New Marker May Help Diagnose Parkinson's Disease in Early Stages

Parkinson's disease, which affects more than 1 million individuals throughout the United States, often arises slowly and without early warning signs. With no standard clinical tests available to identify it, the neurodegenerative disease often goes undiagnosed until neurons in the brain have already been destroyed. Most patients develop the Parkinson's disease later in life, but some—like the actor Michael J. Fox—develop an early-onset form of the condition.

A team led by Dr. Roy Freeman, Director of the Autonomic and Peripheral Nerve Laboratory at Beth Israel Deaconess Medical Center (BIDMC) and Professor of Neurology at Harvard Medical School, has discovered an early clue to the presence of Parkinson's disease. Specifically, the researchers found that high levels of a protein called alpha-synuclein can be detected in the skin of affected patients.

"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," says Dr. Freeman. He notes that with current diagnostic techniques, which involve taking a neurological history and performing an examination, even experts are often inaccurate in diagnosing Parkinson's disease.

Alpha-synuclein is found throughout the nervous system and is the primary component of protein clumps known as Lewy bodies that are the hallmark of Parkinson's disease. Dr. Freeman and his colleagues decided to look for alpha-synuclein in patients' skin because excessive and diminished sweating and changes in skin color and temperature occur in almost two-thirds of those with the disease. "The skin can provide an accessible window to the nervous system, and based on these clinical observations, we decided to test whether examination of the nerves in a skin biopsy could be used to identify a Parkinson's disease biomarker."

In their study, which was recently published in the journal Neurology, 20 patients with Parkinson's disease and 14 healthy individuals of similar age and gender underwent examinations and had skin biopsies taken from three locations on the leg. The researchers measured alpha-synuclein deposition and density of nerve fibers in the biopsies.

In patients, alpha-synuclein was increased in certain nerves that supply the sweat glands and muscles, but it not was not increased in the same types of nerves from healthy individuals. Patients with more advanced Parkinson's disease tended to have the highest levels of alpha-synuclein in their nerves.

The findings suggest that measuring alpha-synuclein deposition within the skin might be a safe and accessible way to screen for Parkinson's disease. The researchers now plan to test whether the protein is also present in the nerves of individuals at risk for Parkinson's disease or in patients who have other neurodegenerative disorders. "There is an unmet need for an accurate diagnostic and prognostic biomarker in Parkinson's disease. We hope that this research will contribute to the efforts to realize that goal," says Dr. Freeman. His team was recently awarded a grant from the Michael J. Fox Foundation to pursue their studies.

Above content provided by Beth Israel Deaconess Medical Center. Dr. Moss reports no financial interests related to this therapy. For advice about your medical care, consult your doctor.

Posted November 2013