Abstract: Objective　To explore the clinical features of anti-Caspr2 antibody-associated encephalitis. Method　The clinical data of anti-Caspr2 antibody-associated encephalitis in a child were retrospectively reviewed. Results　A 5-year-old girl manifested as recent memory loss, irritability, cognitive impairment, hallucination, sleep disorders, and so on. The child had positive serum Caspr2 antibody, and was diagnosed with Caspr2 antibody encephalitis after exclusion of other diseases. The literature search retrieved 50 cases of Caspr2 antibody encephalitis with complete data, including 43 male cases and 7 female cases. The minimum onset age of the disease was 5 years in this case. In addition, 1 patient developed the disease at the age of 8, while the rest developed in adulthood. There were 32 cases (62.75%) of marginal encephalitis and 19 cases (37.25%) of morvan’s syndrome. The most common clinical symptoms were impaired memory, epileptic seizures, and psychiatric symptoms such as anxiety, apathy, irritability, hallucinations or delusions, peripheral nerve hyperexcitability (PNH), cerebellar ataxia and autonomic nervous disorders. Forty-four cases (86.27%) recovered or improved, 8 cases (15.69%) were complicated with tumors and 8 cases (15.69%) relapsed. Conclusion　Caspr2 antibody encephalitis is relatively rare, especially in children. If the patient has marginal encephalitis symptoms, combining with PNH, ataxia and autonomic nerve symptoms, the possibility of Caspr2 antibody encephalitis should be considered.

Key words: autoantibody;　encephalitis;　anti-contact related protein 2;　Morvan’s syndrome