Serum neurofilament light chain (sNfL) and glial fibrillary acidic protein (GFAP) levels were measured.<h4>Results</h4>Patients with newly diagnosed MS and T1DM exhibited cognitive and mood disturbances, elevated sNfL levels, and distinct immunological and biochemical profiles compared with HCs. The gene discussed is NEFL; the disease is myeloid sarcoma.