An Alzheimer's Fingerprint?

For decades, researchers have been trying to devise a reliable diagnostic test for Alzheimer's disease. But the goal has proven elusive. Today, even with the best techniques available, patients are technically classified as having "possible" or "probable" Alzheimer's, with a definitive conclusion becoming possible only upon death, when the brain can be autopsied. That's why a study appearing today in the online version of the journal Annals of Neurology could be so significant. In the new study, Kelvin Lee and Erin Finehout, chemical and biochemical engineers at Cornell University, joined forces with neurologist Norman Relkin at Weill Cornell Medical College to develop and test a new approach to diagnosing Alzheimer's, based on an analysis of proteins in patients' spinal fluid. The approach won't translate into a commercially available test for several years. But when and if it does, it will be a major breakthrough.

It can't come soon enough. Already some 4.5 million Americans have Alzheimer's disease. By 2050, as increasing numbers of seniors reach the age of 85 and older, the tally could swell to as much as 16 million. Researchers are racing to develop drugs that would slow the progression of the disease—but in order for these treatments to be useful, one needs diagnostic tests to determine who can benefit. So how does the possible new testing method work? NEWSWEEK's Anne Underwood spoke with Dr. Relkin. Excerpts:

NEWSWEEK: What is the basis for this potential new test?

Relkin: It's a test for specific proteins whose levels are different in people with Alzheimer's than in other people—either normal people or patients with other forms of dementia. We found 23 proteins with altered levels in the Alzheimer's patients. Together they form a kind of fingerprint of the disease.

What are the proteins you pinpointed?

Some were involved in binding A-beta [the toxic protein in Alzheimer's]. Others play a role in inflammation, and others, in synaptic function—the interaction between brain cells. These are all processes associated with Alzheimer's, so it makes sense.