Juvenile Myoclonic Epilepsy in the Rhodesian Ridgeback

 

Gene: DIRAS1

Transmission: Autosomal recessive

For an autosomal recessive genetic disease an animal must have two copies of the mutation in question to be at risk of developing the disease. Both parents of an affected animal must be carriers of at least one copy of the mutation. Animals that have only one copy of the mutation are not at risk of developing the disease but are carrier animals that can pass the mutation on to future generations.

Mutation: Deletion, DIRAS1 gene; del. c.564_567, p.(D189A fs STOP 11), p.(D189A fs STOP 11), exon1

Medical system: Neurological

Breeds: Rhodesian Ridgeback

Age of onset of symptoms: 6 months of age

Juvenile Myoclonic Epilepsy in the Rhodesian Ridgeback is an autosomal recessive genetic disease of the neurological system.  Clinical signs appear around the age of 6 months and involve uncontrolled episodes of rapid muscle contractions (myoclonus), chiefly of the muscles of the trunk, front legs and neck. The episodes occur during rest. There is no definitive treatment for the disease although antiepileptic medications can be helpful.

 

References:

OMIA link: [2095-9615]

Donner J, Freyer J, Davison S, et al. (2023) Genetic prevalence and clinical relevance of canine Mendelian disease variants in over one million dogs.  PLoS Genet. 19(2):e1010651. [pubmed/36848397]

Wielaender F, James FMK, Cortez MA, et al. (2018) Absence Seizures as a Feature of Juvenile Myoclonic Epilepsy in Rhodesian Ridgeback Dogs. J V Intern Med 32(1), 428-432.  [pubmed/29194766]

Wielaender F, Sarviaho R, James F, et al. (2017) Generalized myoclonic epilepsy with photosensitivity in juvenile dogs caused by a defective DIRAS family GTPase 1. Proc Natl Acad Sci, 114(10), 2669-2674. [pubmed/28223533]

 

Contributed by: Emily Morgan, Class of 2020, Faculty of Veterinary Medicine,University of Montreal.