Indeed, cardiac arrhythmias including Brugada syndrome have been associated with increased ventricular Ito arising from gain-of-function mutations in KCND3 (Giudicessi et al., 2011), but also in KCNE3 (Delpón et al., 2008) and KCNE5 (Ohno et al., 2011). Here, KCND3 is linked to Brugada syndrome.