Several epilepsy modifier genes, including CACNA1G and GABRA2, were first identified in the Scn1a+/− mouse model of Dravet syndrome and later confirmed as epilepsy risk genes in humans (Bergren et al. 2005, 2009; Butler et al. 2018; Calhoun et al. 2016, 2017; Chemin et al. 2018; Feng et al. 2019; Hawkins and Kearney 2012, 2016; Hawkins et al. 2011, 2016; Hernandez et al. 2016; Kearney et al. 2006; Miller et al. 2014). This evidence concerns the gene SCN1A and encephalopathy, progressive, early-onset, with brain edema and/or leukoencephalopathy.