While numerous genes associated with human epilepsy have already been found, this is the first gene associated with canine epilepsy to be discovered.

"Five to 10 percent of dogs have epilepsy compared to about one percent of humans," said one of the study's authors, Dr Berge Minassian, a neurologist and scientist at the Hospital for Sick Children in Toronto, Canada.

"We've found the first dog epilepsy gene and may have explained part of the reason for the high numbers of epilepsy in dogs," he said.

Results of the study appear in the Jan. 7 issue of the journal Science.

Finding an effective animal model
Minassian said he was originally studying the human form of this type of epilepsy, known as Lafora disease. Children appear normal until their teenage years when they begin to have very serious seizures. Minassian said the seizures progress and current medications are ineffective against this form of epilepsy. Eventually, Lafora disease kills those affected by it.

An important step in developing effective treatments for human disease is finding an effective animal model of the disease to test potential therapies. One possibility was dogs, because Minassian said he knew they suffered from an almost identical form of epilepsy called autosomal recessive progressive myoclonic epilepsy (PME).

The dogs most commonly affected by this form are purebred dogs, such as basset hounds, miniature and standard poodles, pointers, corgis, beagles and daschunds, according to the study.

People and dogs with this form of epilepsy can have seizures provoked by light. Something as simple as a hand passing over your eyes can cause enough change in lighting to provoke a seizure, said Minassian.

Canine gene associated with epilepsy
In collaboration with veterinary neurologists in England, researchers at the Hospital for Sick Children compared the genes known to be associated with Lafora to the same genes in affected dogs. They found that one of the canine genes was, in fact, associated with epilepsy.

However, in humans, the genes associated with epilepsy spontaneously mutate, whereas in dogs, the gene repeats itself over and over again until it stops working, and epilepsy results.

Now that the gene has been isolated, Minassian and his colleagues are working on developing a commercially available test to identify the gene so dog breeders can test their dogs to see if they carry the gene. With controlled breeding practices, it could be possible to eliminate this form of canine epilepsy from purebred dogs, said Minassian.

Better quality of life for dogs
Dennis O'Brien, a professor in the College of Veterinary Medicine at the University of Missouri, said, "This study will go a long way to making dogs lives better. It will give dog breeders the tools necessary to breed better dogs."

And, that will improve the lives of pet owners, because having a dog that has seizures can be very stressful since the disease is so unpredictable and seizures often occur at night, said O'Brien.

O'Brien said that while there is no effective treatment for this type of epilepsy in dogs, there are other treatable forms of the disease. "We can control about 70 percent of epilepsy in dogs," he said.

Veterinarians use the same medicines that control epilepsy in humans to control the disorder in dogs, though some of the newer medications are too expensive for most pet owners, said O'Brien.