A gene variation that appears to predict the rate at which Alzheimer's disease will progress has been uncovered by an international team of Alzheimer's disease experts, led by Washington University School of Medicine in St. Louis. Published in the open-access journal PLoS Genetics, the findings help determine how rapidly Alzheimer's patients may develop full-blown dementia after their diagnosis.

Alzheimer's disease, one of the most common neurodegenerative disorders, affects over 4.5 million people in the United States alone. Recent studies have found the presence of a particular form of the tau protein (ptau) in cerebrospinal fluid (CSF) to be an indicator of Alzheimer's disease. By looking at single DNA variations in 846 patients, the researchers were able to identify a genetic marker, linked to elevated ptau levels, that is associated with rapid progression of the disease.

"We have looked at data from three separate, international studies, and in all three, we found the same association. So we are confident that it is real and that this gene variant is associated with progression in Alzheimer's disease," said first author Carlos Cruchaga, PhD.

The genetic finding, combined with the ability to measure ptau in the CSF, may mean that drug inhibition of tau accumulation in the CSF might prevent or delay some of the devastating effects of Alzheimer's disease. This knowledge might initially be most useful in the design of clinical trials, according to the authors; if researchers know in advance that particular patients are going to progress at a rapid rate, they could potentially better evaluate the effects of drugs designed to slow the progression of Alzheimer's disease.