IFN-β: interferon-beta; DMT: disease-modifying therapy; AMP: adenosine monophosphate; RRMS: relapsing-remitting multiple sclerosis; SPMS: secondary progressive multiple sclerosis; CIS: clinically isolated syndrome; JC: John Cunningham; PML: progressive multifocal leukoencephalopathy; Nrf-2: nuclear factor (erythroid-derived 2)-like 2. This evidence concerns the gene IFNB1 and secondary progressive multiple sclerosis.