Noonan Syndrome: Phenotypic Variations and Molecular Genetics

Abstract Noonan syndrome is a genetic multisystemic disorder with a prevalence of 1 in 1000–2500 newborns. This condition is characterized by dysmorphic features, developmental delay, short stature, congenital heart disease, lymphatic malformations, genitourinary anomalies, and bleeding difficulties. Mutations that cause Noonan syndrome alter genes encoding proteins with a role in the RAS/MAPK pathway. Medical management guidelines have been developed for this condition and molecular genetic testing is available diagnostically and may provide further aid in long medical management and prognosis (Roberts et al. [5] ).