title: Association between the dopamine D2 receptor (DRD2) polymorphism and the personality traits of healthy Japanese participants.
abstract: BACKGROUND
  Dopamine neurotransmitter systems have been associated with reward-related and novelty-seeking personality traits. We investigated the possible relationship between the personality traits measured by the Temperament and Character Inventory (TCI) and the TaqI A and -141C Ins/Del polymorphisms in the dopamine D2 receptor gene (DRD2).
  
  
  METHODS
  The sample consisted of 1084 healthy Japanese medical students and medical staff (age=29.0±9.7 years), each of whom completed the TCI. Their genomic DNA was isolated from whole blood and genotyped using the TaqMan allele-specific assay method. The associations between gene polymorphisms and the scores for TCI were statistically analyzed by one-way analysis of covariance (ANCOVA) adjusting age. Males and females were analyzed separately. Epstatis was assesses using two-way ANCOVA between the DRD2 and ANKK1 genes.
  
  
  RESULTS
  Men with the Ins/Del genotype of the -141C Ins/Del polymorphism had significantly higher self-directedness scores than those with the Ins/Ins genotype (p=0.021). None of the TCI scores differed among women with regard to the three genotype groups of the -141C Ins/Del polymorphism. The DRD2/ANKK1 Taq1 A polymorphism did not affect any TCI factor for either men or women. An epistatic analysis did not reveal main effects of the two genes with regard to TCI scores, but an ANKK1×DRD2 interaction significantly predicted TCI scores.
  
  
  CONCLUSIONS
  These findings suggest the possibility that the -141C Ins/Del polymorphism and the DRD2/ANKK1 Taq1 A polymorphism are not strongly linked to personality traits directly, but influences them under the interaction between the DRD2 and ANKK1 genes.
authors.affiliation: Department of Neuropsychiatry, Graduate School of Medicine, Hirosaki University, Hirosaki, Japan.
authors.forename: Shoko
authors.initials: S
authors.lastname: Tsuchimine
authors.forename: Norio
authors.initials: N
authors.lastname: Yasui-Furukori
authors.forename: Kunihiro
authors.initials: K
authors.lastname: Sasaki
authors.forename: Ayako
authors.initials: A
authors.lastname: Kaneda
authors.forename: Norio
authors.initials: N
authors.lastname: Sugawara
authors.forename: Shuichi
authors.initials: S
authors.lastname: Yoshida
authors.forename: Sunao
authors.initials: S
authors.lastname: Kaneko
mesh_terms: D000328:Adult; D000483:Alleles; D044466:Asian People / Q000235:genetics*; D005260:Female; D005787:Gene Frequency; D056726:Genetic Association Studies; D006801:Humans; D007564:Japan; D008297:Male; D010551:Personality / Q000235:genetics*; D010555:Personality Inventory; D011110:Polymorphism, Genetic; D017448:Receptors, Dopamine D2 / Q000235:genetics*
chemical_list: D017448:Receptors, Dopamine D2