To test for an effect of the apoE4 vs. apoE2 alleles (predisposing and protective for Alzheimer’s disease, respectively) on the levels of the various biomarkers, we created two groups (Table 9), one comprising participants carrying isoforms carrying the apoE4 allele (44, 34; apoE[44/34], N = 87) and another comprising participants carrying the apoE2 allele (22, 23; apoE[22/23], N = 44); participants who did not carry apoE4 or apoE2 alleles (i.e. of the apoE33 genotype) were excluded as well as those with the apoE24 genotype, given the known opposite effects of the apoE4 and 2 alleles. This evidence concerns the gene APOE and early-onset autosomal dominant Alzheimer disease.