|
|
Noonan Syndrome
Alternate Names : Turner-Like Syndrome of Males
DefinitionNoonan syndrome is a genetic disorder that causes abnormal development of multiple parts of the body. In particular there is webbing of the neck and different shapes to the chest that are reminiscent of Turner syndrome, hence the former name Turner-like syndrome.
Pictures & Images
 See all Pictures & Images
Overview, Causes, & Risk Factors
Noonan syndrome can be inherited in an autosomal dominant manner. It affects at least 1 in 2,500 children. The fact that some children do not have a parent with Noonan syndrome likely reflects sporadic inheritance, that is, presumably the occurrence of a new mutation. The first specific gene that causes Noonan syndrome, called PTPN11, was discovered in 2001. It is expected that other genes will be discovered that cause Noonan syndrome.
Frequently seen abnormalities include webbing of the neck, changes in the sternum (usually a sunken chest called pectus excavatum), facial abnormalities, and congenital heart disease (especially pulmonic stenosis). Because these abnormalities resemble those of Turner syndrome (which only affects females), Noonan syndrome used to be called "male Turner syndrome," this term is no longer used because Noonan syndrome can affect females also.
Facial abnormalities may include low-set or abnormally shaped ears, sagging eyelids (ptosis), wide-set eyes (hypertelorism), epicanthal folds, and a small jaw (micrognathia). Mild mental retardation is present in about 25% of cases. Hearing loss varies. Puberty is usually delayed, and males may have undescended testicles and a small penis. Adult height is usually decreased.
Today's Top News Stories | • | FDA Backs Cholesterol Drug Vytorin - Jan 08, 2009, 17:00
Review says it lowered bad cholesterol more effectively than Zocor. | • | Many Turn Blind Eye to Racism - Jan 08, 2009, 17:00
They're not quick to condemn hurtful comments, study suggests. | • | Clinical Trials Update: Jan. 8, 2009 - Jan 08, 2009, 10:12
- Rheumatoid Arthritis
- Neurologic Disorders
- Seizure Disorders
| • | Protein Might One Day Prevent Blindness - Jan 08, 2009, 14:00
Researchers find it prolongs lives of key vision cells in mice. | • | Inflammation Markers May Help Predict Stroke Risk - Jan 08, 2009, 16:00
They should be used when assessing traditional risk factors, experts say. |
|
Jump to another section
• Definition
• Noonan Syndrome Overview, Causes, & Risk Factors
• Noonan Syndrome Symptoms & Signs
• Noonan Syndrome Prevention
• Noonan Syndrome Diagnosis & Tests
• Noonan Syndrome Treatment
• Noonan Syndrome Prognosis
• Noonan Syndrome Complications
• Noonan Syndrome Support Groups
• Calling Your Health Care Provider
• Pictures & Images
Topics that might be of interest to you Diseases & Conditions
• Atrial Septal Defect
• Heart Disease
• Mental Retardation
• Ptosis
• Pulmonary Valve Stenosis
Tests & Exams
• Chest X-Ray
• ECG
Other Topics
• Hearing Loss
• Penis
• Short Stature
• Testes
Review Date : 8/6/2003
Reviewed By : Douglas R. Stewart, M.D., Division of Medical Genetics, Hospital of the University of Pennsylvania, Philadelphia, PA. Review provided by VeriMed Healthcare Network.
|
|
