Current densities were significantly increased when KCNE3 was added to the D76N-KCNE1 and G52R-KCNE1-based genetic background in group 4 (51 pA/pF, 95% CI [40.9–61.1], n = 25) and in group 6 (54.3 pA/pF, 95% CI [38.2–70.5], n = 27), in comparison to group 3 (p = 0.0035) and to group 5 (p = 0.0435), representing the same LQT5 genotypes without KCNE3, respectively (Figure 1B). The gene discussed is KCNE3; the disease is long QT syndrome 5.