The goal of this first component is to characterize the microbiota present in the gut of people with MS at the beginning of the illness, throughout the course of the disease, and in response to therapy.


To effectively screen for differences in  microbiota composition between subjects with MS and those without MS, we will study DNA from the gut and from the blood of at least 2,000 pairs of MS and healthy individuals from the same household. We will then confirm our findings using a second population of equal size. There has never been a similar study of this scale, and no single center has the capability to recruit and study a population of that size. Blood and stool samples will be collected from five major metropolitan areas, in the US (San Francisco, Boston, New York), Scotland (Edinburgh), and Argentina (Buenos Aires). We anticipate completing the enrollment and sample collection from 4,000 subjects within three years. Simultaneously, we will perform sequencing of the DNA extracted from these samples, analyze the data, and interpret the findings.