Dopamine D-3 receptor variant and tardive dyskinesia

In the search for genetic factors contributing to tardive dyskinesia, dopam ine receptor genes are considered major candidates. The dopamine D-3 recept or is of primary interest as dopamine D-3 receptor knock-out mice show loco motor hyperactivation resembling extrapyramidal side-effects of neuroleptic treatment. Furthermore, Steen and colleagues (1997) recently reported an a ssociation between tardive dyskinesia and a dopamine D-3 receptor gene vari ant. In the present study we tried to replicate this finding. We investigated 15 7 patients with schizophrenia or schizoaffective disorder receiving long-te rm neuroleptic medication who never or persistently displayed tardive dyski nesia. As advanced age is a main risk factor for tardive dyskinesia, we als o compared older patients with a long duration of schizophrenia not display ing tardive dyskinesia to younger patients with a shorter duration of the i llness displaying tardive dyskinesia. However, we found no evidence that th e dopamine D-3 receptor gene is likely to confer susceptibility to the deve lopment of tardive dyskinesia.