Rs1076560, a functional variant of the dopamine D2 receptor gene, confers risk of schizophrenia in Han Chinese.

The dopamine receptor genes have been implicated in the pathogenesis of schizophrenia, but definitive evidence of association is still lacking. To identify whether functional variants of the D2-like receptors (DRD2, DRD3 and DRD4) confer risk of schizophrenia, we conducted a two-stage association study. We firstly examined the SNPs in functional genomic regions, such as mRNA splicing, protein coding and the promoter regions in DRD2, DRD3 and DRD4, respectively, for association in 289 Han Chinese cases with schizophrenia and 367 healthy controls and then further analyzed the significantly associated single nucleotide polymorphisms (SNPs) with this disorder in an additional Han Chinese sample consisted of 1351 cases and 1640 control subjects. In the first stage, the chi-square test (χ(2)) showed disease association for rs1076560 in DRD2 (p=0.040 for allelic association and p=0.033 for genotypic association, respectively). However, rs6280 in DRD3 and rs3758653 in DRD4 failed to show either allelic or genotypic association with the illness. The association between rs1076560 and schizophrenia was replicated in the second stage. The rs1076560-T allele, which shifts splicing from the D2 short isoform (D2S) to the D2 long isoform (D2L), was over-presented in the patient group (44%) than in the control group (41%) (χ(2)=5.19, p=0.023, OR=1.13, 95% CI=1.02-1.25). Therefore, the rs1076560 variant of DRD2 reliably influences risk of schizophrenia in Han Chinese, although more data are required to elucidate the pathophysiological mechanisms of possessing this risk-conferring variant.