Description
Parkinsons disease (PD) progresses relentlessly and affects five million people worldwide. Laboratory tests for PD are critically needed for developing treatments designed to slow or prevent progression of the disease. We performed a transcriptome-wide scan in 105 individuals to interrogate the molecular processes perturbed in cellular blood of patients with early-stage PD. The molecular marker here identified is strongly associated with risk of PD in 66 samples of the training set (third tertile cross-validated odds ratio of 5.7 {P for trend 0.005}). It is further validated in 39 independent test samples (third tertile odds ratio of 5.1 {P for trend 0.04}). The genes differentially expressed in patients with PD, or Alzheimers or progressive supranuclear palsy offer unique insights into disease-linked processes detectable in peripheral blood. Combining gene expression scans in blood and linked clinical data will facilitate the rapid characterization of candidate biomarkers as demonstrated here with respect to PD.