Disorder of sexual development in a Yorkshire terrier (78, XY; SRY-positive)

Polymorphisms of MAMLD1, SRD5A2, and AR Candidate Genes in Seven Dogs (78,XY; SRY-Positive) Affected by Hypospadias or Cryptorchidism

Knowledge of the molecular background of disorders of sex development (DSD) in dogs with normal sets of XY chromosomes (XY DSD) is very scarce. However, extensive studies have been carried out in humans, showing that polymorphisms and mutations of numerous genes, including SRY, MAMLD1, SRD5A2, and AR, are associated with or responsible for XY DSD. In this study, we analyzed the entire coding sequence of these genes in 7 dogs (78,XY) with ambiguous external genitalia (hypospadias, cryptorchidism, bifid scrotum, or rudimentary penis). The most common disorder was hypospadias (6 cases), followed by cryptorchidism (4 cases). The co-occurrence of both abnormalities was observed in 3 dogs. Polymorphisms were found in MAMLD1 (3 SNPs), SRD5A2 (5 SNPs), and AR (2 STRs and 1 SNP), while SRY was monomorphic. However, the distribution of the polymorphic variants in the DSD dogs and 11 control XY dogs did not differ significantly. Our study suggests that an association between the polymorphisms of the studied candidate genes and hypospadias or cryptorchidism is unlikely in dogs. We thus support the recent suggestion that hypospadias is not rare in this species, and moreover, we show that co-occurrence of hypospadias and cryptorchidism can be quite frequent.

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

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.