PEA15 Gene Deletion Causes Tremors, Head Tilt & Gait Changes in Cats. A heritable change in the PEA15 gene results in kittens with twitching and shaking with a strange high stepping walk that gets better, then worse. Learn about the compelling story of how a change in this gene can affect the life of a domestic cat while application of the science holds therapeutic efforts for children born with the condition.