Comedian and actor Gilbert Gottfried's cause of death has been revealed as a rare genetic muscle disease that affects the heart, his longtime friend and publicist Glenn Schwartz confirmed. He was 67.

The legendary comic died Tuesday from recurrent ventricular tachycardia due to myotonic dystrophy type II, described as an inherited dystrophy that affects the muscles and other systems, which could result in an abnormal heartbeat, according to the Genetic and Rare Diseases Information Center.