Navigation Links
Researchers find 2 more genetic risk factors for Alzheimer's disease

St. Louis, Sept. 6, 2009 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.


Contact: Jim Dryden
Washington University School of Medicine

Related biology news :

1. Researchers restore missing protein in rare genetic brain disorder
2. Mayo Clinic researchers find that protein believed to protect against cancer has a Mr. Hyde side
3. Species diversity helps ASU researchers refine analyses of human gene mutations
4. UT Southwestern researchers examine mechanisms that help cancer cells proliferate
5. Marine biomedicine researchers decode structure of promising sea compound
6. Researchers report gene associated with language, speech and reading disorders
7. Bats use love songs during mating, researchers say
8. Idaho researchers win grant to explore DNA frontier
9. UCSF researchers identify 2 key pathways in adaptive response
10. Disrupting a destructive duo: U of T Mississauga researchers inhibit cancer proteins
11. Researchers boost production of biofuel that could replace gasoline
Post Your Comments:
(Date:5/16/2016)... --  EyeLock LLC , a market leader of iris-based ... IoT Center of Excellence in Austin, Texas ... embedded iris biometric applications. EyeLock,s iris authentication ... with unmatched biometric accuracy, making it the most proven ... platform uses video technology to deliver a fast and ...
(Date:5/9/2016)... Elevay is currently known as ... for high net worth professionals seeking travel for work ... world, there is still no substitute for a face-to-face ... your deal with a firm handshake. This is why ... of citizenship via investment programs like those offered by ...
(Date:4/28/2016)... India , April 28, 2016 ... Infosys (NYSE: INFY ), and Samsung SDS, a ... that will provide end customers with a more secure, ... services.      (Logo: ) , ... services, but it also plays a fundamental part in enabling ...
Breaking Biology News(10 mins):
(Date:6/23/2016)...  The Biodesign Challenge (BDC), a university competition that ... living systems and biotechnology, announced its winning teams at ... New York City . The teams, ... at MoMA,s Celeste Bartos Theater during the daylong summit. ... curator of architecture and design, and Suzanne Lee ...
(Date:6/23/2016)... ... ... STACS DNA Inc., the sample tracking software company, today announced that Dr. Hays ... DNA as a Field Application Specialist. , “I am thrilled that Dr. Young ... DNA. “In further expanding our capacity as a scientific integrator, Hays brings a wealth ...
(Date:6/23/2016)... 23, 2016  Blueprint Bio, a company dedicated to ... medical community, has closed its Series A funding round, ... "We have received a commitment from Forentis ... need to meet our current goals," stated Matthew ... runway to complete validation on the current projects in ...
(Date:6/23/2016)... ... June 23, 2016 , ... ClinCapture, the only free validated ... will showcase its product’s latest features from June 26 to June 30, 2016 ... on Disrupting Clinical Trials in The Cloud during the conference. DIA (Drug ...
Breaking Biology Technology: