Genetic distribution and association analysis of DRD2 gene polymorphisms with major depressive disorder in the Chinese Han population.

Dopamine D2 receptor is involved in reward-mediating mesocorticolimbic pathways. It plays an important role in major depressive disorder (MDD). Three gene polymorphisms Taq1A, C957T and -141C ins/del, were identified in the DRD2 gene among the Western population. These variants in the DRD2 gene might be associated with the susceptibility of MDD patients through affecting the bioeffects of endogenous dopamine neurotransmission. However, little is known about their occurrence in Chinese population and their association with the susceptibility of patients with major depressive disorder. In this study, a total of 338 unrelated adult Chinese Han population, including 224 healthy volunteers and 114 patients with major depressive disorder, were recruited. DRD2 polymorphisms (Taq1A and -141C ins/del) were detected using restriction fragment length polymorphism (RFLP) analysis and the C957T were detected by sequencing directly. As a result, three polymorphisms were identified in Chinese Han population and all were common SNP. However, we could detect no evidence of genetic association between 3 markers in DRD2 and major depressive disorder in the Chinese Han population. To conclude, this result suggests that Taq1A, C957T and -141C ins/del of DRD2 gene may not be associated with major depressive disorder, also may be the sample sizes too small to allow a meaningful test.