Elucidate demographic and clinical boundaries of anti-MOG syndrome as well as its pathological alterations.

Myelin oligodendrocyte glycoprotein (MOG) is a specific antigen on the outer surface of myelin sheaths. During recent years, MOG antibodies have been

described in acute disseminated encephalomyelitis (ADEM), optic neuritis (ON), aquaporin-4 (AQP4) antibodies negative neuromyelitis optica spectrum disease (NMOSD) and even autoimmune encephalitis. 

Case reports

(1) Retrospective serum and CSF analyses confirmed MOG antibodies in a 64-

year-old female patient with 17 clinical episodes (12 times optic neuritis, brainstem involvement twice, myelitis three times) during 16 years, who were compatible with AQP4 antibodies negative NMOSD.

(2) An 83-year-old male patient developed bilateral blurred visions, paresis of lower extremities and bladder dysfunction within a week. MRI showed multiple optic nerve, brain and short spinal cord lesions. He fulfilled diagnostic criteria of AQP4 antibodies negative NMOSD and responded very well to steroids and intravenous immunoglobulin. Retrospective serum analysis confirmed MOG antibodies.  

(3) A 56-year-old male patient present for left ON within a week. He had bilateral ON twelve years ago and responded well to steroids. He was serum MOG antibodies positive this time and recovered after using steroid,  

(4)A 39-year-old female present for a left parietal lesion with mass effect. Concerning neoplastic process, a biopsy was undertaken. Histopathology showed remarkable perivenous inflammatory demyelination. There were activated macrophages, preserved axons, prominent IgG depositions in both relatively normal white matter and demyelination region. There were also robust reactive astrocytes in the perivenous demyelination region. Very few plasma cells infiltrated the brain which compatible with MOG antibodies extrathecal synthesis.

Anti-MOG syndromes can present with dozens of relapses, long recurrence interval and in elderly patients. It may have short segmental spinal cord lesions or brain tumefactive lesions. Its pathological alterations are distinct from AQP4 antibodies positive NMOSD.