Uncovering Why Studying Diverse Populations Is Crucial to Alzheimer’s Research

The DAWN study is an international, multi-site initiative to expand Alzheimer’s disease genetic research in underrepresented African ancestry populations and Latino groups.

In this exclusive MedPage Today video, Margaret Pericak-Vance, PhD, director of the John P. Hussman Institute for Human Genomics at the University of Miami Miller School of Medicine in Florida, discusses how the Alzheimer’s Disease Sequencing Project, which helped uncover the importance of including diverse populations in Alzheimer’s research, led to the subsequent DAWN study.

Following is a transcript of her remarks:

The goal of the Alzheimer’s Disease Sequencing Project was to sequence a large number of individuals to find the genetic variations — those with the disease and those who are cognitively unimpaired — to be able to identify genes that cause risk or even genes that are involved in prevention.

And highly successful; over a hundred genes have been identified. I shouldn’t say genes, I should say loci — so, places on the genome that contribute to Alzheimer’s risk. And one of the things we noticed after this first bolus of a large number of genes, that everybody who was being studied was of European origin. So we realized, and I think the field realized — we realized some of it because of looking at APOE, and that’s showing that there was a difference in risk depending on ancestries, depending on where your ancestral background was.

We saw that Europeans had high risk, the reports of Asians having higher risk, people of European background. But then we had reports of African Americans, when we first got some African Americans involved in the research, that their risk appeared lower than the European risk. And then there was a study out of Indianapolis led by Hugh Hendrie, where he looked at individuals in Nigeria and from the University of Ibadan, and they seemed to have even a lower risk.

So once we did this, everybody realized the importance of including diverse populations in the research was critical. Not only because there may be different genes in different groups, in these different ancestral groups, and therefore a treatment designed for somebody of European background or Asian background might not be the same for somebody of African ancestry. And so it was the right thing to do. If you really want to combat Alzheimer’s, which is a global problem, you have to study it globally.

So the project is the DAWN project, which is an unbelievable undertaking where we’re recruiting 13,000 individuals — half with Alzheimer’s, half who are cognitively unimpaired — over 5 years. And what’s unusual about it is that we’re recruiting 4,000 Hispanic Americans, Hispanic Latino Americans, and we’re also recruiting 4,000 African Americans. But a piece of the project, about 5,000 individuals are coming from Africa. And our collaborator, Dr. Rufus Akinyemi, founded the African Dementia Consortium, which includes — right now, it’s almost up to ten countries — ten different countries that are participating in this global effort to be able to solve the problem of Alzheimer’s.

And it’s really critical, because if you think of African Americans in the U.S. or Caribbean Hispanic [populations] that are admixed, 80% of African Americans genomes come from Africa. So when you’re trying to solve and try to figure out what is causative and what is not causative, you need all these reference populations. So it’s really critical to have the reference original populations before all the admixture occurred and everything, because we’re able to then decipher what is going on in terms of risk and prevention for this disease.

So we’re really excited about that. So far we’ve recruited about almost 3,000 individuals as part of the project. We’re just starting year 3, and it’s really been a great collaboration.

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