OMIA 000621-9796 : Malignant hyperthermia in Equus caballus

In other species: domestic cat , cattle , dog , pig , rabbit , deer , turkey

Possibly relevant human trait(s) and/or gene(s) (MIM number): 145600 (trait)

Mendelian trait/disorder: yes

Mode of inheritance: Autosomal Dominant

Considered a defect: yes

Key variant known: yes

Year key variant first reported: 2004

Cross-species summary: A progressive increase in body temperature, muscle rigidity and metabolic acidosis, leading to rapid death.

Inheritance: As noted by Aleman et al. (2004), the fact that the two affected animals with which they dealt were heterozygous suggests autosomal dominant inheritance. However, a pedigree analysis has still to be conducted.

Molecular basis: By cloning and sequencing a very likely comparative candidate gene (based on the homologous disorder in other species, especially pigs and humans), Aleman et al. (2004) characterised the molecular basis of this disorder in two affected horses: a base substitution (C7360G) in exon 46 of the RyR1 gene results in an amino-acid substitution (R2454G). This codon is also mutated in two of the five exon-46 RyR1 mutations in humans.

Breed: Quarter Horse.

Associated gene:

Symbol Description Species Chr Location OMIA gene details page Other Links
RYR1 ryanodine receptor 1 (skeletal) Equus caballus 10 NC_009153.3 (9633620..9739087) RYR1 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.

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
American Quarter Horse Malignant hyperthermia RYR1 missense Naturally occurring variant 10 c.7360C>G p.(R2454G) 2004 15318347


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.
2009 Aleman, M., Nieto, JE., Magdesian, KG. :
Malignant hyperthermia associated with ryanodine receptor 1 (C7360G) mutation in Quarter Horses. J Vet Intern Med 23:329-34, 2009. Pubmed reference: 19220734. DOI: 10.1111/j.1939-1676.2009.0274.x.
McCue, ME., Valberg, SJ., Jackson, M., Borgia, L., Lucio, M., Mickelson, JR. :
Polysaccharide storage myopathy phenotype in quarter horse-related breeds is modified by the presence of an RYR1 mutation. Neuromuscul Disord 19:37-43, 2009. Pubmed reference: 19056269. DOI: 10.1016/j.nmd.2008.10.001.
Nieto, JE., Aleman, M. :
A Rapid Detection Method for the Ryanodine Receptor 1 (C7360G) Mutation in Quarter Horses. J Vet Intern Med :, 2009. Pubmed reference: 19298609. DOI: 10.1111/j.1939-1676.2009.0281.x.
2005 Aleman, M., Brosnan, RJ., Williams, DC., LeCouteur, RA., Imai, A., Tharp, BR., Steffey, EP. :
Malignant hyperthermia in a horse anesthetized with halothane. J Vet Intern Med 19:363-6, 2005. Pubmed reference: 15954554.
2004 Aleman, M., Riehl, J., Aldridge, BM., LeCouteur, RA., Stott, JL., Pessah, IN. :
Association of a mutation in the ryanodine receptor 1 gene with equine malignant hyperthermia. Muscle Nerve 30:356-65, 2004. Pubmed reference: 15318347. DOI: 10.1002/mus.20084.
1992 Chowdhary, B.P., Harbitz, I., Davies, W., Gustavsson, I. :
Localization of the Calcium Release Channel Gene in Cattle and Horse by In situ Hybridization - Evidence of a Conserved Synteny with Glucose Phosphate Isomerase Animal Genetics 23:43-50, 1992. Pubmed reference: 1315127.

Edit History

  • Created by Frank Nicholas on 10 Sep 2005
  • Changed by Frank Nicholas on 11 Sep 2011
  • Changed by Frank Nicholas on 09 Dec 2011
  • Changed by Frank Nicholas on 17 Oct 2012