The association of 5-HTTLPR and DRD4 VNTR polymorphisms with affective temperamental traits in healthy volunteers

Background: There has been growing evidence that temperamental traits, including affective temperaments, are heritable and associated with genetic polymorphisms. The purpose of the present study was to investigate the possible relationship between affective temperaments and the triallelic serotonin transporter gene-linked polymorphic region (5-HTTLPR) and dopamine receptor D4 (DRD4) polymorphisms in healthy Korean subjects. Methods: Three hundred thirty-five healthy college students were recruited, and 290 participants with a complete data set (172 males, 118 females) were included in the data analysis. The DNA of the subjects was isolated from whole blood cells, and the 5-HTTLPR and DRD4 variable number of tandem repeats polymorphisms were genotyped using polymerase chain reaction. Participants performed the 110-item version of the Temperament Evaluation of Memphis, Pisa, Paris, and San Diego auto-questionnaire (TEMPS-A) measuring five affective temperamental traits. Results: A significant association was found between the DRD4 polymorphism and the cyclothymic and irritable temperaments in male subjects. No significant association was shown between the 5-HTTLPR gene polymorphisms and affective temperaments. Limitation: Our data were collected from a specific group of college students and cannot be generalized easily to other non-clinical populations. In addition, Korean version of the TEMPS-A used in this study has not yet been validated in Korean population. Conclusions: This study showed a possible association between the DRD4 polymorphism and certain affective temperaments in the Korean male population. The clarification of the biological basis of predisposing temperaments such as cyclothymic temperament might help to understand the pathophysiology and mechanisms of mood disorders. (C) 2008 Elsevier B.V. All rights reserved.