KCNE1 and familial long QT syndrome: Perhaps some of the most compelling evidence for clinically relevant functional modulation of hERG by KCNE1 comes from the original study reporting the A8V KCNE1 mutation, as the patient with this mutation exhibited an LQTS phenotype, whereas the A8V mutation affected KCNE1 + hERG current magnitude but not that of KCNE1 + KCNQ1 (Ohno et al. 2007).