title: Association between serotonin transporter gene polymorphisms and heroin dependence: a meta-analytic study.
abstract: BACKGROUND
  Studies have examined the association between heroin dependence and serotonin transporter gene polymorphisms but yielded inconsistent results. The purpose of current study is to determine the overall effect of these polymorphisms on the risk for heroin dependence through a meta-analytic method.
  
  
  METHODS
  A meta-analysis was conducted to examine the association of heroin dependence with two common polymorphisms of serotonin transporter gene, in the promoter (5-hydroxytryptamine transporter-linked promotor region [5-httlpr]) and intron 2 (a various number tandem repeat in serotonin transporter intron 2 [STin2]). Data from studies with5-httlpr(6 studies) andSTin2(8 studies) were synthesized by random effects model.
  
  
  RESULTS
  In the analysis, heroin dependence was found to be significantly associated with the S allele of5-httlpr(odds ratio [OR] =1.22, 95% confidence interval [CI] =1.08-1.41,P=0.002). The association between the S allele of5-httlprand heroin dependence was significant in Caucasian subjects (OR =1.37, 95% CI =1.12-1.68,P=0.003), but not in non-Caucasian subjects. On the other hand, no association withSTin2polymorphism was found (OR =1.14, 95% CI =0.91-1.42,P=0.242).
  
  
  CONCLUSIONS
  The results suggest an ethnic-specific effect of the5-httlprpolymorphism on the risk for heroin dependence, but the influence of the genetic variance in the patients with comorbidities or intermediate phenotypes of heroin dependence needs to be further examined.
authors.affiliation: Department of Psychiatry, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung, Taiwan.
authors.forename: Pao-Yen
authors.initials: PY
authors.lastname: Lin
authors.affiliation: Department of Psychiatry, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung, Taiwan.
authors.forename: Yi-Shan
authors.initials: YS
authors.lastname: Wu
keywords: STin2; ethnicity; heroin; polymorphism; serotonin transporter