Several studies have hypothesized that genes involved in the dopamine system, including dopamine type-2 receptor (DRD2)-related TaqIA polymorphism and monoamine oxidase-A upstream variable number tandem repeat (uVNTR), may be associated with alcoholism. But their results were contradictory because of alcoholism's heterogeneity. Therefore, we examined whether the DRD2TaqIA and MAOA-uVNTR gene polymorphisms are susceptibility factors for alcoholism comorbid with bipolar disorder (ALC + BP) in Han Chinese in Taiwan.
We recruited 101 Han Chinese men with comorbid alcoholism and bipolar disorder, and 328 healthy male controls from the community. Genotyping was done using PCR-RFLP.
There were no significant differences in the genotypic frequencies of the DRD2TaqIA or the MAOA-uVNTR polymorphisms between the 2 groups. The MAOA-uVNTR 3-repeat had a significant protective effect on the ALC + BP (odds ratio = 0.432, p = 0.035) but not on the healthy controls. However, the interaction between the MAOA-uVNTR 3-repeat and DRD2 A1/A2 was a risk factor in the ALC + BP (odds ratio = 3.451, p = 0.018).
We indicated the impact of the association between MAOA-uVNTR 3-repeat and DRD2 A1/A2 with ALC + BP.
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Request Reprint E-Mail: rblu@mail.ncku.edu.tw