There are no standard clinical tests available to identify this Parkinson's disease, though it is the second most prevalent neurodegenerative disorder in the U.S.
There are no standard clinical tests available to identify this Parkinson's disease, though it is the second most prevalent neurodegenerative disorder in the U.S. As a result, Parkinson's disease often goes unrecognized until late in its progression, when the brain's affected neurons have already been destroyed and telltale motor symptoms such as tremor and rigidity have already appeared. Now researchers from Beth Israel Deaconess Medical Center (BIDMC) have discovered that an important clue to diagnosing Parkinson's may lie just beneath the skin.
In a study scheduled to appear in the October 29 print issue of the journal Neurology and currently published on-line, the investigators report that elevated levels of a protein called alpha-synuclein can be detected in the skin of Parkinson's patients, findings that offer a possible biomarker to enable clinicians to identify and diagnose PD before the disease has reached an advanced stage.
Parkinson's disease affects more than 1 million individuals throughout the U.S. Diagnosis is currently made through neurological history and examination, often by a patient's primary care physician.
"Even the experts are wrong in diagnosing Parkinson's disease a large percentage of the time," says senior author Roy Freeman, MD, Director of the Autonomic and Peripheral Nerve Laboratory at BIDMC and Professor of Neurology at Harvard Medical School. "A reliable biomarker could help doctors in more accurately diagnosing Parkinson's disease at an earlier stage and thereby offer patients therapies before the disease has progressed."
Alpha-synuclein is a protein found throughout the nervous system. Although its function is unknown, it is the primary component of protein clumps known as Lewy bodies, which are considered the hallmark of Parkinson's disease. There is accumulating evidence that the protein plays a role in Parkinson's disease development.
"Alpha-synuclein deposition occurs early in the course of Parkinson's disease and precedes the onset of clinical symptoms," explains Freeman, who with his coauthors suspected that the protein was elevated in the skin's structures with autonomic innervation.
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To test this hypothesis, the research team enrolled 20 patients with Parkinson's disease and 14 control subjects of similar age and gender. The participants underwent examinations, autonomic testing and skin biopsies in three locations on the leg. Alpha-synuclein deposition and density of cutaneous sensory, sudomotor and pilomotor nerve fibers were measured.
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"There is a strong and unmet need for a biomarker for Parkinson's disease," says Freeman. "Alpha-synuclein deposition within the skin has the potential to provide a safe, accessible and repeatable biomarker. Our next steps will be to test whether this protein is present in the cutaneous nerves of individuals at risk for Parkinson's disease, and whether measurement of alpha-synuclein deposition in the skin can differentiate Parkinson's disease from other neurodegenerative disorders."
Source-Eurekalert