Anti-NMDA receptor encephalitis is an autoimmune disorder characterized by autoantibodies targeting GluN1. Tumors, primarily ovarian teratomas in women and testicular teratomas or lung carcinomas in men, are associated. Dysregulation of NMDARs leads to a range of neurological and psychiatric symptoms.

Approximately sixty percent of individuals have tumors that contain nerve tissue. Majority of women have ovarian teratoma, while men have tumors like (testicular teratoma and small-cell lung carcinoma).

Anti-NMDA receptor encephalitis is predominantly caused by autoantibodies directed against the GluN1 component of the receptor.

In the acute phase of brain diseases, B cells, plasma cells, CD4 T cells, and, less frequently, CD8 T cells have been detected.

Crossing the blood-brain barrier enables systemically produced antibodies to crosslink NMDA receptors. This leads to their internalization and a severe disruption of synaptic plasticity and NMDA receptor network function.

• A model for the condition proposes that a decrease in NMDARs in inhibitory GABA neurons and glutamate synapses results in numerous effects, including dysregulation of glutamate release, elevated glutamate levels and excitatory circuits.

• The clinical syndrome disinhibits the frontostriatal network, resulting in psychotic, catatonic, stiffness, dystonia, and mutistic symptoms.
• The brainstem central-pattern generator is disinhibited, resulting in complicated movement problems, and the brainstem respiratory network is also disinhibited, leading to respiratory dysfunction.

NMDAR Dysregulation Proposed Symptoms Agonist effect on NMDARs Seizures Synaptic NMDAR hypofunction Amnesia, psychosis, hypoventilation Extrasynaptic NMDAR hyperfunction Catatonia, dyskinesias, seizures Neuronal network imbalance with impaired intraneuronal activity

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