SCN1A and Dravet syndrome: Most DS cases (70–95%) are caused by mutations in the Scn1a gene (MIM#182389), which encodes the pore-forming subunit of a voltage-gated Na+ channel (Nav1.1) (Meisler and Kearney, 2005; Fujiwara, 2006; Catterall et al., 2010; Akiyama et al., 2012).