Progressive Retinal Atrophy, Generalized (Schapendoes Type)

General Information: Progressive Retinal Atrophy, Generalized (gPRA) (Schapendoes Type) is a hereditary eye disorder in dogs, characterized by the degeneration of both rod and cone photoreceptor cells in the retina, crucial for vision in low light and daylight conditions. Dogs typically exhibit symptoms between 2 and 5 years of age, initially showing signs of night blindness and peripheral vision loss, which progressively worsens to complete blindness. Early clinical signs include changes in the reflectivity and appearance of the tapetum, a structure behind the retina, which can be observed during a veterinary eye examination. The progression and severity of gPRA can vary among individual dogs.

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 gPRA in Schapendoes dogs focuses on the CCDC66 gene, which can indicate if a dog is a carrier of the disease. This condition is inherited in an autosomal recessive manner, meaning a dog must inherit two copies of the mutated gene (one from each parent) to develop gPRA. Carrier dogs typically do not exhibit symptoms but can pass the mutation to their offspring. When two carriers are bred, there is a 25% chance of producing an affected pup and a 50% chance of producing a carrier. To prevent the transmission of gPRA, it is crucial to perform genetic testing before breeding and avoid mating two carriers. Ensuring that dogs used for breeding do not carry the mutation helps eliminate the risk of producing affected puppies, although normal results for the CCDC66 gene do not rule out the possibility of other genetic forms of PRA.