Nav1.5 mutations may lead to various cardiac diseases such as LQT3 (long QT syndrome 3), BRGDA1 (Brugada syndrome 1), and SSS1 (sick sinus syndrome 1) (Olson et al., 2005; Song and Shou, 2012; Veerman et al., 2015). The gene discussed is SCN5A; the disease is Brugada syndrome 1.