A gene variation that appears to predict the rate at which Alzheimer's disease will progress has been identified by an international team of experts, led by Washington University School of Medicine in St. Louis.
Whereas previous studies have focused on factors that influence the risk for Alzheimer's, the new research points to a way to determine how rapidly Alzheimer's patients may develop full-blown dementia after their diagnosis.
The investigators studied 846 patients with elevated levels of a protein called tau in their cerebrospinal fluid (CSF).
Recent studies have found that the presence of a particular form of the tau protein in the CSF is an indicator of Alzheimer's disease.
The researchers also looked at single DNA variations in the patients and identified a genetic marker linked to elevated tau levels.
That marker turned out to be associated with rapid progression of Alzheimer's disease.
"People who carry this genetic marker tend to have higher tau levels at any given stage of the disease than individuals without it," says senior investigator Alison M. Goate.
"Until now, most studies of genetic risks associated with Alzheimer's disease have looked at the risk of developing the disease, not the speed at which you will progress once you have it. The genetic marker we've identified deals with progression."
The investigators report their findings online in the journal Public Library of Science (PLoS) Genetics.