KCNA3 and familial long QT syndrome: LQTS is an inherited channelopathy associated with syncope and sudden death in the young, with the two most common LQTS subtypes, LQT1 and LQT2 caused by mutations in genes encoding the potassium channels KCNQ1 (responsible for the slow delayed rectifier current IKs) and KCNH2 (responsible for the rapid delayed rectifier current IKr), respectively [47].