Salivary gland biopsy identifies early Parkinson's disease

By John Murphy, MDLinx
Published February 5, 2016

Key Takeaways

Biopsy of the submandibular gland identified early Parkinson’s disease in about 3 out of 4 patients, according to a study published in the January 2016 issue of the journal Movement Disorders.

“This is the first study demonstrating the value of testing a portion of the submandibular gland to diagnose a living person with early Parkinson’s disease,” said study author Charles Adler, MD, PhD, Professor of Neurology at the Mayo Clinic in Arizona. “Making a better diagnosis in living patients is a big step forward in our effort to understand and better treat patients.”

Currently, there is no accurate test for clinically diagnosing Parkinson’s disease, and the most reliable method of confirming the diagnosis is through postmortem examination.

In this study, investigators reasoned that a peripheral tissue marker—such as submandibular gland biopsy—would be a valuable tool for clinical diagnosis of early Parkinson’s disease in living patients.

The study involved 25 patients who had early Parkinson’s disease (less than 5 years from when motor symptoms began), along with 10 control subjects without Parkinson’s disease. Investigators performed a submandibular gland biopsy in each subject, then blindly tested the samples for phosphorylated alpha-synuclein—a protein that is regularly found in autopsied subjects with Parkinson’s disease.

Researchers detected the abnormal Parkinson’s protein in 14 of the 19 early Parkinson's patients (74%) who had enough tissue to study, while only 2 of 9 control subjects (22%) had a positive result. The research team had previously shown that the biopsy could detect the protein in 9 of 12 patients with advanced Parkinson’s disease.

“This procedure will provide a much more accurate diagnosis of Parkinson’s disease than what is now available,” said study co-author Thomas Beach, MD, PhD, Head and Senior Scientist at the Civin Laboratory for Neuropathology at Banner Sun Health Research Institute in Sun City, AZ. In a previous study, Drs. Adler and Beach found that up to 45% of patients may be misdiagnosed early in the disease.

“One of the greatest potential impacts of this finding is on clinical trials, as at the present time some patients entered into Parkinson’s clinical trials do not necessarily have Parkinson’s disease and this is a big impediment to testing new therapies,” Dr. Beach said.

Share with emailShare to FacebookShare to LinkedInShare to Twitter