The −67 A/T promoter polymorphism in the dopamine transporter gene affects personality traits of Japanese healthy females

Dopamine transporter (DAT) plays a major role in terminating dopamine neurotransmission, which may be involved in the characterization of personality traits. Recently, polymorphisms of the promoter region (−67 A/T) and intron 8 (40-bp variable number of tandem repeats, VNTRs) in the DAT gene were reported to affect DAT expression. In the present study, we examined the associations of these polymorphisms with personality traits in 654 healthy Japanese. Personality traits were assessed by the Temperament and Character Inventory (TCI), and the DAT polymorphisms were identified by PCR-based methods. Regarding the −67 A/T promoter polymorphism, the females without the A allele predictive of high DAT activity had lower scores of self-directedness (p = 0.005) and cooperativeness (p = 0.038) than those with the A allele. In males, none of the TCI scores was different between the two genotype groups. The intron 8 VNTR polymorphism did not affect any TCI score either in males or in females. The present study thus suggests that the −67 A/T promoter polymorphism, but not intron 8 VNTR polymorphism, in the DAT gene affects personality traits of Japanese healthy females.