Pathogenic SCN1B variants have previously been associated with generalized epilepsy with febrile seizures plus, Dravet syndrome, early infantile epileptic encephalopathy, inherited arrhythmia disorders such as Brugada syndrome and various other cardiac abnormalities. This evidence concerns the gene SCN1B and encephalopathy, progressive, early-onset, with brain edema and/or leukoencephalopathy.