LGI1 and Isaacs syndrome: Indeed, rapidly evolving limbic encephalitis has long been recognized as the key manifestation of several AE, such as those with leucine-rich glioma-inactivated 1 (LGI1)-, contactin-associated protein-like 2 (CASPR2)-, α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR)- and γ-aminobutyric acid B receptor (GABABR)-Abs, although other signs and symptoms may coexist (e.g., neuromyotonia in CASPR2-Ab AE, as highlighted in Table 1).