Pathogenic variants of the sodium voltage-gated channel alpha subunit 1 (SCN1A) gene, which encodes the alpha subunit of the voltage-gated sodium channel Nav1.1, lead to impaired inhibitory interneuron function, which results in neuronal hyperexcitability and severe epileptic syndromes, such as Dravet syndrome (DS) [42]. This evidence concerns the gene SCN1A and encephalopathy, progressive, early-onset, with brain edema and/or leukoencephalopathy.