There are approximately 400,000 people in the United States with multiple sclerosis. Worldwide, the number jumps to more than 2.1 million people. Rather than a one-size-fits-all approach to treating the millions with multiple sclerosis, what if doctors could categorize patients to create more personalized treatments? A new study by researchers at Brigham and Women’s Hospital (BWH) may one day make this idea a reality in the fight against the debilitating autoimmune disease.