Noonan syndrome

Noonan syndrome :

Noonan was first recognized as a unique entity in 1963 when Noonan and Ehmke described a series of patients with unusual facies and multiple malformations, including congenital heart disease.

These patients were previously thought to have a form of Turner syndrome, with which Noonan syndrome shares numerous clinical features. The observation that patients with Noonan syndrome have normal karyotypes was important in allowing the distinction to be made between the Turner and Noonan syndromes.

The cardinal features of Noonan syndrome include unusual facies (ie, hypertelorism, down-slanting eyes, webbed neck), congenital heart disease, short stature, and chest deformity.

Approximately 25% of individuals with Noonan syndrome have mental retardation. Bleeding diathesis is present in as many as half of all patients with Noonan syndrome. Skeletal, neurologic, genitourinary, lymphatic, eye, and skin findings may be present to varying degrees.

Facial features of this syndrome:

·         Triangular-shaped face

·         Hypertelorism

·         Down-slanting palpebral fissures

·         Ptosis

·         Strabismus (48%)

·         Amblyopia (33%)

·         Refractive errors (61%)

·         Low-set ears with thickened helices

·         High nasal bridge

·         Short, webbed neck