SLC6A3 and Parkinson disease: Also in line,our group in a previous study, and another cross-sectional study found lower levels of UA in advanced Hoehn and Yahr stages[26, 27].The longitudinal PRECEPT and DATATOP studies also found that PD patients with lower levels of UA at baseline suffered from faster rates of clinical progression, including greater declines in the UPDRS total score and striatal DAT availability[19, 20].