DRD1 and Parkinson disease: Similarly, the DRD1 rs4532 T allele (OR = 21.33; 95% CI, 1.97-230.64; p = 0.0024) and T allele in DRD2/ANKK1 rs1800497 (OR = 3.77; 95% CI, 1.38–10.30; p = 0.0044) were significantly associated with a higher risk of developing ICB in PD patients.