Atypical parkinsonism and intrathecal anti-glutamic acid decarboxylase antibodies - an unusual association: a case report.

BACKGROUND: Immunological causes of parkinsonism are very rare and usually characterized by early presentation, poor response to levodopa, and additional clinical features. CASE PRESENTATION: We describe a 58-year-old white man who presented with a 1-year history of gait disturbance with disequilibrium leading to falls. We report an association between parkinsonism and presence of anti-glutamic acid decarboxylase antibodies in his cerebrospinal fluid, discussing clinical presentation and follow-up. CONCLUSIONS: Besides the possibility of a casual association, this case allows us to hypothesize an alternative pathophysiological mechanism of parkinsonism implying interference with glutamic acid decarboxylase and gamma-aminobutyric acid functions, eventually resulting in basal ganglia circuit dysregulation.