The Noonan syndrome.

Twenty-one patients with Noonan syndrome are presented. Telecanthus low-set ears, epicanthus and facial asymmetry were the commoner facial stigmata. Pterygium colli, pectus excavatum-carinatum and mild physical and mental retardation were also common features. Pulmonary stenosis and patent ductus arteriosus were the most frequent cardiac anomalies. Wide QRS, left axis deviation, giant Q waves and a negative pattern in V6 were useful electrocardiographic signs. We speculate that the Noonan syndrome could be considered as a branchial arch development syndrome.