SCN1A and encephalopathy, progressive, early-onset, with brain edema and/or leukoencephalopathy: SCN1A, a sodium channel present in both excitatory and inhibitory neurons, is of particular relevance to epilepsy given that 80% of patients with Dravet syndrome, which presents with severe epilepsy in children, have loss of function SCN1A mutations (Marini et al., 2011).