In this observational cohort study, patients with anti-leucine-rich glioma-inactivated 1 (LGI1), anti-N-Methyl-D-aspartic acid receptor (NMDA-R), anti-gamma-aminobutyric acid B receptor (GABA-B-R) or anti-contactin-associated protein-like 2 (CASPR-2) encephalitis were included. The gene discussed is CNTNAP2; the disease is viral encephalitis.