Any early infantile epileptic encephalopathy in which the cause of the disease is a mutation in the KCNT1 gene. The disease is developmental and epileptic encephalopathy, 14 (Monarch Disease Ontology identifier MONDO_0013989). Also known as: DEE14, EIEE14, KCNT1 early infantile epileptic encephalopathy, developmental and epileptic encephalopathy 14, early infantile epileptic encephalopathy caused by mutation in KCNT1, epileptic encephalopathy, early infantile, 14, epileptic encephalopathy, early infantile, type 14.