SCN2A and epilepsy: Previous models suggest that SCN2A variants that cause an enhancement of neuronal excitability result in epilepsy and are gain-of-function, whereas, ASD-linked variants are loss-of-function and reduce channel activity (Ben-Shalom et al., 2017; Deneault et al., 2018; Ogiwara et al., 2018; Rubinstein et al., 2018; Sanders et al., 2018; Begemann et al., 2019; Lu et al., 2019; Spratt et al., 2019, 2021; Wang et al., 2021; Zhang et al., 2021).