Apolipoprotein (APOE) Gene

Individuals with two copies of APOE4, have a dramatically increased risk of developing Alzheimer’s disease.

Apolipoprotein (APOE) is a plasma glycoprotein that contains 299 amino acids. APOE transports vitamins, lipoproteins and cholesterol into the lymph system and blood. It is mainly expressed in the liver, but is found in other tissues, including the brain. There are three major isoforms (versions) of APOE – APOE2, APOE3, and APOE4. The APOE4 isoform is particularly associated with Alzheimer’s disease. In individuals with two copies of APOE4, the risk of developing Alzheimer’s disease increases from 20% to 90% and the average age of onset decreases from 84 to 68 years. APOE4 binds to or retains amyloid-beta, which is the primary component of plaques in Alzheimer’s disease.