Progressive Retinal Atrophy, Early Onset (EO-PRA) - Portuguese Waterdog

Progressive retinal atrophy (PRA) is an inherited retinal disorder due to degeneration of the rod and cone type of photoreceptor cells in retina. PRA has been identified in a variety of dog breeds with different inheritance patterns. Some breeds are found to have more than one form of PRA. Early onset progressive retinal atrophy (EO-PRA) is a new form of PRA with an earlier age of onset (2-3 years). Initial clinical signs include visual deficits including difficulty following moving objects and walking into still objects which are worse under dim light, consistent with night blindness. These signs get worse over time. EOPRA has been identified in Portuguese Water dogs. Genetic defect impairs protein physiological function in the eye, thus leading to the EO-PRA phenotype.

Inheritance: autosomal recessive

Mutation: CCDC66 gene

Genetic test: The method used for testing is extremely accurate and allows complete differentiation between affected animals, carriers and healthy dogs. Testing can be done at any age.