Meta-Analysis of the Cystatin C(CST3) Gene G73A Polymorphism and Susceptibility to Alzheimer's Disease

Background: The association between cystatin C(CST3) gene (rs1064039) G73A polymorphism and Alzheimer's disease (AD) is controversial. The objective of the study was to investigate the possible association between CST3 G73A polymorphism and AD. Method: We performed a meta-analysis pooling data from all relevant studies including 2,410 cases and 2,539 controls. We applied a random-effects or fixed-effects model to combine odds ratio (OR) and 95% confidence intervals (95% CI). Results: Positive associations of the CST3 G73A polymorphism with AD risk were found in allele comparison A versus G (OR = 1.61, 95% CI = 1.19-2.18), dominant model AG + GG versus AA (OR = 0.63, 95% CI = 0.47-0.86), and homozygote comparison AA versus GG (OR = 1.61, 95% CI = 1.19-2.18). In subgroup analysis stratified by ethnicity, significant associations were also demonstrated in Caucasians under allele comparison (OR = 1.17, 95% CI = 1.02-1.33), dominant genetic (OR = 0.59, 95% CI = 0.40-0.86) model, and homozygote comparison (OR = 1.73, 95% CI = 1.18-2.54), but not in Asians. In subgroup analysis according to the age of onset, 73A allele (A versus G) was significantly associated with susceptibility to AD in Caucasians (OR = 1.26, 95% CI = 1.06-1.50), However, no association was found in Asians. Conclusion: The CST3 G73A polymorphism is associated with AD in Caucasian populations, but not in Asians.