Polycystic kidney disease or PKD is very uncommon among the Ragdolls (estimated to be less than 1%).
PKD is a kidney disease of genetic origin, which affects the kidneys and affects mainly the Persian and related breeds.
It is characterized by cysts that compress the renal tissue and prevent the kidney to function properly. The cysts multiply and grow with the cat's age, leading to renal failure which is usually expressed between 3 and 10 years. PKD affected cats drink and urinate more.
Other clinical signs may develop gradually: dehydration, loss of appetite, weight loss, vomiting, lethargy and depression.
The growth rate of the cysts is highly variable from one cat to another: some live many years without showing clinical signs, for others renal insufficiency leads to premature death.
If a cat is affected, a proper diet and some treatments will help it to have a normal life over a longer or shorter term, according to the speed of evolution.
Le treatment is palliative and will not heal the cat. It will extend its wellbeing and life to the utmost.
There is a genetic test which will detect the polycystic kidney desease, associated with a mutation in the PKD1 gene, which is described among the Persians and related breeds.
This test has, unfortunately not yet been validated for the Ragdoll
It can, on the other hand, provide an indication for the non traditional coloured Ragdolls which have Persian or other crossings in their pedigrees.
At this stage, though, the echography remains the only really reliable way to diagnose PKD with a Ragdoll.
A study showed that the cysts of affected cats were visible during an echography. At ten months 95% of the tested cases were visible and that percentage grows over time (as the disease evolves).
Please note that two parents free of PKD will not transmit PKD to their kittens.