A Case of Ambiguous External Genitalia in a Thoroughbred Male Horse with the 63,XO/64,XY Mosaic Karyotype

Fumio SATO; Keiichi HIROTA; Teruaki TOZAKI; Katsumi ITO; Pramod DHAKAL; Kazuyoshi TAYA; Yoshiro ENDO; Harutaka MURASE; Yasuo NAMBO

doi:10.1292/jvms.11-0473

Theriogenology

A Case of Ambiguous External Genitalia in a Thoroughbred Male Horse with the 63,XO/64,XY Mosaic Karyotype

Fumio SATO, Keiichi HIROTA, Teruaki TOZAKI, Katsumi ITO, Pramod DHAKAL, Kazuyoshi TAYA, Yoshiro ENDO, Harutaka MURASE, Yasuo NAMBO

Author information

Fumio SATO
Hidaka Training and Research Center, Japan Racing Association, 535–13 Nishicha, Urakawa, Hokkaido 057–0171, Japan
Department of Clinical Veterinary Science, United Graduate School of Veterinary Sciences, Gifu University, 1–1 Yanagido, Gifu 501–1193, Japan
Keiichi HIROTA
Department of Molecular Genetics, Laboratory of Racing Chemistry, 1731–2 Tsurutamachi, Utsunomiya, Tochigi 320–0851, Japan
Teruaki TOZAKI
Department of Molecular Genetics, Laboratory of Racing Chemistry, 1731–2 Tsurutamachi, Utsunomiya, Tochigi 320–0851, Japan
Katsumi ITO
Hidaka Horse Breeders Association, 14 Nobuka, Urakawa, Hokkaido 059–3454, Japan
Pramod DHAKAL
Department of Clinical Veterinary Science, United Graduate School of Veterinary Sciences, Gifu University, 1–1 Yanagido, Gifu 501–1193, Japan
Kazuyoshi TAYA
Laboratory of Veterinary Physiology, Department of Veterinary Medicine, Faculty of Agriculture, Tokyo University of Agriculture and Technology, Fuchu, Tokyo 183–8509, Japan
Department of Basic Veterinary Science, United Graduate School of Veterinary Sciences, Gifu University, 1–1 Yanagido, Gifu 501–1193, Japan
Yoshiro ENDO
Hidaka Training and Research Center, Japan Racing Association, 535–13 Nishicha, Urakawa, Hokkaido 057–0171, Japan
Harutaka MURASE
Hidaka Training and Research Center, Japan Racing Association, 535–13 Nishicha, Urakawa, Hokkaido 057–0171, Japan
Yasuo NAMBO
Hidaka Training and Research Center, Japan Racing Association, 535–13 Nishicha, Urakawa, Hokkaido 057–0171, Japan
Department of Clinical Veterinary Science, United Graduate School of Veterinary Sciences, Gifu University, 1–1 Yanagido, Gifu 501–1193, Japan

Keywords: ambiguous genitalia, horse, mosaic karyotype

JOURNAL FREE ACCESS

2012 Volume 74 Issue 10 Pages 1327-1331

DOI https://doi.org/10.1292/jvms.11-0473

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Abstract

A Thoroughbred colt with ambiguous external genitalia was presented for clinical and histological examinations. The colt had a short penis that faced backward between his hind limbs. The measurements of luteinizing hormone, follicle stimulating hormone, testosterone and ir-inhibin showed a tendency to increase gradually from April. Both the sex-determining region of the Y chromosome and amelogenin gene fragments were detected by the PCR method. A cytogenetic analysis revealed the 63,XO/64,XY mosaic karyotype (ratio 83:17). In autopsy, immature symmetrical subcutaneous testes were found in the inguinal regions. The testes and other accessory sex organs were histologically normal. These results add to our knowledge of chromosomal abnormality and information concerning disorders of sex development in the horse.

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