IRX1 and multiple sclerosis: In contrast, IRX1-positive (n = 30) patients had preserved 30-year grey matter fraction [+0.76% (0.28–1.29), P = 8.4 × 10−3], lower risk of cortical lesions [OR = 0.22 (0.05–0.99), P = 0.049] and lower 30-year EDSS [−1.35 (−0.87,−3.44), P = 0.026; multiple sclerosis cases: −2.12 (−0.87, −3.44), P = 5.02 × 10−3] than IRX1-negative patients (n = 30).