A very popular cat breed worldwide is the Ragdoll. Ragdoll breeders often advise clients to watch for future renal disease in their cats. Most of these questions center around potential chronic interstitial nephritis and polycystic kidney disease (PKD). There is minimal scientific evidence regarding risk of renal disease in this breed. The Veterinary Medical College at Ghent University in Belgium performed a retrospective evaluation of Ragdolls screened for renal disease over an 8-year period. The screening methods included abdominal ultrasonography, measurement of serum creatinine and urea concentrations, and genetic testing for the PKD-1 mutation. The study population was made up of 244 Ragdoll cats: 172 females and 72 males.
In this study, 8.6% of the screened cats showed ultrasonographic abnormalities that could be compatible with chronic kidney disease (CKD). The suspected CKD cats were significantly older and had significantly higher urea and creatinine concentrations compared to cats with normal ultrasound results. Ragdolls are one of the breeds that have been outcrossed with Persians, so Ragdoll cats could be at risk for PKD. The researchers found a PKD prevalence of less than 3% in the study cats, considerably lower than the 31-42% prevalence of PKD described in European studies of Persians and related cats. Only one PKD-positive and one suspected PKD-positive Ragdoll cat were noted in the last 7 years of the study. This could mean that PKD screening before breeding is effective at eradicating PKD in this breed. All genetically tested cats tested negative for PKD.
In conclusion, almost 10% of this healthy Ragdoll population had ultrasonographic findings compatible with CKD, and PKD occurs at a low prevalence in Ragdoll cats in Belgium and the Netherlands. [VT]