[Autoimmune glial fibrillary acidic protein astrocytopathy with posterior column ataxia: two case reports].

The patients were a 59-year-old man and a 53-year-old woman, both of whom had preceding fever, followed by impaired consciousness, urinary retention, and unsteadiness while standing. Neurological examination revealed truncal ataxia. Cerebrospinal fluid testing was positive for anti-glial fibrillary acidic protein (GFAP) α antibodies, leading to a diagnosis of GFAP astrocytopathy. Both patients showed improvement following steroid therapy. Somatosensory evoked potential (SEP) in the tibial nerve stimulation demonstrated prolonged N21-P38 conduction times in both cases, suggesting involvement of the posterior columns of the spinal cord. These findings indicate that posterior column dysfunction may contribute to ataxia in GFAP astrocytopathy, and that SEPs may be a useful diagnostic tool for lesion localization in this condition.