developmental and epileptic encephalopathy, 43 (Monarch Disease Ontology identifier MONDO_0014921) is any early infantile epileptic encephalopathy in which the cause of the disease is a mutation in the GABRB3 gene. Also known as: DEE43, EIEE43, GABRB3 early infantile epileptic encephalopathy, developmental and epileptic encephalopathy 43, early infantile epileptic encephalopathy caused by mutation in GABRB3, epileptic encephalopathy, early infantile, 43, epileptic encephalopathy, early infantile, 43; EIEE43, epileptic encephalopathy, early infantile, type 43.