A 3-year-old female with a GluN2A-N615K variant exhibits early-onset EE, an abnormal EEG, and a severe DD75, whereas for a GluN2B-N615I variant, the patient had West syndrome, hypsarrhythmia, and ID due to neurodevelopment disorders80,84 and GluN2B-N615K patient had ID and DD84. Here, GRIN2B is linked to Hypsarrhythmia.