What is (are) Noonan syndrome 1 ?
Noonan syndrome is a genetic disorder that causes abnormal development of multiple parts of the body. Features of Noonan syndrome may include a distinctive facial appearance, short stature, a broad or webbed neck, congenital heart defects, bleeding problems, skeletal malformations, and developmental delay. Noonan syndrome may be caused by mutations in any one of several genes including the PTPN11, KRAS, RAF1, SOS1, NRAS and BRAF genes. It is sometimes referred to as a specific subtype based on the responsible gene in an affected person. Noonan syndrome is typically inherited in an autosomal dominant manner but many cases are due to a new mutation and are not inherited from an affected parent.