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Progressive retinal atrophy

Unfortunately around eighteen years or so ago it was discovered the Glen of Imaal Terrier suffers from an hereditary eye disease called Progressive Retinal Atrophy. The breed worldwide pulled together to combat this & the two research projects ,Optigen in the United States and Bochum in Germany, arrived at the self same discovery within weeks of each other!

DEFINITION OF PRA   

~ Progressive  a slowly developing disease process ~ the affected dog will gradually lose its sight and will usually adjust to its handicap  

~ Retinal  of the retina ~ the light-sensitive area at the back of the eye  

~ Atrophy  degeneration or deterioration ~ of the specialised light-sensitive cells in the retina  

HOW A DOG SEES  

Light passes through the lens and is directed onto the retina, which contains specialised photoreceptor (light-sensitive) cells called rods and cones. These cells convert the light into electrical nerve signals, which pass along the optic nerve to the brain, where they are "translated" into images.  

~ rods are responsible for vision in dim light i.e. night vision  

~ cones are responsible for vision in bright light i.e. daytime and colour vision  

DISEASE PROGRESSION   

Initially, a dog with PRA will develop "night-blindness" i.e. it will eventually be unable to see in dim light conditions or in the dark. This is due to atrophy, or degeneration, of the rods. The owner may notice that the dog is reluctant to go out in the dark and hesitant to do down stairs in poor light. The dog may also appear to be a little "clumsy" i.e. bumping into things.   

In the later stages of the disease, the cones are affected, and the dog's daytime vision will gradually deteriorate.   

PRA in Glens is considered late-onset as all cases have been discovered after 9 months of age. An eye examination is needed (only done by a KC recognised eye vet) to determine your Glen’s status, this should be done annually & the results will appear on the Kennel Club website

It is a mutation in the Adam9 gene that causes PRA in Glen of Imaal Terriers. As this has been discovered it means that there is a simple DNA test to determine whether your Glen is afflicted with the problem and to what extent-affected or carrier-or if they are clear.

This means your Glen’s blood must be sent away to a specialist laboratory, rather than your local one, but it is really quite easy. Jean Rogers will be happy to give you full details.

RESULTS OF UK DNA TESTED GLENS  APPEAR ON THE KC WEBSITE  BUT  OTHER GLEN FOLK AROUND THE WORLD ARE ALSO TESTING

Want the full Glen of Imaal Terrier/ DNA and breeding story?

The document cover on the left will take you to the DNA/Glen of Imaal Terrier story (full digital copy) in a lot more depth & it is suggested you do it if you are thinking of mating your Glen either now or in the future. If you are thinking of breeding AT ALL you owe it to Glendom (and the owners of any of your puppies) to make sure your dog or bitch has been DNA tested !!

Prefer a video presentation on PRA ?

Have a look here

Even though Glens now have a test for PRA DO still eye test regularly as we need to make sure that nothing else is creeping into the breed!