Aggressive course in encephalitis with opsoclonus, ataxia, chorea, and seizures: the first pediatric case of γ-aminobutyric acid type B receptor autoimmunity.

Importance: Autoantibodies to the γ-aminobutyric acid type B (GABAB) receptor have recently been identified as a cause of autoimmune encephalitis. Most patients with GABAB encephalitis have presented with limbic encephalitis. About half of the cases reported have been paraneoplastic in origin, with the majority of tumors representing small cell lung cancer.