To further elucidate the tissue‐expression pathways of the specific genes implicated in the eQTL analysis (MTERF4, GNL3, ITIH4, IL1RL1, IL18R1, CLHC1, GLYCTK, and ITIH4) we applied MetaXcan using the all GTEx cortical brain tissues (Barbeira et al., 2016; Gamazon et al., 2015). MetaXcan may have increased power to detect significant gene/phenotype associations by combining genetic variants in a sparse elastic net prediction model rather than focusing on association results from single SNPs (eQTLs). All genes, excluding CLHC1, reached significance in at least one tissue. Four genes near the 3p21 region showed at least one FDR significant association (ITIH4, GNL3, GLYCTK, and TEX264 as an additional gene within the region). Figure 4 shows the −log10(p‐value) for all genes with FDR significant effects in at least one tissue (indicated by the dot). ITIH4 showed a more widespread association across tissues (significant in hypothalamus), whereas GLYTCK showed a rather specific hippocampal expression for both occipital and Cz alpha power. Immune genes IL1RL1 and IL18R1 on chromosome 2 also reached the threshold for significance in the significant association with cortical and subcortical expression with
