Progressive Retinal Atrophy, PRA1 (Papillon Type)

General Information: Progressive Retinal Atrophy, PRA1 (Papillon Type) is a genetic eye disorder that causes the degeneration of rod photoreceptor cells in the retina, which are crucial for vision in dim light. Dogs affected by this condition typically begin showing signs between 4 and 6 years of age, such as poor night vision. A veterinary eye examination may reveal changes in the tapetum, a reflective structure behind the retina, and thinning of the retinal blood vessels, indicating reduced blood flow to the retina. PRA1 progresses slowly, and some affected dogs may retain daylight vision for many years or even the rest of their lives, despite their night vision being compromised.

How to Read Your Dog's Test Results for this Genetic Variant:

Two Variants Detected: Dog Likely Affected

One Variant Detected: Dog Unlikely Affected

No Variants Detected: No Effect

Gene / Testing Information: Genetic testing for the CNGB1 gene is essential for identifying carriers and dogs affected by Progressive Retinal Atrophy, PRA1 (Papillon Type). This disease is inherited in an autosomal recessive pattern, meaning that a dog must inherit two copies of the mutated gene, one from each parent, to manifest the disease. Carrier dogs, which have one normal and one mutated gene, do not show symptoms but can pass the mutation to their offspring. Breeding two carriers is risky, as each puppy has a 25% chance of developing the disease and a 50% chance of being a carrier. To prevent producing affected puppies and to eradicate the mutation from breeding lines, it is crucial to avoid mating two carriers. Since PRA1 symptoms typically appear in adulthood, genetic testing for the CNGB1 mutation should be conducted before breeding decisions are made. Although testing for CNGB1 significantly reduces the risk of PRA1, it is important to note that other types of PRA are caused by mutations in different genes. Therefore, a clear result for CNGB1 does not completely rule out the potential for progressive retinal atrophy in a dog's lineage. Comprehensive genetic testing helps ensure the health and visual well-being of future generations of Papillons and other affected breeds.