Association of serotonin transporter gene promoter region polymorphisms with major depressive disorder

Abstract

Objective To explore the association of serotonin transporter gene promoter region polymorphisms with the onset of major depressive disorder. Methods A case-control association study was taken, 350 patients which met the diagnostic and statistical manual of mental disorders in the fourth edition (DSM-IV) criteria for major depressive disorder (MDD), and 370 age- and gender-matched controls were recruited. HAMD-17 was used to evaluate the severity of depression. Peripheral blood of all the objects was collected, and genomic DNA was extracted. Polymerase chain reaction-restriction fragment length polymorphisms (PCR-RFLP) was used to detect 5-HTTLPR/rs25531 genotypes. SPSS19.0 statistical software was used for statistical analysis. Results The 5-HTTLPR genotypes and alleles frequency distribution between MDD patients (LL, LS, SS genotypes: 10.9%, 38.0%, 51.1%; L, S alleles: 29.9%, 70.1%) and controls (LL, LS, SS genotypes: 12.4%, 40.5%, 47.1%; L, S alleles: 32.7%, 67.3%) had no significant difference (P=0.522; P=0.245). However, the frequency of 5-HTTLPR/rs25531 genotypes and alleles distribution between MDD patients(L’L’, L’S’, S’S’ genotypes: 6.6%, 34.5%, 58.9%; L’, S’ alleles: 21.7%, 78.3%)and controls(L’L’, L’S’, S’S’ genotypes: 8.1%, 42.4%, 49.5%; L’, S’ alleles: 29.3%, 70.7%) had statistically significance(P=0.041; P=0.019). Logistic regression analysis showed that S’S’ (SS, LGS, LGLG) was the risk genotype for MDD (P=0.016, OR=1.461, OR95%CI=1.072-1.991). Conclusion No significant association was found between 5-HTTLPR polymorphism and the onset of major depressive disorder, 5-HTTLPR/rs25531 S’S’ genotype and S’ maybe the risk genes. Key words: Major depressive disorder; Serotonin transporter; Gene polymorphism