A Supersmeller Can Detect the Scent of Parkinson's, Leading To An Experimental Test For the Illness

Diana Kwon writes via Scientific American: A Scottish woman named Joy Milne made headlines in 2015 for an unusual talent: her ability to sniff out people afflicted with Parkinson's disease, a progressive neurodegenerative illness that is estimated to affect nearly a million people in the U.S. alone. Since then a group of scientists in the U.K. has been working with Milne to pinpoint the molecules that give Parkinson's its distinct olfactory signature. The team has now zeroed in on a set of molecules specific to the disease -- and has created a simple skin-swab-based test to detect them. [...] The researchers used mass spectrometry to identify types and quantities of molecules in a sample of sebum, an oily substance found on the skin's surface. They discovered changes to fatty molecules known as lipids in people with Parkinson's. In their latest study, published on September 7 in the American Chemical Society journal JACS Au, the researchers revealed the results of using a simple skin-swab-based test to detect the lipid signature that is indicative of Parkinson's. By comparing sebum samples from 79 people with Parkinson's and 71 people without the illness, the team zeroed in on a set of large lipids that could be detected in a matter of minutes using a special type of mass spectrometry in which substances are rapidly transferred from a swab to an analyzer using just a piece of paper. "I think it's a very promising set of biomarkers," says Blaine Roberts, a biochemist at Emory University, who wasn't involved in the work. He adds that one of the big open questions that remains is how exacting this test can be. While the authors of the September 7 study reported the detailed chemical profile of the unique Parkinson's signature, they did not include an assessment of its accuracy. According to Barran, based on not-yet-published data, their test appears to be able to determine whether an individual has Parkinson's with more than 90 percent accuracy. [...] The team is now working with local hospitals to determine whether this sebum-based test can also be conducted in clinical labs -- a key step toward determining whether it can be used as a diagnostic tool. Ultimately, Barran says, the hope is to use the test to help identify individuals who have been referred to their neurologists by their general practitioner for suspected Parkinson's so they can receive a faster diagnosis. The researchers are also working with a group at Harvard "to determine whether sebum-based biomarkers are detectable in people who have constipation, a reduced sense of smell or other early signs of Parkinson's but have not yet received a diagnosis," reports Kwon. Meanwhile, Milne is working with scientists to sniff out people with Alzheimer's, cancer, and tuberculosis -- all of which she says have a unique smell.

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