After genetic testing, there are six possible outcomes: e2/e2, e2/e3, e2/e4, e3/e3, e3/e4, e4/e4 APOE e2: The presence of an APOE e2 allele may provide some protection against Alzheimer’s disease. APOE e3: The APOE e3 allele is the most common allele and is a neutral allele, meaning there is no increased or decreased risk with the presence of this allele. APOE e4: The APOE e4 allele is linked to an increased risk of developing Alzheimer’s disease at potentially a younger age of onset. If a person has one APOE e4 allele, they have a three-fold increased risk of developing Alzheimer’s. Individuals that carry two APOE e4 alleles have 10 – 15 times the normal risk of developing Alzheimer’s.