title: TPH1 and 5-HTTLPR Genes Specifically Interact in Opiate Dependence but Not in Alcohol Dependence.
abstract: BACKGROUND
  Different drug dependencies may have unique genetic vulnerabilities. Changes in serotonin availability and function have been linked to addiction. We investigated whether 2 serotonergic polymorphisms, TPH1 A218C (rs1800532) and 5-HTT-linked promoter region (5-HTTLPR) (rs25531), are differently associated with alcohol or opiate dependence.
  
  
  METHODS
  Alcohol-dependent patients (n = 292), opiate-dependent patients (n = 309), and healthy controls (n = 301) were recruited from the Han Chinese population in Taiwan. Genotypes of TPH1 A218C and 5-HTTLPR polymorphisms were analyzed using a polymerase chain reaction with restriction fragment length polymorphism.
  
  
  RESULTS
  The genotype frequencies of the TPH1 A218C polymorphisms were not significantly different in the 3 groups. The genotype frequencies of the 5-HTTLPR S+ (S/S, S/LG, LG/LG) polymorphisms were significantly higher in opiate-dependent patients (x03C7;2 = 8.77, p = 0.01), but not after controlling for the covariates of age, gender, and interaction effect in logistic regression analysis. Moreover, there was a significant interaction between the TPH1 A218C A/C and 5-HTTLPR S+ gene polymorphisms in opiate-dependent (OR 2.72, p = 0.01), but not in alcohol-dependent patients.
  
  
  CONCLUSIONS
  Our data suggested that there may be a differential genetic vulnerability in serotonergic genes for alcohol and opiate addiction. However, replications of our findings are still needed.
authors.affiliation: Department of Psychiatry, National Cheng Kung University Hospital, Kaohsiung, Taiwan.
authors.forename: Tzu-Yun
authors.initials: TY
authors.lastname: Wang
authors.forename: Sheng-Yu
authors.initials: SY
authors.lastname: Lee
authors.forename: Yi-Lun
authors.initials: YL
authors.lastname: Chung
authors.forename: Shiou-Lan
authors.initials: SL
authors.lastname: Chen
authors.forename: Chia-Ling
authors.initials: CL
authors.lastname: Li
authors.forename: Yun-Hsuan
authors.initials: YH
authors.lastname: Chang
authors.forename: Liang-Jen
authors.initials: LJ
authors.lastname: Wang
authors.forename: Po See
authors.initials: PS
authors.lastname: Chen
authors.forename: Shih-Heng
authors.initials: SH
authors.lastname: Chen
authors.forename: Chun-Hsien
authors.initials: CH
authors.lastname: Chu
authors.forename: San-Yuan
authors.initials: SY
authors.lastname: Huang
authors.forename: Nian-Sheng
authors.initials: NS
authors.lastname: Tzeng
authors.forename: Tsai-Hsin
authors.initials: TH
authors.lastname: Hsieh
authors.forename: I Hui
authors.initials: IH
authors.lastname: Lee
authors.forename: Kao Chin
authors.initials: KC
authors.lastname: Chen
authors.forename: Yen Kuang
authors.initials: YK
authors.lastname: Yang
authors.forename: Jau-Shyong
authors.initials: JS
authors.lastname: Hong
authors.forename: Ru-Band
authors.initials: RB
authors.lastname: Lu
mesh_terms: D000328:Adult; D000437:Alcoholism / Q000235:genetics*; D004843:Epistasis, Genetic; D005260:Female; D020022:Genetic Predisposition to Disease; D005838:Genotype; D006801:Humans; D008297:Male; D008875:Middle Aged; D009293:Opioid-Related Disorders / Q000235:genetics*; D020641:Polymorphism, Single Nucleotide; D050486:Serotonin Plasma Membrane Transport Proteins / Q000235:genetics*; D014365:Tryptophan Hydroxylase / Q000235:genetics*
chemical_list: D050486:Serotonin Plasma Membrane Transport Proteins; C497467:TPH1 protein, human; D014365:Tryptophan Hydroxylase