From Wikipedia, the free encyclopedia. Michael John Berryman (born September 4, 1948) is an American actor. He has appeared in several horror movies and other B movies. Berryman is famous for having a distinctive physical appearance as a result of hypohidrotic ectodermal dysplasia, a rare genetic condition which prevents him from developing hair, sweat glands or fingernails. According to his own statements in an interview for the DVD release of The Hills Have Eyes, he was born with twenty-six birth defects.