Anti-MOG associated encephalomyelitis

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Anti-MOG associated encephalomyelitis represents a group of inflammatory demyelinating disorders united by the presence of IgG antibodies to myelin oligodendrocyte glycoprotein (MOG) that overlap but are distinct from acute disseminated encephalomyelitis (ADEM), neuromyelitis optica spectrum disorder (NMOSD) and multiple sclerosis (MS).

Terminology

Research in anti-MOG related diseases is rapidly evolving with new terminology being frequently proposed, including MOG-IgG-associated Optic Neuritis, Encephalitis, and Myelitis (MONEM), MOG antibody-associated diseases, anti-MOG encephalitis and other variations on this theme .

Epidemiology

Anti-MOG encephalomyelitis is primarily encountered in children and young adults . In children with acquired demyelination syndrome, MOG-IgGs are more commonly detected than aquaporin 4 antibodies .

Additionally, children with anti-MOG associated encephalomyelitis are more likely to present with an ADEM-like clinical picture, whereas adults are more likely to present with an NMO-like syndrome .

Clinical presentation

Clinical presentation is that of other acquired demyelinating conditions and varies from individual to individual. Not all presentations are equally prevalent, however.

Additionally, it appears that in approximately half of cases there is viral prodrome .

No specific presentation distinguishes individuals with anti-MOG antibodies from those presenting with similar clinical manifestation but without the antibodies and at the time of writing (2020) no single set of diagnostic criteria are universally accepted .

Radiographic features

There are no specific imaging features of anti-MOG associated diseases and as such, these are discussed as part of the overall clinical manifestation.

Treatment and prognosis

Although treatment and prognosis remain to be fully understood, it appears that generally, individuals with anti-MOG antibodies have fewer relapses and less severe clinical course than individuals with anti-aquaporin 4 antibodies presenting with NMOSD .

Acute management with intravenous methylprednisolone, plasma exchange, intravenous immunoglobulin and cyclophosphamide have been reported and appear to be efficacious .

It remains unclear what, if any, long-term medications are required in individuals with a relapsing time course, although it seems that response to immunotherapeutic agents is different to multiple sclerosis and that some agents efficacious in the latter may actually worsen anti-MOG related diseases  .