Correlation between dopamine receptor D2 expression and presence of abnormal involuntary movements in Wistar rats with hemiparkinsonism and dyskinesia.
From 37 candidate studies on levodopa toxicity, 18 genes were found associated, of which, CA<sub>n</sub> STR 13, 14 (DRD2) was most significantly associated with dyskinesia, followed by rs1801133 (MTHFR) with hyper-homocysteinemia, and rs474559 (HOMER1) with hallucination.
Since genetic factors could play a role in determining the occurrence of these problems, the aim of the present study was to investigate whether possible functional polymorphisms among DRD2 and ANKK1 genes are associated with the risk of developing dyskinesia and motor fluctuations in Parkinson's disease patients.
The pathogenesis of dyskinesia may result from divergent changes in dopamine D1 receptors (DRD1) and dopamine D2 receptors (DRD2) in the brain while aging.
Certain alleles of the short tandem repeat polymorphism of the dopamine receptor D2 gene reduce the risk of developing peak-dose dyskinesias and could contribute to varying susceptibility to develop peak-dose dyskinesias during levodopa therapy.