More than 20 disease-causing genes have been reported in almost 70% LQTs patients, including KCNQ1 (30.1%, type-1 of LQTs), KCNH2 (23.2%, type-2 of LQTs) and SCN5A (5.7%, type-3 of LQTs). This evidence concerns the gene KCNQ1 and familial long QT syndrome.