbing gene regulation may account for significant proportion of DSD cases.性发育异常（Disorders of sex development, DSD）的严重程度跨度较大，从轻度生殖器异常直至完全性反转，一直是患者及其家属面临的重大健康关切。DSD多由调控性腺发育的遗传程序紊乱所引发。尽管目前已在这类发育通路中鉴定出部分基因，但超过50%的46,XY型DSD病例仍未明确致病突变。本研究采用Affymetrix全基因组人类SNP芯片6.0（Affymetrix Genome-Wide Human SNP Array 6.0），对23例因性腺发育不全（gonadal dysgenesis, GD）导致不明原因46,XY型DSD的个体开展拷贝数变异（Copy Number Variation, CNV）分析。本研究鉴定出3处可能为GD致病诱因的离散性拷贝数改变：其一，我们在X染色体上发现了一处包含DAX1（NR0B1）的大片段重复；其二，我们鉴定出一处染色体重排，其似乎会影响已知睾丸基因SOX9内一个全新的性腺特异性调控区域。令人意外的是，该患者未表现出任何弯曲骨发育不良的临床症状，提示此次缺失仅干扰了SOX9在性腺中的表达。对该缺失区域内潜在的性别决定区Y（Sex-determining Region Y, SRY）结合位点的功能分析，共鉴定出5个推定增强子，这表明除已知的SRY结合TES增强子外，还存在其他序列可调控人类睾丸特异性SOX9的表达；其三，我们在GATA4基因紧邻下游区域发现了一处小片段缺失，这佐证了GATA4在人类性腺发育中发挥的调控作用。本次拷贝数变异分析为人类性腺发育及功能异常相关通路提供了全新的研究视角，并提示非编码序列的重排干扰基因调控，可能在相当比例的DSD病例中参与致病。