A comprehensive study of disorder of sex development in Staffordshire bull terrier dog

Abstract

An 8‐month‐old female Staffordshire bull terrier was clinically examined because of external sexual organs abnormality—clitoral hypertrophy. As stated by the owner, the female dog had not been in heat yet. Serum profile of testosterone (3.39 ng/ml), as well as an anti‐Műllerian hormone (24.0 ng/ml), suggested the presence of testicular tissue. On the contrary, the estimated level of 17β‐oestradiol (24.6 pg/ml) was approximately two times higher when compared with the normal anoestrus values (5–10 pg/ml). A midline laparotomy was performed to detect the cranial parts of the genital system. Gonads resembling testicle or ovotestis (left) and hypoplastic testicle (right) was visible. Cranial portion of gonads was attached to structures indicative of bilateral epididymidis. The next tubular structures—oviducts were resected along with adherent parts of a hypoplastic uterus. Histological evaluation confirmed that the examined gonad samples were testicles with modified interstitial testicular tissue. Hypertrophy of interstitial space was predominantly formed by Leydig cells. Examination of a cross‐section through the head of suspected epididymidis confirmed their characteristic structures. In addition, the characteristic configuration of the oviducts was presented. The uterus consisted of three walls, in which the endometrium was hypoplastic with the presence of endometrial glands. No Y chromosome was detected by chromosomal analysis using CFA Y probe and the amplification of SRY‐gene coding region (813 bp) indicated genotype 78, XX; SRY‐negative. Sequencing of SOX9 gene exons 1–3 did not reveal any differences in exon 1 and 3. On the contrary, a few changes were determined in the SOX9 exon 2 sequences: G instead of A at position 103; C instead of reference T at position 115; GCG instead of reference CGC at position 138–140; T instead of reference C at positions 161, 164 and 167.