A new study published in the journal Nature Communications reports that a single blood-based biomarker can detect the presence of 13 neurodegenerative diseases, from frontotemporal dementia to motor neuron disease.
The test cannot specifically distinguish between each disorder, but is instead proposed as a way to determine whether patients suffer from memory problems from the early stages of the neurodegenerative disease.
The light chain of neurofilaments (NfL) is a protein released into the cerebrospinal fluid when brain cells are damaged. It can be detected in the blood, and researchers have long studied this biomarker as a way to easily diagnose neurodegenerative diseases such as Alzheimer's.
The new study examined more than 3,000 blood samples from different cohorts of subjects to find out whether NfL levels in the blood could distinguish cognitively healthy subjects from people with neurodegenerative diseases.
The study found that NfL levels can effectively identify subjects with one of 13 different neurodegenerative disorders, including amyotrophic lateral sclerosis (ALS), frontotemporal dementia, and Alzheimer's disease.
Also, more importantly, NfL levels can be used to determine whether patients with moderate to severe depression suffered in the early stages of neurodegeneration.
Abdul Khe, a co-author of the study, says this particular finding means that NfL levels can be used in a clinical setting to help doctors determine whether a patient's cognitive symptoms are an early sign of neurodegeneration or another type of psychiatric problem.
Although the study found that NfL levels in the blood cannot diagnose specific neurodegenerative conditions, the researchers note that this biomarker does have implications for tracking nuance in certain patient groups.
For example, high levels of NfL in the blood of patients with Parkinson's disease have been found to indicate atypical cases of the disease. In subjects with Down syndrome, high levels of NfL were found to correlate with dementia.
"This suggests that the new biomarker could potentially be used to improve the diagnosis of Alzheimer's disease in people with Down syndrome, as well as to be used as a biomarker to determine the effectiveness of treatment," explains study co – author Andre Strydom. "Surprisingly, all that might be required is a simple blood test, which is better tolerated by people with Down syndrome than a brain scan."
Because NfL levels naturally rise with age, the new study also suggests age thresholds that separate normal NfL levels from abnormal ones.
This will help clinicians determine whether NfL levels in the blood are a sign of neurodegeneration or just a natural build-up that occurs with age.
The new study was published in the journal Nature Communications.