Association of DRD2 gene polymorphisms with mood disorders: a meta-analysis.

Background: In the past few decades, a number of studies have investigated the association of dopamine D2 receptor (DRD2) gene polymorphisms with mood disorders, but the findings are not always consistent. The aim of our study was to assess the association between DRD2 gene polymorphisms and mood disorders by using a meta-analysis.

Methods: Data were collected from the following electronic databases: PubMed, Elsevier Science Direct, Cochrane Library, Chinese Biomedical Literature Database, China National Knowledge Infrastructure, and Wanfang, with the last report up to June 2010. Meta-analysis was performed in a fixed/random effect model by using the software Review Manager 4.2.

Results: We identified 19 separate studies using search, but only 14 separate studies (2157 cases and 3272 controls) were included in the current study. Meta-analysis was performed for three DRD2 gene polymorphisms (-141Cins/del, Ser311/Cys311, and TaqI A1). We performed meta-analysis in overall, Caucasian, and Asian populations. We also performed disease-specific meta-analysis in unipolar disorder and bipolar disorder. We found no association between DRD2 gene -141Cins/del polymorphism and mood disorders in overall and Caucasian populations (P>0.05). We also found no association between DRD2 gene Ser311/Cys311 polymorphism and mood disorders in overall, Caucasian, and Asian populations (P>0.05). An association of DRD2 gene TaqI A1 polymorphism with mood disorders was found in overall population, and the individuals with A1A1 genotype were more susceptible to mood disorders in comparison to those with A2A1 and A2A2 genotypes (OR=1.84, 95% CI=1.07-3.17, P=0.03).

Limitation: Meta-analysis is retrospective research that is subject to the methodological deficiencies of the included studies.

Conclusion: This meta-analysis suggests that mood disorders may be associated with DRD2 gene TaqI A1 polymorphism, but not -141Cins/del and Ser311/Cys311.