For instance, the LQT3-associated mutation SCN5A-T1620K showed electrophysiological properties similar to those of hNaV1.5, hNaV1.5a, and hNaV1.5c, but different effects in the hNaV1.5d background (Gaetano et al., 2011). Here, SCN5A is linked to long QT syndrome 3.