The diagnosis of myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) in children

Over the last two decades, immunoglobulin G (IgG) antibodies against myelin oligodendrocyte glycoprotein (MOG), previously thought to be a biomarker of multiple sclerosis (MS), have been shown to cause a distinct disease called MOG antibody-associated disease (MOGAD). MOGAD accounts for approximately one-third of all demyelinating syndromes in children and is the second most common central nervous system (CNS) demyelinating disease after MS. The diagnosis is made by detecting anti-MOG IgG antibodies against the natural MOG antigen, in the presence of compatible clinical and neuroradiological features. However, due to controversies in the methodologies for detecting anti-MOG antibodies and their diagnostic cutoff values, as well as the expanding clinical spectrum, accurate diagnosis may be challenging, at least in a subset of patients. Clinical presentations of MOGAD vary by age; the highest rates are seen in acute disseminated encephalomyelitis in younger children and optic neuritis, myelitis, or brainstem symptoms in older children. Although it was previously thought to be a milder demyelinating disorder and to have a monophasic course in the majority of patients, recent studies have shown that relapses occur in about half of the patients and sequelae develop in a significant proportion of them, especially in those with persistently high antibody titers, leukodystrophy-like magnetic resonance imaging (MRI) lesions, and spinal cord involvement. However, due to the monophasic course in about half of the patients, long-term treatment is not recommended after the first clinical episode but is recommended for patients who experience relapse. Accurate and early diagnosis of MOGAD is essential for proper management and better outcome. This review covers the challenges in the diagnosis of MOGAD in children.