SCN1A and encephalopathy, progressive, early-onset, with brain edema and/or leukoencephalopathy: Febrile seizure due to infection or prolonged heat exposure is a common mechanism contributing to the onset and progression of Dravet syndrome (DS) symptoms, and similar hyperthermia-induced disease exacerbation is recapitulated in juvenile Scn1a-deficient mice (59, 60).