APOE-e4 or Apolipoprotein E-e4 is the only variation known of an APOE gene to increase the risk of having Alzheimer’s. There are other variations of APOE, such as APOE-e2 or APOE-e3. Many people in our society have 2 copies of the gene APOE-e3. Yet, people who inherit 2 copies of the APOE-e4 gene are in high risk of having Alzheimer’s. APOE-e4 is located from base pair 44,905,748 to base pair 44,909,394 on chromosome 19. APOE-e4 is ,when few, benign and helps the body. However, when APOE-e4 accumulates it can risk many diseases like Alzheimer’s or dementia. The APOE-e4 gene accumulates beta-amyloid as chromosome-21 or APP(amyloid precursor protein).
Sources used: http://ghr.nlm.nih.gov/gene/APOE