Featured Research

from universities, journals, and other organizations

More Genetic Risk Factors For Alzheimer's Disease Found

Date:
September 7, 2009
Source:
Washington University School of Medicine
Summary:
An international team of scientists has identified two more genetic risk factors for Alzheimer's disease. The group completed the largest genome-wide association study ever involving patients with Alzheimer's disease. The study pooled DNA samples from more than 19,000 older European and US residents.

An international team of scientists has identified two more genetic risk factors for Alzheimer's disease.

The findings are reported in the online edition of the journal Nature Genetics.

The group, led by investigators from the School of Medicine at Cardiff in the United Kingdom and including scientists from Washington University School of Medicine in St. Louis, completed the largest genome-wide association study ever involving patients with Alzheimer's disease. The study pooled DNA samples from more than 19,000 older European and U.S. residents. Seven thousand had Alzheimer's disease, and the others had no clinical symptoms of the disorder.

Prior to this study, only four genes had been definitively associated with Alzheimer's disease. Three genetic mutations have been identified as causes of rare, inherited forms of early-onset Alzheimer's. The fourth gene, APOE4, is the only one previously linked to the more common late-onset form of the disease.

By looking at more than 600,000 common DNA markers, researchers on the current study were able to identify two new genes that appeared to be involved in elevated risk for Alzheimer's and confirmed the importance of APOE4.

"There's good evidence that these new genes may be novel risk factors, the first discovered since APOE in 1993," says Washington University researcher and co-author Alison M. Goate, D.Phil. "So it's a very important observation because this study is the first to provide such significant evidence of novel genetic risk factors for the most common form of Alzheimer's disease."

Goate, who in 1991 led a team in England that identified the first early-onset Alzheimer's mutation in the APP gene on chromosome 21, is now the Samuel and Mae S. Ludwig Professor of Genetics in Psychiatry and professor of neurology at Washington University. She says the new genes identified in this study are APOJ, also called clustrin on chromosome 8, and PICALM on chromosome 11.

"The power of the new Genome Wide Association Study methods is that with large datasets we can now identify genes that earlier techniques were unable to confirm," says co-author John C. Morris, M.D., of Washington University. "These new genes associated with Alzheimer's disease provide new clues about how the illness develops."

Morris, the Harvey A. and Dorismae Hacker Friedman Distinguished Professor of Neurology, is the director of Washington University's Alzheimer's Disease Research Center (ADRC). He says previous ADRC research suggests that in mice, the clustrin gene may be involved in the formation of amyloid deposits in the brain. Amyloid makes up the senile plaques that dot the brains of people with Alzheimer's.

"These genes are both significant, but their effect appears to be much smaller than that of the APOE gene," Goate says. "Using statistical methods, we've been able to estimate the amount of risk attributable to APOE at about 19 or 20 percent. The newly identified genes each come in under 10 percent, so it appears they have a much smaller effect."

But not an insignificant one, Goate says, noting that although it isn't yet clear how these new genes influence Alzheimer's disease risk, levels of clustrin tend to rise when brain tissue is injured or becomes inflamed, and some researchers have noted increased clustrin levels in the brain and cerebrospinal fluid of Alzheimer's patients.

The other gene, PICALM, appears to be involved in the breakdown of synapses, structures that allow neurons in the brain to communicate. Some scientists also hypothesize that the gene may be involved in the development of amyloid deposits, but Goate says much more work is required to identify exactly how PICALM elevates Alzheimer's risk.

She expects many more genes also are involved in Alzheimer's risk. In fact, this study identified 13 more gene variants worthy of further investigation.

The consortium of more than 80 scientists was led by Denise Harold, Ph.D., and Julie Williams, Ph.D., and their colleagues at Cardiff University. They used brain and blood tissues made available and analyzed by dozens of laboratories in the United Kingdom, Ireland, German, Belgium, Greece and the United States.

This study was supported by several public and private funding agencies, including the Wellcome Trust and the National Institutes of Health.


Story Source:

The above story is based on materials provided by Washington University School of Medicine. Note: Materials may be edited for content and length.


Journal Reference:

  1. Harold et al. Genome-wide association study identifies variants at CLU and PICALM associated with Alzheimer's disease. Nature Genetics, 2009; DOI: 10.1038/ng.440

Cite This Page:

Washington University School of Medicine. "More Genetic Risk Factors For Alzheimer's Disease Found." ScienceDaily. ScienceDaily, 7 September 2009. <www.sciencedaily.com/releases/2009/09/090906161106.htm>.
Washington University School of Medicine. (2009, September 7). More Genetic Risk Factors For Alzheimer's Disease Found. ScienceDaily. Retrieved August 27, 2014 from www.sciencedaily.com/releases/2009/09/090906161106.htm
Washington University School of Medicine. "More Genetic Risk Factors For Alzheimer's Disease Found." ScienceDaily. www.sciencedaily.com/releases/2009/09/090906161106.htm (accessed August 27, 2014).

Share This




More Mind & Brain News

Wednesday, August 27, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Alice in Wonderland Syndrome

Alice in Wonderland Syndrome

Ivanhoe (Aug. 27, 2014) It’s an unusual condition with a colorful name. Kids with “Alice in Wonderland” syndrome see sudden distortions in objects they’re looking at or their own bodies appear to change size, a lot like the main character in the Lewis Carroll story. Video provided by Ivanhoe
Powered by NewsLook.com
Stopping Schizophrenia Before Birth

Stopping Schizophrenia Before Birth

Ivanhoe (Aug. 27, 2014) Scientists have long called choline a “brain booster” essential for human development. Not only does it aid in memory and learning, researchers now believe choline could help prevent mental illness. Video provided by Ivanhoe
Powered by NewsLook.com
Personalized Brain Vaccine for Glioblastoma

Personalized Brain Vaccine for Glioblastoma

Ivanhoe (Aug. 27, 2014) Glioblastoma is the most common and aggressive brain cancer in humans. Now a new treatment using the patient’s own tumor could help slow down its progression and help patients live longer. Video provided by Ivanhoe
Powered by NewsLook.com
Brain Surgery in 3-D

Brain Surgery in 3-D

Ivanhoe (Aug. 27, 2014) Neurosurgeons now have a new approach to brain surgery using the same 3D glasses you’d put on at an IMAX movie theater. Video provided by Ivanhoe
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins