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

Gene Thought to be Linked to Alzheimer's is Marker for Only Mild Impairment

Published: Monday, February 18, 2013
Last Updated: Monday, February 18, 2013
Bookmark and Share
Defying the widely held belief that a specific gene is the biggest risk factor for Alzheimer's disease, report says that people with that gene are more likely to develop mild cognitive impairment -- but not Alzheimer's.

The study suggests that older adults with healthy brain function can get genetic tests to predict increased risk of future mild cognitive impairment. However, once they are impaired cognitively, the tests won't predict their likelihood of developing Alzheimer's.

"Right now, genetic tests are used in exactly the opposite way. That is, healthy people don't get the tests to predict their risk of mild cognitive impairment, but impaired people get them to predict their risk of Alzheimer's disease," said Charles Brainerd, professor of human development and the study's lead co-author with Valerie Reyna, professor of human development. "So, impaired people think that tests will tell them if they are at increased risk of Alzheimer's, which they won't. And healthy people think that tests won't tell them whether they are at increased risk of cognitive impairment, which they will."

The researchers describe their findings in the January issue of Neuropsychology (27:1).

The work builds on previous research by Brainerd and associates that suggested the ε4 allele of the APOE genotype increases the risk of mild cognitive impairment as well as Alzheimer's.

The researchers analyzed data from the only nationally representative dataset of its kind, the National Institute on Aging's Aging, Demographics and Memory Study. They looked at data from 418 people over age 70 to see if those who carried the allele were more likely to develop mild cognitive impairment compared with those who did not have the allele. They also looked at whether ε4 carriers with mild cognitive impairment were more likely to develop Alzheimer's disease compared with non-carriers with mild cognitive impairment.

They found that healthy ε4 carriers were nearly three times -- 58 percent -- more likely to develop mild cognitive impairment compared with non-carriers. However, ε4 carriers with mild cognitive impairment developed Alzheimer's at the same rate as non-carriers.

While previous studies showed that the ε4 allele was more common in people with Alzheimer's disease, this study shows that it does not increase the risk that healthy or impaired people will become demented. Rather, ε4 increases the risk that healthy people will become cognitively impaired, and impaired people are the primary source of new Alzheimer's diagnoses, Brainerd explained. "The reason ε4 is a risk factor for mild cognitive impairment, but not for progression from mild cognitive impairment to Alzheimer's disease, is that this allele is a marker of initial cognitive declines -- for example, memory and executive function -- that are associated with mild cognitive impairment but not of subsequent declines in cognition or in daily functioning that are associated with forms of Alzheimer's disease."

Brainerd also noted that the effects of ε4 in healthy adults can be detected by the mid-20s. While ε4 is not a risk factor for the severe cognitive declines that signal dementia, it is risk factor for the weaker declines that eventually produce mild cognitive impairment.

The co-authors of the paper are Ronald Petersen and Glenn Smith of the Mayo Clinic; Anna Kenney '11, Caroline Gross '12 and Emily Taub '10 of Cornell -- all of whom helped conduct the research as undergraduates in Brainerd's lab; Brenda Plassman of Duke University Medical Center; and Gwenith Fisher of the University of Michigan.

Further Information
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 2,600+ scientific posters on ePosters
  • More than 3,800+ 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 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

Tumor-suppressing Gene Lends Insight to Cancer Treatment
Researchers have found that delicate replication process derails if a gene named PTEN has mutated or is absent.
Tuesday, July 14, 2015
$5.5M NSF Grant Aims to Improve Rice Crops with Genome Editing
Researchers to precisely target, cut, remove and replace DNA in a living cell to improve rice.
Friday, May 08, 2015
A ‘STAR’ is Born: Engineers Devise Genetic 'On' Switch
A new “on” switch to control gene expression has been developed by Cornell scientists.
Tuesday, February 03, 2015
Computer Model Reveals Cancer's Energy Source
Findings focused on the energy-making process in cancer cells known as the Warburg Effect.
Tuesday, August 19, 2014
For Cancer Patients, Sugar-Coated Cells are Deadly
Paszek’s lab will focus on developing high-resolution microscopy to further study cell membrane-related cancer mechanisms.
Friday, June 27, 2014
Shark, Human Proteins are Surprisingly Similar
Despite widespread fascination with sharks, the world’s oldest ocean predators have long been a genetic mystery.
Friday, December 06, 2013
Gold-Plated Nano-Bits Find, Destroy Cancer Cells
Scientists have merged tiny gold and iron oxide particles, then added antibody guides to steer them through the bloodstream toward colorectal cancer cells.
Monday, October 21, 2013
Using Genes to Rescue Animal and Plants from Extinction
With estimates of losing 15 to 40 percent of the world’s species over the next four decades researchers whether science should employ genetic engineering to the rescue.
Friday, September 27, 2013
Dad’s Genes Build Placentas
Though placentas support the fetus and mother, it turns out that the organ grows according to blueprints from dad.
Monday, August 12, 2013
Physicists Tease out Twisted Torques of DNA
Like an impossibly twisted telephone cord, DNA, the molecule that encodes genetic information, also often finds itself twisted into coils.
Monday, July 01, 2013
Expelled DNA that Traps Toxins May Backfire in Obese
The body’s most powerful immune cells may have a radical way of catching their prey that could backfire on people who are overweight.
Wednesday, June 19, 2013
Genetic Switches Play Big Role in Human Evolution
Study offers further proof that the divergence of humans from chimpanzees was profoundly influenced by mutations to DNA sequences.
Wednesday, June 12, 2013
Genome Offers Clues to Amphibian-Killing Fungus
A fungus that has decimated amphibians globally is much older than previously thought.
Thursday, May 30, 2013
Scientists Find Clues to Some Inherited Heart Diseases
Cornell researchers have uncovered the basic cell biology that helps explain heart defects found in diseases known as laminopathies.
Tuesday, May 07, 2013
Scientists Develop World's Smallest Drug Deliverer
Cornell researchers have created a pore in “Cornell Dots” – brightly glowing nanoparticles nicknamed C-Dots – that can carry medicine.
Friday, April 12, 2013
Scientific News
Genes That Protect African Children From Developing Malaria Identified
Variations in DNA at a specific location on the genome that protect African children from developing severe malaria, in some cases nearly halving a child’s chance of developing the life-threatening disease, have been identified in the largest genetic association study of malaria to date.
Researchers Disguise Drugs As Platelets to Target Cancer
Researchers have for the first time developed a technique that coats anticancer drugs in membranes made from a patient’s own platelets.
Dormant Viral Genes May Awaken to Cause ALS
NIH human and mouse study may open an unexplored path for finding treatments.
Scientists Create World’s Largest Catalog of Human Genomic Variation
An international team of scientists from the 1000 Genomes Project Consortium has created the world’s largest catalog of genomic differences among humans, providing researchers with powerful clues to help them establish why some people are susceptible to various diseases.
Five Genetic Regions Implicated In Cystic Fibrosis Severity
An international consortium of researchers conducted the largest-ever CF genome-wide analysis to find new therapeutic targets.
Greater Understanding Of Polycystic Ovary Syndrome
A new genetic study of over 200,000 women reveals the underlying mechanisms of polycystic ovary syndrome, as well as potential interventions.
New Autism Genes Are Revealed in Largest-Ever Study
Work draws more detailed picture of genetic risk, sheds light on sex differences in diagnosis.
A Fundamental Protection Mechanism Against Formalin In Mammals is Revealed
Formaldehyde, or formalin, is well known to all of us as a common chemical used in many industrial processes and also as a preservative, remarkably we also produce formaldehyde in our bodies.
A New Single-Molecule Tool to Observe Enzymes at Work
A team of scientists at the University of Washington and the biotechnology company Illumina have created an innovative tool to directly detect the delicate, single-molecule interactions between DNA and enzymatic proteins.
Genetic Adaptations to Diet and Climate
Researchers found genetic variations in the Inuit of Greenland that reflect adaptations to their specific diet and climate.
Skyscraper Banner

Skyscraper Banner
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
2,600+ scientific and medical posters
A library of 2,500+ scientific videos on LabTube
3,800+ scientific videos