Smelling Parkinson’s: How one woman’s sense of smell could save lives

Parkinson’s disease affects around 145,000 people in the UK with two more new cases diagnosed every hour. The disease is believed to occur due to a combination of genetic and environmental factors. It is triggered by the loss of nerve cells in the brain, leading to a reduction in the amount of dopamine circulating in the body. Dopamine is extremely important in regulating body movement and a loss of these nerve cells leads to slow movement and rigid muscles.

Despite the high prevalence and extensive research into the disease, there is currently no cure for Parkinson’s. However, medications like Levodopa can help relieve symptoms. Levodopa is administered in tablet or liquid form and is broken down into dopamine. In this way, treatments for Parkinson’s aim to maintain the quality of life for patients.

An unexpected hero

There is no specific test for Parkinson’s disease, making a definite diagnosis difficult. However, scientists have found a surprising way to detect those with early-stage Parkinson’s disease. This is all thanks to an unexpected hero, Joy Milne, whose husband Les was diagnosed with Parkinson’s at the age of 45, 12 years after Joy had first noticed an odd smell coming from her husband.

Joy has a rare condition known as hereditary hyperosmia which gives her a heightened sense of smell. This allowed her to detect the “musty rather unpleasant smell,” given off by Les. After her husband’s diagnosis, Milne was able to put two and two together while meeting others in a Parkinson’s UK support group. She realised the distinctive smell was present in all of those attending the support group.

Sniffing out a diagnosis

This discovery intrigued a large group of scientists who began to discuss the possibility of using Milne’s sensitivity to odours to develop an early diagnostic test. The scientists put Milne’s nose to the test, asking her to smell six t-shirts worn by patients with Parkinson’s and six t-shirts worn by healthy volunteers. Milne was then asked to determine which participants had Parkinson’s based on the smell of their t-shirts. She was able to correctly identify all but one patient, a healthy volunteer who she misdiagnosed with Parkinson’s. Eight months after this experiment, it was found that the patient did in fact have the disease.

After this study, scientists took swabs from the volunteers and analysed them using mass spectroscopy, a process which allows scientists to understand what individual molecules a compound is made up of. From this, researchers hoped to identify a unique molecule which could be screened for in patients with suspected Parkinson’s to aid early diagnosis.

A breakthrough

Now, researchers at The University of Manchester have developed a simple cotton swab test which can be performed in as little as 3 minutes. It involves taking a swab of sebum from the neck, an oily substance which is secreted from glands under the skin. Altered sebum production is known to occur in patients with Parkinson’s. In particular, triacyl glycerides and diglycerides, have been shown to be expressed at higher levels in the sebum of those with the disease. It is these changes in the sebum of PD patients which produced the distinctive odour detected by Joy Milne, and now forms the basis of a diagnostic test for Parkinson’s disease.

This quick and non-invasive test “has the potential to massively improve the diagnosis and management of people with Parkinson’s disease”. Professor Perdita Barran, a researcher at UoM, said “we are tremendously excited by these results which take us closer to making a diagnostic test for Parkinson’s Disease that could be used in the clinic.”

Looking to the future

The current focus now is to do just that. The University of Manchester has launched a new company, Sebomix Ltd., which enables the development of this test, in order for it to be used in the clinic. With the involvement of charities including Parkinson’s UK, trials have begun, with over 2000 patients being recruited.

The hope is that it is not long until an early diagnosis is standard in those presenting symptoms of Parkinson’s. As for Joy, she is proud of the work she’s done with her nose. She says this was the last thing she and Les spoke about, and he made her promise to continue helping in the search for a diagnostic test for Parkinson’s. In her own words, “I’ve kept my promise. So it should make an awful lot of difference.”