Association of BDNF and BCHE with Alzheimer's disease: Meta-analysis based on 56 genetic case-control studies of 12,563 cases and 12,622 controls

Alzheimer's disease (AD) is a common neurodegenerative disorder that can destroy the memory of sufferers and lead to distress for the individual and society. Brain-derived neurotrophic factor (<i>BDNF</i>) and butyrylcholinesterase (<i>BCHE</i>) are two genes associated with β-amyloid plaques and neurofibrillary tangles that are two key factors in the pathophysiology of AD. The aim of the current meta-analysis was to evaluate the association between <i>BDNF</i> Val66Met (rs6265), <i>BDNF</i> C270T (rs2030324) and <i>BCHE</i>-K (rs1803274) polymorphisms and AD. A comprehensive meta-analysis was performed using the online database PubMed without a time limitation. A total of 56 articles evaluating 12,563 cases and 12,622 controls were selected for the current meta-analysis. The results showed a moderate association of the <i>BDNF</i> C270T polymorphism with the risk of AD in Asians under a dominant model (P=0.03; odds ratio, 1.88; 95% confidence interval, 1.08-3.27). No other significant association was found during the meta-analysis for the other two polymorphisms (P>0.05). The current meta-analysis suggests that <i>BDNF</i> C270T is a risk factor for AD in Asians. This meta-analysis has been, to the best of our knowledge, the most comprehensive meta-analysis of <i>BDNF</i> Val66Met, <i>BDNF</i> C270T and <i>BCHE</i>-K to date.