KCNH2 and short QT syndrome: Loss-of-function hERG mutations are well established to underlie the LQT2 form of congenital Long QT syndrome (LQTS; Vandenberg et al. 2001; Sanguinetti and Tristani-Firouzi 2006; Witchel and Hancox 2000) and, within the last decade, gain-of-function hERG mutations have been linked to the SQT1 form of the short QT syndrome (Brugada et al. 2004; Hong et al. 2005; Sun et al. 2011).