Abstract
Phenotypes of apolipoprotein E (apoE) were determined with an isoelectric focusing method in 39 patients with sporadic Alzheimer's disease (AD), 38 patients with dementia from cerebrovascular disease (CVD), and 100 healthy subjects without hyperlipidemia. There was a striking difference in the distribution of apoE phenotypes between patients with AD and healthy subjects (p<0.001) . Such a difference was attributable to different frequencies of phenotype E4/3 and E3/3. The apoE4/ 3 phenotype was detected in 38.5% (15 of 39) patients with AD, more than 3 times higher than in healthy subjects (12.0%, 12 of 100) . In contrast, apoE3 / 3 phenotype, a wild type apoE phenotype, was detected in 81.0% (81 of 100) of healthy subjects but only in 38.5% (15 of 39) of patients with AD. The frequency of apoE-ε4 allele assessed on the basis of obtained apoE phenotypes in patients with AD (0.269) was significantly higher than that in healthy subjects (0.08, p<0.001) and in patients with dementia from CVD (0.118, p<0.01) . Furthermore, the frequencies of apoE-ε4 in AD were 0.190 in patients older than 70 years and 0.333 in patients younger than 70 years. These results indicate a strong association between apoE-ε4 and sporadic AD and suggest that apoE-ε4 assessed from apoE phenotypes may be a possible risk factor for AD.
