Noonan Syndrome – Unusual Facies & Malformations

Noonan syndrome was recognized first as an entity in 1963 when Ehmke and Noonan described it when a series of patients faced unusual facies with multiple malformations which also included congenial heart disease.

At first it was thought that the patients had a form of Turner syndrome with which Noonan syndrome shares various clinical features. The main feature of Noonan syndrome comprises of unusual facies which is hypertelorim, webbed neck, down slanting eyes, 50% cases of congenital have heart disease, short stature together with chest deformity.

Around twenty percent of the people with Noonan syndrome have mental retardation. Besides this, bleeding diathesis is also present in half of the patients suffering with this syndrome while skeletal, neurologic, lymphatic, genitourinary, eye and skin findings may tend to vary.

Affects Various Areas of the Body

Noonan syndrome is an ailment which may affect various areas of the body and is characterized by unusual facial characteristics as mentioned above.

People with this syndrome have distinctive facial features like a deep groove in the area between the nose and mouth or philtrum, widely placed eyes which are usually blue or blue-green in colour with low set ears which are rotated backward.

The affected person may also have a high arch in the roof of the mouth, a high arched palate, poor alignment of the teeth with a small lower jaw. Most of the children with Noonon syndrome tend to have a short neck and children as well as adults may have excess neck skin which is called webbing together with a low hairline at the back of the neck.

Pectus Excavatum/Carinatum

Between fifty to seventy percent of individuals with this condition tend to have short stature and at birth they are generally of normal length and weight but their growth slows down over a period of time which could be due to the abnormal levels of growth hormone that may contribute to the slow growth.

These individuals have a sunken chest known as pectus excavatum or a protruding chest called pectus carinatum while some of them may also have an abnormal side to side curvature of the spine or scoliosis.

Most of the Noonan syndrome patients have a heart defect, the most common being the narrowing of the valve which controls blood flow from the heart to the lungs.

 Some of the affected people have hypertrophic cardiomyopathy, a thickening of the heart muscle which forces the heart to work more to pump blood.

Associated with a Variety of Bleeding Disorders

A variety of bleeding disorders are associated with this ailment and some people may also have excessive bruising, nosebleed or even prolonged bleeding after an injury or a surgery. Women who have a bleeding disorder may have excessive bleeding during menorrhagia or childbirth.

Noonan syndrome in adolescent males may experience delayed puberty and affected individuals go through puberty from the age of 13 or 14 with a reduced pubertal growth while females with Noonan syndrome typically have normal puberty and fertility.

Noonan syndrome may cause various other signs and symptoms and most of the children diagnosed with this ailment have normal intelligence though a small percentage has special educational needs while some have intellectual disability.