Herein, we prospectively describe the clinical course of a female patient with anti-septin-5 encephalitis.<h4>Methods</h4>We describe diagnostic workup, treatment and follow-up of a 54-year-old patient presenting with vertigo, unsteady gait, lack of drive and behavioral changes.<h4>Results</h4>Clinical examination revealed severe cerebellar ataxia, saccadic smooth pursuit, upbeat-nystagmus, and dysarthria. Here, SEPTIN5 is linked to encephalitis.