A 51-year-old Japanese man presented with slowly progressing cerebellar ataxia from age 49. Anti-thyroglobulin, anti-thyroid peroxidase, and anti-NAE antibodies were detected. Brain magnetic resonance imaging showed moderate atrophy of the pons, cerebellum, and middle cerebellar peduncle. Dopamine transporter single-photon emission computed tomography showed normal uptake. With the diagnosis of Hashimoto’s encephalopathy, repeated steroid pulse therapy and intravenous immunoglobulin therapy were administered; however, they were ineffective for cerebellar ataxia. Afterwards, autonomic failure and parkinsonism became evident. The final diagnosis was MSA of the cerebellar type. Immunotherapies for patients with MSA with anti-NAE antibodies should be carefully considered.

Multiple system atrophy (MSA) is a sporadic, progressive, adult-onset neurodegenerative disease characterized by a variable combination of parkinsonism, cerebellar ataxia, and autonomic failure. MSA can be classified into two main subtypes, the parkinsonian (MSA-P) and the cerebellar (MSA-C) types. MSA-C is characterized by cerebellar ataxia dominance rather than parkinsonism, and often presents with progressive pure cerebellar ataxia in the early stage [1].

In patients with pure cerebellar ataxia, Hashimoto’s encephalopathy (HE) is one of the differential diagnoses known to be accompanied by the presence of several specific antibodies (anti-thyroglobulin (Tg), anti-thyroid peroxidase (TPO), and anti-NH2-terminal of α-enolase (NAE) antibodies) [2]. HE is also known as immunotherapy-responsive encephalopathy.

Here, we report an MSA patient with anti-Tg, anti-TPO, and anti-NAE antibodies treated with immunotherapies.

A 51-year-old Japanese man visited our outpatient clinic with gradually developed gait disturbance and difficulty in skillful hand movement from the age of 49 years. He had no specific medical history or regular medication. There were no episodes of heavy drinking or a family history of neurodegenerative diseases. On examination, his Glasgow Coma Scale score was 15 (E4, V5, M6); body temperature, 36.4 °C; blood pressure, 116/69 mmHg; and heart rate, 64 beats/min. Neurological examination showed

The unique point of the present case is that several immunotherapies were not effective for an MSA patient with anti-NAE antibody.

Anti-NAE antibody has been reported as a disease-specific antibody with a moderate sensitivity (68%) and a high specificity (83%) in patients with HE [4]; however, the antibody was recently found to be present in several diseases other than HE. In particular, parkinsonian syndrome occasionally shows anti-NAE antibody, and about 25% of MSA-C patients are positive,

This report presented a case of an MSA patient with anti-NAE antibodies refractory to repeated immunotherapies. This is a case report and more case studies are needed to further understand this disease.

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