Any early infantile epileptic encephalopathy in which the cause of the disease is a mutation in the SCN8A gene. The disease is developmental and epileptic encephalopathy, 13 (Monarch Disease Ontology entry MONDO_0013801). Also known as: DEE13, EIEE13, SCN8A early infantile epileptic encephalopathy, developmental and epileptic encephalopathy 13, early infantile epileptic encephalopathy caused by mutation in SCN8A, early infantile epileptic encephalopathy-13, epileptic encephalopathy, early infantile, 13, epileptic encephalopathy, early infantile, type 13.