Anti-Purkinje Cell Cytoplasmic Antibody Type 2 Associated Autoimmune Cerebellar Degeneration in Children -Different Phenotype from Adults

Background: The anti-Purkinje Cell Cytoplasmic autoantibody type 2 antibodies(PCA2-Abs) were associated with various neurological presentations. There were no related studies in children. This study aimed to characterize the clinical features and outcomes of pediatric PCA2-Abs-related autoimmune cerebellar degeneration.Methods: Between June 2015 and September 2022, we recruited 357 pediatric patients with acute or subacute cerebellar ataxia. PCA2-Abs were identified in four patients whose information on clinical manifestations, responses to treatment, and outcomes were collected and analyzed.Results: Two boys and two girls were included. The onset age was six to twelve years old. Axial ataxia was remarkable (4/4), followed by dysmetria (3/4), dysarthria (2/4), and nystagmus (1/4). The extra-cerebellar symptoms were found in three patients, including peripheral neuropathy and mild cognitive impairment. One patient had pelvic neuroblastoma before ataxia. The cerebrospinal fluid(CSF) oligoclonal bands(OCB) were positive and the cerebellum atrophy was remarkable in all four patients. Immunotherapy was applied, and three of them responded.Discussion: PCA2-Abs-associated autoimmune cerebellar degeneration(ACDs) were rare in children. Timely and appropriate immunotherapies were beneficial. There were fewer symptoms than that in adults.