TPO and autoimmune encephalitis: The involuntary movements resulted in motor deterioration and forced him to be bedridden. Although no neuronal autoantibodies were detected, we hypothesized that the boy’s neurological deterioration was triggered by an autoimmune response based on the elevation of serum anti-glutamic acid decarboxylase and serum anti-thyroid peroxidase antibodies and hypermetabolism of bilateral lenticular nuclei on 18-fluorodeoxyglucose positron emission tomography that resembled those reported in patients with other types of autoimmune encephalitis.