title: Equine disorders of sexual development in 17 mares including XX, SRY-negative, XY, SRY-negative and XY, SRY-positive genotypes.
abstract: We described the clinical, cytogenetic and molecular findings of 17 clinical equine cases presented for abnormal sexual development and infertility. Six horses with an enlarged clitoris had an XX, SRY-negative genotype, which displayed male-like behavior (adult individuals). Bilateral ovotestes were noted in 2 of those cases, while another case showed increased levels of circulating testosterone. Six horses with a female phenotype, including normal external genitalia, had an XY, SRY-negative genotype. These individuals had small gonads and an underdeveloped internal reproductive tract. Four horses with normal appearing external genitalia had an XY, SRY-positive genotype, 3 of them had hypoplastic testes and male-like behavior. In addition, one young filly with enlarged clitoris and hypoplastic testes had the same genotype but did not show male-like behavior due to her age. Three of these horses were related with 2 being siblings. These findings demonstrate the diversity of disorders of sexual development seen in the horse. Furthermore, they emphasize the need for further research to identify genes involved in abnormal sex determination and differentiation in the horse.
authors.affiliation: Department of Biomedical Sciences, University of Guelph, Guelph, Ontario, Canada. dvilla@cucba.udg.mx
authors.forename: D A F
authors.initials: DA
authors.lastname: Villagómez
authors.forename: T L
authors.initials: TL
authors.lastname: Lear
authors.forename: T
authors.initials: T
authors.lastname: Chenier
authors.forename: S
authors.initials: S
authors.lastname: Lee
authors.forename: R B
authors.initials: RB
authors.lastname: McGee
authors.forename: J
authors.initials: J
authors.lastname: Cahill
authors.forename: R A
authors.initials: RA
authors.lastname: Foster
authors.forename: E
authors.initials: E
authors.lastname: Reyes
authors.forename: E
authors.initials: E
authors.lastname: St John
authors.forename: W A
authors.initials: WA
authors.lastname: King
mesh_terms: D000818:Animals; D002871:Chromosome Banding; D012734:Disorders of Sex Development / Q000235:genetics / Q000473:pathology / Q000662:veterinary*; D005260:Female; D017353:Gene Deletion; D024282:Genes, sry; D005835:Genitalia / Q000002:abnormalities; D006734:Horse Diseases / Q000235:genetics* / Q000473:pathology; D006736:Horses / Q000235:genetics; D017404:In Situ Hybridization, Fluorescence; D008297:Male; D010641:Phenotype; D019849:Sex Determination Processes / Q000235:genetics; D012733:Sex Differentiation / Q000235:genetics