Association of microtubule-associated protein tau gene polymorphisms with the risk of sporadic Alzheimer's disease: a meta-analysis

Background: Numerous epidemiological studies were published to investigate the role of microtubule-associated protein tau (MAPT) gene variations (rs7521G/A, rs242557G/A, rs1467967A/G, rs2471738C/T and rs3785883G/A) in SAD, and these genetic polymorphisms may be a risk factor for sporadic Alzheimer's disease (SAD). However, controversial results were revealed. Methods: The MEDLINE, Embase and HuGEnet databases were searched to identify eligible studies. The odds ratios (ORs) and 95% confidence intervals (CIs) were calculated to evaluate the genetic association of MAPT with the risk of SAD. Results: A total of 30 studies were included in this meta-analysis to assess the association between five single-nucleotide polymorphisms and susceptibility to SAD. The pooled results exhibited no significant association between rs1467967A/G, rs3785883G/A, rs2471738C/T and rs7521G/A polymorphisms and the risk of SAD. However, a lower risk of SAD was observed in the GG versus (GA + AA) model of rs242557G/A polymorphism (OR = 0.86, 95% CI = 0.751-0.983, P = 0.027). Conclusion: The present meta-analysis showed that rs1467967A/G, rs3785883G/A, rs2471738C/T and rs7521G/A polymorphisms were not associated with the risk of SAD. However, rs242557G/A genetic polymorphism was associated with susceptibility to SAD, and individuals with a GG genotype of rs242557G/A might be at a lower risk of SAD. Further studies with a larger sample size are required to validate these conclusions.