Extract Noonan syndrome is an autosomal dominant genetic condition with multisystem involvement and an estimated prevalence of one in 1000 to 2500 live births 1. Its unifying biological feature is dysregulation of the RAS/MAP kinase signalling pathway with pathogenic variants most commonly found in PTPN11 (∼50%), SOS1 (10%), RAF1 (5–15%) and RIT1 (10%) 2, 3. Cardiovascular manifestations are among the most clinically significant features, including pulmonary stenosis in 50–60% of individuals, hypertrophic cardiomyopathy in 20%, and secundum-type atrial septal defects in 6–10% 3.
Garry et al. (Mon,) studied this question.