DRD2 haplotype associated with negative symptoms and sustained attention deficits in Han Chinese with schizophrenia in Taiwan

Previous studies have reported significant associations between schizophrenia and the dopamine receptor D2 gene (DRD2) variants. The relationships between DRD2 and clinical phenotypes are of particular interest because DRD2 has been shown to associate with treatment response and prefrontal dopamine transmission. Glatt et al. reported significant associations between schizophrenia and DRD2 variants (two single-nucleotide polymorphisms (SNPs) rs1079727 and rs2283265, and two haplotypes, block 3 (rs1079727(A)-rs2440390(C)-rs2283265(G)) and block 4 (rs1801028(G)-rs1110977(A)-rs1124492(C)-rs2734841 (T))) in 2408 Han Chinese individuals in Taiwan. To further investigate the relationships between the SNPs/haplotypes of DRD2 and clinical symptoms and neuropsychological function, we compared the quantitative phenotypes in patients with risk alleles/haplotypes and those without. The results showed that the A allele of rs1079727, G allele of rs2283265, A allele of rs1124492 and the risk haplotype (A-C-G) of block 3 were associated with more severe negative symptoms. With regard to neuropsychological performance, the risk haplotype (G-A-C-T) of block 4 was associated with poorer performance in the sustained attention task. Our results imply that the genetic variants of DRD2 might not only have a role in susceptibility to schizophrenia, but also influence the phenotypes of negative symptoms and sustained attention in schizophrenia. This association warrants further validation.