Early Parkinson's detection with an RNA-based blood test

Diagnosis of neurodegenerative diseases is these days around the level that cancer diagnosis was 50 years ago: disease is identified when most of the relevant neurons have already died, and it is therefore too late to cure. To address this problem, a research team led by The Hebrew University of Jerusalem has developed a blood test that could enable early diagnosis of Parkinson’s disease (PD), paving the way for timely interventions and improved patient outcomes. Their work has been described in the journal Nature Aging.

The test introduces a novel approach to detecting PD at its earliest stages through the analysis of transfer RNA fragments (tRFs): small RNA molecules with the potential to reveal significant changes in the body linked to neurodegeneration. The researchers identified two key biomarkers — an increase in PD-specific tRFs carrying a conserved sequence motif (RGTTCRA-tRFs) and a decrease in mitochondrial tRFs (MT-tRFs). By measuring the ratio between these biomarkers, the new test can distinguish pre-symptomatic Parkinson’s patients from healthy controls with an accuracy surpassing that of existing clinical diagnostic tools.

“This discovery represents a major advancement in our understanding of Parkinson’s disease and offers a simple, minimally invasive blood test as a tool for early diagnosis,” said Professor Hermona Soreq. “By focusing on tRFs, we’ve opened a new window into the molecular changes that occur in the earliest stages of the disease.”

The test employs a straightforward, dual qPCR assay, measuring the ratio between the repeated short motif and an exemplary mitochondrial sequence, making it cost-effective and accessible for use in a wide range of healthcare settings. In trials involving samples from multiple international cohorts, including the Parkinson’s Progression Markers Initiative, the test achieved a diagnostic accuracy of 0.86, significantly outperforming traditional clinical scoring methods. Moreover, the study found that RGTTCRA-tRF levels decrease following deep brain stimulation, further linking these RNA fragments to both disease mechanisms and treatment responses.

Lead researcher Nimrod Madrer emphasised the importance of early detection, noting that Parkinson’s disease is often diagnosed only after significant brain damage has occurred. “This test has the potential to alleviate the uncertainty faced by patients and clinicians, offering a reliable and rapid method to identify the disease in its earliest stages,” he said.

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