Striatal D1 and D2 receptor binding in patients with Huntington's disease and other choreas A PET study

Abstract

We have used PET to study striatal D₁ and D₂ receptor binding in 10 patients with either the choreic or akineticrigid variants of Huntington's disease and in three patients with other causes of chorea. Background rigidity and bradykinesia in choreic patients were scored with a fourpoint scale. PET studies showed a severe and parallel reduction of both striatal D₁ and D₂ receptor binding in Huntington's disease patients irrespective of their predominant phenotype (mean reduction 60%). Huntington's disease patients with rigidity showed more pronounced reduction of striatal D₁ and D₂ binding compared with those without rigidity. A case of chorea associated with systemic lupus erythematosus had normal D₂ binding. These results suggest that the presence of chorea per se may not be determined by alterations in striatal dopamine receptor binding, but that rigidity in Huntington's disease is associated with severe striatal D₁ and D₂ receptor loss.