KCNH2 and familial long QT syndrome: human Ether-à-go-go-Related Gene (hERG) encodes the pore-forming subunit of cardiac rapid delayed rectifier K+ current (IKr) channels, which play important roles in ventricular repolarization, in protecting the myocardium from unwanted premature stimuli, and in drug-induced Long QT Syndrome (LQTS).