Association of insulin degrading enzyme gene polymorphisms with Alzheimer's disease: a meta-analysis

Alzheimer's disease (AD) is a chronic degenerative disorder. It is caused by both genetic and environmental factors. The association of Insulin Degrading Enzyme (IDE) genotypes rs4646953, rs2251101 and rs1544210 with AD has been detected, but the findings were conflicted, however, Apolipoprotein-E (APOE)-ε4 allele has been observed as a genetic risk factor for AD. To investigate the issue, a meta-analysis was performed. We searched PubMed, Springer Link, AlzGene and CNKI for relevant literatures published by June 2013. Pooled odds ratio (OR) with 95% confidence interval (CI) was calculated to explore the significant association. A total of 11 studies comprising 5771 cases and 5474 controls were considered in final meta-analysis. We found that weak connections existed between rs4646953 (TT vs. CC: z = 2.24, p = 0.025, OR = 1.536) and AD, but no significant associations have been found between other IDE gene single nucleotide polymorphisms of rs4646953, rs2251101 and rs1544210 with AD. We certified that APOE-ε4 allele was still be a suspected factor to AD. There was no evidence for obvious publication bias in overall meta-analysis. Furthermore, larger-scale randomized controlled trials are necessary to validate the association between IDE gene polymorphisms with AD.