SCN5A and familial long QT syndrome: Current guidelines recommend genetic analysis of the three main prevalent LQTS-associated genes: KCNQ1 (encoding the Kv7.1, 30–35% of cases), KCNH2 (encoding the Kv11.1 potassium channel, 25–30% of cases) and SCN5A (encoding the Nav1.5 sodium channel, 5–10% of cases) [10].