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 various ways: unusual facial characteristics, short stature, heart defects, other physical problems and possibly lower intelligence.
Noonan syndrome is caused by a genetic mutation and is acquired when a fetus 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. Growth hormone may be used to treat short stature in some people with Noonan syndrome.
Genital and kidney problems
When to see a doctor
The cause of Noonan syndrome is a mutation in a particular gene. Currently, scientists know of seven genes that can cause 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. Children who have one parent with Noonan syndrome have a 50 percent chance of developing the disorder.
Defects in these seven genes cause them to produce 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.
In some people, none of the seven genes has a mutation, which may mean that some other, still undiscovered genes cause Noonan syndrome.
Autosomal dominant inheritance pattern
In an autosomal dominant disorder, the mutated gene is a dominant gene located on one of the nonsex chromosomes (autosomes). You only need one mutated gene to be affected by this type of ...
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:
Preparing for your appointment
If it's suspected that you or your child has Noonan syndrome, you're likely to start by seeing your primary care doctor or your child's pediatrician. However, depending on the signs and symptoms, you or your child may be referred to a specialist. For example, if you or your child has signs and symptoms of heart disease, you'll likely be referred to a cardiologist or a pediatric cardiologist.
Because appointments can be brief, and because there's often a lot of ground to cover, it's a good idea to be well prepared. Here's some information to help you get ready, and what to expect from your doctor.
What you can do
Your time with the doctor is limited, so preparing a list of questions will help you make the most of your time together. List your questions from most important to least important in case time runs out. For Noonan syndrome, some basic questions to ask your doctor include:
What to expect from your doctor
Tests and diagnosis
A diagnosis of Noonan syndrome is usually made after a doctor observes some of the key signs of the disease, but this can be difficult because some of the features associated with this disorder are subtle and can be hard to identify. Sometimes, Noonan syndrome isn't diagnosed until adulthood, after a person has a child who is more obviously affected by the condition. Molecular genetic testing may help make a diagnosis.
If there's evidence of heart problems, your doctor will likely recommend an:
These tests can be used to assess the type and severity of the condition. These tests are usually done by a doctor who specializes in heart conditions (cardiologist).
Treatments and drugs
Treatment of the symptoms and complications that occur with Noonan syndrome depends on their type and severity. Many of the health and physical issues associated with this syndrome are treated just the way they are in the general population.
The treatment approach that your doctor may recommend to address various aspects of Noonan syndrome may include:
Coping and support
A number of support groups are available for people with Noonan syndrome and their families. Talk to your doctor about finding a support group in your area. There are also good resources on the Internet that can direct you to local support groups and sources of information about this syndrome. One such group is the Noonan Syndrome Support Group. You can reach them online or by calling 888-686-2224.
If you have a family history of Noonan syndrome, talk to your doctor about undergoing genetic counseling before you have children. However, because many of the cases of this disease occur spontaneously, there's no known way to prevent it.
If Noonan syndrome is detected early, it's possible that ongoing and comprehensive care may lessen some of its complications, such as heart disease.
Last Updated: 2011-01-08
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