Alzheimer’s is a progressive brain disorder that has no cure. When a person develops the disease, they develop amyloid plaques as well as neurofibrillary tangles. As the condition worsens, the neurons deteriorate, eventually dying out.
Both early and late onset Alzheimer's disease have a genetic factor. Some individuals have a risk of developing the disease because of their unique set of genes.
People with early onset Alzheimer’s comprise only about 10% of all Alzheimer’s patients. Several cases result from an inherited gene mutation known as the familial Alzheimer’s disease. The mutations cause the protein called APP to abnormally form. Although the function of this protein is still unknown, the production is clearly associated with the forming of amyloid plaques, which is a manifestation of Alzheimer’s. Someone with parents who had this specific genetic mutation has a 50% chance of inheriting this disease.
The most common form of Alzheimer's is late onset Alzheimer's, which means patients develop the disease in their mid-60s. Still, other than genetics, lifestyle and environmental factors, researchers do not identify a single cause for Alzheimer's disease. This mutation, however, on chromosome 19 called Apolipoprotein E (APOE) clue researchers in.
APOE is not just a single gene. It has different forms like, APOE2, APOE3 and APOE4.
APOE2 carriers develop the disease later in life and may provide protection against early onset Alzheimer’s. APOE3, on the other hand, is a neutral form neither lessening nor increasing a patient’s risk for the condition. Lastly, APOE4 increases the risk of the gene carriers for Alzheimer’s. The more APOE4 is present, the higher the probability is. This is also associated with an early formation of the disease. However, not everyone with this gene will surely develop Alzheimer’s. In fact, there are patients who have no traces of APOE4 protein in their genes.
APOE4 Gene's effect on Alzheimer's disease
Researcher already knew that APOE4 increases the risk for Alzheimer's.
A recent study conducted by the Gladstone Institutes shows that having the gene doubles the risk for the condition. Also, when an individual has two copies of APOE4, the risk is 12 times higher than those who do not have one. The researchers arrived at these findings by studying Alzheimer’s patients who had two copies of the gene and compared it with healthy individuals with the same amount of APOE4 in their genes.
Experts showed that APOE4 creates APOE4 protein, which increases the presence of amyloid beta protein in the genes. The danger lies in the creation of these amyloid beta proteins as they could clump and form plaques, which can disrupt messages between neurons and cause other symptoms to show.
The recent study focused on creating ways to prevent the presence of Alzheimer's symptoms with the APOE4 mutation. Researchers devised a way to change the structure of the protein and make it harmless. The result demonstrated that without an APOE4 gene, the nerve cell damage can be removed. This brought increased brain cell survival and better cognitive function.
This finding carries a huge weight in the field of Alzheimer’s research as it could alter the course of drug development. The study also was conducted with human cells, rather than animal cells. Previous studies done on mouse models did not increase the amyloid beta production with the presence of APOE4. So, this finding was rather surprising.
While this is a breakthrough, these results have yet to be repeated among human patients. Right now, researchers are attempting to create a compound for human trials at an industrial level. Soon, clinical trials will be underway, and a cure might be closer than you think.
Genetic testing for Alzheimer's: Know that these tests only show a possibility for Alzheimer's
A blood test can identify the presence of APOE in someone's genes, but it cannot identify your risk for Alzheimer's. It also doesn't predict Alzheimer's with a 100% accuracy. But, why? Well, Alzheimer's disease has other risks that you have to keep in mind, and these factors contribute greatly to its overall development and progression. While it can help both patients and caregivers, researchers still do not recommend it because it can cause some unneeded anxiety.
APOE4 has a significant connection with many Alzheimer’s symptoms, so APOE testing is now used in the field of research. With this test, researchers can identify who has a higher risk for developing Alzheimer's. It can also help them detect any early neurological changes. This amount of research can help create effective treatments for those with varying genetic profiles.
APOE testing may not prove useful in determining a single person’s risk for Alzheimer’s. This is because comparisons are necessary to accurately describe and diagnose conditions, which is why you need to study Alzheimer's with a large group. Results are verified by several trials and cross-checked with other factors that may affect Alzheimer’s. Biological tests are also currently being studied to assess people’s risk of Alzheimer’s.
Final thought: The discovery of changes in this gene is a breakthrough
Researchers proved that genetic factors play a crucial role in understanding the risk factors associated with Alzheimer’s disease. However, there are still plenty of unanswered questions, like how the disease begins and why some people experience cognitive issues while others don't.
Another interest in research is determining how genes interact with environmental, lifestyle, and other factors. Currently, identifying those who are at most risk is in the center of research. Knowing the disease's effects can lead to new treatments and new approaches to prevent Alzheimer's.