Case Report: Neurexin-3α-associated autoimmune encephalitis with co-existence of possible anti-MOG-associated...

Autoimmune encephalitis (AE) associated with neurexin-3α antibodies is a rarely reported disorder that commonly presents with severe neuropsychiatric manifestations.

We report a patient who tested positive for neurexin-3α and myelin oligodendrocyte glycoprotein (MOG) antibodies at low titers. The patient presented with seizures, mental and behavioral disturbances, and cognitive impairment. Brain MRI showed increased signal intensity in the bilateral hippocampus and leptomeningeal enhancement in the left cerebral hemisphere. Serum cell-based assay findings, confirmed by tissue-based assay, were positive for neurexin-3α antibodies. The patient was diagnosed with anti-neurexin-3α encephalitis, with possible concurrent anti-MOG-associated involvement. Clinical symptoms improved after treatment with glucocorticosteroids and intravenous immunoglobulin.

Although overlapping antibodies in AE are relatively common, the co-occurrence of neurexin-3α and MOG antibodies has not been previously reported. This case provides new insights into the diagnosis and treatment of neurexin-3α-associated AE.