Moreover, the fact that KCND3 variants which cause unique electrophysiological abnormalities (both gain- and loss-of-function) of Ito are associated with a novel cardiocerebral channelopathy may also suggest the association between unique electrophysiological properties of IKs and epileptiform activity (or epilepsy) (Takayama et al., 2019; Nakajima et al., 2020b). This evidence concerns the gene KCND3 and epilepsy.