Ocular flutter as the presenting manifestation of autoimmune glial fibrillary acidic protein astrocytopathy.

A 39-year-old man exhibited ocular flutter and cerebellar ataxia following a subacute disturbance of consciousness and partial seizure. He was diagnosed with autoimmune glial fibrillary acidic protein (GFAP) astrocytopathy by tissue- and cell-based antibody assays. Brain single-photon emission computed tomography detected a significant increase in blood flow in the fastigial nucleus, a critical region for eye saccade control. Immunotherapies diminished the ocular flutter and reduced hyperperfusion in the fastigial nucleus. This case suggests that autoimmune GFAP astrocytopathy can cause ocular flutter and provides strong imaging evidence supporting the hypothesis that ocular flutter is caused by hyperactivity or disinhibition of the fastigial nucleus.