Noonan syndrome

This article needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. Find sources: "Noonan syndrome" – news · newspapers · books · scholar · JSTOR (August 2021) (Learn how and when to remove this message)

Noonan syndrome
Other names	Male Turner syndrome, Noonan–Ehmke syndrome, Turner-like syndrome, Ullrich–Noonan syndrome[1]
A 12-year-old girl with Noonan syndrome, displaying typical webbed neck and double structural curve with rib deformity.
Specialty	Medical genetics, pediatrics
Symptoms	Mildly unusual facial features, short height, congenital heart disease, bleeding problems, skeletal malformations[1]
Complications	Leukemia[1]
Usual onset	Present at birth[2]
Types	Type 1 to 6[3]
Causes	Genetic mutation (autosomal dominant)[1]
Diagnostic method	Suspected based on symptoms, confirmed with genetic testing[4][2]
Differential diagnosis	Cardiofaciocutaneous syndrome, Turner syndrome, Costello syndrome, neurofibromatosis type 1[2][3]
Treatment	Based on the symptoms[3]
Medication	Growth hormone[3]
Prognosis	Depends on the severity of heart problems[3]
Frequency	1 in 1000 (1 in 2,000 severe disease)[4]
Named after	Jacqueline Noonan

Noonan syndrome (NS) is a genetic disorder that may present with mildly unusual facial features, short height, congenital heart disease, bleeding problems, and skeletal malformations.^[1] Facial features include widely spaced eyes, light-colored eyes, low-set ears, a short neck, and a small lower jaw.^[1] Heart problems may include pulmonary valve stenosis.^[1] The breast bone may either protrude or be sunken, while the spine may be abnormally curved.^[1] Intelligence is often normal.^[1] Complications of NS can include leukemia.^[1]

A number of genetic mutations can result in Noonan syndrome.^[1] The condition may be inherited as an autosomal dominant condition or occur as a new mutation.^[3][1] Noonan syndrome is a type of RASopathy, the underlying mechanism for which involves attenuation of the RAS/MAPK cell signaling pathway.^[1] The diagnosis may be suspected based on symptoms, medical imaging, and blood tests.^[2][4] Confirmation may be achieved with genetic testing.^[2]

No cure for NS is known.^[5] Treatment is based on the symptoms and underlying problems, and extra support in school may be required.^[3] Growth hormone therapy during childhood can increase an affected person's final height.^[3] Long-term outcomes typically depend on the severity of heart problems.^[3]

An estimated 1 in 1,000 people are mildly affected by NS, while about 1 in 2,000 have a more severe form of the condition.^[4] Males appear to be affected more often than females.^[2] The condition was named after American pediatric cardiologist Jacqueline Noonan, who described her first case in 1963.^[2]