For instance in the case of Alzheimer's disease (AD), individuals that are homozygous or heterozygous for ApoE ε4, have a significantly increased risk of developing the disease with an earlier onset [3] compared with individuals with the most common ApoE ε3/ε3 genotype [1,3,4,9-11]. This evidence concerns the gene APOE and early-onset autosomal dominant Alzheimer disease.