However, Nav1.1 is the major sodium channel in interneurons, and a loss of function of this channel in GABAergic interneurons explains the hyperexcitability found in Dravet syndrome (Catterall et al., 2010; Mantegazza et al., 2021; Mantegazza & Broccoli, 2019). This evidence concerns the gene SCN1A and encephalopathy, progressive, early-onset, with brain edema and/or leukoencephalopathy.