The Apo E ε4 allele frequencies were 45% (15 with Apo E ε3/4 genotype and 3 with Apo E ε4/4 genotype) in the AD group and 12% (3 with Apo E ε3/4 genotype and 1 with Apo E ε2/4 genotype) in the control group. Here, APOE is linked to Alzheimer disease.