Many people with MS keep getting worse over time even with today’s treatments. This project studies how a genetic variation (FUT2) may weaken the gut barrier and change the microbiome, allowing bacteria (or bacterial fragments) to leak into the body and trigger wider inflammation that can reach the brain. By testing this in genetically matched models, the team aims to identify which patients are genetically prone to gut-driven progression, opening the door to more personalized interventions that target a root cause.