Duplication of SOX3 in an SRY-negative 46,XX male with prostatic utricle: case report and literature review

Abstract

Background: 46,XX male disorders of sex development are rare. Approximately 80% of cases of testicular tissue differentiation may be due to translocation of SRY to the X chromosome or an autosome. SRY-negative 46,XX males show overexpression of pro-testis genes, such as SOX9 and SOX3, or failure of pro-ovarian genes, such as WNT4 and RSPO1, which induces testis differentiation, however, almost all testicles exhibit dysgenesis. Following inadequate exposure to androgens during the embryo stage, remnants of the Mullerian duct and incomplete closure of the urogenital sinus lead to enlargement of prostatic utricles. This condition is associated with proximal hypospadias and disorders of sex development. Many cases are asymptomatic, but show increased rates of postoperative complications and surgical failure. Case presentation: A 5-year-old Chinese boy with scrotal hypospadias and bilateral cryptorchidism with prostatic utricles was presented. Gonadal histology showed ovo-testicular tissue on the right side and testicular tissue on the left side; all testicular tissue exhibited dysgenesis. Furthermore, chromosome karyotype analysis revealed 46,XX and, the presence of SRY was ruled out by polymerase chain reaction analysis. Whole-genome analysis showed the boy has a 1.4-Mb duplication in the Xq27.1q27.2 region (arr[hg19]Xq27.1q27.2:139585794–140996652) involving SOX3. No SOX3 duplication was observed in the parents, who had a normal phenotype. Conclusions: We report the first case of an SRY-negative 46 XX male with prostatic utricle caused by SOX3 duplication. SOX3 duplication may cause sex reversal, and all 46,XX SRY-negative males should be screened for SOX3 mutations. Gonadal biopsy is recommended to evaluate ovarian and testicular tissue development. Testicular dysgenesis and low exposure to male hormones during fetal development can lead to enlarged prostatic utricles. Thus endoscopic examination should be performed preoperatively to detect prostatic utricles in SRY-negative 46,XX males to determine the surgical plan and reduce postoperative complications.