In this review, we discuss how this evolving paradigm is already changing the way we approach conditions like multiple sclerosis (MS), neuromyelitis optica spectrum disorder (NMOSD), myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD), optic neuritis (ON), autoimmune encephalitis, and immune-mediated neuropathies in the clinical practice. The gene discussed is OMG; the disease is multiple sclerosis.