TinyPersians has DNA tested all their Sire and Dam breeders and all have a Negative test result !

Polycystic Kidney Disease

(PKD) is an inherited disorder that can lead to feline kidney failure. PKD causes small fluid-filled cysts to form in both of your cat's kidneys. ... Common in Persian, Exotic Shorthair and some other cats

A responsible breeder will DNA test their sires and dams for PKD