GRIN2B and Parkinson disease: Logistic regression analysis (adjusted for gender, age, ethnicity, dosage of medication and duration of PD) showed that there was a significantly higher risk of ICB that was associated with the DRD1 rs4867798 C allele (OR = 24.53; 95% CI, 1.68-357.28; p = 0.0054) and the GRIN2B rs7301328 C allele (OR = 25.07; 95% CI, 1.30-483.41; p = 0.0097).