A48G polymorphism in the D1 receptor genes associated with bipolar I disorder.

Several lines of evidence point to a role for dopamine in mood disorders and, in particular, in bipolar disorders. In line with a considerable amount of evidence, the dopamine D1 receptor gene (DRD1) is considered to be a good candidate gene for bipolar disorders. Several studies did not find any association between bipolar 1 patients and DRD1. In this study, we investigate a possible association between BP disorder and -48A/G polymorphism of the DRD1. We genotyped 107 bipolar 1 patients and 129 healthy control subjects of exclusively Sardinian descent. A statistically significant difference in genotype (chi2 = 6.29, df = 2, P = 0.042) and allele (chi2 = 5.46, df=1, P = 0.019; OR = 1.53, 95% CI = 1.08-2.16) frequencies was found, suggesting an association between the DRD1 gene and bipolar I disorder (BP I) in the Sardinian population.