Noonan's syndrome

Noonan Syndrome is a genetic disorder that prevents normal development in various parts of the body. A person can be affected by Noonan syndrome in a myriad of ways, including unusual facial characteristics, short stature, heart defects, other physical problems and possible developmental delays.

Signs and Symptoms

Noonan syndrome is associated with a range of signs and symptoms. Common features include facial abnormalities such as a deep groove in the area between the nose and mouth (philtrum), widely spaced eyes that are often pale blue or blue-green in color, and low-set ears that are rotated backward. Affected individuals may also have a high arch in the roof of the mouth (palate), poor teeth alignment and a small lower jaw (micrognathia).

Many people with Noonan syndrome have short stature. Both children and adults are typically below average height for their age and gender. Heart defects are common, occurring in 50-80% of individuals. The most common heart defect is Pulmonic stenosis, a narrowing of the pulmonary valve.

Causes

Noonan syndrome is a genetic disorder. It is caused by mutations in several different genes, including PTPN11, SOS1, RAF1, KRAS, and RIT1. These genes are all part of the RAS-MAPK pathway, which is important for controlling cell growth and division. Mutations in these genes disrupt the normal function of the pathway, leading to the characteristic features of Noonan syndrome.

Diagnosis

Diagnosis of Noonan syndrome is often based on the characteristic signs and symptoms. Genetic testing can confirm the diagnosis. This testing can identify mutations in the genes associated with Noonan syndrome.

Treatment

There is no cure for Noonan syndrome. Treatment is focused on managing the symptoms and complications. This can include surgery to correct heart defects, growth hormone therapy for short stature, and educational support for learning difficulties.

Prognosis

The prognosis for individuals with Noonan syndrome varies depending on the specific symptoms and severity. Many individuals live healthy lives with normal lifespan. However, those with serious heart defects may have a poorer prognosis.

See Also

• Genetic disorder
• RASopathies
• Pulmonic stenosis

Noonan's syndrome Resources
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