Alzheimer’s disease has no known cure. The few medications that are available help to lessen some symptoms of the disease and provide temporary, partial relief-but having no real effect on cognitive decline. Currently, there are no medications that can stop the progression of the disease.
A complicating factor for researchers is that there is no known single cause of Alzheimer’s disease. However, many risk factors have been identified.
Genetics appears to play an important role in Alzheimer’s disease; we now know several genes that increase the risk of-or protect against-the disease.
It is also documented that Alzheimer’s can run in families. For example, inheriting one copy of the APOE4 gene variant (which is found in about 20% of the population) will cause up to 4X the normal risk of developing Alzheimer’s disease. Inheriting two copies of APOE4 (one from each parent) will dramatically raise the risk: up to 10X normal levels. But, having a family member with Alzheimer’s disease is not a guarantee of developing the disease.
Known genetic factors account for a small percentage of all Alzheimer’s disease cases, but current research supported by Cure Alzheimer’s Fund indicates far more genetic influence than was previously known. Many candidate genes are currently being discovered and studied for their role in the disease. The genes we know about account for a large percentage of early-onset cases. The rare Presenilin 1 and 2 genes, for instance, virtually guarantee development of early-onset Alzheimer’s.
Individuals with Down syndrome almost always develop early-onset Alzheimer’s disease. Down syndrome occurs in those carrying an extra copy of chromosome 21. This chromosome happens to include the APP gene, which controls Abeta production, a major factor in Alzheimer’s disease pathology.