Definition

A group of rare conditions caused by mutations (changes) in certain genes that make proteins involved in the Ras/MAPK cell signaling pathway. This pathway plays an important role in controlling many cell functions, including cell growth, cell maturation, and cell death. There are many different RASopathy syndromes. Most of these syndromes are marked by unusual facial features, heart defects, skin abnormalities, and problems with the eyes, muscles, and bones. There may also be gastrointestinal and nervous system problems and growth, learning, and developmental delays. Having a RASopathy syndrome may increase a person’s risk of certain types of cancer. RASopathy syndromes include cardiofaciocutaneous syndrome, Costello syndrome, Legius syndrome, neurofibromatosis type 1, Noonan syndrome, and capillary malformation-arteriovenous malformation syndrome.