Both FLT4 duplications and loss-of-function mutations have been previously described in patients with TOF.6,7,14,30 This indicates that FLT4 duplication may cause CHD phenotypes other than TOF, as the patients in our setting had atrioventricular septal defect and ASD with pulmonary stenosis. This evidence concerns the gene FLT4 and familial atrioventricular septal defect.