KCNH2 and familial long QT syndrome: The hERG cryo-EM structure is particularly valuable in addressing the structural context of natural channel mutations that underlie hERG-related channelopathies and the potential this may afford for optimising therapeutic intervention with hERG blocking antiarrhythmic agents (in the case of SQTS (Hancox et al., 2018)) or activators in the case of LQTS (Sanguinetti, 2014).