Androgen insensitivity syndrome in a thoroughbred mare (64, XY–testicular feminization).

The research paper recounts a case of a Thoroughbred mare exhibiting unusual stallion-like behaviour, which was diagnosed as androgen insensitivity syndrome (64, XY–testicular feminization), and successfully treated through surgical removal of abdominal testicles.

Introduction and Presentation of the Case

• A Thoroughbred mare was brought to the attention of veterinarians due to its exhibition of typically male, or stallion-like, behaviours. This formed the basic premise for further investigation.

Diagnostic Procedure

• For a more comprehensive understanding of the situation, the mare underwent several examinations. These evaluations included a reproductive and ultrasonographic examination, testosterone assays, and karyotyping.
• The assessments provided substantial confirmation that the mare was suffering from androgen insensitivity syndrome (AIS), also known as 64, XY–testicular feminization. This is a rare condition in which a genetic male is resistant to male hormones (androgens), causing them to exhibit female physical traits.
• In this particular case, the karyotyping results were instrumental in the diagnosis. Karyotyping showed 64, XY chromosomal pattern typical to a male, despite the mare’s physical appearance being female.

Treatment and Outcome

• The mare underwent a surgical procedure to remove the abdominal testicles, the presence of which was a result of the AIS. These testicles were located internally, unlike typical external stallion testicles.
• Post-surgery, a marked change was observed in the mare’s behavior, which successfully returned to normal female behavior. This confirmed that the surgical intervention to remove the internal testicles effectively treated the mare’s behavioral abnormality.

Discussion

• The researchers discussed this particular case in the light of existing scientific literature on androgen insensitivity syndrome. The relevance and implications of this case contribute to the broader understanding of such rare conditions in equine veterinary medicine.