SCN8A and developmental and epileptic encephalopathy, 13: SCN8A-developmental and epileptic encephalopathy (DEE) or early infantile epileptic encephalopathy type 13 (EIEE13) (OMIM #614558) is a severe rare autosomal dominant disorder characterized by early-onset intractable seizures, moderate to severe ID, cortical vision impairment, lack of language, motor disorders, inability to walk, and elevated risk of sudden unexpected death.44 Variable phenotypes emanate from different SCN8A mutations.