Polycystic Kidney Disease (PKD) is a disease in which a large number of fluid filled cysts form within the kidneys. These cysts are present from birth in affected cats but they start off very small and then gradually increase in size until eventually they compromise the surrounding normal kidney tissue and cause kidney failure.

Polycystic kidney disease is now recognised as a particular problem in Persians and Exotic Shorthairs because it is an inherited disease which has become very common in these breeds. Many Persian breeders are now aware of this problem and are aiming to avoid breeding from affected cats.