Health Issues in the Persian Cat - PKD

POLYCYSTIC KIDNEY DISEASE (PKD)

PKD is similar to HCM in that it only takes one parent to pass the disease. PKD is an inherited kidney disease that passes from a genetically affected parent at a statistical rate of about 50%. It can be a relatively silent disease for many years until it manifests later in life as renal failure. Or it can strike early and unexpectedly with renal demise characterized by multiple cysts in both kidneys. This disease, like HCM, can have variable expression from cat to cat. For decades, the two most common diseases that cats died from were kidney disease and cancer. Cardiomyopathy is now competing for a similar rank.

When sonograms became available to the veterinarian world, specialty veterinarians began offering kidney ultrasounds to cat owner clients. Accuracy of the ultrasounds was considered to be approximately 95% in cats that were 10 months of age or older. Like HCM at a minimum of two years of age, early signs of PKD could be detected in most cats at a minimum of 10 months of age. One such cat was found to be positive for PKD at Donegal Cattery and quelled from breeding. You can read about Misty on the HandiCats Donegal page of this web site.

Having ultrasounds allowed conscientious breeders to “breed away from” the disease and eliminate it in their breeding cats. Unfortunately, some breeders continue to use positive cats either because they haven’t had them genetically tested or because they simply don’t care. There was a period of time where chocolate and lilac breeders were using positive PKD cats and selectively keeping negative offspring because that color gene pool in the Persian breed was very small. That is no longer necessary with having had scores of years of outcrossing chocolates and lilacs to negative Persian cats who did not carry the chocolate gene.

Unlike the genetic marker for HCM which appears to be breed specific, PKD is genetically similar in several breeds of cats. Persians have been used in those breeds and may or may not account for the origin of this disease. According to UC Davis: “The heritable form of PKD1 may not have initially occurred in Persians as a new mutation, but perhaps in random bred cats.” So in the cat world those breeds, which include but are not limited to British Shorthair, Persians (including Himalayans), Exotics, and Scottish Folds, share a common genetic marker for the disease referred to as PKD1 and they can be tested genetically for this disease.

The following facilities test for the PKD1 gene in Persian cats for a nominal fee:

Texas A & M University Animal Genetics Laboratory
www.catdnatest.org
The University of California Davis Veterinary Genetics Laboratory
www.vgl.ucdavis.edu

All Persian breeders should have their breeding cats DNA tested for this disease. If both parents are DNA negative then neither parent can pass the disease to its progeny. At this point in the breeding world of Persian cats there is no longer any excuse for using a PKD DNA positive cat for breeding.