Any early infantile epileptic encephalopathy in which the cause of the disease is a mutation in the GRIN2D gene. The disease is MONDO_0014947 (developmental and epileptic encephalopathy, 46). Also known as: DEE46, EIEE46, GRIN2D early infantile epileptic encephalopathy, GRIN2D-related DEE, GRIN2D-related complex neurodevelopmental disorder, GRIN2D-related developmental and epileptic encephalopathy, developmental and epileptic encephalopathy 46, early infantile epileptic encephalopathy caused by mutation in GRIN2D.