Edinburgh Impact

Discovering the smell of Parkinson’s

In 2012, stem cell biologist Dr Tilo Kunath had just finished a public talk about his research on Parkinson’s disease when he was asked a surprising question – “Why aren’t you using smell to detect Parkinson’s?” Nine years on, this simple question has led to ground-breaking research into new ways to detect this devastating disease.

Joy Milne and Dr Tilo Kunath
Joy Milne and Dr Tilo Kunath

By Ellie Roger, Communication and Engagement Officer, Centre for Regenerative Medicine, Institute for Regeneration and Repair

Engaging the Parkinson’s community

Having started his career as a developmental biologist, over time Tilo’s work became focused on Parkinson’s disease – a degenerative brain disorder for which there are currently no tests or cures. He now runs his own laboratory at the University’s Centre for Regenerative Medicine, where he pioneers work into the development of cell replacement therapies to treat the disease.

It was as his research became more centred on Parkinson’s that Tilo began to engage more with the Parkinson’s community, regularly meeting with patient and charity groups to share his research. He soon found that this interaction was a two-way process and he was learning as much from them as they were from him.

“Interacting with the patient community, for me, is an extremely important activity,” Tilo says. “Not only do I get massive enthusiasm and encouragement but I also get ideas for experiments. Through interaction with the patients, you really understand what would most benefit them going forward.”

It was at one such meeting in Edinburgh that Tilo had a chance encounter with Joy Milne.

The woman who can smell Parkinson’s

Joy Milne’s husband Les was diagnosed with Parkinson’s at the age of 45. However, it had been 12 years earlier when Joy had first noticed that something was different about him.

Joy has a rare condition called hereditary hypersomnia that gives her a heightened sense of smell. When Les was 33, she noticed that he had started to develop an odour, which she described as a subtle, musky smell.

She also noticed the same distinct smell when attending meetings organised by the charity Parkinson’s UK. It was at this point that she was able to link the smell to the disease.

Dr Tilo Kunath
Dr Tilo Kunath

As both Les and Joy had a background in medicine, they knew this finding was significant. It was Les who then chose for them to approach Tilo, feeling that his interaction and close work with the Parkinson’s community would stir his curiosity.

On 19 April 2012, at a Parkinson’s UK meeting hosted by Tilo at the Centre for Regenerative Medicine, Joy took her opportunity to ask him why smell couldn’t be used to diagnose Parkinson’s.

This question and Joy’s ‘super smeller’ abilities would soon go on to make headlines around the world.

Birth of a unique collaboration

The question at first puzzled and confused Tilo. He had never before been asked about smell and it was not something he had previously come across in his research.

Although not directly related to his own Parkinson’s research, Tilo was curious and discussed it with his colleague Professor Perdita Barran, then a University of Edinburgh researcher who is now based at the University of Manchester. This was the beginning of a long-term collaboration to discover the identity of what Joy was smelling.

The scientists believed that the scent may be caused by a chemical change in skin oil, known as sebum, that is triggered by the disease. They developed a pilot study where Joy was asked to smell and identify t-shirts worn by Parkinson’s patients.

The test involved six t-shirts worn by Parkinson’s patients and six from a control group. Joy correctly identified the six from the patient group. She also identified one from the control group. However, eight months later, that individual got in touch with Tilo to reveal that he too had subsequently been diagnosed with Parkinson’s.

This extraordinary finding indicated that it might be possible to develop a test that could provide an early diagnosis of the disease.

Dr Tilo Kunath in the lab
Dr Tilo Kunath in the lab

“Our early results suggested that there may be a distinctive scent that is unique to people with Parkinson’s,” Tilo explains. “If we could identify the molecules responsible for this, it could help us develop ways of detecting and monitoring the condition.”

Progress towards a skin swab test

These early findings were exciting and encouraging. The scientists knew that if they were able to identify a unique chemical signature in the skin linked to Parkinson’s, they may eventually be able to diagnose the condition from simple skin swabs.

There is currently no definitive test for Parkinson’s disease, with diagnosis based on a patient’s symptoms and medical history, a process that can take several years. The development of a test like this would therefore be a game-changer for the Parkinson’s community.

With Joy’s help, the research team, now led by Perdita at the University of Manchester, continued to make progress. In 2019, they announced a major breakthrough – the discovery of chemicals enriched in skin swabs from people with Parkinson’s.

This key discovery led to further research to profile the complex chemical signature in sebum of people with Parkinson’s. Through this work, scientists found subtle but fundamental changes as the condition progressed.

This meant that a skin swab could potentially not only be used to diagnose Parkinson’s, but could also be used to monitor the development of the condition.

Professor Perdita Barran said: “We believe that our results are an extremely encouraging step towards tests that could be used to help diagnose and monitor Parkinson’s. Not only is the test quick, simple and painless but it should also be extremely cost-effective because it uses existing technology that is already widely available.

“We are now looking to take our findings forwards to refine the test to improve accuracy even further and to take steps towards making this a test that can be used in the NHS and to develop more precise diagnostics and better treatment for this debilitating condition.”

In June 2021, the research team, including Joy and Tilo, won the 2021 Analytical Division Horizon Prize: Robert Boyle Prize for Analytical Science, a prestigious award that was presented to them by the Royal Society of Chemistry.

Community recognition

This unique research collaboration and its ground-breaking discoveries are a direct legacy of Tilo’s engagement with the Parkinson’s community.

In 2019, he received recognition for his role in the project and his wider work with the Parkinson’s community when he was awarded the prestigious Tom Isaacs Award. This prize is presented to a researcher who has shown the greatest impact on the lives of people living with Parkinson’s and/or has involved people with Parkinson’s in a participatory way in their work.

Dr Tilo Kunath receiving the Tom Isaacs award
Dr Tilo Kunath receiving the Tom Isaacs award

Tilo received multiple nominations from members of the Parkinson’s community, who praised his commitment, support, advocacy and willingness to engage. The judges unanimously concluded that Tilo had an ‘enthusiastic impact on the lives of people living with Parkinson’s.’

The award was presented to Tilo by Joy Milne in the very same room where she had listened to him speak and asked her question all those years before.

Video: Edinburgh Impact - Discovering the smell of Parkinsons
The Cure Parkinson's Trust is delighted to announce this year's Tom Isaacs Award winner 2019 - Dr Tilo Kunath.

“From the very beginning Tilo demonstrated the qualities that Les had hoped for, the scientific ‘out of the box’ mind of a true researcher,” Joy said. “ He asked others in the Parkinson’s disease and research science communities and instigated and developed the first testing of odour in sebum for Parkinson’s disease.

“His only disappointment, but most significant discovery, was that having run around the block several times in one of these T-shirts, I told him the smell was on the back of the neck not under the arms. Hence, he was the first scientist to discover it was sebum, which was then scientifically verified by Professor Perdita Barran.”

Photography: Courtesy of Robin Morton, Centre for Regenerative Medicine