What is Noonan Syndrome, Causes and Symptoms of Noonan Syndrome

Noonan Syndrome

  • Posted on- Jun 02, 2018
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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 different ways. These involve unusual facial characteristics, short stature, heart defects, other physical problems and possible developmental delays.

The prime cause of the noonan syndrome is a genetic mutation and it is acquired when a child inherits a copy of an affected gene from a parent (dominant inheritance). It can also occur as a spontaneous mutation, meaning there's no family history involved.

There's no specific treatment for Noonan syndrome. Management focuses on controlling the disease's symptoms and complications. To treat short stature in some people with noonan syndrome, growth hormone can be used.

Causes of Noonan syndrome

The mutation can be inherited from a parent who carries the defective gene (autosomal dominant), or it can develop because of a new mutation in children who don't have a genetic predisposition for the disease.

Disorders in these genes cause them to generate proteins that are continually active. Because these genes play a role in the formation of many tissues throughout the body, this constant activation of their proteins disrupts the normal process of cell growth and division.

Complications related with Noonan syndrome

Many of the symptoms associated with Noonan syndrome are treated just as they would be for anyone else experiencing a health problem. Taken together though, the many problems this disorder can cause require coordinated management by your health care team.

Complications can arise that may require special attention, including:

  • Developmental issues - If your child is affected developmentally, he or she may have difficulty with organization and spatial sense. Sometimes the developmental challenges are severe enough to require a special plan to address your child's learning and educational needs.
  • Bleeding and bruising – Excessive bleeding and bruising can be caused by noonan syndrome. This can create problems at the time of surgery or dental work. If excess bleeding and bruising affects you or your child, ignore aspirin or aspirin-containing products as aspirin can affect clotting of the blood. In general, children need to avoid aspirin because of its association with Reye's syndrome.
  • Complications related to lymphatic conditions – At times, fluid can be collected in the cavity area around the heart and lungs, requiring a chest tube to drain. Sometimes, this can result in weight loss or infection, if the draining is prolonged or needs to be repeated.
  • Complications related to genital and urinary tract - Males can surely have a low sperm count and other fertility problems because of undescended testicles (cryptorchidism). Structural abnormalities in the kidneys may increase the rate of urinary tract infections.


Talk to your doctor about undergoing genetic counseling before you have children if you are having a family history of noonan syndrome. As many of the cases of noonan syndrome occur spontaneously, there's often no known way to prevent it.

If noonan syndrome is identified early, it is possible that regular and comprehensive care can reduce some of its complications, like heart disease.




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