Peer-reviewed veterinary case report
A case of equine cryptorchidism with undetectable serum anti-Müllerian hormone.
- Journal:
- The Journal of veterinary medical science
- Year:
- 2020
- Authors:
- Murase, Harutaka et al.
- Affiliation:
- Equine Science Division · Japan
- Species:
- horse
Plain-English summary
A 4-year-old uncastrated Thoroughbred racehorse was found to have no visible testicles, which led to a diagnosis of bilateral cryptorchidism (a condition where the testicles do not descend). However, tests showed that the horse had undetectable levels of a hormone called anti-Müllerian hormone (AMH), which is usually present in horses with this condition. Further testing indicated that the horse was actually a gelding, meaning it had been castrated, but genetic analysis confirmed it was a genetically-intact stallion. The presence of only one small, degenerated testis in the abdomen and the low levels of certain cells may explain the unusual hormone levels. Ultimately, this case highlights a rare situation where a stallion shows no detectable AMH.
Abstract
Serum anti-Müllerian hormone (AMH), a marker of equine cryptorchidism, is detectable in intact and cryptorchid stallions but not in geldings because it is secreted from Sertoli cells. A 4-year-old uncastrated Thoroughbred racehorse had no visible testes; therefore, the horse was considered a bilateral cryptorchidism. However, the serum AMH was undetectable (<0.08 ng/ml). Human chorionic gonadotrophin (hCG) stimulating test result indicated that the horse was a gelding. The results of sex chromosomal analysis and sequence analysis of SRY gene suggested that the horse was a genetically-intact stallion (X/Y). Only one small degenerative testis was present in the abdominal cavity. The reasons of undetectable serum AMH levels and negative response to hCG stimulation might be low numbers of Sertoli and Leydig cells. This study reports a case of serum AMH-undetectable cryptorchid stallion.
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Search related cases →Original publication: https://pubmed.ncbi.nlm.nih.gov/31875577/