First early-detection blood test for Parkinson's shows promise

Screen uses 'metabolomic profile' to spot disease-linked changes, Weill Cornell team reports

NEW YORK (March 11, 2008) -- A test that profiles molecular biomarkers in blood could become the first accurate diagnostic test for Parkinson's disease, new research shows.

The screen relies on changes in dozens of small molecules in serum. These "metabolomic" alterations form a unique pattern in people with Parkinson's disease, according to a team led by researchers at the Weill Cornell Medical College in New York City.

They published the findings in the journal Brain.

"A reliable blood test for Parkinson's disease would revolutionize not only the care of people with this debilitating illness, it would facilitate research as well," notes study senior author Dr. M. Flint Beal, chairman and Anne Parrish Titzell Professor of Neurology at Weill Cornell Medical College, and neurologist-in-chief at NewYork-Presbyterian Hospital/Weill Cornell Medical Center.

According to the National Parkinson Foundation, an estimated 1.5 million Americans have the neurodegenerative disease, and 60,000 new cases are diagnosed each year. Actor Michael J. Fox, boxer Muhammad Ali, and former U.S. Attorney General Janet Reno all suffer from Parkinson's, which strikes men and women in roughly equal numbers.

"Right now, a Parkinson's diagnosis is made solely on a clinical review of symptoms -- we have no biologic test," notes Dr. Beal. At best, a symptom-based screen is still only 90 percent accurate, he adds.

"That can cause real problems, because that remaining 10 percent of patients -- who may have look-alike conditions such as multi-system atrophy or progressive supranuclear palsy -- end up getting treated with Parkinson's drugs," Dr. Beal says. "These medicines may appear to help them a little while, but in the meantime, they haven't been getting the treatment that's necessarily best for them."

An early-detection test would also be enormously useful in tracking the health of patients who may be at higher risk for Parkinson's, such as those with a family history of the disease.

Finally, the integrity of clinical trials is undermined by the lack of an accurate screen, Dr. Beal notes. "Every time you do a clinical trial into Parkinson's and you have patients that are misdiagnosed, it enters 'noise' into the analysis, skewing the results. A truly reliable test could help eliminate that," the researcher notes.