Peer-reviewed veterinary case report
Sex reversal syndrome (64,XY; SRY-positive) in a mare demonstrating masculine behaviour.
- Journal:
- Journal of animal breeding and genetics = Zeitschrift fur Tierzuchtung und Zuchtungsbiologie
- Year:
- 2005
- Authors:
- Switonski, M et al.
- Affiliation:
- Department of Genetics and Animal Breeding
- Species:
- horse
Plain-English summary
A 5-year-old Thoroughbred mare was found to have infertility issues and showed behaviors typically associated with male horses. Tests on her chromosomes revealed that she had a male genetic makeup (64,XY), and further analysis showed she had high levels of testosterone, a hormone usually found in males. The genetic testing did not show any differences in the SRY gene, which is important for male characteristics, when compared to normal male horses. It seems that this mare may have a condition known as androgen insensitivity syndrome, which affects how her body responds to male hormones.
Abstract
A 5-year-old Thoroughbred mare was subjected to cytogenetic and molecular analysis because of infertility and masculine behaviour. Chromosome studies, including painting with the whole X chromosome specific probe, revealed a male chromosome complement (64,XY). The PCR amplification of the SRY and ZFY genes showed the presence of both those genes, while the endocrinological study demonstrated a high level of testosterone (9.7 nmol/l). Sequencing of the SRY gene (1121 bp), comprising also 5'- and 3'-UTRs, did not reveal any differences when compared with the sequence of normal stallions. It was proposed that this mare represents the androgen insensitivity syndrome (testicular feminization syndrome).
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Search related cases →Original publication: https://pubmed.ncbi.nlm.nih.gov/16130458/