Scientifically reviewed by Sharyn Rossi, PhD
About 15-25% of the general population carries the APOE4 gene— the biggest genetic risk factor in developing Alzheimer's. However, the gene does not affect all populations equally.
Prior research has revealed that people of African descent who carry APOE4 have some protection against Alzheimer’s compared to other populations. Now, researchers have identified a probable reason why—opening the possibility of new treatment or prevention strategies across racial and ethnic groups.
A study co-funded by BrightFocus Foundation’s Alzheimer’s Disease Research program found that the difference in risk between African and European populations lies in the inheritance of nearby genetic regions that interact with APOE. Their study identified a mutation at a specific neighboring location in people of African ancestry that reduces the risk effect of APOE4 for developing Alzheimer’s disease.
The study’s authors included Alzheimer’s Disease Research grantees Jeffery M. Vance, MD, PhD, a professor of neurology at the University of Miami Miller School of Medicine, and Margaret A. Pericak-Vance, PhD, director of the John P. Hussman Institute for Human Genomics at the University of Miami Miller School of Medicine.
Highlighting the importance of diversity in research studies
By focusing on a genetic factor that affects the development of Alzheimer’s disease, the discovery may lead to a better understanding of racial differences in dementia and APOE4 as a major therapeutic target. These findings also highlight the importance of diversity and inclusion of all populations in research. The researchers hope that it will encourage additional studies focused on diverse populations where this type of genetic difference can reveal information that can’t be found when studying only a single population.
Using existing data as a springboard
The study focused on the APOE4 gene, which is known to increase the risk of Alzheimer’s. A previous study found that more important than the APOE allele itself is the genetic region surrounding the gene and whether that region has been inherited from African or European ancestry. This study determined which genetic factors play a role in the surrounding region and identified a nearby mutation that interacts with APOE, lowering the risk of developing Alzheimer's disease.
Although the mechanisms behind the interaction are unknown, the findings open the possibility for potential personalized therapies specific to a person’s ancestry. The authors stated that identifying natural protection for Alzheimer’s disease is a critical way to move therapy forward for people of all racial and ethnic backgrounds.
APOE4 contributes almost 40% of the genetic risk in people of European descent and is also associated with developing the disease at an earlier age, although not everyone with the gene will develop dementia.
Ironically, despite their protection from the effects of the APOE4 gene, African Americans and Black people are twice as likely to develop Alzheimer’s disease than white people in the U.S. Chronic conditions associated with higher dementia risk, such as cardiovascular disease and diabetes, disproportionately affect African Americans and Black people, which may partially explain their elevated risk. Other factors contributing to this disparity include how the disease is measured, socioeconomic factors, cultural differences, lack of culturally competent providers, and discrimination.
The study was conducted by a large team of researchers from universities across the U.S., Puerto Rico, and Nigeria, and was published in the scientific journal PLOS Genetics.
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About BrightFocus Foundation
BrightFocus Foundation is a premier nonprofit funder of research to defeat Alzheimer’s, macular degeneration, and glaucoma. Through its flagship research programs—Alzheimer’s Disease Research, National Glaucoma Research, and Macular Degeneration Research—the Foundation is currently supporting a $75 million portfolio of 287 scientific projects. BrightFocus has awarded nearly $275 million in groundbreaking medical research funding since inception and shares the latest research findings, expert information, and English/Spanish disease resources to empower the millions impacted by these devastating diseases. Learn more at brightfocus.org.
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