April 13, 2024

Researchers identify new genetic variants

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Researchers identified 17 new genetic variants associated with Alzheimer’s disease in five genomic regions. Mask/Getty Images
  • Previous studies show that genetics may play a role in the development of Alzheimer’s disease.
  • Researchers recently added to this concept by identifying 17 genetic variants associated with Alzheimer’s disease in five genomic regions.
  • The findings included genetic variant data from ethnic groups historically underrepresented in genetic studies relating to Alzheimer’s disease.

In recent years, more research has supported the idea that genetics may play a role in the development of Alzheimer’s disease (AD) – a type of dementia that affects around 32 million people globally.

Now, researchers at the Boston University School of Public Health and the University of Texas Health Science Center at Houston add even more to this concept with new research that has identified 17 genetic variants — a change in the DNA sequence — associated with Alzheimer’s disease in five genomic regions.

The study was recently published in the journal Alzheimer’s and Dementia: The Journal of the Alzheimer’s Association.

Although scientists are still unsure what causes Alzheimer’s disease, most believe it develops from a combination of factors, including genetics, age-related changes in the brain, and certain lifestyle and environmental factors.

In recent years, more research has uncovered how genetics may play a role in the development of Alzheimer’s disease.

For example, a study published in April 2022 identified 75 genetic locations correlated with an increased risk for Alzheimer’s disease, including 42 sites that had not previously been associated with the disease.

Research published in February 2023 discovered a genetic variant often found in people of African ancestry may increase the risk of Alzheimer’s disease.

A study published in September 2023 reported a genetic mutation in brain immune cells This can increase a person’s risk of Alzheimer’s disease.

“There are limited medications currently available to treat Alzheimer’s disease and none are highly effective,” explained Dr. Anita DeStefano, professor of biostatistics at the Boston University School of Public Health (BUSPH) and lead author of this study. Medical News Today.

“There are currently no therapies that prevent Alzheimer’s disease. Understanding the genetic factors that influence risk for Alzheimer’s disease or protection against Alzheimer’s disease provides new biological insights that could lead to the identification of new drug targets to facilitate the development of new therapeutic approaches.”

— Dr. Anita DeStefano, lead author of the study

For this study, researchers used complete genome sequencing data from the Alzheimer’s Disease Sequencing Project (ADSP) – a genetics initiative launched by the National Institutes of Health in 2012 as part of the National Alzheimer’s Project Act.

Scientists had access to information on more than 95 million genetic variants from nearly 4,600 people with or without Alzheimer’s disease.

After analyzing the data, study researchers discovered 17 significant variants associated with Alzheimer’s disease located in five genomic regions.

“Many recent studies on the genetics of Alzheimer’s disease are genome-wide association studies (GWAS)that analyze the human genome and identify regions associated with Alzheimer’s disease risk,” Dr. Chloé Sarnowski, assistant professor of epidemiology at the University of Texas Health Science Center School of Public Health at Houston and corresponding author of this study told MNT.

“These regions will contain hundreds of genes and thousands of variants, and initially we will not know which gene or gene change is biologically relevant.”

“Whole genome sequence data provides information about every change (variation) in the DNA sequence of study participants and allows us to refine information from GWAS studies as well as make new discoveries.

An analogy is to compare the DNA sequence of the human genome with the sequence of letters that make up a book. Previous GWAS studies identified common “misspellings” and took us to specific pages where important errors occurred, but they did not identify all the letters that changed or were missing. With full genome sequencing, we analyze every letter on the page and more comprehensively understand all changes and ‘spelling errors’.”

— Dr. Chloé Sarnowski, corresponding author of the study

One of the most notable genetic variants, the scientists reported, was lysine acetyltransferase 8 (KAT8) variant.

Previous studies show that KAT8 is important for brain development and may play a role in the development of Dementias related to Alzheimer’s disease and Parkinson’s disease.

Additionally, through the ADSP database, the research team had access to genetic variant data from a wide range of ethnicities, including Black/African American Hispanic/Latinowhich researchers say has historically been underrepresented in genetic studies on Alzheimer’s disease.

“Historically, the vast majority of individuals included in genetic studies of Alzheimer’s disease were of European ancestry,” said Dr. DeStefano.

“We know that the prevalence of Alzheimer’s disease varies between population groups, with African Americans having a higher prevalence. Therefore, to understand the full spectrum of Alzheimer’s disease risk, it is important that studies represent diverse genetic ancestries and diverse environments in terms of social determinants of health.”

MNT discussed this study with Dr. Karen D. Sullivan, board-certified neuropsychologist, owner of I CARE FOR YOUR BRAIN, and Reid Healthcare Transformation Fellow at FirstHealth of the Carolinas in Pinehurst, NC.

Dr. Sullivan called this research a “major breakthrough” that brings science-based interventions a significant step closer to a breakthrough treatment for Alzheimer’s disease.

“I am also impressed that researchers purposefully sought out ethnically diverse participants, as communities of color have historically been underrepresented in genetic studies of Alzheimer’s disease despite its high incidence,” she continued.

“With Alzheimer’s disease being the most common subtype of dementia and a rapidly aging society, we are truly in a race against time to find more effective treatments,” added Dr. Sullivan.

“O cost of care as this massive increase in people with dementia is immense, with treatment as it stands today, and threatens the future viability of healthcare systems to manage it. Beyond the cost, we know that the human cost of dementia is enormous for everyone affected.”

Sullivan said he would like to see the findings of this research extended to much larger samples and the variants linked to their respective expressions or phenotypes.

“For example, what impact does the KAT8 variant, associated with Alzheimer’s disease in both unique and rare variant analysis, have on specific cognitive and behavioral changes in these groups?

We must always remember that brain structure and function do not have a 1 to 1 relationship – just as genotype and phenotype, one does not always perfectly predict the other. So while this is an impressive advance in our understanding of the genetics of Alzheimer’s disease, we still need to link it to what changes in humans with this disease.”

– Dr. Karen D Sullivan, neuropsychologist

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