A study of more than 22,000 people with multiple sclerosis (MS) has discovered the first genetic variant associated with faster disease progression, which can rob patients of their mobility and independence over time. The work resulted from a large international collaboration of more than 70 institutions worldwide, led by researchers from UCSF (USA) and the University of Cambridge (UK). About 3 million people live with multiple sclerosis or MS, but the real number may be higher. Women are more likely to develop MS than men. When diagnosed, the immune system attacks the central nervous system, causing symptoms that range from numbness to disability. Although scientists know MS is associated with genetic risks, MS is not an inherited disease, and doctors have struggled to understand why some cases progress faster than others. This latest study combed through 13,000 patients’ DNA and found a gene that is linked to the onset of severe disability. Sergio Baranzini is a Neurology Professor at the University of California San Francisco. He is the study’s lead author, and he joins us live from San Francisco to discuss the latest updates.