Indeed, RGS9–2 plays a role in the occurrence of motor anomalies in LID, since RGS9–2 KO mice develop dyskinesia associated with D2R dysfunctions, and RGS9–2 overexpression diminishes L-DOPA-induced involuntary movements (Kovoor et al., 2005; Gold et al., 2007). This evidence concerns the gene RGS9 and drug-induced dyskinesia.