OMIA:002095-9615 : Epilepsy, generalized myoclonic, with photosensitivity in Canis lupus familiaris (dog)

Categories: Behaviour / neurological phene

Links to possible relevant human trait(s) and/or gene(s) in OMIM: 607862 (gene)

Mendelian trait/disorder: yes

Mode of inheritance: Autosomal recessive

Considered a defect: yes

Key variant known: yes

Year key variant first reported: 2017

Molecular basis: Wielaender et al. (2017): "a 4-bp deletion in the exon 2 of the DIRAS1 gene (c.564_567delAGAC . . . CanFam3 . . . , resulting in a frameshift and a stop loss. . . . The genotyping of the DIRAS1 deletion in 14 clinically verified RR cases and 26 controls revealed a homozygous mutant genotype in all cases, a heterozygous genotype in the obligate carriers, and the homozygous wild-type genotype in controls."

Clinical features: Affected Rhodesian Ridgeback (RR) dogs present with frequent myoclonic twitches that tend to begin between the age of 6 weeks and 18 months old. These episodes can be triggered by visual stimuli including flashing lights, sudden light exposure or flickering light (Wielaender et al., 2017). Generally, episodes begin when animals are recumbent and relaxed, but occasionally occur when dogs are standing (Wielaender et al., 2017). Twitches are mainly seen in the musculature of the trunk and proximal limb, as well as in cervical musculature and masticatory muscles (Wielaender et al., 2017). In 38% of dogs, the disease advanced to generalised tonic-clonic seizures within 6 months (Wielaender et al., 2017). No changes in behaviour have been noted prior to seizure episodes (Wielaender et al., 2017). Wielaender et al., 2018: "Absence seizures represent another seizure type in juvenile myoclonic epilepsy (JME) in RR dogs." IT thanks DVM student Emily Gee, who provided the basis of this contribution in May 2023.

Breed: Rhodesian Ridgeback (Dog) (VBO_0201135).
Breeds in which the phene has been documented. (If a likely causal variant has been documented for the phene, see the variant table breeds in which the variant has been reported).

Associated gene:

Symbol Description Species Chr Location OMIA gene details page Other Links
DIRAS1 DIRAS family, GTP-binding RAS-like 1 Canis lupus familiaris 20 NC_051824.1 (57202556..57210586) DIRAS1 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 Year Published PubMed ID(s) Acknowledgements
565 Rhodesian Ridgeback (Dog) Epilepsy, generalized myoclonic, with photosensitivity DIRAS1 deletion, small (<=20) Naturally occurring variant CanFam3.1 20 g.56474668_56474671del c.564_567del p.(D189Afs*11) XM_005633100.3; XP_005633157.1; published as DIRAS1:c.564_567delAGAC 2017 28223533 Genomic and protein coordinates in CanFam3.1 provided by Robert Kuhn

Cite this entry

Nicholas, F. W., Tammen, I., & Sydney Informatics Hub. (2023). OMIA:002095-9615: Online Mendelian Inheritance in Animals (OMIA) [dataset].


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.

2018 Wielaender, F., James, F.M.K., Cortez, M.A., Kluger, G., Neßler, J.N., Tipold, A., Lohi, H., Fischer, A. :
Absence seizures as a feature of juvenile myoclonic epilepsy in Rhodesian Ridgeback dogs. J Vet Intern Med 32:428-432, 2018. Pubmed reference: 29194766. DOI: 10.1111/jvim.14892.
2017 Wielaender, F., Sarviaho, R., James, F., Hytönen, M.K., Cortez, M.A., Kluger, G., Koskinen, L.L., Arumilli, M., Kornberg, M., Bathen-Noethen, A., Tipold, A., Rentmeister, K., Bhatti, S.F., Hülsmeyer, V., Boettcher, I.C., Tästensen, C., Flegel, T., Dietschi, E., Leeb, T., Matiasek, K., Fischer, A., Lohi, H. :
Generalized myoclonic epilepsy with photosensitivity in juvenile dogs caused by a defective DIRAS family GTPase 1. Proc Natl Acad Sci U S A 114:2669-2674, 2017. Pubmed reference: 28223533. DOI: 10.1073/pnas.1614478114.

Edit History

  • Created by Frank Nicholas on 23 Feb 2017
  • Changed by Frank Nicholas on 23 Feb 2017
  • Changed by Imke Tammen2 on 27 May 2023
  • Changed by Imke Tammen2 on 29 May 2023