HLA A2 allele is associated with age at onset of Alzheimer's disease

The prevalence of the HLA A2 allele was investigated in a group of Italian patients with sporadic and early-onset familial Alzheimer's disease (AD and FAD) to analyze the potential association of this allele with early age of onset of the disease. The possible interaction between the HLA A2 allele a nd apolipoprotein E epsilon 4 allele was analyzed. Our data suggest that A2 and epsilon 4 alleles may have additive effects on AD onset, and that A2 m ay play an important role in determining or contributing to a very early ag e at onset. These findings further support the hypothesis of the involvemen t of an immune/inflammatory mechanism in the pathogenesis of AD.