The SIRT2 polymorphism rs10410544 and risk of Alzheimer's disease in two Caucasian case-control cohorts

Background: Human sirtuins are a current hotspot for research in neurodegenerative disorders, including Alzheimer's disease (AD). This study investigated whether genetic variants in two members of the sirtuin family, SIRT2 and SIRT3, affected AD susceptibility. Methods: A genetic case-control study was performed, comprising 534 probable AD cases and 638 nondemented control subjects from the north of Italy and Canton Ticino, Switzerland (discovery population). The study was focused on SIRT2 rs10410544, SIRT3 rs4980329, and SIRT3 rs536715 single nucleotide polymorphisms (SNPs). These SNPs were genotyped by real-time polymerase chain reaction allelic discrimination assay or restriction fragment length polymorphism. The SNPs rs7412 and rs429358, mapping within the apolipoprotein E (APOE) gene, were genotyped by real-time polymerase chain reaction allelic discrimination assay too. In a replication population comprising 756 AD cases and 847 nondemented control subjects, SIRT2 rs10410544, APOE rs7412, and APOE rs429358 were genotyped as mentioned previously. Results: In the discovery population, we observed an association between SIRT2 rs10410544 T allele and AD (adjusted odds ratio [OR] = 1.23, 95% confidence interval [Cl]: 1.02-1.50, P = .02, after correction for sex, age, and APOE epsilon 4 genotype). The association between AD and SIRT2 rs10410544 T allele was only present in APOE epsilon 4 noncarriers (adjusted OR = 1.29, 95% CI: 1.03-1.61, P = .03). The replication study did not confirm this evidence. However, the combined analysis on the two cohorts detected the association (adjusted OR = 1.17, 95% CI: 1.02-1.35, P = .02), and only APOE epsilon 4 noncarriers were at risk (adjusted OR = 1.2, 95% CI: 1.02-1.43, P = .03). Conclusions: The SIRT2 rs10410544 T allele deserves further investigation as a novel minor genetic risk factor for AD in the APOE epsilon 4-negative Caucasian population. (C) 2013 The Alzheimer's Association. All rights reserved.