Duplication of SOX9 is not a common cause of 46,XX testicular or 46,XX ovotesticular DSD

Background: Translocation of the SRY gene to the paternal X chromosome is the explanation for testis development in the majority of subjects with 46,XX testicular disorder of sexual development (DSD). However, nearly all subjects with 46,XX ovotesticular DSD and up to one third of subjects with 46,XX testicular DSD lack SRY. SRY-independent expression of SOX9 has been implicated in the etiology of testis development in some individuals. Methods: We amplified microsatellite markers in the region of SOX9 from a cohort of 30 subjects with either 46,XX testicular or 46,XX ovotesticular DSD to detect SOX9 duplications. Results: Duplication of the SOX9 region in 17q was not detected in any subject. Conclusion: Duplication in the region of 17q that contains SOX9 is not a common cause of testis development in subjects with SRY-negative 46,XX testicular or ovotesticular DSD.