This review first outlines how epigenetic dysregulation contributes to psychosomatic disorders through altered expression of genes such as GRM2, TRPA1, SLC6A4, NR3C1, leptin, BDNF, NAT15, HDAC4, PRKCA, RTN1, PRKG1, and HDAC7. This evidence concerns the gene HDAC4 and somatoform disorder.