Progressive myelopathy in myelin oligodendrocyte glycoprotein antibody-associated disease: A new mimicker of progressive multiple sclerosis?

Background MOG-IgG-associated disease (MOGAD) in adults typically presents as a monophasic or relapsing optic, spinal, or opticospinal neuroinflammatory syndrome. Current recommendations discourage testing for MOG-IgG in patients with clinical or paraclinical findings more typical of MS, or in patients with a progressive clinical course. However, this approach may impede identification of the full phenotypic spectrum of this recently described disorder. Methods We retrospectively reviewed charts of 39 MOG-IgG-seropositive patients from two Ohio-based neuroimmunology centers to identify unusual disease patterns. Those with a progressive course were included in this case series. Results We describe five cases of progressive myelopathy associated with MOG-IgG. Most patients had features suggestive of MS, including typical MRI and cerebrospinal fluid findings. However, MOG-IgG positive patients with progressive myelopathy showed poor response to MS disease modifying therapy and better response to intravenous immunoglobulins similar to previous reports on MOGAD patients. Conclusion MOG-IgG-seropositive patients may present with progressive myelopathy and may have a clinical and radiologic phenotype suggestive of primary progressive or secondary progressive MS, or progressive solitary sclerosis. MOG-IgG testing should be considered in patients with progressive myelopathy, especially if clinically worsening on MS therapy.