Andersen-Tawil syndrome Episodes usually begin before age 20 with all or some of the clinical triad: Periodic paralysis Prolonged QT interval and ventricular arrhythmias Dysmorphic physical features Dysmorphic physical features include short stature, high-arched palate, low-set ears, broad nose, micrognathia, hypertelorism, clinodactyly of the fingers, short index fingers, and syndactyly of the toes.