A new study has found that a gene variant found almost exclusively among people of African descent significantly raises the risk of Alzheimer's disease, reported first by UPI.
The variant is in a gene called ApoE3 and is only harmful when it exists in combination with the ApoE4 gene, a well-known risk factor for Alzheimer's.
The study analyzed genetic data and medical records for nearly 32,000 people, mostly of African descent, with 4,800 having Alzheimer's disease and the rest being mentally healthy.
The gene duo was present in only 1% of the 32,000 individuals. However, it was tied to a nearly threefold increase in the risk of developing Alzheimer's.
Unique Genetic Influences
Dr. Michael Greicius, the senior researcher on the study and professor of neurology at Stanford University School of Medicine in California, believes that this finding is significant because the majority of studies on the genetics of Alzheimer's disease have been conducted on White people.
Researchers need to learn more about any unique genetic influences on the risk of Alzheimer's in people of color.
Greicius noted that when people undertake genetic testing to determine their risk of the disease, racial and ethnic ancestry should be taken into account.
He argued that the more knowledge scientists have about the genetics of Alzheimer's, the better equipped they will be to comprehend the biology of the condition and develop treatments based on it.
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Three Variants
The three variants of the ApoE gene-E2, E3, and E4-were the subject of the study. The E4 gene, which increases the risk of the disease, is present in 20% or more of Americans.
Carrying two copies of E4 is even considered worse since it increases a person's risk of Alzheimer's by almost 10 times compared to carrying two copies of E3.
The most prevalent form of the ApoE gene, known as E3, is present in more than half of the general population.
It has also been used as a benchmark in studies on Alzheimer's disease to compare E4 with E2 (which is a rather rare variant). However, the R145C variation of E3 was found in the new study to be harmful when combined with E4.
It is still unclear why the R145C variant causes trouble when paired with E4, but the researchers found that the variant renders ApoE3 proteins weaker, and less able to latch onto body cells and perform their normal duties. This may impair E3's ability to counteract the harmful effects of E4.
The results of the study support recent research contending that E4's effects on Alzheimer's risk may differ by race and ethnicity. Percy Griffin, Director of Scientific Engagement at the Alzheimer's Association and the study's author, thinks that results like these are essential for ongoing research.
The study also underlines the need for more research on the condition among people of color and sheds light on the distinct genetic factors of African's susceptibility to Alzheimer's disease.
The findings were published in the Journal of the American Medical Association.
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