SLC6A3 and Parkinson disease: The performance of PD-MCI patients on VST significantly correlated with 123I-FP-CIT binding in the right caudate nucleus (rs =0.582, p < 0.05), whereas the performance of patients with PD-NC negatively correlated with dopamine transporter (DAT) availability in the left putamen (rs = −0.529, p < 0.05) (Figures 2, 3).