In conclusion, we have performed EWAS of depression symptomatology score in a unique cohort of elderly monozygotic twins and identified blood methylation levels at KLK8, DAZAP2, MAD1L1, SLC29A2, AKT1, and other genes, as well as several DMRs across the genome to be associated with this trait. Here, SLC29A2 is linked to major depressive disorder.