Noonan Syndrome

Incidence between 1:1000-2500 live births

Incidence consistent worldwide

Equal distribution between genders

Airway

Cardiovascular

Hematologic

Infectious

Difficult airway

Cardiovascular complications

Bleeding

Endocarditis

Key features include facial anomalies, neck webbing, short stature, chest deformity, spinal deformity (e.g., scoliosis, atlanto-occipital fusion, cervical fusion), congenital heart disease (e.g., pulmonic stenosis, hypertrophic obstructive cardiomyopathy), bleeding diathesis, mental retardation.

Congenital heart disease may include pulmonic stenosis (in 80% of cases); hypertrophic obstructive cardiomyopathy (20–30%). Less common lesions include ventricular septal defect, tetralogy of Fallot, aortic stenosis, coarctation of the aorta, Ebstein malformation, total anomalous pulm venous return, and patent ductus arteriosus.

Increased incidence of cancers, especially hematologic, with roughly a 3.5-fold increased risk.

Primarily an autosomal dominant disorder; however, sporadic cases are reported.

Mutation on the PTPN11 gene on chromosome 12 in roughly 50% of cases.

Also associated with mutations in genes that are part of the RAS/RAF/MEK/ERK signal transduction pathway (regulators of cell growth).