The haplotypes of the FoxO1 gene showed a significant global association (χ2 = 19.732, df = 13, Pglobal < 0.001) and the less common haplotype (G-A-G-C-T-A) of the A2M gene was significantly associated with MDD (χ2 = 4.931, Peffect = 0.026). The gene discussed is FOXO1; the disease is major depressive disorder.