Amyloid precursor protein and Alzheimer's disease

Professor Kenneth Kosik describes the relationship between the amyloid precursor protein (APP) and Alzheimer’s disease. APP mutations are linked to early-onset Alzheimer’s disease.

As we go deeper in the study of Alzheimer’s disease and move down to the level of the gene, we know that the protein in the senile plaque is encoded by a gene called the amyloid precursor protein gene. That gene is critically important for the Alzheimer’s disease process, not only because it’s the product of that gene that forms the plaque but also, in a few rare cases of the disease, mutations in the amyloid precursor gene can lead to early-onset Alzheimer’s disease. For those reasons we know that this gene is very critical in the pathogenesis of the disease. Another gene that is involved in Alzheimer’s disease is called APOE. Now, APOE has different forms, and we call those forms alleles, and one of the alleles of APOE is APOE 4. If you happen to have that allele your risk for Alzheimer’s disease goes up by a little bit. This is only an increased risk, it does not mean you are going to get the disease, but it does mean that the probability of getting it has increased a bit because of that mutation.