The mean age-at-diagnosis of AD in BCHE-K carriers versus noncarriers was also significantly different from APOE4 heterozygotes (6.7 years; 60.5 versus 67.3 years) and homozygotes (5.7 years; 60.8 versus 66.4 years) (P = 0.013, ANOVA; P = 0.019, ANCOVA) (Fig. 1B). This evidence concerns the gene APOE and Alzheimer disease.