A retrospective study of autoimmune cerebellar ataxia over a 20-year period in a single institution.

BACKGROUND: It is important to differentiate autoimmune cerebellar ataxia (ACA) from neurodegenerative CA, but this is sometimes difficult. We performed a retrospective study in a single institution in Japan over a 20-year period to reveal the clinical features of ACA. METHODS: Patients with CA as the primary neurological symptom were enrolled from those admitted to the Department of Neurology, Hokkaido University Hospital between April 2002 and March 2022. ACA was diagnosed retrospectively according to the following criteria: (1) CA being the predominant symptom; (2) identification of cancer within 2 years of onset; (3) improvement in cerebellar symptoms following immunotherapy; and (4) ruling out alternative causes of CA. Patients fulfilling criteria (1), (2), and (4) were classified as paraneoplastic cerebellar degeneration (PCD), while those fulfilling (1), (3), and (4) were classified as non-PCD and enrolled as patients with ACA. Neurodegenerative diseases, e.g., multiple system atrophy (MSA), were confirmed retrospectively based on generally used diagnostic criteria and enrolled. Furthermore, the ACA diagnostic criteria proposed by Dalmau and Graus were applied retrospectively to the ACA patients to examine the validity of the diagnoses. RESULTS: Among the 243 patients with CA, 13 were enrolled as ACA; five were PCD and eight were non-PCD. Eight of these cases met the proposed diagnostic criteria by Dalmau and Graus. MSA was the most prevalent disease among CA patients, with 93 cases. The incidence of cerebellar atrophy was significantly lower in ACA (3/13) than in MSA (92/92). Cerebrospinal fluid (CSF) pleocytosis was significantly more frequent in ACA than in MSA (4/13 vs. 2/55, respectively). However, there was no significant difference in the presence of oligoclonal bands, increased protein in CSF, and laterality differences in ataxia. CONCLUSION: ACA was present in ~ 5% of Japanese CA patients. The absence of cerebellar atrophy, despite the presence of CA, strongly supports ACA over MSA. While CSF pleocytosis was observed more often in ACA, the positivity rate was only ~ 30%. Since ACA is treatable, further studies are needed to identify additional clinical features and accurate diagnostic biomarkers.

Lambert-Eaton Myasthenic Syndrome Complicated by anti-GABAB Receptor Encephalitis.

A 74-year-old man experienced diplopia, generalized muscle weakness, and acute respiratory failure. He was diagnosed with Lambert-Eaton myasthenic syndrome (LEMS) and treated with immunotherapy, but no improvement was observed, and additional symptoms, including central apnea and hallucinations, appeared. Subsequent serum and cerebrospinal fluid (CSF) analyses confirmed the presence of GABAB receptor antibodies, indicating the coexistence of autoimmune encephalitis. Although there were no findings of malignancy, it is highly likely that occult small-cell lung carcinoma was present. When atypical symptoms occur in patients with LEMS, it is important to consider the possibility of concomitant autoimmune encephalitis.

Practice of Hereditary ATTR Amyloidosis in Non-endemic Areas of Japan.

Objective Hereditary ATTR (ATTRv) amyloidosis was once an incurable disease; however, in recent years, disease-modifying therapies, such as tafamidis and patisiran, have become available. We herein report the medical care situation in an ATTRv amyloidosis non-endemic area of Japan. Methods We confirmed the information in the medical records of our department and analyzed the data retrospectively. Patients Patients with ATTRv amyloidosis who were treated in our department between 2010 and 2021 were included. Results A total of 15 ATTRv amyloidosis cases (8 men and 7 women) were treated in our department during the study period; 9 patients had a family history, and the transthyretin V30M (p.V50M) gene mutation was present in 66% of cases. The average age of the onset was 57 years old, with 73% of the initial symptoms being dysesthesia and 13% being autonomic dysfunction. Ten patients were treated with tafamidis and nine with patisiran. Although it took a long time to start treatment among our experienced cases, there were some cases in which treatment could be introduced relatively early. Conclusion ATTRv amyloidosis is treatable and should be included in the differential diagnosis of neuropathy so that it can be diagnosed early and introduced into treatment. In the near future, the presymptomatic diagnosis of ATTRv amyloidosis and genetic counseling will become more important.

Clinical features of anti-mitochondrial M2 antibody-positive myositis: case series of 17 patients.

OBJECTIVE: In 2012, a large number of myositis cases with anti-mitochondrial M2 (AMA-M2) antibody, which had well been known as the serological hallmark for primary biliary cholangitis (PBC), were reported in Japan. Recently, some case series from Japan, France, America, China and India have shown that approximately 2.5% to 19.5% of patients with myositis have AMA-M2 antibody. The objective of this study was to clarify the prevalence, clinical features, treatment outcome, and severity determinants of AMA-M2 positive myositis. METHODS: This study was a multicenter observational study. We enrolled patients who were diagnosed with myositis during a ten-year period between 2012 and 2021. RESULTS: Of the total of 185 patients with inflammatory myopathy, 17 patients were positive for AMA-M2 antibody. The typical symptoms were weakness mainly involving paravertebral muscles, weight loss, respiratory failure, and cardiac complications. Thirteen of the 17 patients had cardiac complications. A strong correlation was found between respiratory failure and modified Rankin Scale (mRS) score. A strong correlation was also found between respiratory failure and body weight, indicating that weight loss can be an indicator of potential progression of respiratory failure. Six of the 17 patients were complicated by malignancy. CONCLUSIONS: This study showed significant correlations between % vital capacity (VC), body mass index (BMI), and mRS score in patients with AMA-M2-positive myositis. Immunotherapy often improved CK level and respiratory dysfunction. We therefore propose that %VC and BMI should be monitored as disease indicators in treatment of AMA-M2-positive myositis.

Very-Late-Onset Neuromyelitis Optica Spectrum Disorder in a Patient with Breast Cancer and Parkinson Disease.

Anti-aquaporin-4 (anti-AQP-4) antibody-positive neuromyelitis optica spectrum disorder (NMOSD) is a rare autoimmune disorder resulting in severe, recurrent optic neuritis, transverse myelitis, brain stem syndrome, and other types of neurological involvement. Its median age of onset has been reported to be around 40 years. We report herein a case of very-late-onset NMOSD (76 years of age) and try to promote its awareness as a type of neurological deterioration in elder patients. A 76-year-old woman suffering from Parkinson disease was admitted to our hospital because of consciousness disturbance. Cranial magnetic resonance imaging revealed the presence of fluid-attenuated inversion recovery high-signal-intensity lesions in the right peri- and intralateral ventricle. Part of this lesion and the meninges showed gadolinium enhancement. Physical examination revealed the presence of a tumor in the right breast, which was later diagnosed as invasive ductal carcinoma. In addition, laboratory examinations led to the detection of anti-AQP-4 antibodies in her serum; consequently, the patient was diagnosed as having NMOSD. She received initial pulsed steroid therapy, followed by right mastectomy. Although the patient's consciousness improved significantly, she developed abrupt-onset bilateral leg weakness and multiple longitudinal spinal cord lesions. Additional steroid therapy ameliorated the patient's leg weakness and reduced the swelling of the spinal cord.

Incidence of anti-NMDAR encephalitis in patients undergoing resection of ovarian teratoma in a single institution.

OBJECTIVE: The objective of this study was to determine the incidence of anti-NMDAR encephalitis in patients in whom a teratoma was removed. As far as we know, there has been no report on the incidence of anti-NMDAR encephalitis in patients in whom a teratoma was removed. METHODS: This study was a single-institutional observational study. We enrolled patients who were diagnosed with teratoma in the Department of Pathology, Sapporo City General Hospital during a nine-year period between January 2008 and December 2016. RESULTS: In Sapporo City General Hospital, 6 NMDAR encephalitis cases were detected during the 9-year period. In the same 9-year period, a pathological diagnosis of teratoma was made in 343 cases in the hospital. Anti-NMDAR encephalitis patients with a teratoma accounted for only 1.17% of all teratoma patients. Three of the 4 anti-NMDAR encephalitis patients with a teratoma underwent second removal of a teratoma, and no nervous tissue was detected pathologically. CONCLUSIONS: In this study, we determined the association between teratoma with anti-NMDAR encephalitis and teratoma without anti-NMDAR encephalitis in cases in a single institution. As far as we know, this report is the first report on the incidence of anti-NMDAR encephalitis in teratoma patients.

Non-motor Comorbidity of Myasthenia Gravis: Myasthenia Gravis as a Systemic Immunological Disorder Involving Non-motor Systems.

To explore non-motor comorbidities of myasthenia gravis (MG), we present two cases of thymoma-associated MG patients. Alopecia, pure red cell aplasia, and thymoma- associated multiorgan autoimmunity were observed in Case 1, and alopecia, thrombocytopenia, hypogammaglobulinemia and nephrotic syndrome were observed in Case 2. In both cases, autoreactive T lymphocytes inappropriately stimulated by thymus tissue may have played key roles in generating the various autoimmune-associated symptoms. Consequently, systemic immunological involvement due to the thymoma-associated breakdown of immunoregulations in both motor and non-motor systems should be considered in MG patients.

Mutations in COA7 cause spinocerebellar ataxia with axonal neuropathy.

Several genes related to mitochondrial functions have been identified as causative genes of neuropathy or ataxia. Cytochrome c oxidase assembly factor 7 (COA7) may have a role in assembling mitochondrial respiratory chain complexes that function in oxidative phosphorylation. Here we identified four unrelated patients with recessive mutations in COA7 among a Japanese case series of 1396 patients with Charcot-Marie-Tooth disease (CMT) or other inherited peripheral neuropathies, including complex forms of CMT. We also found that all four patients had characteristic neurological features of peripheral neuropathy and ataxia with cerebellar atrophy, and some patients showed leukoencephalopathy or spinal cord atrophy on MRI scans. Validated mutations were located at highly conserved residues among different species and segregated with the disease in each family. Nerve conduction studies showed axonal sensorimotor neuropathy. Sural nerve biopsies showed chronic axonal degeneration with a marked loss of large and medium myelinated fibres. An immunohistochemical assay with an anti-COA7 antibody in the sural nerve from the control patient showed the positive expression of COA7 in the cytoplasm of Schwann cells. We also observed mildly elevated serum creatine kinase levels in all patients and the presence of a few ragged-red fibres and some cytochrome c oxidase-negative fibres in a muscle biopsy obtained from one patient, which was suggestive of subclinical mitochondrial myopathy. Mitochondrial respiratory chain enzyme assay in skin fibroblasts from the three patients showed a definitive decrease in complex I or complex IV. Immunocytochemical analysis of subcellular localization in HeLa cells indicated that mutant COA7 proteins as well as wild-type COA7 were localized in mitochondria, which suggests that mutant COA7 does not affect the mitochondrial recruitment and may affect the stability or localization of COA7 interaction partners in the mitochondria. In addition, Drosophila COA7 (dCOA7) knockdown models showed rough eye phenotype, reduced lifespan, impaired locomotive ability and shortened synaptic branches of motor neurons. Our results suggest that loss-of-function COA7 mutation is responsible for the phenotype of the presented patients, and this new entity of disease would be referred to as spinocerebellar ataxia with axonal neuropathy type 3.

TRIM67 protein negatively regulates Ras activity through degradation of 80K-H and induces neuritogenesis.

Tripartite motif (TRIM)-containing proteins, which are defined by the presence of a common domain structure composed of a RING finger, one or two B-box motifs and a coiled-coil motif, are involved in many biological processes including innate immunity, viral infection, carcinogenesis, and development. Here we show that TRIM67, which has a TRIM motif, an FN3 domain and a SPRY domain, is highly expressed in the cerebellum and that TRIM67 interacts with PRG-1 and 80K-H, which is involved in the Ras-mediated signaling pathway. Ectopic expression of TRIM67 results in degradation of endogenous 80K-H and attenuation of cell proliferation and enhances neuritogenesis in the neuroblastoma cell line N1E-115. Furthermore, morphological and biological changes caused by knockdown of 80K-H are similar to those observed by overexpression of TRIM67. These findings suggest that TRIM67 regulates Ras signaling via degradation of 80K-H, leading to neural differentiation including neuritogenesis.

Pathological study of subacute autoimmune encephalopathy with anti-AQP4 antibodies in a pregnant woman.

A pregnant woman with extensive brain lesions on magnetic resonance imaging was tested positive for anti-aquaporin4 (AQP4) antibodies. An open biopsy of the left temporal lobe showed pathological changes in both the white and gray matter. Hematoxylin and eosin, Klüver-Barrera, and myelin basic protein staining results were indicative of demyelination in the white matter. Loss of AQP4 and glial fibrillary acidic protein was observed in the white matter, and this finding is consistent with the neuropathological findings of neuromyelitis optica spinal lesions. Moreover, loss of AQP4 was observed in the gray matter. The presence of anti-AQP4 antibodies, and the pathology, led to the diagnosis of anti-AQP4 antibodies-related encephalopathy.

Genetic analysis of two Japanese families with progressive external ophthalmoplegia and parkinsonism.

Mutations in the progressive external ophthalmoplegia 1 (PEO1), adenine nucleotide translocator 1 (ANT1) and DNA polymerase gamma (POLG) genes were reported in patients with progressive external ophthalmoplegia and parkinsonism. However, the genotype-phenotype correlation and pathophysiology of these syndromes are still unknown. In order to define the molecular basis of progressive external ophthalmoplegia and parkinsonism, we screened for mutations in PEO1, ANT1, POLG genes and the whole mitochondrial genome in two families. In results, we identified a compound heterozygous POLG substitutions, c.830A>T (p.H277L) and c.2827C>T (p.R943C) in one of the families. These two mutations in the coding region of POLG alter conserved amino acids in the exonuclease and polymerase domains, respectively, of the POLG protein. Neither of these substitutions was found in the 100 chromosomes of ethnically matched control subjects. In the other family, no mutations were detected in any of the three genes and the whole mitochondrial genome in the blood sample, although mitochondrial DNA deletions were observed in the muscle biopsy sample. Progressive external ophthalmoplegia and parkinsonism are genetically heterogenous disorders, and part of this syndrome may be caused by mutations in other, unknown genes.

MRI and pathological findings of rheumatoid meningitis.

Rheumatoid meningitis (RM) is one of the most severe complications of rheumatoid arthritis. The mortality rate of RM is relatively high and diagnosis can be difficult. We present an 80-year-old woman who was diagnosed with microscopic findings of RM after analysis of biopsy specimens taken from a brain lesion. MRI scanning revealed meningeal enhancement in the brain, and the pathological findings were those of meningeal lymphocytic infiltration, vasculitis and rheumatoid nodules. RM is a treatable disease and in this patient RM was diagnosed on the basis of biopsy findings.

Clinical characterization and successful treatment of 6 patients with Churg-Strauss syndrome-associated neuropathy.

OBJECTIVE: To confirm the reported findings and clarify unknown clinical features of Churg-Strauss syndrome (CSS)-associated neuropathy and design appropriate treatment. PATIENTS AND METHODS: We assessed the clinical features of 6 patients with CSS-associated neuropathy. RESULTS: Mononeuritis multiplex was present in 4 cases and polyneuropathy in the remaining cases. Both groups progressed to sensori-motor polyneuropathy in an acute or subacute course. All cases showed bronchial asthma and eosinophilia. Two cases with serum antineutrophil cytoplasmic antibodies to myeloperoxidase (MPO-ANCA) had an acute clinical course and severe symptoms. Nerve conduction studies (NCS) of these 2 cases revealed conduction blocks at the initial stage, although NCS finally indicated sensori-motor axonopathy at the involved extremities. For treatment, high-dose corticosteroid therapy for 4 cases, and cyclophosphamide combined with corticosteroids for 1 case, were effective. For the remaining case, intravenous immunoglobulin (IVIg) at the chronic phase resulted in a slow improvement of neuropathy in the symptomatic aspect. There was no relapse of neuropathy with low-dose corticosteroid treatment for 14-24 months after the initial treatment, except 1 case. There was also no relapse in the other case that was treated with moderate-dose steroids. CONCLUSION: Our study showed that CSS-associated neuropathy is a treatable disorder and that the first choice therapy is high-dose corticosteroid. In cases where corticosteroids are ineffective or for severe cases, immunosuppressive therapy (cyclophosphamide) with steroids should be considered, and IVIg might be a treatment option.

An autopsy case of Sjögren's syndrome with acute encephalomyelopathy.

OBJECTIVE: This study was to clarify the neuropathological findings of acute encephalomyelopathy with Sjögren's syndrome. METHODS: We examined an autopsied case of acute encephalomyelopathy with Sjögren's syndrome. CASE REPORT: A 40-year-old woman developed acute myelopathy and brainstem dysfunction. Magnetic resonance imaging (MRI) revealed high-intensity lesions on T2-weighted axial images (T2WI) in the medulla oblongata and cervical spinal cord. We established a diagnosis of Sjögren's syndrome (SjS) according to the European Community criteria. The patient was treated with intravenous methylprednisolone (500 mg/day) for three days, followed by oral prednisolone. Although her neurological symptoms improved, her general condition deteriorated after the onset of acute colonic pseudo-obstruction and she died of multiple organ failure associated with hemophagocytosis. RESULTS: Autopsy showed atrophy of the secretory glands and an accumulation of lymphocytes around the ducts, confirming the diagnosis of Sjögren's syndrome. Neuropathological examination revealed multifocal lesions in the cervical spinal cord and medulla, along with scattered perivascular lymphocytic infiltration. In addition, there was demyelination, spongy change and axonal swelling in the white matter, but no remarkable vasculitic changes were seen in the central nervous system. CONCLUSION: Although the steroid therapy may have had a significant influence, the main pathological finding in this case was not vasculitis, but rather axonal degeneration with spongy change and axonal swelling.

Transient subacute cerebellar ataxia in a patient with Lambert-Eaton myasthenic syndrome after intracranial aneurysm surgery.

Several reports have presented patients with subacute cerebellar ataxia (CA) and Lambert-Eaton myasthenic syndrome (LEMS). Some clinical features of those patients have been described in the previous reports, manifestation of subacute CA prior to LEMS or a co-existence of both diseases, a high incidence of malignancy, and less efficacy of the treatment for subacute CA compared with that for LEMS. Cerebellar ataxia in some patients with LEMS has been suggested to be caused by antibodies to P/Q-type voltage-gated calcium channels (VGCCs). We report herein a patient with subacute CA and LEMS. Cerebellar ataxia appeared 15 months after the occurrence of LEMS, and the onset of CA was thought to be due to serum anti-P/Q-type VGCC antibodies. The clinical course of this patient was atypical, as follows: (1) LEMS preceded subacute CA, which developed after intracranial aneurysm surgery, (2) no malignancy was detected when both diseases co-existed, (3) symptoms of LEMS did not progress with the onset of CA, and (4) there was a definite improvement in symptoms of CA and (123)I-IMP SPECT imaging findings after steroid administration. In addition, it is remarkable that LEMS became aggravated in electrophysiologic examinations, in contrast to subacute CA. We suggest that these atypical features of subacute CA and the changes in LEMS may be associated with a balance between the amount of serum anti-P/Q-type VGCC antibodies and the susceptibility of the cerebellum and presynaptic nerve terminals to the antibodies. More cases are needed to investigate the mechanisms involved. The subacute CA and LEMS in this patient have remained comparatively silent after the withdrawal of steroids, and we are continuing to observe her condition.