Published: 21 December 2023
Research part-funded by the NIHR Oxford Biomedical Research Centre has led to the development of a new blood test to identify Parkinson’s disease before the main symptoms occur.
Parkinson’s disease
Parkinson's disease is a condition in which parts of the brain become progressively damaged over many years. It is the second most common neurodegenerative disease, affecting seven million people worldwide.
Parkinson's often starts more than 10 years before patients seek help for their symptoms.
The main symptoms of Parkinson's disease are:
- involuntary shaking of particular parts of the body
- slow movement
- stiff and inflexible muscles
When people with Parkinson's start to develop these symptoms their nerve cells are already damaged. Researchers developing treatments want to identify patients at the earliest stages of the disease to reduce the main symptoms and maintain quality of life for as long as possible.
Parkinson's disease causes a loss of nerve cells in the brain. The damage develops over time as abnormal clumps of a protein called alpha-synuclein form in the brain. This damages nerve cells and leads to movement disorder and often dementia.
The study
Researchers based at the Tofaris lab, which is part of Oxford University's Nuffield Department of Clinical Neurosciences, wanted to see if they could predict whether the pathways that handle alpha-synuclein are impaired before the onset of Parkinson’s symptoms. If so, this could help clinicians identify people most likely to benefit from disease-modifying therapies when they become available.
The study was part-funded by the NIHR Oxford Biomedical Research Centre (BRC) and the NIHR Clinical Research Network.
The study looked at:
- 365 at-risk individuals
- 282 healthy controls
- 71 people with genetic or sporadic Parkinson’s disease
It found that those with the highest risk of developing Parkinson’s (more than 80% probability based on research criteria) had a two-fold increase in alpha-synuclein levels. The test could accurately differentiate them from those with low risk (less than 5% probability) or healthy controls.
Overall, the test could distinguish an individual with high risk of developing Parkinson’s from a healthy control with 90% probability.
In a small subgroup of 40 people who went on to develop Parkinson’s and related dementia, the blood test was positive in more than 80% of cases up to as much as seven years before the diagnosis.
Earlier findings by the researchers showed that alpha-synuclein is not increased in patients who do not have Parkinson's but have Parkinson’s-like symptoms.
Together these results suggest doctors could screen individuals at high risk of developing the disease. They could then facilitate the introduction of therapies that are currently at clinical trial stage.
Professor George Tofaris, who receives a grant from NIHR Oxford BRC, said: “Collectively our studies demonstrate how fundamental investigations in alpha-synuclein biology can be translated into a biomarker for clinical application, in this case for the identification and stratification of Parkinson’s risk. A screening test that could be implemented at scale to identify the disease process early is imperative for the eventual instigation of targeted therapies as is currently done with screening programmes for common types of cancer.”
The paper has been published in JAMA Neurology.