Association of serotonin transporter gene polymorphisms and major depressive disorder in Chinese Han population

<正>BACKGROUND:Serotonin transporter（5-HTT） polymorphisms comprise 5-HTT gene-linked polymorphism region（5-HTTLPR） and variable number of tandem repeats（VNTR）.Studies have revealed an association between 5-HTT polymorphism and major depressive disorder,which suggests that the"S"allele of 5-HTTLPR and Stin2.9 of 5-HTTVNTR are associated with major depressive disorder.However,there are a number of studies that do not support the 5-HTT polymorphism effect in major depressive disorder. OBJECTIVE:To study the relationship between 5-HTT gene polymorphism and major depressive disorder in Chinese Han population. DESIGN,TIME AND SETTING:Case-controlled study of 5-HTT gene polymorphism.The experiment was performed at the Central Laboratory,Third Affiliated Hospital of Sun Yat-sen University,China from March 2005 to January 2006. PARTICIPANTS:A total of 99 depressive patients of Chinese Han nationality were recruited for this study.All patients met DSM-Ⅳdiagnostic criteria for major depressive disorder and had a total score of Hamilton Depression Scale（24 items）≥21 points.In addition,101 healthy subjects,matched for age and gender,served as the control group. METHODS:Venous blood was collected from all subjects.5-HTT genotypes and alleles were determined by polymerase chain reaction.Consistent with the Hardy-Weinberg equilibrium,the association between 5-HTT gene polymorphism and major depressive disorder were analyzed by Chi-square test. MAIN OUTCOME MEASURES:5-HTTLPR and 5-HTTVNTR genotypes and allele frequencies were measured. RESULTS:No significant differences in 5-HTTLPR genotypes and allele frequencies were determined between patients and controls（P>0.05）.However,significant differences in 5-HTTVNTR genotypes and allele frequencies were detected（P<0.01）.The Stin2.10 allele and 10/10 genotype associated with major depressive disorder（OR=2.61,7.7,P<0.05;analysis of dose-response relationships x2=12.35,P<0.01）. CONCLUSION:Results from the present study revealed no association between 5-HTTLPR and major depressive disorder.However,a significant association between 5-HTTVNTR and major depressive disorder existed in a population of Chinese Han.The presence of Stin2.10 and 10/10 genotypes increased the risk for major depressive disorder in a dose-dependent manner.