Hypoplastic left heart syndrome (HLHS) is the most commonly studied CHD phenotype [66,67,68,69], but also hiPSCs from patients with NOTCH1-associated bicuspid aortic valve (BAV) [70], GATA4-associated septal defects, and pulmonary stenosis ([71]), pulmonary atresia with intact ventricular septum [72], and elastin haploinsufficiency (Williams-Beuren syndrome) related supravalvular aortic stenosis and pulmonary stenosis [73,74] have been studied. This evidence concerns the gene NOTCH1 and hypoplastic left heart syndrome.