Copy number variation in patients with disorders of sex development due to 46,XY gonadal dysgenesis.

Stefan J White ,Thomas Ohnesorg,Erin Turbitt,Peter Koopman,Lavinia Gordon,Henrik Bengtsson,Jocelyn Van Den Bergen,Hinda Daggag,Jacqueline Hewitt,Éric Vilain ,Kelly N Roeszler ,Katrina M Bell ,Valerie A Arboleda ,Valérie Schumacher ,Patrick S Western ,Garry L Warne ,Vincent R Harley ,Sonja E Gustin ,Amanda J Notini ,John M Hutson ,Terence P Speed ,Craig A Smith ,Denise C Miles ,Andrew H Sinclair

doi:10.1371/journal.pone.0017793

Abstract

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.

Highlights

A defining point during embryogenesis is the commitment to develop as male or female
All patients with a diagnosis of XY complete gonadal dysgenesis met the clinical criteria for this diagnosis, including female external genitalia associated with a 46, XY karyotype, the presence of Mullerian structures suggesting the lack of functional testicular tissue, and high levels of gonadotropins suggesting a primary gonadal failure caused by gonadal dysgenesis
A relatively stringent threshold of 10 consecutive probes was set before a Copy number variation (CNV) was considered genuine

Summary

Introduction

A defining point during embryogenesis is the commitment to develop as male or female. Ovarian development occurs in the absence of the Y-linked SRY gene, and results in a female phenotype. These developmental pathways involve complex networks of genes, the precise regulation of which is vital for the correct development of the gonads and associated anatomical structures [1]. Disruption of these networks can lead to disorders of sex development (DSD), which are congenital conditions with atypical development of the chromosomal, gonadal or anatomical sex [2]. The focus here is on individuals with 46,XY DSD due to gonadal dysgenesis (hereafter referred to as 46,XY GD)

Methods

Results

Conclusion