GFAP and myeloid sarcoma: To distinguish MS subtypes and disability severity levels, models using DMRs achieved area-under-the-curve (AUC) values ranging from 0.67 to 0.81 and models using inferred tissue-of-origin patterns from cfDNA methylation achieved AUC 0.70 to 0.82, outperforming historical benchmark neurofilament light chain (NfL) and glial fibrillary acidic protein (GFAP) in the same cohort.