Despite the strong association between variants of the SCN1A gene and Dravet syndrome, there is considerable heterogeneity in the phenotypes of SCN1A associated epilepsies (Sugawara et al., 2003; Ohmori et al., 2006; Escayg and Goldin, 2010; Liao et al., 2010; Meng et al., 2015; Peters et al., 2016). This evidence concerns the gene SCN1A and Dravet syndrome.