A duplication upstream of SOX9 was not positively correlated with the SRY-negative 46,XX testicular disorder of sex development: A case report and literature review

The 46,XX male disorder of sex development (DSD) is rarely observed in humans. Patients with DSD are all male with testicular tissue differentiation. The mechanism of sex determination and differentiation remains to be elucidated. In the present case report, an 46,XX inv (9) infertile male negative for the sex-determining region of the Y chromosome (SRY) gene was examined. This infertile male was systemically assessed by semen analysis, serum hormone testing and gonadal biopsy. Formalin-fixed and paraffin-embedded gonad tissues were assessed histochemically. The SRY gene was analyzed by fluorescence in situ hybridization (FISH) and polymerase chain reaction (PCR). The other 23 specific loci, including the azoospermia factor region on the Y chromosome and the sequence-targeted sites of the SRY-box 9 (SOX9) gene were analyzed by PCR. The genes RSPO1, DAX1, SOX3, ROCK, DMRT1, SPRY2 and FGF9 were also assessed using sequencing analysis. Affymetrix Cytogenetics Whole Genome 2.7 M Arrays were used for detecting the genomic DNA from the patient and the parents. The patient with the 46,XX inv (9) (p11q13) karyotype exhibited male primary, however, not secondary sexual characteristics. However, the patient's mother with the 46, XX inv (9) karyotype was unaffected. The testicular tissue dysplasia of the patient was confirmed by tissue biopsy and absence of the SRY gene, and the other 23 loci on the Y chromosome were confirmed by FISH and/or PCR. The RSPO1, DAX1, SOX3, ROCK, DMRT1, SPRY2 and FGF9 genes were sequenced and no mutations were detected. A duplication on the 3 M site in the upstream region of SOX9 was identified in the patient as well as in the mother. The patient with the 46,XX testicular DSD and SRY-negative status was found to be infertile. The duplication on the 3 M site in the upstream region of SOX9 was a polymorphism, which indicated that the change was not a cause of 46,XX male SDS. These clinical, molecular and cytogenetic findings suggested that other unidentified genetic or environmental factors are significant in the regulation of SDS.