NOTCH1 and Tetralogy of Fallot: Null mutants of Notch1 exhibit Tetralogy of Fallot, pulmonary stenosis, atrio-VSD, coarctation of the aorta, hyperplastic left heart syndrome, and left ventricular OFT malformations (Swiatek et al. 1994; Conlon et al. 1995; Timmerman et al. 2004; Grego-Bessa et al. 2007).