Is the Val66Met polymorphism of the brain-derived neurotrophic factor gene associated with panic disorder? A meta-analysis.

Although emerging evidence has suggested an association between the Val66Met (rs6265) polymorphisms in brain-derived neurotrophic factor (BDNF) gene and the panic disorder, the conclusion is inclusive given the mixed results. This meta-analysis reviewed and analyzed the recent studies addressing the potential association between the Val66Met polymorphisms and panic disorder susceptibility. Related case-control studies were retrieved by database searching and selected according to established inclusion criteria. Six articles were identified, which explored the association between the BDNF Val66Met polymorphism and panic disorder. Statistical analyses revealed no association for the allele contrast and the dominant model. However, the recessive model showed a significant association between the BDNF Val66Met polymorphism and panic disorder (odds ratio = 1.26, 95% confidence interval = 1.04-1.52, z = 2.39, P = 0.02). Despite of some limitations, this meta-analysis suggests that the Val66Met polymorphism of BDNF gene is a susceptibility factor for panic disorder.