DOSE-DEPENDENT ASSOCIATION OF APOLIPOPROTEIN-E ALLELE EPSILON-4 WITH LATE-ONSET, SPORADIC ALZHEIMERS-DISEASE

We examined the apolipoprotein E (apo E) genotypes in 47 patients with late-onset sporadic Alzheimer's disease (mean age at onset a standard deviation, 72.2 +/- 6.4 years), 8 with late-onset familial Alzheimer's disease (75.5 +/- 5.1 years), 18 with early-onset sporadic Alzheimer's disease (52.8 +/- 4.7 years), and 10 with early-onset familial Alzheimer's disease (52.0 +/- 6.8 years) in Japan and compared them with genotypes in control subjects. In late-onset sporadic Alzheimer's disease, apo E-epsilon 4 frequency increased significantly (epsilon 4 frequency: 0.34 vs 0.095 in controls, P < 0.0001), and the odds ratio, which represents the strength of association between Alzheimer's disease and apo E-epsilon 4, markedly increased with increasing dose of apo E-epsilon 4 gene (3[95% confidence interval, 2-6] in one dose; 43 [95% confidence interval, 12-154] in two doses). This study also suggested that apo E-epsilon 4 is associated with both late-onset (epsilon 4: 0.31) and early-onset familial Alzheimer's disease (epsilon 4: 0.35). In contrast, we found no association between apo E-epsilon 4 and early-onset sporadic Alzheimer's disease (epsilon 4: 0.08). These results indicate that the risk of developing late-onset sporadic Alzheimer's disease is markedly dependent on the dose of apo E-epsilon 4, while apo E-epsilon 4 does not appear to be a major risk factor for early-onset sporadic Alzheimer's disease.