RESUMO
Autoimmune cerebellar ataxia (ACA) is a cerebellar syndrome mediated by autoimmune mechanisms, and ACA with positive anti-Homer3 antibody is very rare. This article reports a 55-year-old male patient admitted to Qilu Hospital, Shandong University, due to dizziness and walking instability for 22 days. The serum and cerebrospinal fluid showed positive results for anti-Homer3 antibody, and the symptoms improved after intravenous immunoglobulin combined with hormone therapy. Based on the review of the case data and relevant literature reports, the pathogenesis, clinical manifestations, auxiliary examination, treatment and prognosis of ACA with positive anti-Homer3 antibody are analyzed, so as to deepen the understanding of clinicians and improve the diagnosis and treatment level.