Relationship between the polymorphism in exon 5 of BACE1 gene and Alzheimer's disease.

Abstract

The β-Site APP-cleaving enzyme 1 (BACE1) gene polymorphism (rs638405) has been extensively investigated for association to Alzheimer's disease (AD). However, results of different studies have been contradictory. The aim of this meta-analysis was to evaluate the association between BACE1 gene polymorphism (rs638405) and AD. All eligible studies were searched in PubMed, Cochrane Library, Embase, SinoMed, and the China Knowledge Resource Integrated Database. Pooled odds ratios (ORs) and 95% confidence intervals (95% CIs) were used to evaluate the strength of the association between BACE1 gene polymorphism and AD. Twenty studies in 19 papers containing 4377 AD patients and 4563 controls were included for rs638405 polymorphism. The results suggested that rs638405 in BACE1 was not associated with the risk of AD. Stratification analyses indicated rs638405 decreased the risk of apolipoprotein-E ε4 (APOE4) positive AD patients. Furthermore, we found rs638405 also decreased the risk of Asian AD patients. By exclusion of three studies that did not conform to Hardy-Weinberg equilibrium (HWE), our data suggested rs638405 in BACE1 was a protective factor of AD. To sum up, our data indicated that BACE1 gene polymorphism in exon 5 might decrease the risk of Asian AD and APOE4 positive patients.