WSU researcher unlocks deadly genetic mutation in Collies

Pullman, Wash.-A Washington State University (WSU) veterinarianhas found a mutant gene responsible for some Collies' sensitivity to commonanti-parasitic drugs, which when used, can result in death.

Dr. Katrina Mealey, a pharmacologist with WSU's College of VeterinaryMedicine, discovered a variation in the gene that codes for P-glycoprotein,a large protein complex that pumps medications out of the brain and intothe bloodstream to be metabolized.

A mutation in the gene has a negative impact on protein function, whichnormally would protect the brain from toxic pharmaceuticals. In Collieswith the mutation, certain anti-parasitic drugs results in severe and oftenfatal neuralgic brain toxicity levels.

"We've known about the breed's sensitivity since the 1980s, butwe never knew the cause," Mealey says. "Now I'm getting a lotof e-mails from pet owners saying veterinarians are still prescribing thedrugs even though it's been known for 20 years that Collies are sensitiveto them."

Far-reaching effects

According to the American Kennel Club, nearly 8,000 Collies were registeredin 2001. Of those, more than half could have the mutation or be carriers,Mealey says.

"One study showed 70 percent of Collies are at least carriers,"she says. "Right now, we have patent applications out for commercialtests to screen for the gene and give rapid turnaround. This would makeit so all owners can afford the test and make it easy for veterinariansto submit samples."

The mutation also is found in Australian Shepherds. Mealey suspects Sheltiesand Border Collies are carriers, too.

Mealey's study was published last month in the American Journal of VeterinaryResearch.