Genetic defects in K+ATP channel genes (64, 188, 190), the insulin gene (191, 192), or the ER-stress related genes WFS1, YIPF5 and MANF (79, 80, 175) that cause neonatal diabetes and congenital hyperinsulinism have been modeled with hPSCs using diverse strategies. The gene discussed is INS; the disease is hyperinsulinism.