Who gets it?
Noonan syndrome is estimated to occur in 1 in 1,000 - 2,500 live births. It affects males and females equally, and occurs in people of all ethnic backgrounds. It may occur spontaneously (no one else in the family has it). However, if a child is discovered to have Noonan syndrome, careful examination of his or her parents might reveal that they, too, are mildly affected. Noonan syndrome can be passed on genetically.
Symptoms
Noonan syndrome is present from birth, but the distinctive facial features may not be apparent until the child is a little older. As the individual ages, the facial features may become less obvious and only able to be recognized through a careful examination. Symptoms of Noonan syndrome may include:
- Unusual facial features such as widely-spaced eyes, triangular face, low-set ears, and short webbed neck
- Short stature (80% of individuals)
- Congenital heart defect (50% of individuals)
- Abnormal chest
- Undescended testes in males (more than 50%)
- Bleeding disorders, especially Factor XI (clotting factor) deficiency
Diagnosis
There is no one test that can diagnose Noonan syndrome, so it is identified by the physical malformations present, especially the facial features. Any child suspected of having the syndrome should have a complete heart examination, to look for heart defects. Blood tests can check for a deficiency of Factor XI or other clotting factors. Putting all these results together can help confirm a diagnosis of Noonan syndrome.
Treatment
Treatment for Noonan syndrome focuses on its symptoms. Close monitoring of the individual's heart condition is important, because heart problems are the most common cause of death for people with the syndrome. Some heart problems may be able to be corrected with surgery. Since the symptoms can vary widely, different specialists might be needed to provide medical care for different individuals.
It is important that any family affected by Noonan syndrome receive genetic counseling. Parents who are only mildly affected by the syndrome have a 5% risk of passing it on to their children. Parents who have many of the symptoms, however, have a 50% chance of passing it to their children. If the parents are not affected by Noonan syndrome there is no increased risk for any future children.
Information for this article was taken from:
Ibrahin, J., & McGovern, M. (2002). Noonan syndrome. eMedicine, accessed at http://www.emedicine.com/ped/topic1616.htm
