The disease appears to work silently for a decade before symptoms emerge
For generations, motor neurone disease has arrived as a sudden verdict — symptoms appearing, life expectancy measured in years. Now, researchers at Johns Hopkins University have discovered that the disease has been writing its signature in the blood for nearly a decade before any outward sign emerges. By identifying 33 proteins that form a molecular fingerprint unique to ALS, their test achieves 98 percent accuracy in detection, suggesting that what medicine understood as a rapid illness is in fact a long, silent unfolding — and that the window for intervention may be far wider than anyone had dared to hope.
- A disease long assumed to strike swiftly has been quietly developing in the body for up to ten years before a single symptom appears, overturning decades of neurological assumption.
- With no cure and a median survival of two to five years after diagnosis, the urgency to intercept ALS earlier has never been more acute — for the 5,000 UK patients living with it and the many more at genetic risk.
- Machine learning analysis of blood plasma identified 33 proteins — 16 of them never before linked to ALS — forming a signature accurate enough to distinguish the disease from Parkinson's, dementia, and healthy aging at a 98 percent rate.
- The test's risk score was shown to rise steadily in pre-symptomatic patients as they approached typical onset age, a pattern absent in healthy participants, ruling out aging as a confounding factor.
- Early detection cannot yet stop the disease, but it could place patients into clinical trials while their neurological systems remain relatively intact — shifting the entire logic of how ALS is managed.
- Fifteen years of cross-institutional collaboration have produced findings now made publicly available, with the explicit goal of accelerating an approved, widely accessible blood test.
Researchers at Johns Hopkins University have developed a blood test capable of detecting motor neurone disease up to a decade before symptoms appear — a discovery that fundamentally reframes how science understands the disease's timeline.
The study, published in Nature Medicine, analyzed blood samples from hundreds of ALS patients, healthy individuals, and people with other neurological conditions. Using machine learning, the team identified 33 proteins forming a molecular signature unique to ALS, sixteen of which had never previously been associated with the disease. Tested against an independent set of samples, the model distinguished ALS from both healthy participants and conditions like Parkinson's disease and dementia with 98 percent accuracy.
The most striking finding concerns timing. Neurology had long held that ALS involved only 12 to 18 months of biological activity before symptoms emerged. The new data tells a different story: among patients whose blood was collected before they developed symptoms, the test's risk score climbed steadily as they approached typical onset age — a pattern absent in healthy participants, ruling out aging as an explanation. The disease, it appears, has been working in silence for roughly a decade.
Motor neurone disease affects around 5,000 adults in the United Kingdom. It progressively destroys the ability to move, swallow, and breathe, with life expectancy typically between two and four years after diagnosis. There is no cure. The disease has claimed figures including rugby player Rob Burrow, who died at 41 after a four-and-a-half-year battle.
The value of early detection lies in its timing. Identifying at-risk individuals years before symptoms emerge could allow enrollment in clinical trials while neurological systems remain relatively intact. Lead investigator Alexander Pantelyat described the test as an opportunity to offer 'promising disease-modifying — and hopefully disease-stopping — medications' before irreversible damage occurs.
The research is the product of 15 years of collaboration across institutions including the University of Turin and the National Institutes of Health. The team has made their findings publicly available to accelerate further work, with the goal of moving toward a widely approved blood test that could shift the entire trajectory of ALS care.
Researchers at Johns Hopkins University have identified a blood test that can predict motor neurone disease a decade before a person shows any symptoms—a finding that fundamentally reshapes how scientists understand the disease's timeline and opens a path toward earlier intervention.
The study, published in Nature Medicine, examined blood samples from 281 patients with amyotrophic lateral sclerosis (ALS), the most common form of motor neurone disease, alongside samples from 258 healthy controls and participants with other neurological conditions. Using machine learning to analyze the plasma, the team identified 33 distinct proteins that form a molecular signature unique to ALS. Sixteen of these proteins had never before been linked to the disease. When the researchers tested their model against additional samples—48 from ALS patients, 42 from healthy people, and 33 from those with other neurological disorders—the test proved 98 percent accurate at distinguishing ALS from both healthy individuals and conditions like Parkinson's disease and dementia.
The implications are striking because they upend the conventional understanding of how quickly the disease progresses. Alexander Pantelyat, the study's lead investigator, explained that neurology had long assumed ALS was a rapid condition, with only 12 to 18 months of biological activity before symptoms emerged. The new data suggests something far different: the disease appears to be working silently in the body for roughly a decade before a patient ever walks into a clinic with complaints. Among the 110 patients whose blood samples were collected before they developed symptoms, the model's risk score climbed steadily as time passed and they approached the typical age of symptom onset—a pattern that did not appear in healthy participants or those with other disorders, ruling out aging as an explanation.
Motor neurone disease is rare but devastating. Around 5,000 adults in the United Kingdom live with the condition. It attacks the brain and nerves, progressively stealing a person's ability to move, swallow, and breathe. Early warning signs include muscle twitches, a weakening grip, leg or ankle weakness, slurred speech, and unexplained weight loss. Once symptoms appear, life expectancy is typically between two and four years, though the disease can deteriorate with brutal speed. There is currently no cure.
The significance of early detection lies not in prevention—the disease cannot yet be stopped—but in timing. If doctors could identify people at risk years before symptoms emerge, those individuals could enroll in clinical trials testing new treatments while their neurological systems remain relatively intact. Pantelyat noted that the field has long lacked a reliable diagnostic method, leaving patients and families in uncertainty. A validated blood test would change that. 'With a test that allows for earlier detection of ALS, we have opportunities to enroll people in observational studies, and by extension, offer promising disease-modifying—and hopefully disease stopping—medications,' he said.
The research represents 15 years of collaboration across institutions, including the University of Turin and the National Institutes of Health. The team has made their findings publicly available to accelerate further biomarker research. The goal is straightforward: to move toward an approved, widely available blood test that could shift the entire trajectory of how ALS is managed. The disease has claimed notable lives—physicist Stephen Hawking lived with it for decades, and rugby player Rob Burrow died from it last year at age 41 after a four-and-a-half-year battle. For the thousands currently living with the condition and the many more at genetic risk, a test that catches the disease a decade early could mean the difference between irreversible paralysis and the chance to access treatments that might slow or stop its advance.
Citações Notáveis
We had always assumed that ALS was a rapid disease that starts 12 to 18 months before symptom onset. But when we look at our findings, we see this has been a process that goes on for a decade or so before the patient ever steps into the doctor's office.— Professor Alexander Pantelyat, Johns Hopkins University School of Medicine
With a test that allows for earlier detection of ALS, we have opportunities to enroll people in observational studies, and by extension, offer promising disease-modifying—and hopefully disease stopping—medications.— Professor Alexander Pantelyat
A Conversa do Hearth Outra perspectiva sobre a história
Why does it matter that the disease starts a decade before symptoms? Can't we just treat people when they notice something is wrong?
Because by the time someone feels weakness or slurred speech, the damage is already done. The neurons are dying. A decade of silent progression means we've lost years we could have used to intervene—to try drugs that might slow or stop the process before it becomes irreversible.
So this blood test is essentially a crystal ball. It tells you you're going to get sick before you actually get sick. Isn't that a heavy burden to carry?
It is. But right now, people with ALS get no warning at all. They get a diagnosis after they're already struggling to move. At least with early knowledge, they could make choices—enroll in trials, plan their lives, access treatments that might help. The burden of knowing seems lighter than the burden of helplessness.
The test is 98 percent accurate. What about the 2 percent? Who are they?
That's the honest part. Some people the test flags might never develop the disease. Others might slip through. It's not perfect. But it's far better than what we have now, which is nothing—just waiting for symptoms and hoping.
You mentioned 33 proteins. Why proteins? Why not look at genes or something else?
Proteins are what actually do the damage in the body. Genes are the blueprint, but proteins are the workers. In ALS, something goes wrong with how proteins fold or accumulate in nerve cells. By reading the protein signature in blood, you're reading the actual disease process as it unfolds, not just the genetic risk.
What happens to someone who tests positive a decade before symptoms?
That's the frontier now. They could join clinical trials testing new drugs. They could work with doctors to monitor their health closely. They could make informed decisions about their future. But honestly, we don't yet know the best way to use this information. That's the next chapter.