Progressive Retinal Atrophy, Cone-Rod Dystrophy 4/cord1 (PRA-cord1/crd4)

Most of canine retinal diseases with known causal mutations are rod-cone degenerations also known as progressive retinal atrophies (PRAs), which are characterized by progressive rod-led photoreceptor degenerations that is followed by cone photoreceptor demise. In contrast, cone-rod dystrophies are characterized by the relatively early loss of cone photoreceptors. Cone–rod dystrophy 1 (cord1 - PRA) is a retinal disease associated with RPGRIP1 gene first described in Dachshund. The earliest signs are detectable at approximately 6 months of age. By the 40th week of age, no photoreceptor function could be detected with ERG. One study reported that not all dogs homozygous for the mutation develop the disease, therefore it is speculated that other genetic factors may influence the disease. In all clinically affected dogs, mutation was found.

Inheritance: autosomal recessive

Mutation: RPGRIP1 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.