Novel Blood Test May Diagnose Various Neurodegenerative Diseases

Simple biomarker – levels of a protein called neurofilament light chain (NfL) in the blood can identify those who might have neurodegenerative diseases such as Down's syndrome dementia, motor neuron disease (ALS), and frontotemporal dementia, when clinical symptoms are not definitive, as per a study at the King's College, London, published in the journal Nature Communications. The study team had determined a set of age-related cut-off levels of NfL which could inform its potential use in primary care settings through a simple blood test.

“For the first time we have shown across a number of disorders that a single biomarker can indicate the presence of underlying neurodegeneration with excellent accuracy. 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,” says Joint Senior Author of the study, Dr. Abdul Hye from the NIHR Maudsley Biomedical Research Centre at King's College London and South London and Maudsley NHS Foundation Trust.

Burden of Neurodegenerative Diseases

Neurodegenerative diseases are debilitating neurological conditions that occur due to damage or death of nerve cells which further results in the release of neurofilament light chain (NfL). This leads to thought, attention, and memory problems.

It is estimated that there are currently around 850,000 people with dementia in the UK which is projected to rise to 1.6 million by 2040. A continuous drive to develop reliable, non-invasive and accessible biomarkers for early recognition and prevention of these diseases have been a centre target of neurodegenerative research community.

Using advanced ultrasensitive tests, NfL can be detected in blood at low levels and is increased in several disorders, unlike phosphorylated tau which is specific for Alzheimer's disease.

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Blood Test for Neurodegenerative Disease

The study team analyzed 3138 samples from King's College London, Lund University and Alzheimer's Disease Neuroimaging Initiative, that included people with no cognitive impairment, people with neurodegenerative disorders, people with Down syndrome and people with depression.

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It was observed that concentrations of NfL in the blood were higher across all neurodegenerative disorders compared to those with no cognitive problems, the highest being in people with Down's syndrome dementia, motor neuron disease, and frontotemporal dementia.

Although blood-based NfL could not differentiate between all the disorders, it could provide insight into different groups within certain disorders.

For example, in those with Parkinson's a high concentration of NfL indicated atypical Parkinson's disorder, and in patients with Down syndrome, NfL levels differentiated between those with and without dementia. This can potentially be used to improve the diagnosis of Alzheimer's in people with Down syndrome.

The NfL Biomarker

The study also assessed age-related thresholds or cut-offs of NfL concentrations. The test was 90% accurate in highlighting neurodegeneration in those over 65 years of age and 100% accurate in detecting motor neurone disease and Down syndrome dementia.

The NfL levels could also distinguish individuals with depression from individuals with neurodegenerative disorders which commonly present with a primary psychiatric disorder in the onset of disease development such as frontotemporal dementia.

“We are entering an exciting period where blood tests like plasma NfL, in combination with other emerging blood biomarkers like phosphorylated tau (p-tau), are starting to give us a meaningful and non-invasive insight into brain disorders,” says Lead author Dr. Nicholas Ashton from King's College London.

Source-Medindia