OMIA:002175-9796 : Curly coat with hypotrichosis in Equus caballus (horse)

Categories: Integument (skin) phene

Possibly relevant human trait(s) and/or gene(s) (MIM number): 608613 (gene)

Links to MONDO diseases: No links.

Mendelian trait/disorder: no

Considered a defect: yes

Key variant known: yes

Year key variant first reported: 2018

Inheritance: Thomer et al. (2018) reported that genotypes at two genes, KRT25 and SP6, each with two alleles, could explain all combinations of curly +/- and hypotrichosis +/-: "Horses heterozygous or homozygous only for KRT25 variant [see below] showed curly coat and hypotrichosis, whereas horses with SP6 variant [see below] only, exhibited curly coat without hypotrichosis. Horses with mutant alleles in both variants developed curly hair and hypotrichosis. Thus, mutant KRT25 allele is masking SP6 allele effect, indicative for epistasis of KRT25 variant over SP6 variant."

Molecular basis: Thomer et al. (2018) identified two likely causal variants: g.21891160G>A; p.R89H in the KRT25 gene, and g. 24022045C>T; p.G364S in the SP6 gene. An independent discovery of the KRT25 variant in relation to Curly coat (see OMIA 000245-9796) was published while the MS by Thomer et al. was undergoing peer review. As explained in the Inheritance section, Tomer et al. (2018) "demonstrated an epistatic effect of KRT25 variant on SP6 variant due to its pleiotropy on hair structure and hair loss."

Genetic engineering: Unknown
Have human generated variants been created, e.g. through genetic engineering and gene editing

Breeds: Bashkir Curly (Horse) (VBO_0000913), Missouri Fox Trotter, Germany (Horse) (VBO_0011358).
Breeds in which the phene has been documented. For breeds in which a likely causal variant has been documented, see the variant table below

Associated gene:

Symbol Description Species Chr Location OMIA gene details page Other Links
SP6 Sp6 transcription factor Equus caballus 11 NC_009154.3 (24099790..24093883) SP6 Homologene, Ensembl , NCBI gene


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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
1040 Bashkir Curly (Horse) Missouri Fox Trotter, Germany (Horse) Curly coat with/without hypotrichosis SP6 missense Naturally occurring variant EquCab3.0 11 g.24096309C>T c.1090G>A p.(D364N) Thomer et al. (2018): "SP6; NC_009154.2:g.24022045C>T, ss3021042887" with respect to EquCab2. Updated coordinates in this entry obtained from EVA rs1095048852; 14 Mar 2019 rs1095048852 rs1095048852 2018 29686323

Cite this entry

Nicholas, F. W., Tammen, I., & Sydney Informatics Hub. (2019). OMIA:002175-9796: Online Mendelian Inheritance in Animals (OMIA) [dataset].


2018 Thomer, A., Gottschalk, M., Christmann, A., Naccache, F., Jung, K., Hewicker-Trautwein, M., Distl, O., Metzger, J. :
An epistatic effect of KRT25 on SP6 is involved in curly coat in horses. Sci Rep 8:6374, 2018. Pubmed reference: 29686323. DOI: 10.1038/s41598-018-24865-3.

Edit History

  • Created by Frank Nicholas on 14 Mar 2019
  • Changed by Frank Nicholas on 14 Mar 2019