Progressive Retinal Atrophy, PRA3 (Tibetan Terrier and Spaniel Type)

General Information: Progressive Retinal Atrophy (PRA3) is a genetic eye disorder that affects Tibetan Terriers and Spaniels, characterized by the degeneration of rod and cone photoreceptor cells in the retina, which are crucial for vision in both dim and bright light. Initially, rod cells are affected, leading to night blindness and loss of peripheral vision. As the disease progresses, dogs also begin to experience vision deficits in bright light. Typically, clinical diagnosis of PRA3 occurs around 5 years of age, when symptoms become more apparent. Over time, the condition can lead to complete blindness, significantly impacting the quality of life of affected 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 Progressive Retinal Atrophy (PRA3) involves screening for mutations in the FAM161A gene to determine carrier status. PRA3 is inherited in an autosomal recessive manner, meaning a dog must inherit two copies of the mutated gene, one from each parent, to develop the disease. Carriers of the gene mutation do not typically show symptoms but can pass the mutation to their offspring. When two carriers are bred, each puppy has a 25% chance of being affected and a 50% chance of being a carrier. To prevent producing affected puppies and eliminate the mutation from breeding lines, it is crucial to avoid breeding two carriers. Genetic testing should be performed before breeding to ensure responsible breeding practices, as dogs not carrying the mutation do not pose a risk of producing affected puppies. It is important to note that other forms of PRA exist, caused by different genetic mutations, so a normal FAM161A result does not completely rule out the presence of PRA in a pedigree.