Since the association between HLA‐DRB1*15:01 and MS risk violated the PH assumption (p < 0.05), we estimated separate HRs for ages ≤ 30 and > 30 (this threshold was chosen based on the Schoenfeld residuals plot shown in Figure S1, where HR decreases as age progresses and stabilizes around the age of 30). The gene discussed is HLA-DRB1; the disease is myeloid sarcoma.