Cartilage–hair hypoplasia (
CHH), also known as
McKusick type metaphyseal chondrodysplasia, is a rare
genetic disorder. It is a highly
pleiotropic disorder that clinically manifests by form of short-limbed
dwarfism due to
skeletal dysplasia, variable level of
immunodeficiency and predisposition to
malignancies in some cases. It was first reported in 1965 by McKusick et al. Actor
Verne Troyer is affected with this form of dwarfism, as was actor
Billy Barty, who was renowned for saying "The name of my condition is Cartilage Hair Syndrome Hypoplasia, but you can just call me Billy."