UCHL1 and Parkinson disease: Initial modeling of PD vs Control using all measured peptides was significant (not shown; Q2 = 0.0.171, p = 0.018) but refinement using the combination of CHGB-NYL, UCHL1-LGF, and DJ1_EGP resulted in an optimized model (Fig. 3; Q2 = 0.297, p = .0051).