SLC6A3 and Parkinson disease: PD patients treated with standard-of-care treatments show reduced DAT+/TH+ PBMCs relative to drug-naïve patients, but still significantly higher than controls (Fig. 2G, H) (One-way ANOVA with Tukey’s correction, F(3,4) = 317.1, p < 0.01, p < 0.001, p < 0.0001).