A Correlational Study Of COMT(Val158Met)Gene Polymorphisms, Life Events And Major Depressive Disorder

Objective:1.To explore the correlation of catechol-O-methyltransferase(COMT) gene polymorphisms(Val158Met) and the onset of major depressive disorder, clinic phenotypes, and severity of depression at molecular level.2.To Analysis the interaction between the genetic factor and life events with the severity of depression.3.To further study the pathogenesis of major depressive disorder.Methods:A case-control study was taken and the enrollment criteria was applied strictly.250patients meet DSM-Ⅳ diagnostic criteria for major depressive disorder, and250age and gender matched controls were recruited. HAMD-17was used to evaluate the severity of depression; and LES was used to assess the life events of patients. Peripheral venous blood was collected, and genomic DNA was extracted. The COMTVal158Met genotypes were determined by the method of polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP).Statistical analysis was performed using SPSS19.0statistical software. P<0.05was set as statistically significance.Result:1. COMTVal158Me has three genotypes, and they are Val/Val, Val/Met and Met/Met respectively. There’s not statistical significance of the genotype distribution between observed and expected frequencies both in case and control group. They were consistent with Hardy-Weinberg equilibrium.2. There are significant differences between case and control group in genotypes and allele frequency distribution (P<0.05).The significant differences were only found in female but not male group (P<0.05).3. GA genotype is a protective factor for depression compared to GG, and G allele is also a protective factor compared with A. This result was only found in female but not in male group.4. HAMD total score, hysteresis factor, Maier factor, the core factor scores in patients with different genotypes were significantly different (P<0.05). There was significant difference in HAMD total score, hysteresis factor, the core factor scores between GA and other genotypes (P<0.05). Only the dilatoriness has significant difference in the all items of HAMD. 5. Life event is a risk factor for the severity of depression; the interaction of genes and life events well predicted the severity of depression.Conclusion:1. There may be significant correlation between COMTVal158Met polymorphisms and the onset of major depressive disorder in Tianjin.2. COMTVal158Met polymorphisms may be significantly associated with the severity of the depression, the core symptoms, hysteresis symptoms and Maier symptoms. GA gene may be significantly correlated with the severity and phenotype of depression.3. Life events as well as the interaction between COMTVal158Met polymorphism and life events were correlated with the severity of depression.