Peer-reviewed veterinary case report
An XY agonadal Oldenburg warmblood horse exhibiting a male phenotype.
- Journal:
- Sexual development : genetics, molecular biology, evolution, endocrinology, embryology, and pathology of sex determination and differentiation
- Year:
- 2010
- Authors:
- Kuiper, H et al.
- Affiliation:
- Institute for Animal Breeding and Genetics · Germany
- Species:
- horse
Plain-English summary
In a 1.5-year-old Oldenburg horse, veterinarians found a structure resembling a clitoris instead of a penis, and they couldn't get the penis to come out even under anesthesia. The horse had been dripping urine continuously and showed signs of mild belly pain starting two weeks after birth. Tests showed very low testosterone levels, which are typical for geldings, and the horse didn't respond to a hormone treatment meant to stimulate testosterone production. There were no signs of female reproductive organs, but some abnormalities in the horse's internal structures might explain the belly pain. This case is notable because it describes a horse with male chromosomes but with a mixed appearance of male and female traits.
Abstract
In a 1.5-year-old Oldenburg horse, a clitoris-like structure instead of a penis was identified in the prepuce. The external genital organs did not show any abnormalities at visual inspection except that exteriorization of the penis was not possible, not even under general anesthesia. The horse's owner observed a continuous dripping of urine and a tendency to mild colics beginning 2 weeks after birth. Testosterone concentration was 0.01 ng/ml and therefore under the threshold for geldings, and the horse did not respond to the application of gonadotropin-releasing hormone (GnRH). The inner genital consisted of a male urinary tract. Gonads and accessory male glands were missing. Residual structures of a female genital tract were not observed. Abnormalities of the mesentery could be found which might explain the recurrent colics of this horse. A cytogenetic examination revealed a 2n = 64,XY-karyotype and a positive result for the SRY-PCR. This is the first report on an agonadal horse with a male karyotype and a pseudohermaphrodite phenotype.
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Search related cases →Original publication: https://pubmed.ncbi.nlm.nih.gov/20980788/