Costello syndrome

Costello syndrome, also called faciocutaneoskeletal syndrome, is a rare genetic disorder that affects many parts of the body. It is marked by delayed development and intellectual disability, distinctive facial features including a large mouth with full lips, unusually flexible joints, and loose folds of extra skin, especially on the hands and feet. Heart abnormalities are common, among them a very fast heartbeat, structural heart defects and overgrowth of the heart muscle. Infants may be large at birth but then grow more slowly and have trouble feeding, and affected people tend to be short in stature. The condition is caused by mutations in the HRAS gene and is a RASopathy. It carries an increased risk of tumors, the most frequent cancer being rhabdomyosarcoma. It was first reported by the New Zealand paediatrician Jack Costello in 1977.