Blood-Based Diagnostic Test Detects Parkinson’s before Nervous System Damage Worsens

Parkinson’s disease affects around 10 million individuals across the globe, ranking as the second-most prevalent neurodegenerative disorder following Alzheimer’s. At present, diagnosis of Parkinson’s disease is dependent primarily on clinical symptoms, which often occur after significant neurological harm has already been done. In a major advancement, researchers have now developed a blood test with the capability to identify Parkinson’s disease, potentially enabling early diagnosis before the damage to the nervous system worsens.

To create their diagnostic tool, researchers led by a team of neuroscientists at Duke Health (Durham, NC, USA) focused on DNA damage in mitochondria. Mitochondria are like cell powerhouses, converting raw energy into the fuel that cells use. They have their own DNA, which can get damaged separately from the nuclear DNA that carries most of an organism's genetic information. Earlier research has linked mitochondrial DNA damage with a higher risk of Parkinson's disease. The Duke team used polymerase chain reaction (PCR) technology to develop a test that successfully measured higher levels of mitochondrial DNA damage in blood cells from people with Parkinson's disease compared to those without the condition.

The new test also found high levels of damaged DNA in the blood samples of people who have the LRRK2 genetic mutation, which has been linked to a higher risk of the disease. The test was able to identify Parkinson's patients with or without LRRK2 mutations. In further experiments on cells from Parkinson's patients, the PCR-based test showed that it could detect lower mitochondrial DNA damage in cells treated with a LRRK2 inhibitor compared to cells from patients who didn't receive the inhibitor. This suggests the test could help identify Parkinson's patients who might benefit from LRRK2 kinase inhibitor treatments, even if they don't have the LRRK2 mutation. The researchers now plan to test the assay on samples from people in the earliest stages of the disease before symptoms appear.

“A simple blood test would allow us to diagnose the disease earlier and start therapies sooner,” said senior author Laurie Sanders, Ph.D., an associate professor at the Duke School of Medicine. “Additionally, a clear-cut diagnosis would accurately identify patients who could participate in drug studies, leading to the development of better treatments and potentially even cures.”

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