Similarly, the SupRep technique was able to substantially increase the shortened APD of hiPSC-CMs carrying the N558K (p.Asn558Lys) gain-of-function mutation in KCNH2 associated with short QT syndrome type 1, although not to the control level, as in our simulations of the SQT3 mutations. The gene discussed is KCNJ2; the disease is Familial short QT syndrome.