A simple blood test could identify if someone has a neurodegenerative disease, according to a new UK study published last night.
The authors of the research, which is detailed in Nature Communications, shows for the first time that the neurofilament light chain (NfL) protein can indicate with high accuracy the presence of underlying neurodegeneration, such as Down’s syndrome dementia, motor neuron disease (ALS) and frontotemporal dementia.
Dr Abdul Hye, joint senior author from the NIHR Maudsley Biomedical Research Centre at King’s College London and South London and Maudsley NHS Foundation Trust said: “Though it is not specific for any one disorder, it could help in services such as memory clinics as a rapid screening tool to identify whether memory, thinking or psychiatric problems are a result of neurodegeneration.”
Current biomarkers used to identify neurodegenerative disorders are taken from the cerebrospinal fluid but because nerve fibre damage is a feature in many of these disorders, and this results in the release of NfL, it was hypothesised that it could be tested instead.
NfL can be detected in blood at low levels using ultrasensitive tests, which means it could be used in the diagnostic process of many neurodegenerative diseases, including Down’s syndrome dementia, ALS and frontotemporal dementia.
The study examined 3138 samples from King’s College London, Lund University and Alzheimer’s Disease Neuroimaging Initiative and the researchers found that concentrations of NfL in the blood were higher across all neurodegenerative disorders compared to those with no cognitive problems. The highest were in people with Down’s syndrome dementia, motor neuron disease and frontotemporal dementia.
They also found although blood-based NfL could not differentiate between all the disorders, it could provide some information into different groups within certain disorders.
They found among individuals who had Parkinson’s, a high concentration of NfL indicated atypical Parkinson’s disorder, while those with Down syndrome were found to have different NfL levels if they had dementia.
Co-author Professor Ammar Al-Chalabi from King’s College London, said: “For neurodegenerative diseases like Alzheimer’s, Parkinson’s or motor neuron disease, a blood test to allow early diagnosis and help us monitor disease progression and response to treatment would be very helpful. Neurofilament light chain is a promising biomarker that could speed diagnosis of neurodegenerative diseases and shorten clinical trials.”
Co-author Professor Andre Strydom, of King’s College London, added: “This study shows that neurofilament light chain levels were particularly increased in adults with Down syndrome who have a genetic predisposition for Alzheimer’s disease.
“Furthermore, we showed that those individuals with a dementia diagnosis following onset of Alzheimer’s disease had higher levels than those who did not. This suggests that the new marker could potentially be used to improve the diagnosis of Alzheimer’s in people with Down syndrome, as well as to be used as biomarker to show whether treatments are effective or not.
“It is exciting that all that could be needed is a simple blood test, which is better tolerated in Down syndrome individuals than brain scans.”
The study assessed age-related thresholds of NfL concentrations and researchers found there was 90% accuracy in highlighting neurodegeneration in those over 65 years of age and 100% accuracy in detecting motor neurone disease and Down syndrome dementia.
NfL was also able to distinguish individuals with depression from individuals with neurodegenerative disorders, which commonly present with primary psychiatric disorder in the onset of disease development.
Aston NJ, Janelizde S, Hansson O et al. A multicentre validation study of the diagnostic value of plasma neurofilament light. Nature Communications 8 June 2021; doi 10.1038/s41467-021-23620-z
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