Dravet syndrome is an epileptic encephalopathy most often caused by loss-of-function mutations in the <i>SCN1A</i> gene, leading to haploinsufficiency of the voltage-gated sodium channel Na<sub>V</sub>1.1. Here, SCN1A is linked to encephalopathy, progressive, early-onset, with brain edema and/or leukoencephalopathy.