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Among the several genes associated with late-onset Alzheimer's disease (LOAD), recently, Sirtuin genes have roused a growing interest because of their involvement in metabolic homeostasis and in brain aging. Particularly SIRT2 gene has been associated with Alzheimer's disease (AD) as well as with mood disorders. The aim of this study is to investigate the possible associations between Sirtuin 2 gene (SIRT2) rs10410544 polymorphism and AD as well as depression in AD. In addition, we performed some exploratory analyses to investigate possible associations between the rs10410544 genotype and clinical features. We investigated these associations in two independent samples: the first one was composed of 275 Greek inhabitants and 117 patients; the second sample counted 181 Italian people and 43 patients. All patients were affected by LOAD. We failed to find any association between rs10410544 genotype and AD in the two samples. On the other hand, we found an association between the single nucleotide polymorphism (SNP) and depressive symptomatology (in the total sample p = 0.002), which was modulated by the tumor necrosis factor (TNF) values. Particularly, TT genotype seems to be protective versus depression. Finally, in the exploratory analyses, we found that the TT genotype was associated with earlier AD onset and a longer duration of the illness. In conclusion, we confirmed the association between SIRT2 gene and mood disturbances, although in AD patients. Further, we provided evidence that the TT genotype may be protective versus depressive symptoms, allowing an easier and thus earlier diagnosis of AD. This awareness may lead to a more detailed approach to these patients concerning diagnosis and therapy.

The pathophysiology of Alzheimer's disease (AD) is influenced by sorting-protein related receptor (sorLa) that is less expressed in AD patients. The gene encoding sorLa (SORL1) has been investigated as a susceptibility factor for late-onset AD (LOAD) with conflicting results. Our objectives were to confirm the association between SORL1 SNPs and LOAD in two independent South-European centers and to perform a mega-analysis of published samples. We analyzed three SORL1 SNPs (intron 6: rs668387; rs689021; rs641120) from the Greece-Italy Genetic Association Study on lateonset AD (GIGAS&#95;LOAD). Greek sample included 96 patients with LOAD (DSM-IV) and 120 unrelated controls. In Italy, a community-based sample is ongoing. 47 LOAD patients and 165 controls were recruited until study endpoint. These samples and previously published ones (Alzgene) were pooled as in a single study. A test for trend was used to analyze genotype association. In the GIGAS&#95;LOAD sample no association was detected between SORL1 genotypes and LOAD. Conversely all SNPs were associated with LOAD in mega-analysis based on ordinal classification of genotypes (Armitage's test: p < 0.001). Although our analysis of pooled samples has positive results for the association between SORL1 and AD, there is substantial heterogeneity across studies. Thus further examination into SORL1 SNPs and the population is necessary to determine the role of SORL1 in LOAD.

Interleukin-1 (IL1) can contribute to pathophysiology of Alzheimer's disease (AD) by promoting deposition of amyloid-beta in the brain. The gene encoding IL1 alpha (IL1A) has a common polymorphism in its 5' regulatory region (rs1800587) with possible functional effects. IL1A T/T genotype has been associated with AD but the overall effect is modest and negative studies have been published. The aim of this study was to investigate the association of the IL1A rs1800587 polymorphism with AD in two independent case-control groups from Greece (Athens) and Italy (Faenza and Granarolo). Preliminary results from the ongoing sample (110 patients with sporadic AD and 130 nonpsychiatric controls) showed no association between IL1A variants and AD, however C/T heterozygotes had more severe depression in AD (Cornell Scale for Depression in Dementia) compared to other genotypes (F = 4.56, d.f = 1, p = 0.037) after controlling for age, illness duration and cognitive impairment (MMSE). Despite the small sample size and the possibility of a false negative finding, our preliminary data support the hypothesis the IL1A rs1800587 variants are not associated with AD. The effect of the IL1A on depressive symptomatology warrants further investigations, however the lack of a gene-dose relationship would suggest a false positive.