Noonan Syndrome
Noonan syndrome is caused by several alterations in one or several autosomal dominant genes. The genes that have presently been identified include PTPN11, SOS1, KRAS, and RAF1. Currently, Noonan syndrome is seen in about 1 in 1,000 to 1 in 2,500 people, most of them coming from European descent. About 270,000 Americans have Noonan syndrome.
Symptoms of Noonan syndrome include distinct facial features, such as a large head, broad nose, shortened and webbed neck, low ears, and wide-spaced eyes; short, stocky stature; congenital heart defects; minor eye problems, including strabismus; history of bleeding problems; mild developmental disorders; unusual chest shapes and low set nipples; and, in males, undescended testes.
Treatment for Noonan syndrome is similar to that of Down syndrome. Depending on the symptoms present in the individual, various degrees of medical care will be needed. Some may need growth hormone treatment, intervention for developmental issues, and so on.
