An additional six rare forms of LQTS involve ion channels: KCNE1 (LQT5) as potassium voltage-gated channel subfamily E regulatory subunit 1, KCNE2 (LQT6) encoding potassium voltage-gated channel subfamily E regulatory subunit 2, KCNJ2 (LQT7) for inward rectifier potassium channel KIR2.1, CACNA1 (LQT8) for L-type calcium channel subunit, SCN4B (LQT10) for sodium channel-β4, and KCNJ5 (LQT13) for KIR3.4 [2, 6]. Here, KCNE2 is linked to familial long QT syndrome.