Arteriovenous malformation presenting as hemidystonia.

Two men, aged 25 and 33 years, had progressive hemidystonia and an arteriovenous malformation (AVM) in the contralateral cerebral hemisphere. One patient with an AVM in the posterior basal ganglia of the right hemisphere had an older brother with severe generalized dystonia. The second patient had an AVM in the left cortical and subcortical parietal area with no obvious lesion in the basal ganglia. Unlike generalized dystonia, a focal lesion is commonly found in patients with unilateral dystonia. The association of AVM-induced hemidystonia and family history of dystonia suggests that genetic predisposition may be important in some patients with hemidystonia.