GSTM1 null genotype as risk factor for late-onset Alzheimer's disease in Italian patients

Alzheimer's disease (AD) is the most common form of dementia in the elderly. The causes of AD are very complex but there is general agreement about the existence of a link between Alzheimer's disease and oxidative stress. The Glutathione S-transferases (GSTs) act to detoxify products of oxidation that cause damage to macromolecules. Particular attention has been focused on GST genes because polymorphisms are important determinants of disease risk. To evaluate if GSTA1, GSTM1, GSTP1, and GSTT1 genes are associated with LOAD we screened a case-control population (n=311). Differences in genotype distributions between AD patients and controls were found only for the GSTM1 null genotype (P<0.001). In addition, a logistic regression analysis also conferred a positive association between the GSTM1 null genotype and LOAD after adjustment for age and gender (OR=2.09; 95%CI=1.31-3.35). The GSTM1 enzyme detoxifies substances such as exogenous and endogenous metabolites and plays a regulatory role in cellular signaling. Previous studies have highlighted that GSTM1 has a role in neurodegenerative disorders, but no data have associated the GSTM1 gene with AD risk. Our outcome suggests that the GSTM1 null genotype is a risk factor for AD in Italian patients.