Lawton M, et al. - As blood biomarkers could assist in predicting prognosis in Parkinson disease (PD) that has important implications for individual prognostication and clinical trials design and targeting novel treatments, researchers here evaluated 4 blood biomarkers (apolipoprotein A1, C-reactive protein, uric acid, and vitamin D) in this study that might predict prognosis. From the Oxford Discovery prospective cohort, serum from 624 Parkinson disease individuals was examined for baseline biomarker measures. These measures were compared against PD subtypes derived from clinical features in the baseline cohort using data-driven approaches. The PD subtypes differed in apolipoprotein A1 and C-reactive protein levels, with the severe motor disease phenotype, poor psychological well-being, and poor sleep subtype having decreased apolipoprotein A1 and higher C-reactive protein levels. They observed an association of reduced apolipoprotein A1, higher C-reactive protein, and reduced vitamin D with worse baseline activities of daily living. This work thereby lends support to biological validity to subtyping approaches. They recognized no blood biomarker as predictive of motor or nonmotor prognosis.