Rather than generating mutated iPSC-CMs from LQTS patients, the ion channel genes KCNQ1 and KCNH2 with dominant negative mutations causing long-QT syndrome types 1 and 2, respectively, were stably integrated into a safe harbor AAVS1 locus using zinc finger nuclease technology [251]. This evidence concerns the gene KCNQ1 and familial long QT syndrome.