GRIA1 and encephalitis: Identification of Anti-NMDAR Encephalitis Subtype. Antibodies to multiple synaptic targets have been identified in patients with symptoms of encephalitis, including the glutamate receptors GluA1 and GluA2, subunits of the alpha-amino-3-hydroxy-5-Methyl-4-isoxazolepropionic acid receptor (AMPAR) [14], the leucine-rich glioma-inactivated 1 protein (LGI1) [15], the B1 subunit of the -aminobutyric acid-B receptor (GABABR) [16], and the metabotropic glutamate receptor 5 [17].