The APOE e4 allele is a variant of the Apolipoprotein E (APOE) gene, which is located on chromosome 19. This gene plays a critical role in the metabolism of lipids by encoding a protein involved in the transport and clearance of cholesterol and other fats. There are three common alleles of the APOE gene: e2, e3, and e4. Among these, the e4 variant has been extensively studied due to its strong association with various health conditions, particularly Alzheimer's disease and cardiovascular diseases.
