SCN1A and encephalopathy, progressive, early-onset, with brain edema and/or leukoencephalopathy: SCN1A, a Nav1.1 α subunit composed of 26 coding exons and located in the 85-kb gene region, is the most common epileptic gene and the most common pathogenic gene in the Dravet syndrome (DS), a catastrophic and intractable epileptic encephalopathy (EE) (3).