A blood test can help doctors detect ALS, or amyotrophic lateral sclerosis, and predict how the degenerative disease will progress in patients, a new study suggests.
People with ALS have three times higher blood levels of neurofilament light chain proteins, which are produced when nerve cells are injured or die, than people with other brain diseases, researchers reported Feb. 26 in the journal Neurology.
A blood test looking for neurofilament light chain proteins accurately identified ALS patients more than 80% of the time, researchers said.
The test also can help predict survival for people with ALS, results show.
Within a year, more than 40% with neurofilament light chain proteins below a certain set point were still alive. None with levels above that point remained alive.
“While more research needs to be done to confirm these findings, having better information about prognosis is valuable for people with ALS and their families as well as the doctors who treat them,” senior researcher Dr. Sylvain Lehmann, director of the University of Montpellier's Institute for Neurosciences in France, said in a news release.
ALS, also known as Lou Gehrig’s disease, is a progressive disease that affects nerve cells in the brain and spinal cord. Nerves that signal and control muscles degenerate, causing patients to lose control of their movement.
For the study, researchers compared blood samples from 139 patients with ALS against 70 from patients with other similar brain disorders like lower motor neuron disease and primary lateral sclerosis.
The research team looked specifically at three potential types of blood markers: neurofilament light chain proteins, glial acidic proteins and phosphorylated tau 181.
Glial acidic proteins are released when cells work to repair injury, and phosphorylated tau 181 is linked to the buildup of toxic amyloid proteins in the brain, a hallmark of Alzheimer’s disease.
“Having an effective biomarker can be highly valuable — in addition to helping in making the diagnosis, it can help in predicting prognosis, evaluating what stage of the disease people are in, and tracking their progress or their response to treatments,” Lehmann said.
Results showed that neurofilament light chain protein levels provide a much better means of detecting and tracking ALS than the other two measures.
The other two markers produced accurate results only about 50% of the time, researchers said.