Here, we describe three adult patients with variants in GRIN2A, affected by developmental and epileptic encephalopathy, focusing on seizure semiology, EEG, and response to antiseizure medications (ASMs) to better delineate the electroclinical features, treatment options, and long-term outcome of epilepsy associated with GRIN2A variants. This evidence concerns the gene GRIN2A and Epileptic encephalopathy.