developmental and epileptic encephalopathy, 27 (MONDO_0014505, a Monarch Disease Ontology id) is any early infantile epileptic encephalopathy in which the cause of the disease is a mutation in the GRIN2B gene. Also known as: DEE27, EIEE27, GRIN2B early infantile epileptic encephalopathy, developmental and epileptic encephalopathy 27, early infantile epileptic encephalopathy caused by mutation in GRIN2B, epileptic encephalopathy, early infantile, 27, epileptic encephalopathy, early infantile, type 27.