Progressive Retinal Atrophy (PRA Rdy) (Abyssinian)

A form of blindness called “rod cone dysplasia”, or “Rdy” has been identified in Abyssinian and Somali cats. This progressive retinal atrophy differs from the "rdAc" (CEP290 mutation) progressive retinal atrophy. The mutation underlying "Rdy" is a single base pair deletion in a different gene, CRX, which results in a defective protein that is critical for eye development. Cats carrying one copy of this mutation have retarded development and degeneration of photoreceptor cells, which leads to early-onset blindness by 7 weeks of age. Current information suggests that the “Rdy” mutation is restricted to the Abyssinian and Somali breeds. The “Rdy” mutation is inherited as a dominant trait: cats that have one or two copies of the mutation will be affected. The Rdy mutation is rare.

To assist owners and breeders in identifying affected and carrier cats, the VGL offers DNA tests for the two mutations known to cause the two different forms of PRA in cats - rdAc (CEP290) and Rdy (CRX). Breeders can use these tests as tools to avoid breeding two carriers of rdAc which would produce 25% affected offspring, or to test for the presence of “Rdy” in the CRX gene of suspected affected cats.

Since both forms of blindness are found in the Abyssinian breed, all associated breeds may have a concern for these diseases. A novel form of blindness occurs in the Bengal cat, and a separate causative mutation has been identified (a genetic test for the Bengal-specific PRA is available here). However, since Bengal cats have had Abyssinian breedings in their ancestry, genetic testing for rdAc and Rdy may also be warranted in some Bengal lines.