Overlapping the expression of genes potentially underpinning PD GWAS risk loci10, identified five significantly differentially expressed genes (BST1, FCGR2A, SIPA1L2, NOD2 and VAMP4, log2FC > 0.1/ < −0.1, FDR < 0.05) in PPMI, although none passed multiple testing correction in ICICLE-PD (Fig. 2e and Supplementary Data 5). This evidence concerns the gene NOD2 and Parkinson disease.