Summary
XY gonadal agenesis, or testicular regression syndrome (TRS) is a very rare disease encompassing a spectrum of genital anomalies resulting from regression of testis development between 8 and 14 weeks of gestation. The phenotype of patients varies depending on the timing and extent the fetal testicular regression and ranges from a female to anorchic male phenotype among patients with a 46,XY karyotype. If fetal testicular regression occurs between 8-10 weeks of gestation, patients may have female external genitalia with or without ambiguity, associated with lack of gonads, hypoplastic uterus and rudimentary genital ducts. Regression of the testes after 12-14 weeks results in phenotypic males with anorchia or streak gonads (rudimentary testes). Intermediary phenotypes occur with sexual ambiguity (masculin pseudohermaphrodism) associated with variable degrees of genital duct, urogenital sinus, and external genitalia differentiation anomalies. Patients have either absent or streak gonads. The cause of TRS is unknown. The report of kindreds with parental consanguinity and several affected individuals suggests a genetic disorder with an autosomal recessive inheritance. Mutations in one or several autosomal genes involved in gonadal development upstream of the sex-determining region Y gene (SRY) are suspected. *Author: Orphanet (February 2005)*.
