Genetics

MS genetics has matured from a short list of “risk genes” into a nuanced map that separates two big questions patients and clinicians care about: what makes MS begin, and what drives disability to build over time. Drawing on Sahi et al. (2025), this post explains how large GWAS efforts uncovered hundreds of susceptibility variants—many tied to immune activation—while newer severity-focused studies point toward partly different biology, including the first genome-wide severity locus linked to faster progression and neuroaxonal injury markers. Along the way, it unpacks why predicting prognosis is so much harder than predicting risk, and what better phenotypes, diverse cohorts, and integrated models could mean for more personalized MS care.