Combined with the fact that all 19 SNPs are both meQTL and eQTL SNPs for gene TOX2 in the frontal cortex and the fact that hypomethylation has been previously suggested to be correlated with up-regulation of gene expression (46), consistent evidence from both methylation and gene expression data indicated that the minor alleles (protective) of MDD-associated SNPs upregulate the gene expression of TOX2 in the frontal cortex (Supplemental Tables S8 and S10). This evidence concerns the gene TOX2 and major depressive disorder.