Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Alzheimer’s found to be mostly genetic

07.02.2006


Largest twin study ever undertaken confirms highest estimates of genetic risk



Alzheimer disease has a genetic cause in up to 80 percent of cases, according to a University of Southern California- led study of nearly 12,000 twin pairs. The study appears in the February 2006 issue of Archives of General Psychiatry, a journal of the American Medical Association.

Margaret Gatz, professor of psychology in the USC College of Letters, Arts, and Sciences, led an international team of researchers from Göteborg University, Jönköping University and Karolinska Institutet in Sweden, as well as from USC, the University of California at Riverside and the University of South Florida.


Past estimates of Alzheimer’s risk varied widely, with the highest numbers sometimes greeted with skepticism.

"Our finding confirms the higher estimates that have been suggested previously. The important thing is that no one has had this large a sample before," Gatz said, adding the size was 10 times that of any previous study.

The study raises doubts about the widely held view that Alzheimer’s has two forms: the "familial," with genetic roots, and the "sporadic," with environmental causes.

"In essence what we’re doing is taking the folks who would have formerly been called sporadic, and testing how important genetic influences are ... and we’re finding genetic influences are tremendously important," Gatz said. "It does suggest that there is an underlying genetic basis."

Gatz warned, "This doesn’t mean that environment is not important. Environment may be relevant not only for whether but also for when one gets the disease. Also, you can’t go from these results to any one individual."

Even identical twins, who share all their genes, differ in their vulnerability. The study found only a 45 percent concordance rate for identical male pairs. This means that of all pairs where one twin has Alzheimer’s, 55 percent of the healthy twins either will never get the disease or will develop it later in life.

In her previous research with twins, Gatz identified possible preventive or delaying factors, such as a low incidence of inflammatory disease or a work environment with a high degree of human interaction.

The sample for the study consisted of all participants in the Swedish Twin Registry aged 65 or older in 1998 - the year the study began -- for a total of 11,884 twin pairs.

Of these, 392 pairs showed evidence of Alzheimer’s in at least one twin.

In the model that best fit the data, genetic influence accounted for 79 percent of Alzheimer’s risk, with 95 percent confidence in a range of 67 to 88 percent.

The other 21 percent of Alzheimer’s risk was due to non- shared environmental causes. Risk from shared environments, such as childhood settings that were the same for both twins, was statistically negligible.

Genetic risk for Alzheimer’s was the same for men and women after controlling for age.

The study is notable for its careful approach to Alzheimer’s diagnosis. All individuals were screened for cognitive dysfunction. Suspected cases of dementia, of which Alzheimer’s is the most common form, received complete, in-home clinical diagnostic evaluations by a doctor and nurse. Autopsy confirmation of diagnoses is being collected.

The research for this study was supported by grants from the National Institute on Aging and the Alzheimer’s Association.

The other USC researcher on the study was co-principal investigator Nancy Pedersen, a research professor with a joint appointment as professor at Karolinska Institutet.

Carl Marziali | EurekAlert!
Further information:
http://www.usc.edu

More articles from Studies and Analyses:

nachricht Smart Data Transformation – Surfing the Big Wave
02.12.2016 | Fraunhofer-Institut für Angewandte Informationstechnik FIT

nachricht Climate change could outpace EPA Lake Champlain protections
18.11.2016 | University of Vermont

All articles from Studies and Analyses >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Electron highway inside crystal

Physicists of the University of Würzburg have made an astonishing discovery in a specific type of topological insulators. The effect is due to the structure of the materials used. The researchers have now published their work in the journal Science.

Topological insulators are currently the hot topic in physics according to the newspaper Neue Zürcher Zeitung. Only a few weeks ago, their importance was...

Im Focus: Significantly more productivity in USP lasers

In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.

Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...

Im Focus: Shape matters when light meets atom

Mapping the interaction of a single atom with a single photon may inform design of quantum devices

Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

Researchers identify potentially druggable mutant p53 proteins that promote cancer growth

09.12.2016 | Life Sciences

Scientists produce a new roadmap for guiding development & conservation in the Amazon

09.12.2016 | Ecology, The Environment and Conservation

Satellites, airport visibility readings shed light on troops' exposure to air pollution

09.12.2016 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>