Familial 46,XY sex reversal without campomelic dysplasia caused by a deletion upstream of the SOX9 gene

Abstract

Background: 46,XY sex reversal is a rare disorder and familial cases are even more rare. The purpose of the present study was to determine the molecular basis for a family with three affected siblings who had 46,XY sex reversal.

Methods: DNA was extracted from three females with 46,XY sex reversal, two normal sisters, and both unaffected parents. All protein coding exons of the SRY and NR5A1 genes were subjected to PCR-based DNA sequencing. In addition, array comparative genomic hybridization was performed on DNA from all seven family members. A deletion was confirmed using quantitative polymerase chain reaction. Expression of SOX9 gene was quantified using reverse transcriptase polymerase chain reaction.

Results: A 349kb heterozygous deletion located 353kb upstream of the SOX9 gene on the long arm of chromosome 17 was discovered in the father and three affected siblings, but not in the mother. The expression of SOX9 was significantly decreased in the affected siblings. Two of three affected sisters had gonadoblastomas.

Conclusion: This is the first report of 46,XY sex reversal in three siblings who have a paternally inherited deletion upstream of SOX9 associated with reduced SOX9 mRNA expression.

Keywords: Gonadal dysgenesis; NR5A1; SOX9; SRY; XY sex reversal.