KITTANNING, Pa. — A coroner says former Buffalo Bills lineman Mitch Frerotte died of a thickening of the heart muscle, a condition that can cause sudden death.

The coroner said today that Frerotte's family has a history of hypertrophic cardiomyopathy. The American Heart Association calls it the most common cause of sudden death in young athletes.

Frerotte was 43 when collapsed and died suddenly Wednesday at home in Kittanning, about 30 miles from Pittsburgh. He played for the Bills in 1987, then during their Super Bowl seasons of 1990-92. He played mostly as a reserve and on special teams.