DRD3 and Tremor: We performed kmeans-clustering for 91 patients with idiopathic PD (iPD) including the following variables: DRD2 Taq1A (rs1800497) and DRD3 Ser9Gly (rs6208) polymorphisms, standardized medication response, the age at onset, symptom onset side, a score relating the tremor/akinetic-rigidity score, disease progression in the OFF state, and gender (cf. Table 1).