Hereditary diseases of cats

Progressive Retinal Atrophy (PRA) is the general name for a group of diseases of the retina that cause damage to photoreceptor cells (rods and cones) until they die. For Abyssinian, Ocicat and Somali cats, a PRA form called PRA-Rdy is described. In sick cats, there is a delay in the development of photoreceptor cells, followed by their degeneration. The disease develops early enough, around 7 weeks of age, and progresses rapidly. Complete blindness usually occurs between the ages of 12-16 months. PRA-Rdy is caused by a single nucleotide deletion of n.546delC in exon 4 of the CRX gene (cone-rod homeobox). The CRX gene is a member of a family of proteins required for the development of mammalian eyes.