Inflammatory demyelinating diseases of the central nervous system are a group of diseases associated with immune-mediated specific or primary origin in the brain and/or spinal cord and characterized by myelin damage or loss, including optic neuromyelitis optica spectrum diseases and multiple sclerosis. 1, MOG is a glycoprotein on the membrane surface of oligodendrocytes in the central nervous system, and its function is not yet fully understood. 2, MOG antibodies and acute disseminated encephalomyelitis Acute disseminated encephalomyelitis (ADEM) can be seen at any age, but is more common in children.ADEM is an acute or subacute onset first occurrence of demyelinating disease with encephalopathic manifestations (abnormal behavior or impaired consciousness), affecting multiple regions of the central nervous system. Acute disseminated encephalomyelitis is mostly monophasic in course. Children with ADEM who are positive for MOG antibodies are usually younger than 5 years old and have more typical clinical features, often with an explosive disease process that manifests as significant encephalopathy, multifocal symptoms, typical MRI and other clinical features. 3. MOG antibodies and optic neuromyelitis optica spectrum disease In 2007, WingerchukDM et al. introduced the concept of optic neuromyelitis optica spectrum disease (NMOSD), but in about 10-40% of NMOSD patients, AQP4-IgG could not be detected even with the most sensitive assay available. in some cases of NMOSD with negative AQP4 antibodies In some NMOSD cases with negative AQP4 antibodies, positive MOG antibodies can be detected in the serum. MOG-positive NMOSD patients are usually younger than AQP4-positive patients, and are more common in males, with a monophasic course, often invading the optic nerve but often recovering well on both sides, and spinal cord lesions often appearing in the thoracolumbar segment. 4. MOG antibodies have age-dependent characteristics The autoimmune response to MOG is age-dependent. The positivity rate of MOG antibodies in children with ADS is 35%, and the rate is higher in children of younger age. In ADS cases with positive MOG antibodies, the younger the child is, the more clinical presentation tends to be AEDM, while adults tend to present with NMOSD-like clinical presentation. 5. Prognostic impact of MOG antibodies Persistent high titers of MOG antibodies suggest a poor prognosis and possible distant relapses. With increasing age, the clinical presentation of MOG antibody-positive children will increasingly resemble that of adults. 6. Summary In the diagnosis and differential diagnosis of the various subtypes of inflammatory demyelinating diseases of the central nervous system, it is still necessary to combine clinical, imaging and other laboratory tests, but a preliminary judgment on the prognosis of the disease can be made. It has also been suggested that MOG antibody-positive cases share similarities and can be diagnosed and treated as a new class of diseases, so the concept of MOG antibody-associated demyelinating diseases has been proposed. MOG antibodies are age-related, more common in children and prone to optic nerve damage, and should be tested for in all pediatric demyelinating diseases, while in adults, in patients with clinical and imaging manifestations of atypical MS, especially with isolated or recurrent optic neuritis, MOG antibodies should be tested.