OMIA:001230-9796 : Ovotesticular DSD (Disorder of Sexual Development) in Equus caballus

In other species: Japanese medaka , dog , domestic cat , pig , Western roe deer , cattle , rabbit , wood lemming

Categories: Reproductive system phene

Possibly relevant human trait(s) and/or gene(s)s (MIM numbers): 400044 (trait) , 300018 (trait) , 612965 (trait) , 154230 (trait) , 613080 (trait) , 613762 (trait) , 233420 (trait) , 614279 (trait) , 480000 (gene)

Links to MONDO diseases: No links.

Mendelian trait/disorder: yes

Mode of inheritance: Y-linked

Considered a defect: yes

Key variant known: yes

Year key variant first reported: 1995

Cross-species summary: Previously known as Sex reversal: XY female, SRY-negative. The present name (ovotesticular DSD) corresponds to the recommendations on nomenclature for disorders of sexual development (DSD) proposed by Lee et al. (Pediatrics 2006;118;e488; DOI: 10.1542/peds.2006-0738).

Markers: Ghosh et al. (2020) "characterized a homozygous ~200 kb deletion in ECA29 as a risk factor for equine DSDs and reproductive disorders. These conclusions were based on the following notions: i) the deletion eliminates functionally relevant AKR1C genes, which have been associated with DSDs in humans; ii) the frequency of the deletion was higher in abnormal horses (8–9%) compared to normal population (1–5%), and iii) the majority (79%) of horses with the homozygous deletion were phenotypically abnormal. Even though denoted as a risk factor because of difficulties to establish statistically sound causative genotype–phenotype relationship, the findings add to the currently very short list of genomic regions underlying equine disorders of sex development and reproduction". Given the obvious and well-informed caution of the authors, this variant has not been tabulated as a likely causal variant.

Molecular basis: By cloning and sequencing a very likely comparative candidate gene (based on the homologous disorder in other species), Pailhoux et al. (1995) showed that "at least the DNA-binding domain of the SRY gene was deleted from the Y chromosome of the XY mare".

Raudsepp et al. (2010) reported molecular heterogeneity in 13 cases of Y-linked XY sex reversal, all of which included deletion of the SRY gene: "the smallest deletions spanned about 21 kb, while the largest involved the entire euchromatic region".

Associated gene:

Symbol Description Species Chr Location OMIA gene details page Other Links
SRY sex determining region Y Equus caballus - no genomic information (-..-) SRY Homologene, Ensembl , NCBI gene


By default, variants are sorted chronologically by year of publication, to provide a historical perspective. Readers can re-sort on any column by clicking on the column header. Click it again to sort in a descending order. To create a multiple-field sort, hold down Shift while clicking on the second, third etc relevant column headers.

WARNING! Inclusion of a variant in this table does not automatically mean that it should be used for DNA testing. Anyone contemplating the use of any of these variants for DNA testing should examine critically the relevant evidence (especially in breeds other than the breed in which the variant was first described). If it is decided to proceed, the location and orientation of the variant sequence should be checked very carefully.

Since October 2021, OMIA includes a semiautomated lift-over pipeline to facilitate updates of genomic positions to a recent reference genome position. These changes to genomic positions are not always reflected in the ‘acknowledgements’ or ‘verbal description’ fields in this table.

OMIA Variant ID Breed(s) Variant Phenotype Gene Allele Type of Variant Source of Genetic Variant Reference Sequence Chr. g. or m. c. or n. p. Verbal Description EVA ID Inferred EVA rsID Year Published PubMed ID(s) Acknowledgements
659 American Trotter (Horse) Ovotesticular DSD (Disorder of Sexual Development) SRY deletion, gross (>20) Naturally occurring variant Y "at least the DNA-binding domain of the SRY gene was deleted from the Y chromosome of the XY mare" 1995 7558880


Note: the references are listed in reverse chronological order (from the most recent year to the earliest year), and alphabetically by first author within a year.

2022 Castaneda, C., Radović, L., Felkel, S., Juras, R., Davis, B.W., Cothran, E.G., Wallner, B., Raudsepp, T. :
Copy number variation of horse Y chromosome genes in normal equine populations and in horses with abnormal sex development and subfertility: relationship of copy number variations with Y haplogroups. G3 (Bethesda) 12:jkac278, 2022. Pubmed reference: 36227030 . DOI: 10.1093/g3journal/jkac278.
2021 Pirosanto, Y., Laseca, N., Valera, M., Molina, A., Moreno-Millán, M., Bugno-Poniewierska, M., Ross, P., Azor, P., Demyda-Peyrás, S. :
Screening and detection of chromosomal copy number alterations in the domestic horse using SNP-array genotyping data. Anim Genet 52:431-439, 2021. Pubmed reference: 34013628 . DOI: 10.1111/age.13077.
2020 Ghosh, S., Davis, B.W., Rosengren, M., Jevit, M.J., Castaneda, C., Arnold, C., Jaxheimer, J., Love, C.C., Varner, D.D., Lindgren, G., Wade, C.M., Raudsepp, T. :
Characterization of A Homozygous Deletion of Steroid Hormone Biosynthesis Genes in Horse Chromosome 29 as A Risk Factor for Disorders of Sex Development and Reproduction. Genes (Basel) 11:, 2020. Pubmed reference: 32120906 . DOI: 10.3390/genes11030251.
2018 Neuhauser, S., Handler, J., Schelling, C., Pieńkowska-Schelling, A., Neuhauser, S., Handler, J., Schelling, C., Pieńkowska-Schelling, A. :
Disorder of Sexual Development in a Mare with an Unusual Tentative Mosaic Karyotype: 63,X/64,Xdel(Y). Sex Dev :, 2018. Pubmed reference: 30071527 . DOI: 10.1159/000490861.
2012 Pujar, S., Meyers-Wallen, V. :
Sequence variations in equine candidate genes for XX and XY inherited disorders of sexual development. Reprod Domest Anim 47:827-834, 2012. Pubmed reference: 22239239 . DOI: 10.1111/j.1439-0531.2011.01976.x.
2010 Raudsepp, T., Durkin, K., Lear, T.L., Das, P.J., Avila, F., Kachroo, P., Chowdhary, B.P. :
Molecular heterogeneity of XY sex reversal in horses. Anim Genet 41 Suppl 2:41-52, 2010. Pubmed reference: 21070275 . DOI: 10.1111/j.1365-2052.2010.02101.x.
2003 Bugno, M., Klukowska, J., Slota, E., Tischner, M., Switonski, M. :
A sporadic case of the sex-reversed mare (64,XY; SRY-negative): molecular and cytogenetic studies of the Y chromosome Theriogenology 59:1597-603, 2003. Pubmed reference: 12559464 .
2001 Cadario, M.E. :
Case notes and commentary: XY sex reversal in mares: testicular feminization or gonadal/ovarian dysgenesis? Compendium on Continuing Education for the Practicing Veterinarian 23:753-+, 2001.
1999 Abe, S., Miyake, Y.I., Kageyama, S.I., Watanabe, G., Taya, K., Kawakura, K. :
Deletion of the Sry region on the Y chromosome detected in a case of equine gonadal hypoplasia (XY female) with abnormal hormonal profiles Equine Veterinary Journal 31:336-338, 1999. Pubmed reference: 10454094 .
Makinen, A., Hasegawa, T., Makila, M., Katila, T. :
Infertility in two mares with XY and XXX sex chromosomes Equine Veterinary Journal 31:346-349, 1999. Pubmed reference: 10454097 .
1995 Pailhoux, E., Cribiu, E.P., Parma, P., Cotinot, C. :
Molecular analysis of an XY mare with gonadal dysgenesis Hereditas 122:109-112, 1995. Pubmed reference: 7558880 .
1993 Nie, G.J., Momont, H.W., Buoen, L. :
A Survey of Sex Chromosome Abnormalities in 204 Mares Selected for Breeding Journal of Equine Veterinary Science 13:456-459, 1993.
1988 Kent, M.G., Shoffner, R.N., Hunter, A., Elliston, K.O., Schroder, W., Tolley, E., Wachtel, S.S. :
XY sex reversal syndrome in the mare: clinical and behavioral studies, H-Y phenotype Human Genetics 79:321-328, 1988. Pubmed reference: 3410457 .
Kent, M.G., Elliston, K.O., Schroeder, W., Guise, K.S., Wachtel, S.S. :
Conserved repetitive DNA sequences (Bkm) in normal equine males and sex-reversed females detected by in situ hybridization Cytogenetics and Cell Genetics 48:99-102, 1988. Pubmed reference: 3197456 .
1987 Bowling, A.T., Millon, L., Hughes, J.P. :
An update of chromosomal abnormalities in mares Journal of Reproduction and Fertility :149-155, 1987. Pubmed reference: 3479571 .
1986 Kent, M.G., Shoffner, R.N., Bouen, L., Weber, A.F. :
XY sex-reversal syndrome in the domestic horse Cytogenetics and Cell Genetics 42:8-18, 1986. Pubmed reference: 3720361 .
Power, M.M. :
XY sex reversal in a mare. Equine Vet J 18:233-6, 1986. Pubmed reference: 3732247 .

Edit History

  • Created by Frank Nicholas on 12 Sep 2005
  • Changed by Frank Nicholas on 11 Sep 2011
  • Changed by Frank Nicholas on 08 Oct 2011
  • Changed by Frank Nicholas on 09 Dec 2011
  • Changed by Frank Nicholas on 31 Aug 2012
  • Changed by Frank Nicholas on 31 Dec 2015
  • Changed by Frank Nicholas on 05 Mar 2020