Scientists link human gene to risk of developing Mild Cognitive Impairment

Connecting a human gene to the risk of developing the Alzheimer's precondition known as Mild Cognitive Impairment has been somewhat of a holy grail for scientists, but a team led by researchers from Cornell University has ended the quest.

"We're excited about these findings because they help identify the segment of the population who will most benefit from effective treatments to prevent Alzheimer's type dementia," said Charles Brainerd, Cornell professor of Human Development in the College of Human Ecology and co-lead author of the study "Is Apolipoprotein E Genotype a Biomarker for Mild Cognitive Impairment? Findings From a Nationally Representative Study," which was published online this month by the journal Neuropsychology.

Previous research had identified e4 allele of the Apolipoprotein E genotype with the Alzheimer's precondition, but scientists had been unable to examine the gene using data that is both statistically significant and reliable. Brainerd, along with co-author Valerie Reyna, Cornell professor of human development, and researchers from the Mayo Clinic in Rochester, Minn., assembled large data sets from multiple institutions that more accurately represent older adults from all regions, racial groups and ethnic groups in the United States.

Classifying subtypes of Mild Cognitive Impairment was also critical to the study's success. The study outlines how new criteria for different impairment subtypes helped control the errors that plagued previous studies attempting to identify a link between the e4 allele and the Alzheimer's precondition.

"Knowing whether or not you're an e4 carrier, much like knowing whether you carry genetic markers for breast cancer, allows you to make life style choices that will minimize later risks of impairment. Smoking, alcohol and secondary diabetes are all associated with earlier transitions to Mild Cognitive Impairment and Alzheimer's," said Brainerd, who adds the findings will also help advance research in the field, as e4 carriers are prime research subjects.