Apolipoprotein E epsilon4 allele frequency in vascular dementia.

The aim of the study was to investigate whether possession of the epsilon4 allelic form of the apolipoprotein E (APOE) gene increases the risk of developing vascular dementia (VaD). APOE allele and genotype frequencies were determined by PCR in 89 patients with possible and probable VaD and compared with those in 97 patients with possible and probable Alzheimer's disease (AD) of similar age of disease onset and ethnic background, and with 766 control subjects drawn from the same geographical region. The APOE epsilon4 allele frequency in all 97 patients with possible and probable AD was significantly higher (p < 0.001) than that in control subjects. However, the APOE epsilon4 allele frequency in all 89 patients with possible and probable VaD was also significantly higher (p < 0.001) than that in control subjects, but not significantly different from that in AD. The APOE epsilon4 allele frequency was similarly, and still significantly (p < 0.001), increased when only those patients with probable AD or probable VaD were considered. Possession of APOE epsilon4 allele increases the risk of VaD.