The smell of Parkinson’s
13th of December 2018
Joy Milne can smell Parkinson’s disease (PD). Joy is hyperosmic, meaning she has a heightened sense of smell. Years before her deceased husband was officially diagnosed with Parkinson’s she noticed that his smell changed. A very subtle, woody, musky smell teased her nostrils. When she and her husband attended a gathering for PD patients in 2012, she came to the conclusion that all patients in there smelled the same. She spoke up about her ability to smell Parkinson’s and the research team of professor Perdita Berran at the University of Edinburgh listened and acted.
To test Joy’s superior sense of smell, she was given twelve T-shirts of which six had been worn by Parkinson’s patients. She picked the right six without a doubt plus one extra from a person without Parkinson’s. At least, that’s what the research team thought. Eight months later the seventh person was also diagnosed with Parkinson’s. More than enough reason to dig into the matter and try and find out the ‘molecular signature’ of the smell of Parkinson’s.
Unravelling the smell of PD
Since 2012, when Joy’s discovery was picked up, progress has been made. Recently, a preprint was published on bioRxiv (2) in which Joy is mentioned as one of the authors. Joy helped scientists discover the volatile substances that smell like Parkinson’s. The researchers took sebum samples from the upper back of 64 participants (21 people without and 43 with Parkinson’s), a piece of skin where the smell of Parkinson’s is strong according to Joy. Sebum is a waxy substance that is excreted by the sebaceous glands in the skin.
The researchers used TD-GC-MS (Thermal Desorption Gas Chromatography Mass Spectrometry) to distinguish the volatile substances from the sebum samples. With TD-GC-MS, a sample is first heated to release the volatile substances and then the substances are separated on the basis of their mass. They all come out of the TD-GC-MS one by one and can be smelled seperately. Using Joy’s sense of smell, the researchers discovered that the skin of Parkinson’s patients secretes relatively much of the volatile substances eicosane, perillic acid and octadecanol. The results could indicate an altered activity of micro-organisms in the skin.
The research results show once again that Joy is right and legitimise the setting up of a larger study. In this study the researchers want to use both human ‘super smellers’ as canine smellers.
WHY IS THIS WORK IMPORTANT?
This work is important in more than one way:
- If the smell of Parkinson’s is unraveled, the next step – the development of a diagnostic test for Parkinson’s – will come closer;
- The molecular signature of the Parkinsonian odor probably provides insights into the underlying disturbances that lead to this odor. This gives us new leads in the search for possible causes of Parkinson’s disease.
WHY IS THIS WORK IMPORTANT TO ME?
For me, the personal relevance of this work is that patients have been taken very seriously in their observations. Patients and their partners see different things than caregivers. By working together, changing perspectives and fostering serendipity we can solve the complex puzzle called Parkinson’s faster.
Serendipity means an unplanned, fortunate discovery. The notion of serendipity is a common occurrence throughout the history of scientific innovation.
(1) Morgan, J. (2016). Joy of super smeller: sebum clues for PD diagnostics. The Lancet Neurology. 15, 138–139. Retrieved from sci-hub.tw/10.1016/S1474-4422(15)00396-8
(2) Trivedi, D.K., Sinclair, E., Xu, Y., Sarkar, D., Liscio, C., Banks, P., Milne, J., Silverdale, M., Kunath, T., Goodacre, R., Barran, P. (2018). Discovery of volatile biomarkers of Parkinson’s disease from sebum. http://doi.org/10.1101/469726.Retrieved from: