Apr 4, 2024

How a New Skin Biopsy Helps Diagnose Parkinson’s Disease

The Eastside Neuroscience Institute is one of the region’s first centers offering an innovative skin biopsy that can help physicians diagnose – or rule out – Parkinson’s disease.

Diagnosing Parkinson’s can be tricky, especially in its early stages. This is partly because Parkinson’s shares symptoms with essential tremor and other disorders.

The new test helps with diagnosis by detecting whether a patient has an abnormal form of the alpha-synuclein protein in their skin. Alpha-synuclein is closely correlated with Parkinson’s and related disorders including multiple system atrophy, dementia with Lewy bodies and pure autonomic failure.

“For detecting abnormal alpha-synuclein, the test has a sensitivity of 95.5% and a specificity of 96.7%, so it gives us an accurate data point that can inform our diagnosis. We use the test several times a month, mostly in patients who are early in the course of disease, when symptoms can be subtle,” says Daniel Burdick, MD, a neurologist at the Eastside Neuroscience Institute and medical director of the Booth Gardner Parkinson’s Care Center at EvergreenHealth.

Fine-Tuning Diagnoses

The test comprises a punch biopsy from three sites: above the ankle, above the knee and the back of the neck. It’s particularly useful when a patient presents with a tremor but shows few, if any, other signs of Parkinson’s.

“If the test comes back positive, we can be more confident that the patient has Parkinson’s or another, less common synucleinopathy. If it’s negative, it gives us more certainty that the patient only has essential tremor,” Dr. Burdick says.

There are other cases where a patient has the hallmark symptoms of Parkinson’s, but physicians aren’t sure if their condition is a synucleinopathy or is Parkinsonism from a different cause.

“In those cases, a negative test result helps our team consider other causes such as progressive supranuclear palsy, which can lead to Parkinsonism but isn’t associated with abnormal alpha-synuclein,” Dr. Burdick says.

Informing Treatment

The information provided by the skin biopsy also helps our team decide on or refine treatment. For example, if a patient only has a tremor and the test comes back negative, it gives our team confidence proceeding with treatment for essential tremor.

If the test confirms the patient has a synucleinopathy, “I know I should be aggressive with medications for Parkinson’s disease. And if the patient is having trouble tolerating those medications, I know I should encourage them to stick with the treatment until side effects improve so they can get the therapeutic benefits,” Dr. Burdick says.

How Early Diagnosis Helps

Because the skin biopsy and other advances are helping us diagnose Parkinson’s earlier than ever, physicians should consider referring patients as soon as they notice a patient has a tremor or other signs of Parkinson’s. Diagnosing a patient early in the course can have several benefits, including:

  • Shortening the period where patients are anxious and worry about what life will hold if they have Parkinson’s. “An early diagnosis means patients can get to a degree of acceptance sooner, which means they can start making lifestyle changes and taking other actions that will improve their quality of life in the future,” Dr. Burdick says.
  • Opportunities to participate in clinical trials of drugs that could slow the disease’s progression. The Eastside Neuroscience Institute and the Booth Gardner Center offer one of the region’s largest portfolios of Parkinson’s trials; our goal is to have a trial available for every patient at every stage of disease.
  • Helping patients start working with specialized providers – including physical, speech and occupational therapists – who are experts in helping Parkinson’s patients manage the disease’s physical and psychological aspects.

“Parkinson’s is a complex, multi-system, multi-domain bio-psycho-social disease that requires many people to be involved, and all of those people should have expertise in Parkinson’s,” Dr. Burdick says. “Providing that comprehensive care is the crux of what the Booth Gardner Center was founded to do.”

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