Sarah Watts is a health and science writer based in Chicago. Follow her on Twitter at @swattswrites.
Thirty-seven years ago, Joy Milne, a nurse from Perth, Scotland, noticed a musky odor coming from her husband, Les.
To her surprise, at a local support group meeting, she caught the familiar scent once again, hanging over the group like a cloud.
At first, Milne thought the smell was a result of bad hygiene and badgered her husband to take longer showers. But when the smell persisted, Milne learned to live with it, not wanting to hurt her husband's feelings.
Twelve years after she first noticed the "woodsy" smell, Les was diagnosed at the age of 44 with Parkinson's Disease, a neurodegenerative condition characterized by lack of dopamine production and loss of movement. Parkinson's Disease currently affects more than 10 million people worldwide.
Milne spent the next several years believing the strange smell was exclusive to her husband. But to her surprise, at a local support group meeting in 2012, she caught the familiar scent once again, hanging over the group like a cloud. Stunned, Milne started to wonder if the smell was the result of Parkinson's Disease itself.
Milne's discovery led her to Dr. Tilo Kunath, a neurobiologist at the Centre for Regenerative Medicine at the University of Edinburgh. Together, Milne, Kunath, and a host of other scientists would use Milne's unusual sense of smell to develop a new diagnostic test, now in development and poised to revolutionize the treatment of Parkinson's Disease.
"Joy was in the audience during a talk I was giving on my work, which has to do with Parkinson's and stem cell biology," Kunath says. "During the patient engagement portion of the talk, she asked me if Parkinson's had a smell to it." Confused, Kunath said he had never heard of this – but for months after his talk he continued to turn the question over in his mind.
Kunath knew from his research that the skin's microbiome changes during different disease processes, releasing metabolites that can give off odors. In the medical literature, diseases like melanoma and Type 2 diabetes have been known to carry a specific scent – but no such connection had been made with Parkinson's. If people could smell Parkinson's, he thought, then it stood to reason that those metabolites could be isolated, identified, and used to potentially diagnose Parkinson's by their presence alone.
First, Kunath and his colleagues decided to test Milne's sense of smell. "I got in touch with Joy again and we designed a protocol to test her sense of smell without her having to be around patients," says Kunath, which could have affected the validity of the test. In his spare time, Kunath collected t-shirt samples from people diagnosed with Parkinson's and from others without the diagnosis and gave them to Milne to smell. In 100 percent of the samples, Milne was able to detect whether a person had Parkinson's based on smell alone. Amazingly, Milne was even able to detect the "Parkinson's scent" in a shirt from the control group – someone who did not have a Parkinson's diagnosis, but would go on to be diagnosed nine months later.
From the initial study, the team discovered that Parkinson's did have a smell, that Milne – inexplicably – could detect it, and that she could detect it long before diagnosis like she had with her husband, Les. But the experiments revealed other things that the team hadn't been expecting.
"One surprising thing we learned from that experiment was that the odor was always located in the back of the shirt – never in the armpit, where we expected the smell to be," Kunath says. "I had a chance meeting with a dermatologist and he said the smell was due to the patient's sebum, which are greasy secretions that are really dense on your upper back. We have sweat glands, instead of sebum, in our armpits." Patients with Parkinson's are also known to have increased sebum production.
With the knowledge that a patient's sebum was the source of the unusual smell, researchers could go on to investigate exactly what metabolites were in the sebum and in what amounts. Kunath, along with his associate, Dr. Perdita Barran, collected and analyzed sebum samples from 64 participants across the United Kingdom. Once the samples were collected, Barran and others analyzed it using a method called gas chromatography mass spectrometry, or GS-MC, which separated, weighed and helped identify the individual compounds present in each sebum sample.
Barran's team can now correctly identify Parkinson's in nine out of 10 patients – a much quicker and more accurate way to diagnose than what clinicians do now.
"The compounds we've identified in the sebum are not unique to people with Parkinson's, but they are differently expressed," says Barran, a professor of mass spectrometry at the University of Manchester. "So this test we're developing now is not a black-and-white, do-you-have-something kind of test, but rather how much of these compounds do you have compared to other people and other compounds." The team identified over a dozen compounds that were present in the sebum of Parkinson's patients in much larger amounts than the control group.
Using only the GC-MS and a sebum swab test, Barran's team can now correctly identify Parkinson's in nine out of 10 patients – a much quicker and more accurate way to diagnose than what clinicians do now.
"At the moment, a clinical diagnosis is based on the patient's physical symptoms," Barran says, and determining whether a patient has Parkinson's is often a long and drawn-out process of elimination. "Doctors might say that a group of symptoms looks like Parkinson's, but there are other reasons people might have those symptoms, and it might take another year before they're certain," Barran says. "Some of those symptoms are just signs of aging, and other symptoms like tremor are present in recovering alcoholics or people with other kinds of dementia." People under the age of 40 with Parkinson's symptoms, who present with stiff arms, are often misdiagnosed with carpal tunnel syndrome, she adds.
Additionally, by the time physical symptoms are present, Parkinson's patients have already lost a substantial amount of dopamine receptors – about sixty percent -- in the brain's basal ganglia. Getting a diagnosis before physical symptoms appear would mean earlier interventions that could prevent dopamine loss and preserve regular movement, Barran says.
"Early diagnosis is good if it means there's a chance of early intervention," says Barran. "It stops the process of dopamine loss, which means that motor symptoms potentially will not happen, or the onset of symptoms will be substantially delayed." Barran's team is in the processing of streamlining the sebum test so that definitive results will be ready in just two minutes.
"What we're doing right now will be a very inexpensive test, a rapid-screen test, and that will encourage people to self-sample and test at home," says Barran. In addition to diagnosing Parkinson's, she says, this test could also be potentially useful to determine if medications were at a therapeutic dose in people who have the disease, since the odor is strongest in people whose symptoms are least controlled by medication.
"When symptoms are under control, the odor is lower," Barran says. "Potentially this would allow patients and clinicians to see whether their symptoms are being managed properly with medication, or perhaps if they're being overmedicated." Hypothetically, patients could also use the test to determine if interventions like diet and exercise are effective at keeping Parkinson's controlled.
"We hope within the next two to five years we will have a test available."
Barran is now running another clinical trial – one that determines whether they can diagnose at an earlier stage and whether they can identify a difference in sebum samples between different forms of Parkinson's or diseases that have Parkinson's-like symptoms, such as Lewy Body Dementia.
"Within the next one to two years, we hope to be running a trial in the Manchester area for those people who do not have motor symptoms but are at risk for developing dementia due to symptoms like loss of smell and sleep difficulty," Barran says. "If we can establish that, we can roll out a test that determines if you have Parkinson's or not with those first pre-motor symptoms, and then at what stage. We hope within the next two to five years we will have a test available."
But a definitive Parkinson's test, however revolutionary, would likely not be made available to the general population – at least, not for a while.
"We would likely first give this test to people who are at risk due to a genetic predisposition, or who are at risk based on prodomal symptoms, like people who suffer from a REM sleep disorder who have a 50 to 70 percent chance of developing Parkinson's within a ten year period," Barran says. "Those would be people who would benefit from early therapeutic intervention. For the normal population, it isn't beneficial at the moment to know until we have therapeutic interventions that can be useful."
Milne's husband, Les, passed away from complications of Parkinson's Disease in 2015. But thanks to him and the dedication of his wife, Joy, science may have found a way to someday prolong the lives of others with this devastating disease.
[Ed. Note: This hit article from our archives originally ran on September 3, 2019.]
Sarah Watts is a health and science writer based in Chicago. Follow her on Twitter at @swattswrites.
At age 52, Glen Rouse suffered from arm weakness and a lot of muscle twitches. “I first thought something was wrong when I could not throw a 50-pound bag of dog food over the tailgate of my truck—something I use to do effortlessly,” said the 54-year-old resident of Anderson, California, about three hours north of San Francisco.
In August, Rouse retired as a forester for a private timber company, a job he had held for 31 years. The impetus: amyotrophic lateral sclerosis, or ALS, a progressive neuromuscular disease that is commonly known as Lou Gehrig’s disease, named after the New York Yankees’ first baseman who succumbed to it less than a month shy of his 40th birthday in 1941. ALS eventually robs an individual of the ability to talk, walk, chew, swallow and breathe.
Rouse is now dependent on ventilation through a nasal mask and uses a powerchair to get around. “I can no longer walk or use my arms very well,” he said. “I can still move my wrists and fingers. I can also transfer from my chair to the toilet if I have two of my friends help me.”
It’s “shocking” that modern medicine has very little to offer to people with this devastating condition, Rouse said. But there is hope on the horizon. Yesterday, the U.S. Food and Drug Administration approved Relyvrio, a drug made up of two parts, sodium phenylbutyrate and taurursodiol, to treat patients with ALS.
“This approval provides another important treatment option for ALS, a life-threatening disease that currently has no cure,” said Billy Dunn, director of the Office of Neuroscience in the FDA’s Center for Drug Evaluation and Research, in a statement. “The FDA remains committed to facilitating the development of additional ALS treatments.”
Until this point, the FDA had approved only two other medications—Riluzole (rilutek) in 1995 and Radicava (edaravone) in 2017—to extend life in patients with ALS, which typically kills within two to five years after diagnosis. That’s why earlier this week, Rouse was optimistic about the FDA’s likely approval of a controversial new drug for ALS.
When Relyvrio is taken in addition to Riluzole, it appears to slow functional decline by an additional 25 percent and extend life by another 6 to 10 months, said Richard Bedlak, director of the Duke ALS Clinic. “It is not a cure, but it is definitely a step forward.”
“The whole ALS community is extremely excited about it,” he said the day before Relyvrio’s expected approval. “We are very hopeful. We’re on pins and needles.”
A study of 137 ALS patients did not result in “substantial evidence” that Relyvrio was effective, the agency’s Peripheral and Central Nervous System Drugs Advisory Committee concluded in March. However, after some persuasion from FDA officials, patients and their families, the committee met again and decided to recommend approving the drug.
In January 2019, following an ALS diagnosis in October the previous year, Jeff Sarnacki, of Chester, Maryland, was accepted into a trial for Relyvrio. “Because of the trial, we did experience hope and a greater sense of help than had we not had that opportunity,” said Juliet Taylor, his wife and caregiver. They both believed the drug “worked for him in giving him more time.”
In June 2019, Sarnacki chose an open-label extension, offered to patients by drug researchers after a study ends, and took the active drug until he died peacefully at home under hospice care in May 2020, five days after his 60th birthday. A retired agent with the federal Bureau of Alcohol, Tobacco, Firearms and Explosives who later worked as a security consultant, Sarnacki lived about 19 months after diagnosis, which is shorter than the typical prognosis.
His symptoms had begun with leg cramps and foot drop in late fall 2017. At the end of life, he could only move a few fingers on his left hand and could not speak or eat by mouth; a feeding tube became necessary, Taylor said. He also took Radicava and Riluzole, the two previously approved drugs, for his ALS. “We were both incredulous that, so many years after Lou Gehrig’s own diagnosis, there were so few treatments available,” she said.
The dearth of successful treatments for ALS is “certainly not for lack of trying,” said Karen Raley Steffens, a registered nurse and ALS support services coordinator at the Les Turner ALS Foundation in Skokie, Ill. “There are thousands of researchers and scientists all over the world working tirelessly to try to develop treatments for ALS.”
Unfortunately, she adds, research takes time and exorbitant amounts of funding, while bureaucratic challenges persist. The rare disease also manifests and progresses in many different ways, so many treatments are needed.
As of 2017, the Centers for Disease Control and Prevention estimated that more than 31,000 people in the U.S. live with ALS, and an average of 5,000 people are newly diagnosed every year.
Most cases of ALS are sporadic, meaning that doctors don’t know the cause. There is about a one-year interval between symptom onset and an ALS diagnosis for most patients, so many motor neurons are lost by the time individuals can enroll in a clinical trial, said Richard Bedlack, professor of neurology and director of the Duke ALS Clinic in Durham, North Carolina.
Bedlack found the new drug, Relyvrio, to be “very promising,” which is why he testified to the FDA in favor of approval. (He’s a consultant and disease state speaker for multiple companies including Amylyx, manufacturer of Relyvrio.)
The “drug has different mechanisms of action than the currently approved treatments,” said Bedlack, who is also chief of neurology at the Durham Veterans Affairs Medical Center. He adds that, when Relyvrio is taken in addition to Riluzole, it appears to slow functional decline by an additional 25 percent and extend life by another 6 to 10 months. “It is not a cure, but it is definitely a step forward.”
T. Scott Diesing, a neurohospitalist and director of general neurology at the University of Nebraska Medical Center in Omaha, said he hopes the drug is “as good as people anticipated it should be, because there are not too many options for these patients.”
So far, Rouse's voice is holding up, but he knows the day will come when ALS will steal that and much more from him.
ALS is 100 percent fatal, with some patients dying as soon as a year after diagnosis. A few have lasted as long as 15 years, but those are the exceptions, Diesing said.
“If this drug can provide even months of additional life, or would maintain quality of life, that’s a big deal,” he notes, adding that “the patients are saying, ‘I know it’s not proven conclusively, but what do we have to lose?’ So, they would like to try it while additional studies are ongoing.” The drug has already been approved in Canada.
As his disease progresses, Rouse hopes to get a speech-to-text voice-generating computer that he can control with his eyes. So far, his voice is holding up, but he knows the day will come when ALS will steal that and much more from him. He works at I AM ALS, a patient-led community, and six of his friends have already died of the disease.
“Every time I lose a friend to ALS, I grieve and am sad but I resolve myself to keep working harder for them, myself and others,” Rouse said. “People living with ALS find great purpose in life advocating and trying to make a difference.”
The Friday Five covers important stories in health and science research that you may have missed - usually over the previous week, but today's episode is a lookback on important studies over the month of September.
Most recently, on September 27, pharmaceuticals Biogen and Eisai announced that a clinical trial showed their drug, lecanemab, can slow the rate of Alzheimer's disease. There are plenty of controversies and troubling ethical issues in science – and we get into many of them in our online magazine – but this news roundup focuses on scientific creativity and progress to give you a therapeutic dose of inspiration headed into the weekend and the new month.
This Friday Five episode covers the following studies published and announced over the past month:
- A new drug is shown to slow the rate of Alzheimer's disease
- The need for speed if you want to reduce your risk of dementia
- How to refreeze the north and south poles
- Ancient wisdom about Neti pots could pay off for Covid
- Two women, one man and a baby