 Lyons has helped develop DNA tests for polycystic kidney disease (PKD), an inherited condition that shortens the life of cats by causing them to suffer kidney cysts.Previous tests for this condition involved ultrasound and were not very accurate, unlike the DNA test devised by Lyons.Approximately one third of all Persian cats carried the PKD gene at one time, but because of ultrasound testing and the newer, more accurate DNA tests, these PKD-carrier cats are gradually being identified and removed from the feline gene pool by spaying and neutering.