In an analysis of a cohort of 109 Dravet syndrome patients, 50% of whom had SCN1A mutations, we found 8 additional SCN9A variants within the transmembrane domains and intracellular and extracellular loops of Nav1.7 in 9 patients (Table 1). This evidence concerns the gene SCN9A and encephalopathy, progressive, early-onset, with brain edema and/or leukoencephalopathy.