No association of genetic variants in BDNF with major depression: A meta‐ and gene‐based analysis

Major depressive disorder (MDD) is a complex psychiatric condition with strong genetic predisposition. The association of MDD with genetic polymorphisms, such as Val66Met (rs6265), in the brain derived neurotrophic factor ( BDNF ), have been reported in many studies and the results were conflicting. In this study, we performed a systematic literature search and conducted random‐effects meta‐analysis to evaluate genetic variants in BDNF with MDD. A gene‐based analysis was also conducted to investigate the cumulative effects of genetic polymorphisms in BDNF . A total of 28 studies from 26 published articles were included in our analysis. Meta‐analysis yielded an estimated odds ratio (OR) of 0.96 (95% CI: 0.89–1.05; P  = 0.402) for Val66Met (rs6265), 0.83 (95% CI: 0.67–1.04; P  = 0.103) for 11757C/G, 1.16 (95% CI: 0.74–1.82; P  = 0.527) for 270T/C, 1.03 (95% CI: 0.18–5.75; P  = 0.974) for 712A/G and 0.98 (95% CI: 0.85–1.14; P  = 0.831) for rs988748. The gene‐based analysis indicated that BDNF is not associated with MDD ( P  > 0.21). Our updated meta‐ and novel gene‐based analyses provide no evidence of the association of BDNF with major depression. © 2012 Wiley Periodicals, Inc.