New blood test spots key sign of Parkinson’s disease before symptoms emerge

DURHAM, N.C. – A new blood test has the potential to diagnose Parkinson’s disease before it starts causing significant damage to the nervous system. Developed by a team of Duke Health neuroscientists, this test focuses on the damage to DNA in the blood, which appears to have an association with the disease.

Currently, the diagnosis of Parkinson’s, the second most common neurological disease after Alzheimer’s, is primarily based on clinical symptoms that manifest after substantial neurological damage has already occurred. Researchers are optimistic that this new test could enable the diagnosis of patients before this damage happens.

Parkinson’s is a progressive disorder that affects the nervous system and the parts of the body controlled by nerves, impacting around 10 million people worldwide. The team from Duke University School of Medicine centered their research on the damage to the DNA in mitochondria.

Mitochondria, the powerhouses within cells, convert raw energy into a form that powers cells. They contain their own DNA, which can incur damage independently from the nuclear DNA that encodes most of an organism’s genome. Previous studies have demonstrated a link between mitochondrial DNA damage and an elevated risk of Parkinson’s disease. Duke researchers have previously reported an accumulation of DNA damage in the brain tissue of deceased Parkinson’s patients.

Utilizing polymerase chain reaction (PCR) technology, the study team developed a test that successfully measured higher levels of mitochondrial DNA damage in blood cells collected from patients with Parkinson’s disease compared to those without the disease. Interestingly, the new test also identified elevated levels of damaged DNA in the blood samples of individuals carrying the genetic mutation LRRK2, which is associated with an increased risk of developing the disease. The test was able to detect patients with Parkinson’s disease, both with and without LRRK2 mutations.

Additionally, further analysis of cells from Parkinson’s patients was conducted to assess whether the team’s PCR-based test could determine the effectiveness of a therapy targeting the effects associated with the LRRK2 mutation.

Researchers are hopeful that the new test will not only facilitate earlier diagnosis of Parkinson’s but may also eventually contribute to finding a cure for this degenerative disease.

Scroll down to see the most common Parkinson’s symptoms

Senior man suffering from hand tremors due to Parkinson's disease
Senior man suffering from hand tremors due to Parkinson’s disease (© Pixel-Shot –

“Currently, Parkinson’s disease is diagnosed largely based on clinical symptoms after significant neurological damage has already occurred,” says senior author Laurie Sanders, Ph.D., an associate professor in Duke School of Medicine’s departments of Neurology and Pathology and member of the Duke Center for Neurodegeneration and Neurotherapeutics.

“A simple blood test would allow us to diagnose the disease earlier and start therapies sooner,” Sanders continues in a media release. “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.”

“Our hope is that this assay could not only diagnose Parkinson’s disease, but also identify drugs that reverse or halt mitochondrial DNA damage and the disease process,” Sanders concludes. “This disease takes a terrible toll on people, and we are still just treating the symptoms. It’s important to get new, effective treatments over the finish line.”

The Duke University team’s study is published in the journal Science Translational Medicine.

The 8 most common symptoms of Parkinson’s disease

It’s important to note that not every individual with Parkinson’s will experience all of these symptoms, and the severity can vary widely from person to person.

  • Tremors: A tremor, or shaking, often starts in a limb, often your hand or fingers. This is one of the most noticeable early signs.
  • Bradykinesia (slowness of movement): Over time, Parkinson’s may slow your movement, making simple tasks difficult and time-consuming.
  • Rigid muscles: Muscle stiffness may occur in any part of your body. This can limit your range of motion and cause pain.
  • Impaired posture and balance: Your posture may become stooped, or you may have balance problems.
  • Loss of automatic movements: In Parkinson’s disease, you may have a decreased ability to perform unconscious movements, including blinking, smiling, or swinging your arms when you walk.
  • Speech changes: Speech may become soft, quick, slur, or hesitate before talking. Your speech may be more of a monotone rather than having the usual inflections.
  • Writing changes: It may become hard to write, and handwriting may appear small.
  • Non-motor symptoms: These can include issues like depression and other emotional changes, difficulty swallowing, chewing, and speaking, urinary problems or constipation, skin problems, and sleep disruptions.

If you or someone you know is experiencing these symptoms, please seek professional medical advice. It’s important to have these symptoms evaluated by a healthcare provider, as they can also be caused by medications or other conditions.

South West News Service writer James Gamble contributed to this report.

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