Use

Detecting septin-5 IgG by cell-binding assay using serum specimens. Septin-5 IgG is a biomarker of a rapidly progressive, but treatable, form of autoimmune cerebellar ataxia. Patients present with subacute onset of cerebellar ataxia with prominent eye movement symptoms (oscillopsia or vertigo). Improvement may occur after immunotherapy. Seropositivity for septin antibodies by indirect immunofluorescence is consistent with a diagnosis of autoimmune disease of the central nervous system. Cell-binding assay (CBA) testing for septin-5 IgG is required to confirm the diagnosis.