Several publications support the fact that pathogenic variants in KCNQ1, ANK2, KCNE1, KCNE2, KCNH2, KCNJ2 and SCN5A can lead to a complex overlapping phenotype of LQTS, CPVT and ventricular ectopy [42,48,92]. Here, KCNJ2 is linked to familial long QT syndrome.