RARE Daily

Researchers Discover New Biomarker for Rare Autoimmune Disease

August 30, 2019

Rare Daily Staff

Researchers at the University of Alberta say they have identified a unique biomarker that can be used to identify the presence of the rare autoimmune disease myasthenia gravis, predict the course of the disease, and identify new, personalized treatments.

Myasthenia gravis affects approximately one in 5,000 people, most often women under age 40 or men over 60. Typically, the disease affects the voluntary muscles in the face, head and neck, and may affect torso and limb muscles as well. Patients can experience eyelid drooping and double vision, difficulty speaking and chewing, and weakness in the limbs. In severe cases, the disease can affect breathing and swallowing muscles, which can be fatal.

In a study published in the journal Metabolomics, the researchers used metabolic analysis of serum to find a unique pattern of metabolites specific to myasthenia gravis. After identifying more than 10,000 compounds in the serum samples, they found a unique pattern of 12 metabolites exclusive to patients with myasthenia gravis.

“This is really important because now we have a way to easily separate a patient with myasthenia gravis from someone with rheumatoid arthritis or another autoimmune disease,” said Zaeem Siddiqi, a member of the University of Alberta’s Women’s and Children’s Health Research Institute and the Neuroscience and Mental Health Institute. “What’s more, now we’re able to explore how those 12 metabolites change in mild, moderate or severe cases so we can make this biomarker more robust and more effective for predicting the course of the disease and developing treatment plans.”

Current methods for diagnosing myasthenia gravis only tell physicians whether a patient has the disease. There are no other biomarkers that can reliably predict the course of myasthenia gravis in a patient, or the best therapeutic response. Although there is no known cure, there are treatments for the disease that can manage the symptoms throughout the rest of the patient’s life.

“Right now, we don’t have the ability to manage myasthenia gravis in a more specific way,” said Siddiqi. “We treat all patients the same.”

Siddiqi is hoping to soon expand the team’s research by examining patients at different stages of the disease to get a more precise picture of how each stage affects the metabolites and make their biomarker more robust.

“Finding the antibodies is good for diagnosis, but they do not tell us how the patient will react to a specific drug or which drug will be most effective,” Siddiqi said. “What we’re trying to do with this biomarker discovery is develop treatments specific to the needs of the patient, to have more precise management and to be able to more accurately predict the effects of the treatments.”

Photo: Neurologist Zaeem Siddiqi and graduate student Derrick Blackmore

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