| Feline Health Issues |
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| Progressive Retinal Atrophy ( PRA) |
| A genetically inherited problem with the retina- the tissue layer in the back of the eye that contains the photoreceptor cells (rods and cones) for processing light- which eventually leads to blindness. ------------------------------------------------------------------------- While PRA in the Abyssinian breed has been fairly well documented since the 1970's, very little is known about PRA in the Persian breed. Although PRA in the Persian breed has been known to exist since atleast 1973, very little research had been done until recently in the late 1990's. PRA was discovered in USA Persian bloodlines over 30 years ago. Some of these bloodlines have been shipped not only overseas but were also used in related breeds such as Himalayans and Exotic Shorthairs. Although reports of blind "pure Persian", Himalayan, CPC and Exotic Shorthair kittens appear to be still fairly uncommon, the gene by now has been spread worldwide. Since some Veterinarians and many Persian breeders are unaware of the PRA gene being in the Persian gene pool, many times the cause of blindness is misunderstood and/or misdiagnosed. Other conditions can be blamed such as Panleukopenia, poor nutrition, taurine levels, head injury - just to name a few. The Persian PRA is caused by a mutation in one gene which is also a recessive gene. A "carrier" has one copy of the mutated gene. When 2 "carriers" are bred together, only the offspring inheriting the gene from BOTH parents will be "affected" (blind). Any kittens inheriting one copy will be "carriers". The problem lies with the "carriers". The "carriers" can NOT be identified by eye examinations. At this time, only when a blind ("affected") kitten is born, can the parents be identified as PRA "carriers". When 2 "carriers" are bred together approximately 1 out of 4 kittens could be blind. Though, it could be as many as the whole litter being blind or as few as 1 out of 12 kittens. Many times, an unknown "carrier" is bred to non-carriers, producing approximately 50% of it's offspring being "carriers". Some offspring will not inherit the PRA gene. Through the "carriers", the gene is able to continue to spread without detection. Hopefully, this will soon change through the research being conducted at UC Davis, by Dr. Leslie Lyons. ( Click here for more information about the current Persian PRA research at UC Davis ) |
| If you produce a litter of Persian or Persian related kittens, containing any blind kittens, please contact Dr. Leslie Lyons at UC Davis. [email protected] Tel: (530) 754-5546 Fax: (530) 752-4278 Pedigrees and blood tests of parents, siblings and the blind kittens are very important in the research of blindness due to PRA. The parents and siblings of any PRA blind kittens must NOT continue to be used in breeding programs but should be altered ... after talking to Dr. Leslie Lyons. Otherwise, the PRA gene will continue to be spread further. All information reported to Dr. Lyons is confidential. |