New saliva gland test may better diagnose patients with Parkinson's

It’s difficult for patients to absolutely know if they have Parkinson’s disease.

To date, the only way to diagnose someone with Parkinson’s is to do a clinical exam to access his or her symptoms.  And in order to definitively get an answer, an autopsy is performed on the brain – only after the person has died.

But now, a conclusive clinical test may soon be available.  Researchers from the Mayo Clinic in Arizona have found that examining a specific portion of a person’s saliva gland may be able to diagnose someone with Parkinson’s.

The idea to focus on such a small part of the human body came when lead author Dr. Charles Adler conducted a long-term study, examining people for Parkinson’s and dementia – for the course of their lives.  Once the patients in the study had died, Adler and his team would perform whole body autopsies, looking at all the organs in the body.

“[During the autopsy] you can see the protein alpha-synuclein” – an abnormal protein associated with Parkinson’s disease – “and we find that in multiple areas of the body as well,” Adler, with the Mayo Clinic Arizona and a fellow of the American Academy of Neurology, told FoxNews.com.  “However, the area that seemed to be most dense in the body was the submandibular gland – the salivary gland right under the jaw.”

Currently, the way to determine through autopsy if a person has Parkinson’s is to look for an aggregate of proteins called Lewy bodies in the mid-section of the brain.  One of the proteins located in the Lewy bodies is the alpha-synuclein protein.  Because of the protein’s association with Parkinson’s, Adler felt confident the protein’s location in the gland was specific to the disease.

After identifying the salivary gland to be significant for Parkinson’s patients, Adler conducted another experiment, examining all of the submandibular glands of his autopsy patients.  Of his already pre-determined Parkinson’s patients, all 28 of them had the alpha-synuclein protein in their submandibular glands.

Moving on to the third phase of his research, Adler decided to do biopsies on the submandibular glands of living Parkinson’s patients, to determine if this test made sense to do in living individuals.

“In the study we’re reporting now, we biopsied 15 living patients,” Adler said.  “Unfortunately, in four of those cases, there was not enough gland tissue – so we had 11 cases to analyze.  Of those 11 cases, nine of the 11 had that abnormal protein.  So that’s 82 percent, which is pretty exciting.”

According to Adler, an 82 percent positive diagnosis is significant because the accuracy of Parkinson’s diagnosis to date is only about 80 percent of living individuals.  Even if a patient is determined to have Parkinson’s during their lifetime, 20 percent of them turn out not to have the condition; they actually had a Parkinson’s –like illness instead.

“It definitely proves the concept that by doing a biopsy of living people with Parkinson’s, we have the opportunity to better diagnose the disease while their alive,” he added.