Disorder of sexual development in a Cocker spaniel dog: Sry-negative XX sex reversal

Abstract

A 3-year-old Cocker spaniel was presented for evaluation because of a mass protruding from the vulva. This mass confirmed the presence of an internal bone in clitoris on the radiography. We recommended to the owner of the surgical removal of the gonads and uterus as well as the excision of the enlarged clitoris and os clitoris. The dog had gonads in the region of where the ovaries were located and presented what appeared to be a bicornate uterus and ductus deferens. Histological analysis revealed a morphologically normal uterus and two testes with their epididymis and ductus deferens. Karyotyping revealed a normal female chromosome constitution (78, XX), and polymerase chain reaction (PCR) identified the absence of Sry. Based on these findings, the patient was diagnosed with Sry-negative XX sex reversal.