Overlapping autoimmune syndrome: A case of concomitant anti-NMDAR encephalitis and myelin oligodendrocyte glycoprotein (MOG) antibody disease.

Anti-N-methyl-d-aspartate receptor (NMDAR) encephalitis is an autoimmune disorder of the central nervous system that commonly manifests as a complex neuropsychiatric syndrome. Antibodies against myelin oligodendrocyte glycoprotein (MOG) are associated with a range of clinical presentations including acute disseminated encephalomyelitis (ADEM), optic neuritis, and transverse myelitis. The concurrence of NMDAR encephalitis and demyelinating syndromes is rare. We describe the case of a 29-year-old male with NMDAR encephalitis and overlapping MOG antibody disease. The aim of this report is to add to the growing knowledge of phenotypic characteristics of overlap syndromes as their clinical and prognostic features may differ from those of single antibody disease.