Question

The examples we discussed in various case study are familial forms of Alzheimer’s disease. There is also a sporadic form, which arises in germ line or somatic cells. Which genes do you think are mostly likely to be affected in the sporadic form of Alzheimer’s disease? Why?

Answer 1

The APOE gene is affected by the sporadic form of Alzheimer's disease, which has been proven. 40 to 80% of people with alzheimer's possess at least one APOE sigma4 allele. The APOE sigma4 allele increases the risk of the disease by three times in heterozygotes and by 15 times in homozygotes. The APOE gene normally codes for making apolipoprotein E. Apolipoprotein E combines with lipids in the body to form lipoproteins. Lipoproteins are responsible for packaging cholesterol and other fats and carrying them through the bloodstream. Other susceptible gene that have been identified by genome-wide association studies (GWAS) are CASS4, CELF1, FERMT2, HLA DRB5, INPP5D, MEF2C, NME8, PTK2B, SORL1, ZCWPW1, SlC24A4, CLU, PICALM, CR1, BIN1, MS4A, ABCA7, EPHA1, TREM2 and CD2AP. When mutation occurs in TREM2 gene, white blood cells in the brain will not be able to control the amount of beta amyloid present.