Noonan syndrome type 3

Noonan syndrome type 3

A relatively common (1:2500 live births) autosomal dominant condition (OMIM:609942) characterised by dysmorphic facial features, short stature, hypertelorism, cardiac anomalies, deafness, motor delay and a bleeding diathesis; it may be associated with juvenile myelomonocytic leukaemia.

Molecular pathology
Defects in KRAS, which encodes a small GTPase, cause Noonan syndrome type 3.