Disorder - Progressive retinal atrophy

Organ Systems Involved
Nervous/sensory

Alternative Names
Inherited blindness; Central PRA; Primary retinal degeneration

Presenting Signs

Progressive retinal atrophy is a group of inherited disorders that cause progressive loss of vision in both cats and dogs. In this disease the retina is gradually destroyed. The retina is the inner portion of the eye which contains the cells called rods and cones that receive the light (light receptors). In other species either rod or cone photoreceptors may be affected individually, however this has not been shown to happen in cats. Typically, these light receptors are first destroyed at the edges of the retina; destruction then progresses toward the optic disk at the centre of the retina. Patchy degeneration may also occur, however the ultimate result is that vision is gradually lost. Due to the slow progressive nature of the disease, symptoms of vision loss are not usually seen until 1.5 to 2 years of age; however, they may occur earlier.

The way that the disease is inherited is thought to be dependent on the breed. In Persians only a recessive mode of inheritance is recognised. This means that both parents must be carrying the gene for a kitten to be affected. In Abyssinians inheritance may be both dominant (the kitten can acquire the disorder if only one parent carries the gene) and recessive.

Cats at Risk

Many Persian breeders consider the condition to be linked with the chocolate coat colour. Studies suggest that there is no link between the gene encoding coat colour and those that result in progressive retinal atrophy.

Breeds Affected
Abyssinian
Persian


PubMed References
Progressive retinal atrophy

Contributor
Neil Christensen