Noonan syndrome

Question 1

What is Noonan syndrome?

Answer 1

Noonan syndrome is a genetic condition. There are a number of different genes that cause Noonan syndrome. The majority for cases are inherited in an autosomal dominant way. There is variation in the signs and symptoms of Noonan syndrome, depending on the underlying cause.

Question 2

Features of Noonan syndrome?

Answer 2

Short stature
Broad forehead
Downward sloping eyes with ptosis
Hypertelorism (wide space between the eyes)
Prominent nasolabial folds
Low set ears
Webbed neck
Widely spaced nipples

Question 3

Associated conditions Noonan syndrome?

Answer 3

Congenital heart disease, particularly pulmonary valve stenosis, hypertrophic cardiomyopathy and ASD
Cryptorchidism (undescended testes) can lead to infertility. Fertility is normal in women.
Learning disability
Bleeding disorders
Lymphoedema
Increased risk of leukaemia and neuroblastoma

Question 4

Management Noonan syndrome?

Answer 4

There is no treatment for the underlying genetic defect. Management is supportive with involvement of the multidisciplinary team. The main complication is congenital heart disease and often patients will require corrective heart surgery.