A woman who can smell Parkinson's disease could hold the key to early diagnosis
The chemicals she's detecting could be biomarkers that could reveal early onset of the disease
It turns out that there's a unique smell to Parkinson's disease. And Joy Milne, a 69-year-old retired nurse from Scotland, can detect it. Now researchers have identified the chemicals she's smelling, and hope to be able to develop a diagnostic test based on them.
Parkinson's disease is a neurodegenerative disorder that's characterized by hand tremors, slurred speech and slowed movement. These symptoms, however, only appear after the disease has done substantial neurological damage.
Perdita Barran, Professor of Mass Spectroscopy at the University of Manchester, worked together with Milne and identified the chemicals involved in creating the smell of Parkinson's. She and her colleagues hope they can use these chemicals as biomarkers to detect the disease early — before the onset of symptoms and serious neurological damage.
Joy Milne has a superb nose that's on par with the professional noses around the world that end up working in the perfume or food industry.
About three decades ago, she noticed that her husband's scent had changed.
"He had a lovely male smell and then all of a sudden changed," said Milne.
She described the odour as musky and animal-like. A decade later, Les was diagnosed with Parkinson's at age 45.
At that point, she didn't connect her husband's Parkinson to the smell she'd been detecting for years. Then one day, they attended a meeting of Parkinson's patients.
"We got home and I told him 'those people in that room smell the same as you.' All Parkinson's people have the smell," Milne recalled. That led them to seek out scientists to develop a diagnostic test based on the smell.
Finding the biomarkers for Parkinson's
Milne eventually connected with Barran through Barran's colleague who studies Parkinson's disease.
Barran set up an experiment with 12 participants where only half had Parkinson's disease. Milne was given T-shirts worn by participants, and in every case, Milne was able to tell whether the anonymous wearer had Parkinson's or not.
Initially, they thought she'd made one error. She detected the characteristic odour on one T-shirt worn by a patient in the non-Parkinsons's group. However, that person was diagnosed with the disease months later.
In a follow-up experiment, Barran recruited 60 participants, where 40 had Parkinson's and 20 didn't.
With Milne's help, she traced the source of the smell to sebum from the upper back of Parkinson's patients — sebum is an oily substance secreted from oily glands on the skin.
Barran and her team took a sample from each participant's back, and found between two to three hundred molecules in each sample when they analyzed them using gas chromatography to separate the different compounds.
Next, they measured the mass of each molecule extracted from the samples through a mass spectrometer, and found three molecules that were significantly more abundant in participants with Parkinson's compared to those who don't., and one molecule that was significantly less abundant.
Those four molecules, according to Barran, are the key contributors to the Parkinson's smell, and could potentially be used as biomarkers to detect the disease before any of the motor symptoms arise.
Barran's working on that now and says, "If we can do that, then that means we can identify people who would benefit from trying medication that might alleviate the motor symptoms or prevent the neurological damage that happens when the motor symptoms arise."