Epilepsy in dogs is frequently genetic, especially in purebred breeds. Idiopathic epilepsy, the most common form of seizure disorder in dogs, has no identifiable structural or metabolic cause and is widely believed to have a hereditary basis. It affects roughly 1 to 2.6% of dogs depending on the population studied, with certain breeds carrying significantly higher risk than others.
How Genetics Drive Canine Epilepsy
Idiopathic epilepsy is classified into three subcategories: genetic epilepsy (where a specific causative gene has been found), suspected genetic epilepsy (where breed predisposition strongly suggests a genetic link), and epilepsy of unknown cause. For most breeds, the condition falls into the “suspected genetic” category. Researchers know the seizures run in families and cluster in specific breeds, but the exact genes responsible remain unidentified in most cases.
The exception is a handful of breeds where specific mutations have been pinpointed. In Lagotto Romagnolos, a mutation in the LGI2 gene causes Benign Familial Juvenile Epilepsy, a condition where puppies develop whole-body tremors and sometimes lose consciousness starting at five to nine weeks of age. The seizures completely resolve by four months, and the dogs go on to live normally. This mutation is breed-specific and has not been found in any other breed tested. In Miniature Wirehaired Dachshunds, Lafora disease is an inherited progressive seizure disorder passed down in an autosomal recessive pattern, meaning a puppy must inherit the faulty gene from both parents to be affected.
Breeds With the Highest Risk
A hereditary basis for idiopathic epilepsy has been suggested in at least 14 breeds: Beagles, British Alsatians, Keeshonds, Labrador Retrievers, Golden Retrievers, Bernese Mountain Dogs, Belgian Tervurens, Boxers, Shetland Sheepdogs, Vizslas, English Springer Spaniels, Irish Wolfhounds, Standard Poodles, and Greater Swiss Mountain Dogs. If your dog belongs to one of these breeds, epilepsy is more likely to have a genetic origin than an environmental one.
Purebred dogs are particularly susceptible because of what geneticists call the founder effect. When a breed originates from a small number of founding dogs, any seizure-related genes those founders carried get amplified across the entire breed population over generations. This is the same reason many breed-specific diseases exist, and it’s why mixed-breed dogs generally have lower rates of idiopathic epilepsy.
When Genetic Epilepsy Typically Appears
Dogs with idiopathic epilepsy of genetic or suspected genetic origin usually have their first seizure between six months and six years of age. This age window is one of the key diagnostic markers veterinarians use. If seizures begin before six months or after six years, the cause is more likely structural (a brain tumor, inflammation, or vascular problem) or metabolic rather than inherited.
In one study of Irish Setters with idiopathic epilepsy, the average age of first seizure was 41 months, right in the middle of that expected window. Dogs whose parents had epilepsy tended to develop seizures at a younger age than dogs from unaffected parents, further reinforcing the genetic connection.
How Genetic Epilepsy Is Diagnosed
There is no single blood test that confirms genetic epilepsy in most breeds. Instead, the diagnosis works by ruling out every other possible cause. The International Veterinary Epilepsy Task Force established a three-tier diagnostic system for this purpose.
At the first tier, a vet looks for two or more unprovoked seizures at least 24 hours apart, onset between six months and six years, a normal neurological exam between seizures, and clean baseline blood work. This alone gives a reasonable confidence level. The second tier adds fasting bile acid tests (to rule out liver problems), brain MRI, and spinal fluid analysis. The third tier involves electroencephalography to detect abnormal electrical patterns in the brain. Most pet owners will go through the first and sometimes second tier. The deeper you go, the more confident the diagnosis.
For Miniature Wirehaired Dachshunds and Lagotto Romagnolos, DNA tests for their specific mutations do exist. For every other breed, genetic testing for epilepsy is not yet commercially available because the causative genes haven’t been identified.
What This Means for Breeding
Because idiopathic epilepsy is a diagnosis of exclusion, breeding decisions require careful consideration. Dogs diagnosed with epilepsy, and dogs that have produced epileptic offspring, are generally recommended to be removed from breeding programs. The International Veterinary Epilepsy Task Force emphasizes that a correct diagnosis directly impacts breeding decisions, not just treatment.
Some breed clubs have taken active steps. Dutch Keeshond breeders, for example, have been using outcrossing (mating with dogs outside the immediate breed line) with permission from the Dutch Kennel Club to increase genetic diversity and reduce the prevalence of epilepsy in the breed. If you’re purchasing a puppy from a predisposed breed, asking the breeder about seizure history in the parents and grandparents is one of the most practical things you can do. A breeder who tracks this information and avoids pairing dogs with epilepsy in their lineage is significantly reducing your puppy’s risk.
Genetic vs. Non-Genetic Causes
Not all seizures in dogs are genetic. Structural epilepsy results from identifiable brain problems like tumors, infections, inflammation, or stroke. Reactive seizures can be triggered by toxins, low blood sugar, or organ failure. These causes can affect any breed at any age.
The distinction matters because treatment and prognosis differ. A dog with structural epilepsy may need surgery or targeted medication for an underlying condition, while a dog with genetic idiopathic epilepsy will typically be managed with long-term anti-seizure medication. Dogs with genetic epilepsy often respond well to treatment, and many live full, normal lives with proper management. The Lagotto Romagnolo form is even more encouraging: puppies simply outgrow it within a few months with no lasting effects.