GAD2 and autoimmune encephalitis: Due to rapid clinical deterioration and fluctuating cognition, autoimmune testing was expanded to a full antibody panel, which identified elevated serum anti-glutamic acid decarboxylase 65 (anti-GAD65) antibodies (60 UI/mL, reference range 0-5 UI/mL), establishing a possible coexisting diagnosis of anti-GAD65 autoimmune encephalitis.