ROC analyses revealed that both TH+ PBMCs (AUC = 0.72) and DAT+ PBMCs (AUC = 0.72) exhibit a significantly greater than chance (p < 0.0001) predictive value in identifying PD patients even among a small of 96 subjects (Fig. 2 I, J). This evidence concerns the gene SLC6A3 and Parkinson disease.