Sights set on genetic test for eye disease

A Western College of Veterinary Medicine (WCVM) research team is working to pinpoint the genetic cause of pigmentary uveitis (PU), a painful, inherited condition that commonly affects golden retrievers.

“When it gets to the point when it causes them to go blind, it’s very sad for [the owner],” says Dr. Lynne Sandmeyer, one of the WCVM’s veterinary ophthalmologists and the research study’s lead investigator.

Initial symptoms of PU may be redness and a little extra tearing. Using specialized equipment, a veterinary ophthalmologist can see the first signs of the condition, which appear as cysts. Gradually inflammation develops, then adhesions inside the eye, which then promote development of glaucoma.

“It can be years of treatment and maintenance before they go blind,” Sandmeyer says.

For breeders, the disease can be “devastating,” she says.

Because the disease typically appears in older animals, dogs with the genetic condition may have unknowingly been bred many times before PU is detected.

As diagnosis of PU increases, golden retriever breeders have become vigilant about preventing the condition from being passed down to new litters of puppies, and have been highly supportive of further research.

This fall, Sandmeyer’s team will begin collecting genetic material for screening from a large population of dogs owned by breeders in Alberta, Saskatchewan and Manitoba.

The study, which received a 2019-20 Companion Animal Health Fund research grant, involves ophthalmology researchers at the WCVM and the University of California, Davis (UC Davis).

They are capitalizing on information gained during a previous WCVM research project in which a student evaluated the exam files of more than 800 golden retrievers. By tracing these dogs’ pedigrees, the researchers were able to follow the disease through multiple generations. 

Using that information, Sandmeyer’s team is now looking for the specific genetic cause of the condition.

By figuring out where PU lives on the canine genome, the team hopes that a genetic test could one day be possible. This type of test could give owners and breeders peace of mind – and the ability to see what’s coming years before their beloved pet develops any clinical signs of the disease.

This article originally appeared in the Fall 2019 edition of Vet Topics, the official publication of the WCVM's Companion Animal Health Fund.