Apolipoprotein E-4 gene dose in clinically diagnosed Alzheimer's disease: prevalence, plasma cholesterol levels and cerebrovascular change.

The prevalence of the apolipoprotein E-4 allele (ApoE-4) was significantly higher in a referral population of 40 patients with clinically diagnosed Alzheimer's disease than in a sample of non-demented elderly controls (P < 0.01). The highest plasma cholesterol levels were found in demented patients homozygotic for Apo E-4, but no significant increases of glucose, triglycerides and thyroxine or of leuko-araiosis and brain infarcts were verified in this preliminary study.