Isolated Chorea Associated with LGI1 Antibody

Background Leucine-rich glioma inactivated 1 (LGI1) antibody produces a syndrome of limbic encephalitis, hyponatremia, and facio-brachial dystonic seizures that is non-paraneoplastic and responsive to corticosteroids. Parkinsonism, tremor, and generalized chorea are rare manifestations of LGI1, but, when present, commonly accompany other signs of limbic encephalitis. Case Report We present a case of LGI1-related isolated chorea in a 53-year-old Japanese male. His chorea responded to high-dose steroids, suggesting a potential role for this synaptic antibody in triggering chorea. Discussion This case highlights a new treatable etiology of chorea