Overview
Noonan syndrome describes a set of features seen due to mutations affecting the RAS/MAPK signalling pathway. It is autosomal dominant.
Noonan syndrome is often thought of as ‘male Turner syndrome’, however, this is incorrect.
Epidemiology
- Noonan syndrome has an estimated incidence of up to 1 in 1000 children
Presentation
- Short stature
- Webbed neck
- Hypertelorism – widely-spaced eyes
- Low-set ears
- Triangular-shaped face
- Pulmonary stenosis
- Easy bruising and bleeding due to clotting factor deficiencies – seen in around 40% of affected people
