Blood proteins can predict multiple sclerosis years before diagnosis

A new study has revealed a group of blood proteins, that are altered in people who go on to develop multiple sclerosis (MS), in some cases more than a decade before diagnosis. The findings offer hope that a simple blood test could one day identify people at high risk of MS in time to act before damage occurs.

The best cure for neurological diseases like MS is prevention. Brain damage already done is difficult or impossible to repair, but if MS is caught early, the worst of its debilitating effects can often be prevented. Unfortunately, in many cases, diagnosis comes only after the disease is well underway and the window for early intervention has passed.

A team of scientists led by Dr. Adil Harroud, a neurologist and researcher at The Neuro (Montreal Neurological Institute-Hospital) of McGill University, sought ways to detect signs of future MS in patients' blood years before they were diagnosed. They focused on proteins, the molecules that carry out most of the body's functions.

Out of more than 2,500 blood proteins screened using a statistical technique known as Mendelian Randomization, the team found that 39 were linked to MS risk, most of them in the signalling pathways immune cells use to communicate. To know whether these proteins could serve as an early warning, they turned to UK Biobank, a comprehensive biomedical dataset which collected blood samples from half a million UK volunteers between 2006-2010 and has tracked their health since. Among them, 124 went on to develop MS, allowing the researchers to look back at samples taken on average six years before diagnosis, and in some cases more than a decade earlier.

In those samples, the scientists found that eight proteins were already altered in people who would later be diagnosed with MS. One of them, DKKL1, was linked to both a lower risk of developing MS and a milder course of disease in those who did, making it a candidate marker for both risk and prognosis. The logic resembles cholesterol screening for heart disease, where blood levels can flag risk years before a heart attack and give doctors time to intervene.

In MS, we now know that intervening early can delay or even prevent symptoms altogether. What we lack is a way to identify the right people in time. These blood markers point toward a way to do that, and to act before damage is done."

Dr. Adil Harroud, neurologist and researcher, The Neuro (Montreal Neurological Institute-Hospital) of McGill University

The team plans to validate the findings in larger cohorts and to test whether these markers, combined with other tools, can be developed into screening tests.

The study was published in the journal Annals of Neurology on May 22, 2026. It was supported with funds from Fonds de Recherche du Québec Santé, the Bougie Family Young Investigator

Award, the Brain Canada Foundation, and the Canada Brain Research Fund. The UK Biobank application number for this project is 45551.