The main function of the APOE gene is to direct the synthesis of apolipoprotein E (APOE). The main function of APOE is to participate in the transformation and metabolism of lipoproteins, participate in the regulation of lipid metabolism in the body, and is an important internal factor affecting the level of blood lipids in the body, considered to be an important susceptibility gene for hyperlipoproteinemia and atherosclerotic vascular disease.
Due to the polymorphism of the APOE genotype, the APOE protein is also polymorphic, with three different protein isoforms: APOE4, APOE3, APOE2. Some people have only one major isomer, that is, homozygotes; some people can have two major isomers, that is, heterozygotes. It can be seen that there are six different phenotypes in the population.