Although cognitive impairment, seizures and behavioral abnormalities typically dominate the clinical picture, some LGI1-Ab patients develop parkinsonism (2–6%) [10, 26] or involuntary movements (2–12%) such as chorea or myoclonus [10, 12, 26, 71], which may raise the suspicion of a neurodegenerative disorder. The gene discussed is LGI1; the disease is Parkinson disease.