In AD patients, the APOE alleles presented the following frequency distributions ε2: 1.5%, ε3: 75.5%, ε4: 23%, whereas in aMCI cases, the frequencies of APOE alleles (ε2: 6.4%, ε3: 80.1%, ε4: 13.5%) resembled those ones of controls (ε2: 8%, ε3: 78%, ε4: 14%). Here, APOE is linked to Alzheimer disease.