SCN1A and encephalopathy, progressive, early-onset, with brain edema and/or leukoencephalopathy: The studies identified several genetic modifiers such as Hlf, the gene encoding hepatic leukemia factor, Cacna1g, the gene encoding Cav3.1 and Gabra2, the gene encoding the GABAA receptor α2 subunit that influence the phenotypes and severity of Scn1a+/− mouse model of Dravet syndrome (Hawkins and Kearney, 2016; Calhoun et al., 2017; Hawkins et al., 2021).