PIN1-842G/C and -667T/C polymorphisms are not associated with the susceptibility of Alzheimer's disease: pooled analysis of epidemiologic studies.

Associations between PIN1 gene polymorphisms and Alzheimer's disease (AD) risk remain controversial, possibly because single studies often lack sufficient statistical power. In this study, we performed a meta-analysis to evaluate the association of two commonly studied PIN1 polymorphisms, -842G/C and -667T/C, with the risk of AD. Relevant studies were identified from PubMed, EMBASE, and China National Knowledge Infrastructure up to October 2012. Data were available from a total of 7 case-control studies with 2504 cases and 2322 controls. Crude odds ratios (OR) and 95% confidence intervals (CI) were used to investigate the strength of the association. The results showed no significant association between PIN1-842G/C polymorphism and AD risk in all comparison models (GG vs. GC: OR=0.84, 95%CI=0.61-1.18; GG vs. CC: OR=0.70, 95%CI=0.35-1.41; GC vs. CC: OR=0.81, 95%CI=0.39-1.69; G vs. C: OR=0.89, 95%CI=0.69-1.17; GG vs. GC+CC: OR=0.81, 95%CI=0.56-1.17; GG+GC vs. CC: OR=0.72, 95%CI=0.36-1.45). For the PIN1-667T/C polymorphism, lack of an association was also found. Subgroup analyses by the ethnicity and patients with late-onset AD did not change the results. Conclusively, the present meta-analysis revealed that PIN1 gene polymorphisms (-842G/C and -667T/C) were unlikely to contribute to AD susceptibility.