Early Alzheimer’s Tests Show Promise
Tests Could Allow Detection, Treatment Before Symptoms Arise
June 12, 2007 -- Research appears to be moving closer to developing early tests for Alzheimer’s disease, a milestone that could allow treatment for the degenerative disease to begin at a much earlier stage than it does today.
Most patients today do not begin treatment until after significant deficits show up, making the prospect of early predictive tests highly attractive. If perfected, the tests could allow physicians to be on close watch for memory loss and other early signs of memory loss that presage the onset of Alzheimer’s.
Drugs currently approved for treating Alzheimer’s are limited to addressing its symptoms. The tests could also become more valuable if drugs treating the underlying biological mechanisms of the disease become available. In that case, prevention may become possible.
At the 2007 Alzheimer’s Association International Conference on Prevention of Dementia in Washington, a team of Norwegian researchers announced they had isolated some 1,200 genes that, taken together, can closely predict Alzheimer’s.
When researchers combined the genes and tested the blood of known Alzheimer’s patients, they found the genes could predict onset of the disease with 85% accuracy.
A second test containing just 96 genes predicted the disease with 80% accuracy, though presumably at a potentially lower cost than the more complex screen.
The tests are currently in large-scale trials with results expected next year, Anders Lönneborg, PhD, research director at DiaGenic ASA, the company pursuing the test, said at the International Conference on the Prevention of Dementia.
Testing for Proteins
Early detection could also get a boost from another blood test under investigation at a Belgian company. Researchers say they can use existing lab tests to predict which patients are at risk for developing dementia later.
Scientists identified two forms of amyloid protein circulating in the blood. Since the protein is known to be a marker for Alzheimer’s disease in the brain, finding abnormalities in blood levels could also wind up being a reliable early predictor of disease.
Early tests show that a blood test comparing the two amyloid proteins identifies most patients at risk for Alzheimer’s, said Geert DeMeyer, PhD, a biostatistician with Innogenetics, the firm hoping to market the test.
The test does not definitively tell who will develop the disease. “This is not a diagnostic test," DeMeyer said. "What it can do is predict what could happen to people down the road."