Myelin oligodendrocyte glycoprotein antibody-associated disease

Synonyms

MOGAD, MOG antibody disease, MOG-Ab disease, MOG-EM,

Overview

Myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) is a rare, inflammatory autoimmune disorder of the central nervous system (CNS) where antibodies attack the myelin sheath protecting nerve fibers in the brain, spinal cord, and optic nerves. It causes distinct episodes of demyelination—often presenting as optic neuritis, transverse myelitis, or acute disseminated encephalomyelitis (ADEM)—and is clinically distinct from multiple sclerosis or AQP4-IgG+ NMOSD.

Symptoms

Key symptoms include sudden onset vision loss/pain (optic neuritis), limb weakness/numbness (transverse myelitis), and, particularly in children, confusion and encephalopathy (ADEM). Symptoms often involve the brain, spinal cord, and optic nerves. 

Causes

Myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) is an autoimmune disorder where the immune system mistakenly produces antibodies (MOG-IgG) that attack myelin in the central nervous system. The exact cause of this malfunction is unknown, but it is often triggered by prior infections, vaccinations, or molecular mimicry, where immune responses to viruses cross-react with myelin proteins. 

Diagnosis

The disease is diagnosed by detecting MOG-IgG antibodies in the serum using cell-based assays, combined with clinical symptoms like optic neuritis, myelitis, or ADEM. It is a distinct, often relapsing, autoimmune demyelinating disease of the central nervous system (CNS), separate from MS and AQP4-IgG NMOSD. 

Prognosis

MOGAD generally has a favorable long-term prognosis with good recovery from attacks, often better than multiple sclerosis or AQP4-IgG NMOSD. While some patients have a single episode, others experience relapses, with persistent MOG antibodies indicating a higher risk of recurrence. 

Treatment

Treatment focuses on rapid suppression of acute inflammation and, if necessary, long-term relapse prevention. Initial attacks are treated with high-dose intravenous corticosteroids, often followed by plasma exchange (PLEX) or intravenous immunoglobulin (IVIG) if symptoms persist. Chronic, relapsing cases may require maintenance immunosuppression, such as rituximab or mycophenolate mofetil.