We tested a subset of biomarkers including FAXDC2 (C5ORF4), COPZ1, EFTUD2, SLC14A1-s, HNF4A, PTBP1 and PTPN1. The biomarkers evaluated in this study have been implicated in pathways involved in the pathogenesis of PD. Here, SLC14A1 is linked to Parkinson disease.