SCN2A and Down syndrome: Likewise, mutations in the SCN2A gene (A467T), that encodes the voltage-gated sodium channel Nav1.2, have been shown to elicit seizure behavior such as in generalized epilepsy with febrile seizure plus (GEFS+) syndrome by also enhancing sodium currents (Schmunk and Gargus, 2013; Wolff et al., 2017).