A more recent observational study of 162 MS patients treated with interferon beta for at least 2 years, found that compared to patients with no relapses in the first 2 years, those with 1 or ≥ 2 relapses were more likely to exhibit early sustained disability progression (Hazard Ratio for 1 relapse: 3.4, p = 0.05; Hazard Ratio for ≥2 relapses: 4.3, p < 0.001). The gene discussed is IFNB1; the disease is myeloid sarcoma.