The Cause of Alzheimers

According to the Alzheimer’s Foundation of America, Alzheimer’s is defined as “progressive mental deterioration that can occur in middle or old age, due to generalized degeneration of the brain.” When I was in middle school, a close uncle of mine developed Alzheimer’s disease. At first it was just little things like forgetting where he put something or zoning out more often. Then after the years passed, his symptoms have gradually grown worse and worse, to the point where he cannot form a sentence. Ever since we began learning about viruses, genes, and mutations in AP Biology, it began to make me think about how such a disease is caused.

As of now, there is no cure for Alzheimer’s disease, but scientists continue to discover new things and unravel the mystery of the disease. The National Institute of Aging states that even before symptoms begin to appear, brain damage has been in process for ten or more years. Even though symptoms have not shown up in early stages of Alzheimer’s drastic changes to the brain have occurred. Neurons begin to stop functioning due to an abnormal release of proteins. These neurons lose connection with other neurons, inevitably causing them to die. The disease effects the hippocampus, where memories are formed and then starts to spread to other parts of the brain. Imaging has allowed scientists to watch as Alzheimer’s develops.  They can see an abnormal spread of amyloid and tau proteins in the brain.

So what can cause Alzheimer’s disease? The three main causes for the disease (which are usually the three main causes for everything) are mutations in the brain, aging, genetics, and environmental factors.

Drastic mutations in genes can cause early-onset Alzheimer’s and late-onset Alzheimer’s is caused by gradual mutations in the brain. In most cases, Alzheimer’s disease is found in people in their 60’s. The disease has been in their brain for awhile, but symptoms just begin to show up at that point in their lives. As people age, the brain most likely accumulates a few mutations and brain tissue begins to shrink with age. Taking this into account, the development of Alzheimer’s is more common with the elderly. While the disease is most prevalent in people in their 60’s, people as young as 30 can develop the disease as well. However, this only accounts for five percent of cases.

Genes also play a role in the development of the disease. Often times, a gene called the apolipoprotein E (APOE) gene is found in people who have Alzheimer’s. The gene increases the likelihood of developing both early and late-onset Alzheimer’s, but people who have this gene do not always develop the disease. On the other hand, people without the APOE gene have been known to acquire Alzheimer’s disease as well. It is also common for people with Down syndrome to develop the disease due to the extra 21st chromosome that contains amyloid.

Lastly, a major influence of Alzheimer’s is environment and health. It is possible that things related to vascular and metabolic conditions may increase of decrease the risk of the disease. Also, people who live healthy lifestyles and stimulate their brain tend to have a less likelihood of developing Alzheimer’s.

Alzheimer’s can be cause by many different factors and it is a disease that hopefully will not be a problem in the future. It is important to stay healthy to decrease the chance of developing Alzheimer’s disease and other diseases as well.


  • “Alzheimer’s Disease Fact Sheet.” National Institute on Aging. N.p., May 2015. Web. 4 Feb. 2016.
  • “Alzheimer’s Foundation of America – Definition of Alzheimer’s Disease.” Alzheimer’s Foundation of America – Definition of Alzheimer’s Disease. N.p., n.d. Web. 04 Feb. 2016.

About Mr. Mohn

Biology Teacher

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