KCNQ1 and familial long QT syndrome: GATA-4 is required for normal heart development as well hypertrophic responses in cardiac myocytes.26 In a human in vitro cardiac model, researchers suggested that KCNQ1-SupRep gene therapy by CRISPR-Cas9 in induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) can be considered for complete correction of long QT syndrome.27 Similarly, Yamamoto et al28 using Cas9 double nickase system in hiPSCs, generate in vitro allele-specific knockout models of channelopathy long QT syndrome (LQTS).