Studies have demonstrated that after viral infection in the CNS, some patients develop parainfectious AE.[8–11] AE occurs in 27% of patients.[12] In this case, the patient first showed signs of herpesvirus encephalitis, was later found to have a positive CASPR2 antibody, and was subsequently considered to have an infection due to AE. Here, CNTNAP2 is linked to viral infectious disease.