Genetic association between the apolipoprotein E (APOE) gene and differentforms of Alzheimer's disease

Allele epsilon4 of the apolipoprotein E (APOE) gene is associated with high er risk for family or sporadic Alzheimer's disease (AD) in many, though not all, ethnic groups. The APOE allele and genotype frequency distributions w ere evaluated in 207 AD patients without vascular disorders, 62 AD patients with vascular disorders (combined AD), and 206 control individuals (ethnic Russians from the Russian population). The frequency of allele epsilon4 in patients with early-onset and late-onset AD was three times higher than in controls (P<0.000001). The increase in the frequency of <epsilon>4 in mixe d dementia cases over controls was somewhat less but still significant (P=0 .0019). Relative risk of AD in carriers of allele epsilon4 was five times h igher than in carriers of alleles epsilon2 and epsilon3 (P<0.000001). Allel e <epsilon>2 showed evidence of a protective effect in the early-onset AD g roup (P=0.015). These results suggest that APOE allele epsilon4 is a univer sal factor of early-onset, late-onset, and combined AD in ethnic Russians f rom Russia.