Instead, carrying one or two APOE2 alleles protects from developing AD (Reiman et al., 2020), whereas APOE4 increases the risk to develop AD, with each additional APOE4 copy increasing the risk and reducing the age at onset of the disease (APOE4 homozygotes, which are less than 2% of the population, have a 60% chance of developing AD by the age of 85) (Fortea et al., 2024; Genin et al., 2011). This evidence concerns the gene APOE and Alzheimer disease.