A simple blood test may help identify people at the earliest stages of Parkinson’s disease, long before they begin to show symptoms, new research has found.

The study, published on Friday in the journal Nature Aging, is the latest to identify early warning signs of Parkinson’s, a neurodegenerative condition that affects about 10 million people worldwide and occurs when the brain slowly stops producing the chemical dopamine in areas that control movement and balance. 

There is no cure for Parkinson’s, which causes tremors, stiffness, slow movement, and cognitive impairment. 

Most people are diagnosed based on these symptoms, but by that point, more than 60 per cent of dopamine neurons have already degraded – which is why scientists are hunting for ways to diagnose patients earlier.

For the new study, Israeli researchers compared blood and brain tissue data between Parkinson’s patients and those in good health. 

They focused on small RNA molecules known as transfer RNA fragments (tRFs), which appear to play a role in neurological issues such as Parkinson’s.

Two key biomarkers emerged; one that’s linked to Parkinson’s and another to the progression of the disease. Using a blood test to measure the distance between them could serve as an additional early diagnostic for the condition, the findings suggest.

“By focusing on tRFs, we’ve opened a new window into the molecular changes that occur in the earliest stages of the disease,” said Hermona Soreq, one of the study’s authors and a professor of molecular neuroscience at the Hebrew University of Jerusalem.

More research needed to confirm findings

But the researchers said bigger studies that follow a more diverse group of Parkinson’s patients over time are needed to confirm their results and understand how changes to these biomarkers affect patient outcomes.

It’s also not clear whether the blood test would be able to differentiate between Parkinson’s and other conditions with similar early symptoms.

“More work is needed to continue to test and validate this possible test, especially understanding how it can distinguish between other conditions that have similar early signs to Parkinson’s,” David Dexter, director of research at Parkinson’s UK, told Euronews Health.

“This research represents a new angle to explore in the search for a biological marker for Parkinson’s,” added Dexter, who was not involved with the study.

Other scientists have found additional biomarkers of interest. 

One EU-funded study published last year identified eight proteins in the blood that could help identify Parkinson’s patients up to seven years before major symptoms appear.

The prospect of a quick, reliable blood test for Parkinson’s could “alleviate the burden of uncertainty from suffering individuals, assist clinicians’ care of those patients early in the disease process and open routes for developing and testing new therapeutics,” the Israeli researchers said.