NEDD9 rs760678 polymorphism and the risk of Alzheimer's disease: a meta-analysis

The NEDD9 rs760678 polymorphism has been extensively investigated for association to Alzheimer's disease (AD), however, results of different studies have been inconsistent. The objective of this study is to assess the relationship of NEDD9 rs760678 polymorphism and AD risk by using meta-analysis. Systematic searches of electronic databases Pubmed and Embase, as well as hand searching of the references of identified articles were performed. Statistical analyses were performed using software Revman 4.2 and STATA 11.0. A total of 4436 cases and 4420 controls in 11 case-control studies were included. The results indicated that the homozygote GG had a 13% decreased risk of AD, when compared with the C allele carriers (CC+CG) (OR=0.87, 95%CI=0.77-0.99, P=0.04 for GG vs. CG+CC). In the subgroup analysis by ethnicity, significant decreased risk was associated with homozygote GG or G allele carriers in Caucasians (OR=0.84, 95%CI=0.74-0.96, P=0.008 for GG vs. CG+CC; OR=0.79, 95%CI=0.69-0.91, P=0.001 for GG vs. CC; OR=0.90, 95%CI=0.84-0.96, P=0.002 for G vs. C), but not in Asians. This meta-analysis suggests that the GG genotype of NEDD9 rs760678 polymorphism would be a protective factor for AD in Caucasians but not in Asians. To further evaluate the effect of gene-gene and gene-environmental interactions between NEDD9 rs760678 polymorphism and the risk of AD, more studies with larger number of subjects are required.