KCNQ1 and familial long QT syndrome: Since 2007, sporadic cases have revealed that LVHT can be co-phenotype with genetic confirmed LQT-1(KCNQ1 p.D611T, p.L273F) [3, 4] or LQT-2(KCNH2 p.A561V, p.D501N, p.T1019Pfs×38, p.Y616C) [5–7], or LQTS with SCN5A variants [8].