DPP6 and autoimmune encephalitis: Earlier reports on autonomic central nervous system receptor autoantibodies including N-methyl-d-aspartate-receptor subunit NR1 (NMDAR1), α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR), GABAB receptor (GABABR) and dipeptidyl aminopeptidase-like protein 6 (DPPX), were described in autoimmune encephalitis [33,34].