OBJECTIVES: To expand the spectrum of the clinical presentation of anti-glutamic acid decarboxylase antibodies-related limbic encephalitis and to improve the recognition of this entity. DESIGN: Case study. SETTING: University hospital. PATIENT: An 11-year-old-girl with progressive mood and behavioral disorder, speech impairment, and short-term memory impairment who manifested cerebellar ataxia with nystagmus during the disease course. INTERVENTIONS: Blood and cerebrospinal fluid analysis including autoantibodies, electroencephalography, brain and spinal magnetic resonance imaging, and cognitive and neuropsychological assessment were performed. High-dose methylprednisolone sodium succinate pulses, cycles of intravenous immunoglobulins, mycophenolate mofetil, and rituximab as well as antipsychotics and benzodiazepine were administered. RESULTS: Diagnosis of anti-glutamic acid decarboxylase antibodies-related limbic encephalitis was made. The clinical features during the first months of disease included only mood, behavioral, and memory impairment. After 5 months, despite immunotherapies, cerebellar ataxia with nystagmus appeared with brain magnetic resonance imaging evidence of cerebral atrophy. No clinical or infraclinical seizures were recorded during follow-up. CONCLUSIONS: Anti-glutamic acid decarboxylase antibodies-related limbic encephalitis can present with only behavioral or neuropsychological symptoms without any epileptic disorder. Moreover, cerebellar ataxia related to anti-glutamic acid decarboxylase antibodies can be observed in patients with limbic encephalitis during the disease course.