SCN1A and encephalopathy, progressive, early-onset, with brain edema and/or leukoencephalopathy: Dravet Syndrome (DS) is a severe encephalopathy with epilepsy linked in most cases to de novo loss of function mutations of the SCNA1 gene encoding for the α subunit of Nav1.1 voltage-dependent sodium channels (Claes et al., 2001; Catterall et al., 2010; Dravet, 2011).