A, Induced pluripotent stem cells (iPSCs) were derived from patients with hypoplastic left heart syndrome (HLHS) and controls. IPSCs were differentiated into cardiomyocytes (iPSC-CMs) using standard Wnt pathway modulation protocols. On day 30 of differentiation, iPSC-CMs were subjected to assays of contractility, RNA sequencing (RNA-seq), and mitochondrial function. B, Cardiac troponin T (cTnT) expression in control and HLHS day 30 iPSC-CMs was measured by using flow cytometry. No significant difference was identified in cardiac differentiation efficiency comparing pooled iPSC lines from control individuals (n= 5 lines, 6 biological replicates) with those from 3 HLHS individuals (HLHS1, HLHS2, HLHS3, n= 12 biological replicates each).(Continued)