Juvenile Myoclonic Epilepsy (JME Dog)
Juvenile myoclonic epilepsy (JME) is a form of epilepsy with sudden, electroshock-like muscle twitches and seizures. These often occur during the initial sleep phase or can also be triggered by sudden bright light. Most dogs have daily seizures.
The disease occurs in the Rhodesian Ridgeback. The inheritance is autosomal recessive.
Synonym: generalized myoclonic epilepsy
Genetic Test: available in Shop
Symptoms
- Epileptic seizures
- Muscle twitching
- Spasms
For examples of what JME seizures look like, videos by Wielaender et al. (2017) have been made available on the PNAS website. (Generatio is not responsible for the content of the linked pages).
General Information
- Juvenile myoclonic epilepsy (JME) is a form of epilepsy.
- Most dogs have daily seizures and some even have up to 150 short attacks a day.
- Symptoms often occur during the initial sleep phase or can also be triggered by sudden bright light.
- Usually dogs are diagnosed at around 6 months of age, but rarely as early as 6 weeks or as late as 18 months.
- Up to 15% of tested Rhodesian Ridgebacks are carriers of the mutation.
Breeds affected
Rhodesian Ridgeback
Test Information
This mutation test detects a deletion of 4 base pairs (c.564_567delAGAC) in exon 2 of the DIRAS1 gene.
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Genotype and Lab Report
Inheritance: autosomal recessive
→ The disease only occurs when both alleles of the gene are affected by the mutation (jme/jme). Dogs that have only one allele with the causative mutation (N/jme) are clinically healthy carriers.
Genotypes:
N/N = genetically normal
The dog has no variants for JME and thus cannot pass it on to offspring.
N/jme = a carrier
The dog is a clinically healthy carrier. The variation is passed on 50% to the offspring, which are also carriers.
jme/jme = affected
The variation will be passed on to 100% to the offspring.
Recommendations
- Carrier animals can be bred to normal animals (N/jme x N/N). Before using the offspring in breeding, it should be tested whether they are normal or carriers.
- Mating two carrier animals (N/jme x N/jme) should be avoided because there is a 25% chance that the offspring will be affected.
- Affected animals (jme/jme) should be excluded from breeding.
Literature
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(10), 2017. Pubmed reference: 28223533. Doi:10.1073/pnas.1614478114.
Further information is available at: Online Mendelian Inheritance in Animals.