Disease Injury Nutrition Poison ... Pectus excavatum Noonan syndrome Definition: Noonan 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.
Alternative Names: Turner-like syndrome of males
Causes, incidence, and 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 , 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. | |
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