Noonan Syndrome

Noonan Syndrome is a genetic disorder that stops normal development of a range of body parts. Someone who has Noonan Syndrome will have unusual facial features, heart defects, short stature and other physical problems. Possible lower than normal intelligence, has been described. It is caused by a genetic mutation and occurs when a fetus inherits a mutated gene from a parent, (dominant inheritance). It can also happen spontaneously, (no family history). There is no cure for Noonan Syndrome, it can only be managed. In some cases, the short stature is treated with growth hormone. It affects about 1 in 2,500 children.

Symptoms of Noonan Syndrome

Facial Features: – the way a person’s face appears, is often the first key Noonan Syndrome diagnosis, and changes as the person ages. A baby will have wide set and downward slanting eyes, ears that are low set, low hairline at the back of the head, a deep groove in their upper lip and a short neck. An older infant can have bulging eyes and a depressed nose with a prominent tip and a wide base. A lack of any real degree of facial expression is often reported in childhood. In adolescence the face is typically triangular with a wide forehead and a pointed chin. The eyes are less prominent and the facial features are sharper. Lengthening of the neck reveals extra skin folds (webbed neck) and sometimes prominent neck muscles (trapeziums). In adults the lines that run from the side of the nose to the corner of the mouth are more pronounced and can be wrinkled in appearance and transparent. Wide set nipples are another feature.

Heart Disease: It is estimated that over 75% of people with Noonan Syndrome, have a congenital (since birth) heart disease. Some of these defects include;

Pulmonary Valve Stenosis: This is a condition wherein flap of tissue that separates the lower right chamber of the heart from the Pulmonary artery and that which supplies blood to the lungs narrows. For Noonan Syndrome sufferers it is the most common heart defect.

Hypertrophic Cardiomyopathy:  This is an abnormal thickening of the heart muscle and affects approximately 20-25 % of people with Noonan Syndrome.

Other Defects: – Ventricular Septal Defect which is a hole in the wall of the heart that causes separation of the two lower chambers and Pulmonary Arterial Stenosis  which is the narrowing of the arteries that carry oxygenated blood to the lungs.

Skeletal: – Noonan Sndrome sufferers will often have a raised sternum (pectus carinatum)or a sunken sternum (pectus excavatum) which causes an unusual shaped chest.

Eye Problems: – Differences in the size and shape  of the eyes are very clear and obvious. Crossed eyes, near sightedness and far sightedness as well as rapid eyeball movement are all common in people with Noonan Syndrome.

Bleeding: – Abnormal bleeding and heavy bruising are not uncommon. It is often undiscovered until the person undergoes surgery and experiences hemorrhaging.

Kidney and Genital Problems:- Males especially can have genital and kidney problems. Kidney problems are usually mild however a vast amount of males have undescended testes.

Skin Problems: – People with Noonan Syndrome often have problems that affect the texture and color of their skin. They often have curly, coarse or sparse hair.





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