Several inherited Nav channelopathies are caused by LoF mutations such as Brugada syndrome, a cardiac arrhythmia due in part to Nav1.5 gating defects, and Dravet syndrome, a severe and lifelong form of pediatric epilepsy due to Nav1.1 haploinsufficiency (Loussouarn et al., 2015; Mantegazza et al., 2021). This evidence concerns the gene SCN1A and encephalopathy, progressive, early-onset, with brain edema and/or leukoencephalopathy.