Unusual cardiac phenotype in a newborn with noonan syndrome.

Noonan syndrome (NS; MIM #163950) is an autosomal dominant syndrome characterized by hypertelorism, downward slanting of the palpebral fissures, ptosis, low-set posteriorly angulated ears, short stature, and congenital heart disease, most commonly pulmonary valve stenosis, hypertrophic cardiomyopathy (HCM), and atrial septal defects (ASDs). We report a 6-day-old girl who had an unusual combination of supravalvular pulmonary stenosis (PS), obstructive HCM, secundum ASD, and abnormal mitral chordae. Diagnosis was based on characteristic dysmorphic features and presence of HCM. Subsequent cardiac catheterization confirmed the presence of hemodynamically significant PS, and surgical correction was planned. Supravalvular PS is an unusual cardiac phenotype in NS and its association with HCM and ASD has not been reported previously. A detailed echocardiographic examination is mandatory in NS patients for accurate diagnosis of cardiac phenotype and for further treatment plans.