Early-Onset Epilepsy (Parson Russell Terrier Type)
Affected Genes: PITRM1
Inheritance: Autosomal Recessive
Variant(canFam6):
chr2:29217124-29217129: 6 bp deletion CTGTCC
Breed: Parson Russell Terrier
General Information: Early-Onset Epilepsy in Parson Russell Terriers presents as a grave neurological disorder where affected puppies begin exhibiting signs of frequent, uncontrollable seizures at a very young age, usually between 8 and 10 weeks. The seizures are often severe and do not typically respond well to medical treatments. This rapid progression of the disease often leads to a poor quality of life, resulting in euthanasia shortly after the onset of symptoms to alleviate suffering. The condition is particularly distressing due to its early onset and rapid progression, impacting the puppy's development and the emotional well-being of the caretakers.
How to Read Your Dog's Test Results for this Genetic Variant:
Two Variants Detected: Dog Likely Affected
One Variant Detected: Dog Unlikely Affected
No Variants Detected: No Effect
Gene / Testing Information: Genetic testing for Early-Onset Epilepsy in Parson Russell Terriers targets mutations in the PITRM1 gene. This form of epilepsy is autosomal recessive, meaning that two copies of the mutated gene—one from each parent—are necessary for a puppy to develop the disorder. Dogs carrying only one copy of the gene (carriers) do not show symptoms but can pass the mutation on to their offspring. Breeding decisions should be informed by reliable genetic testing: mating two carriers results in a 25% chance of producing affected offspring and a 50% chance of producing another carrier. To prevent the birth of affected puppies and to help eradicate this debilitating condition from the breed, it is recommended not to breed carriers together. Testing is crucial for breeders to make informed decisions, ensuring that affected genes are not passed on, thereby maintaining the health and vitality of future generations. As with all genetic testing, a clear result for this mutation does not rule out other potential genetic diseases, emphasizing the importance of comprehensive health testing in breeding programs.
References:
Hytönen, M.K., Sarviaho, R., Jackson, C.B. et al. In-frame deletion in canine PITRM1 is associated with a severe early-onset epilepsy, mitochondrial dysfunction and neurodegeneration. Hum Genet. 140 1593–1609 (2021).