2.4. Association of Investigated Gene Variants with Circulatory Molecular Indicators of Processes Associated with Ferroptosis: Lipid Peroxidation (MDA, 4-HNE and HEL), GSH-Related Antioxidant Defense (GSH, GSSG and GPX4) and Iron Metabolism (Free Iron, Transferrin and Ferritin), in MS Patients. This evidence concerns the gene GPX4 and myeloid sarcoma.