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 distinctive facial features, short stature, congenital heart disease, skeletal abnormalities, and learning difficulties.

Facial features

People with Noonan syndrome have distinctive facial features such as a deep groove in the area between the nose and mouth (philtrum), widely spaced eyes that are usually pale blue or blue-green in color, and low-set ears that are rotated backward.

Short stature

At birth, children with Noonan syndrome are typically of normal length and weight, but growth slows over time. Short stature may be alleviated with hormone treatment.

Heart disease

Most people with Noonan syndrome have some form of congenital heart disease. The most common condition is pulmonic stenosis, a narrowing of the pulmonary valve.

Skeletal abnormalities

Some people with Noonan syndrome have chest deformities, either a sunken chest (Pectus excavatum) or a protruding chest (Pectus carinatum). Other skeletal abnormalities include a curved spine (Scoliosis) and flat feet (Pes planus).

Learning difficulties

While most individuals with Noonan syndrome have normal intelligence, learning disabilities are common. These can include speech and language difficulties, problems with math, and issues with fine motor coordination.

Causes

Noonan syndrome is a genetic disorder. It is caused by mutations in several genes, including PTPN11, SOS1, RAF1, KRAS, and RIT1. These genes are all part of the RAS-MAPK pathway, which is important for controlling cell division and growth.

Diagnosis

Diagnosis of Noonan syndrome is based on the presence of typical clinical features. Genetic testing can confirm the diagnosis in about 75% of cases.

Treatment

There is no cure for Noonan syndrome. Treatment is aimed at managing the symptoms and may include surgery for heart defects, hormone treatment for short stature, and educational support for learning difficulties.

See also

• Genetic disorder
• Congenital heart disease
• Learning difficulties

Noonan's Syndrome Resources
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