Peer-reviewed veterinary case report
Cat with female look has male chromosomes and enlarged clitoris
By Yoshimura, Aritada et al.·Published in The Journal of veterinary medical science·2026·Tokyo University of Agriculture and Technology, Japan·View original on PubMed →
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Original publication title: 37,X/38,XY mosaicism in a cat with a female phenotype and an enlarged clitoris.
- Species:
- cat
Plain-English summary
A 10-month-old mixed-breed cat was brought to the vet because she had an enlarged clitoris and unusual genitalia. Upon examination, the vet found that her ovaries were replaced by underdeveloped testes, and she had a unique chromosomal makeup that is rarely seen in cats. This condition, known as 37,X/38,XY mosaicism, is typically associated with male characteristics, but in this case, it presented with a female appearance. The cat's unusual anatomy was confirmed through surgery and genetic testing, making this a very rare case.
People also search for: cat enlarged clitoris · cat genitalia problems · mixed-breed cat unusual anatomy · cat genetic conditions
Abstract
A 10-month-old mixed-breed cat was presenting a female appearance; however, a detailed examination of external genitalia revealed an enlarged clitoris with spines. The urethra opened into the vagina. Laparotomy and subsequent histopathological examination revealed that both ovaries were replaced by hypoplastic testes, with underdeveloped uteruses located caudal to them. Chromosome and genetic testing using peripheral blood revealed that the cat displayed a nearly 1:1 mosaicism of the 37,X and 38,XY chromosomes and presence of the SRY gene. Only two cases of 37,X/38,XY mosaicism have been reported in cats, both displaying a normal penis and prepuce, indicating a male phenotype. To the best of our knowledge, this is the first report of 37,X and 38,XY mosaicism manifesting as a female phenotype.
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Search related cases →Original publication on PubMed: https://pubmed.ncbi.nlm.nih.gov/41339016/