A novel mutation in the KCNH2 gene associated with short QT syndrome

►A novel T618I mutation in the KCNH2 gene underlies the SQT1. ►Steady current of the mutant HERG channels is 6-fold greater than WT. ►The voltage dependence of inactivation is shifted in the positive direction. ►Quinidine and sotalol effectively inhibit steady currents of mutant channels.