Corporate Banner
Satellite Banner
Genomics
Scientific Community
 
Become a Member | Sign in
Home>News>This Article
  News
Return

AD GWAS in African Americans Confirms, Reshuffles AlzGene List

Published: Thursday, April 11, 2013
Last Updated: Thursday, April 11, 2013
Bookmark and Share
African Americans carrying a variant in a cholesterol-processing gene have double the risk for Alzheimer’s than non-carriers.

This gene, for a membrane transporter protein called ABCA7, is the greatest difference between African American and Caucasian Alzheimer’s risk to emerge from the largest genomewide association study (GWAS) for AD performed in African Americans to date. The study appears April 10 in the Journal of the American Medical Association. In African Americans, ABCA7 variation is the strongest genetic risk factor for AD outside of the ApoE4 allele. Other than that, the genes involved in African American AD risk paralleled those in whites, reported the study authors representing the Alzheimer's Disease Genetics Consortium.

Led by senior author Richard Mayeux at Columbia University in New York City, the researchers examined single-nucleotide polymorphisms from nearly 2,000 people with late-onset Alzheimer’s, and almost 4,000 control participants. The group collected all the data it could get from African Americans seen at more than 20 study centers, said first author Christiane Reitz, also at Columbia.

While many of the previously reported GWAS data come from people of European and European American ancestry, Reitz noted that it is important to investigate whether those genetic findings extend to people beyond that white slice of humanity. A GWAS in Hispanics is ongoing.

Several of the genes the current study picked out in African Americans matched those found in GWAS with white people. ApoE4 was the strongest risk factor; a single copy more than doubled risk of Alzheimer’s with an odds ratio of 2.31 in this report. “Replicating an association for the same alleles in different ethnic groups strengthens the case for these variants being important in increasing disease susceptibility,” commented Robert Nussbaum of the University of California, San Francisco, in an editorial accompanying the publication.

After ApoE, ABCA7 was second on the hit list. ABCA7 variants had been reported to increase risk in white people, but ABCA7 was in the middle of the pack among genes linked to AD, most of which boost risk by an average of 10-20 percent, Reitz said (Hollingworth et al., 2011). ABCA7 currently ranks fourth on the AlzGene Top 10. In the new study’s African American population, an ABCA7 variant increased one’s chances of AD by almost double, with an odds ratio of 1.79.

This kind of race-based difference is not uncommon, Reitz noted. She suspects that the ABCA7 polymorphisms found in Caucasians point to specific functional mutations different from those carried by African Americans, but the researchers have not yet sequenced the gene to check. It is also possible that the genetic background of each race, as well as environmental factors, conspire with ABCA7 variants to produce a higher risk in African American carriers than in whites.

It is too early to think about genetic testing or ABCA7-based therapies, Reitz said. For now, researchers have to confirm the disease association in an independent population and study the biological function of the gene. That is no small task. ABCA7’s functions fit with the AD literature in that lipid dysregulation and cardiovascular disease are known risk factors (Breteler, 2000; Shepardson et al., 2011). ABCA7 encodes an ATP-binding transporter that participates in lipoprotein biogenesis, and secretion of phospholipids and cholesterol (Tanaka et al., 2011). It also influences the transport of amyloid precursor protein across the plasma membrane (Chan et al., 2008). “There are multiple ways in which ABCA might affect risk of late-onset Alzheimer's disease,” the study authors wrote.


Further Information

Join For Free

Access to this exclusive content is for Technology Networks Premium members only.

Join Technology Networks Premium for free access to:

  • Exclusive articles
  • Presentations from international conferences
  • Over 3,300+ scientific posters on ePosters
  • More than 4,800+ scientific videos on LabTube
  • 35 community eNewsletters


Sign In



Forgotten your details? Click Here
If you are not a member you can join here

*Please note: By logging into TechnologyNetworks.com you agree to accept the use of cookies. To find out more about the cookies we use and how to delete them, see our privacy policy.

Related Content

AD GWAS in African Americans Confirms, Reshuffles AlzGene List
African Americans carrying a variant in a cholesterol-processing gene have double the risk for Alzheimer’s than non-carriers.
Monday, April 15, 2013
Scientific News
Liquid Biopsies: Miracle Diagnostic or Next New Fad?
Thanks to the development of highly specific gene-amplification and sequencing technologies liquid biopsies access more biomarkers relevant to more cancers than ever before.
Cancer Gene-Drug Combinations Ripe for Precision Medicine
The study aims to expand the number of cancer gene mutations that can be paired with a precision therapy.
Targeting BRAF Mutations in Thyroid Cancer
Treating metastatic thyroid cancer patients harboring a BRAF mutation with vemurafenib showed anti-tumor activity in a third of patients.
Colon Cancer Blocked in Mice
Case Western Reserve University Researchers block common type of colon cancer tumour in mice, laying groundwork for human clinical trial.
Cancer Related Immune Response Genes Uncovered
Researchers at the SBP have identified over 100 new genetic regions that affect the immune response to cancer.
New Therapeutic Targets For Small Cell Lung Cancer Identified
Researchers at UTSW Medical Center have identified a protein termed ASCL1 that is essential to the development of small cell lung cancer.
Deciphering Inactive X Chromosomes
Untangling the Barr body of inactive X chromosomes valuable for understanding chromosome structure and gene expression.
Micro Disease-Detecting Sensor Created
Researchers at McMaster University have created a microscopic disease-detecting sensor that can turn on to detect trace amounts of substances.
Liquid Biopsies Treating Ovarian Cancer
Researchers have discovered a promising monitor and treat recurrence of ovarian cancer. Detecting cancer long before tumours reappear.
Uncovering a New Principle in Chemotherapy Resistance in Breast Cancer
The NIH study has revealed an entirely unexpected process for acquiring drug resistance that bypasses the need to re-establish DNA damage repair in breast cancers that have mutant BRCA1 or BRCA2 genes.
Skyscraper Banner

SELECTBIO Market Reports
Go to LabTube
Go to eposters
 
Access to the latest scientific news
Exclusive articles
Upload and share your posters on ePosters
Latest presentations and webinars
View a library of 1,800+ scientific and medical posters
3,300+ scientific and medical posters
A library of 2,500+ scientific videos on LabTube
4,800+ scientific videos
Close
Premium CrownJOIN TECHNOLOGY NETWORKS PREMIUM FOR FREE!