Positive association between the brain-derived neurotrophic factor (BDNF) gene and bipolar disorder in the Han...

Brain-derived neurotrophic factor (BDNF) is the most widely distributed neurotrophin in the central nervous system (CNS), and services many biological functions such as neural survival, differentiation, and plasticity. Previous studies have suggested that the Val66Met (also known as rs6265 or G196A) variant of BDNF is associated with bipolar disorder (BPD), but the results have been inconclusive. We therefore genotyped the Val66Met polymorphism in a Han Chinese population sample (498 cases and 501 control subjects). We found that the BDNF genotype is associated with BPD in this population (chi(2) = 9.4666, df = 2, P = 0.00884). Furthermore, our data suggested that the Met allele rather than the Val allele increased the risk for BPD in our Han population (OR = 1.44; 95% CI = 1.070-1.950; P = 0.016). Further studies are necessary to elucidate the involvement of the BDNF gene in the pathophysiology of BPD.