Functional evaluation of novel variants of B4GALNT1 in a patient with hereditary spastic paraplegia and the general population.

Hereditary spastic paraplegia (HSP) is a heterogeneous group of neurological disorders that are characterized by progressive spasticity and weakness in the lower limbs. SPG26 is a complicated form of HSP, which includes not only weakness in the lower limbs, but also cognitive impairment, developmental delay, cerebellar ataxia, dysarthria, and peripheral neuropathy, and is caused by biallelic mutations in the B4GALNT1 (beta-1,4-N-acetylgalactosaminyltransferase 1) gene. The B4GALNT1 gene encodes ganglioside GM2/GD2 synthase (GM2S), which catalyzes the transfer of N-acetylgalactosamine to lactosylceramide, GM3, and GD3 to generate GA2, GM2, and GD2, respectively. The present study attempted to characterize a novel B4GALNT1 variant (NM_001478.5:c.937G>A p.Asp313Asn) detected in a patient with progressive multi-system neurodegeneration as well as deleterious variants found in the general population in Japan. Peripheral blood T cells from our patient lacked the ability for activation-induced ganglioside expression assessed by cell surface cholera toxin binding. Structural predictions suggested that the amino acid substitution, p.Asp313Asn, impaired binding to the donor substrate UDP-GalNAc. An in vitro enzyme assay demonstrated that the variant protein did not exhibit GM2S activity, leading to the diagnosis of HSP26. This is the first case diagnosed with SPG26 in Japan. We then extracted 10 novel missense variants of B4GALNT1 from the whole-genome reference panel jMorp (8.3KJPN) of the Tohoku medical megabank organization, which were predicted to be deleterious by Polyphen-2 and SIFT programs. We performed a functional evaluation of these variants and demonstrated that many showed perturbed subcellular localization. Five of these variants exhibited no or significantly decreased GM2S activity with less than 10% activity of the wild-type protein, indicating that they are carrier variants for HSP26. These results provide the basis for molecular analyses of B4GALNT1 variants present in the Japanese population and will help improve the molecular diagnosis of patients suspected of having HSP.

Conventional magnetic resonance imaging key features for distinguishing pathologically confirmed corticobasal degeneration from its mimics: a retrospective analysis of the J-VAC study.

PURPOSE: Due to the indistinguishable clinical features of corticobasal syndrome (CBS), the antemortem differentiation between corticobasal degeneration (CBD) and its mimics remains challenging. However, the utility of conventional magnetic resonance imaging (MRI) for the diagnosis of CBD has not been sufficiently evaluated. This study aimed to investigate the diagnostic performance of conventional MRI findings in differentiating pathologically confirmed CBD from its mimics. METHODS: Semiquantitative visual rating scales were employed to assess the degree and distribution of atrophy and asymmetry on conventional T1-weighted and T2-weighted images. Additionally, subcortical white matter hyperintensity (SWMH) on fluid-attenuated inversion recovery images were visually evaluated. RESULTS: In addition to 19 patients with CBD, 16 with CBD mimics (progressive supranuclear palsy (PSP): 9, Alzheimer's disease (AD): 4, dementia with Lewy bodies (DLB): 1, frontotemporal lobar degeneration with TAR DNA-binding protein of 43 kDa(FTLD-TDP): 1, and globular glial tauopathy (GGT): 1) were investigated. Compared with the CBD group, the PSP-CBS subgroup showed severe midbrain atrophy without SWMH. The non-PSP-CBS subgroup, comprising patients with AD, DLB, FTLD-TDP, and GGT, showed severe temporal atrophy with widespread asymmetry, especially in the temporal lobes. In addition to over half of the patients with CBD, two with FTLD-TDP and GGT showed SWMH, respectively. CONCLUSION: This study elucidates the distinct structural changes between the CBD and its mimics based on visual rating scales. The evaluation of atrophic distribution and SWMH may serve as imaging biomarkers of conventional MRI for detecting background pathologies.

Anti-contactin-associated protein 1 antibody-positive nodopathy presenting with central nervous system symptoms.

Contactin-associated protein 1 (Caspr1) is widespread in both the peripheral and central nervous systems (CNS). However, anti-Caspr1 antibody-positive nodopathy associated with CNS symptoms has not previously been reported. In this case, a 69-year-old man presented with polyneuropathy and memory loss. The patient had negative myoclonus, positive myoclonus, and pseudoathetosis in the upper limbs, and we detected anti-Caspr1 antibodies in the serum and cerebrospinal fluid. Therefore, anti-Caspr1 nodopathy was diagnosed. After rituximab treatment, all symptoms of polyneuropathy, involuntary movements, and memory impairment improved. In conclusion, anti-Caspr1 antibodies might also affect the CNS; therefore, CNS symptoms of anti-Caspr1 nodopathy require attention.

[Two patients of immunotherapy-responsive autoimmune cerebellar ataxia fulfilled with criteria of multiple system atrophy].

We report two patients with autoimmune cerebellar ataxia who fulfilled the diagnostic criteria of multiple system atrophy (MSA) and responded to immunotherapies. Patient 1 was a 72-year-old man who was diagnosed with clinically probable MSA according to Movement Disorder Society criteria. Patient 2 was a 68-year-old man who was diagnosed with clinically established MSA according to Movement Disorder Society criteria. Both patients showed cerebellar ataxia, autonomic dysfunction, and pyramidal tract signs; however, they also had atypical clinical features. Patient 1 exhibited self-|limiting mild improvement of clinical symptoms and had inflammatory findings in his cerebrospinal fluid. Patient 2 showed a rapidly progressive clinical course. We therefore examined anti-neuronal antibodies using tissue-based immunohistochemical assays with frozen rat cerebellum sections. We detected autoantibodies that mainly reacted with the cytoplasm of Purkinje cells. The two patients then underwent immunotherapies, which led to substantial improvements in their clinical symptoms. Our findings indicate that some patients with autoimmune cerebella ataxia have clinical features that resemble MSA, and respond well to immunotherapies.

A case of chronic progressive autoimmune GFAP astrocytopathy with extensive meningoencephalomyelitis and contrast enhancement on MRI.

•We herein present a case of chronic progressive autoimmune GFAP astrocytopathy.•Symmetrical high-intensity signals on FLAIR were observed in the white matter of the temporal and occipital lobes, lateral cerebral ventricle walls, hippocampus, amygdala, and occipital cortex, with extensive Gd enhancement in radial perivascular lesions and the ependyma in the choroid plexus.•Improvements were achieved by 4 courses of IVMP and one of IVIg.

[A case of autoimmune glial fibrillary acidic protein astrocytopathy with various symptoms such as optic disc edema and cerebellar ataxia].

A 59-year-old man had developed visual abnormality, nausea, headache, and weight loss since three months before. The ophthalmologist found severe optic disc edema in both eyes, and referred him to our hospital. The patient had mild cerebellar ataxia. Increased cerebrospinal fluid pressure, increased protein and cell counts, positive oligoclonal band, and contrast-enhanced head MRI showed multiple linear perivascular radial gadolinium enhancement around bilateral lateral ventricles. His subjective and objective findings significantly improved with steroid treatment. The cerebrospinal fluid was found to be positive for glial fibrillary acidic protein (GFAP) antibodies, and a diagnosis of GFAP astrocytopathy was obtained. When optic edema or radial contrast effects was observed on contrast-enhanced MRI, GFAP astrocytopathy should be considerd. Prompt immunotherapy is required to circumvent the development of permanent visual impairment.

Anti-IgLON5 disease as a differential diagnosis of multiple system atrophy.

INTRODUCTION: Anti-immunoglobulin-like cell adhesion molecule 5 (IgLON5) disease is a rare autoimmune encephalitis that can mimic progressive supranuclear palsy or corticobasal syndrome. Moreover, anti-IgLON5 disease can present with symptoms characteristic of multiple system atrophy (MSA), such as cerebellar ataxia and autonomic dysfunction. However, the clinical features of anti-IgLON5 disease resembling MSA have not been well established. METHODS: We enrolled 35 patients with suspected MSA for whom anti-IgLON5 antibody tests were requested. We evaluated immunoglobulin G (IgG) against IgLON5 using cell-based assays. We also summarized the clinical characteristics of patients who were positive for anti-IgLON5 antibodies. RESULTS: We identified serum and cerebrospinal fluid anti-IgLON5 antibodies in three patients. These patients had many clinical features characteristic of MSA, including parkinsonism, cerebellar ataxia, severe orthostatic hypotension, acute respiratory failure, sleep parasomnia, vocal cord paralysis, and pyramidal tract signs. Clinical features atypical for MSA were myorhythmia, horizontal eye movement restriction, fasciculations, and painful muscle cramps. CONCLUSION: Anti-IgLON5 disease may be an important differential diagnosis of MSA. A comprehensive physical examination, including assessments of eye movement, lower motor neuron signs, and atypical involuntary movements, is important to avoid misdiagnosis.

Delivering the diagnosis of multiple system atrophy: a multicenter survey on Japanese neurologists' perspectives.

BACKGROUND: Multiple system atrophy (MSA) is a progressive, incurable, life-threatening neurodegenerative disease uniquely characterized by the risk of sudden death, which makes diagnosis delivery challenging for neurologists. Empirical studies on breaking a diagnosis of MSA are scarce, with no guidelines currently established. This study aimed to investigate neurologists' current practices and experiences in delivering the diagnosis of MSA. METHODS: We conducted a multicenter online survey and employed a mixed-methods (quantitative and qualitative) study design in which responses to open-ended questions were analyzed qualitatively using critical incident technique. RESULTS: Among the 194 neurologists surveyed, 166 opened the survey (response rate = 85.6%), of whom 144 respondents across various Japanese regions completed the survey. Accordingly, 92.3% and 82.8% of the participating neurologists perceived delivering the diagnosis of MSA and explaining the risk of sudden death as difficult, respectively. Factors independently associated with difficulties in diagnosis delivery included explaining the importance of the family decision making process in life-prolonging treatment, perceived difficulties in delivering information regarding the risk of sudden death, and perceived difficulties in differential diagnosis of MSA. CONCLUSIONS: Our findings showed that the majority of neurologists perceived delivering the diagnosis of MSA and explaining the risk of sudden death as difficult, which could have been associated with the difficulty of breaking the diagnosis of MSA. Difficulty in conveying bad news in MSA are caused by various factors, such as empathic burden on neurologists caused by the progressive and incurable nature of MSA, the need to explain complex and important details, including the importance of the family decision-making process in life-prolonging treatment, difficulty of MSA diagnosis, and communication barriers posed by mental status and cognitive impairment in patients or their family members. Neurologists consider various factors in explaining the risk of sudden death (e.g., patient's personality, mental state, and degree of acceptance and understanding) and adjust their manner of communication, such as limiting their communication on such matters or avoiding the use of the term "sudden death" in the early stages of the disease. Although neurologists endeavor to meet the basic standards of good practice, there is room for the multiple aspects for improvement.

Weight and Muscle Mass Loss Associated with Acute Disease Can be Reversed with Appropriate Nutrition Therapy and Exercise in a Patient with Amyotrophic Lateral Sclerosisa: A Case Report.

Introduction Nutritional interventions targeting weight loss are useful for the treatment of amyotrophic lateral sclerosis (ALS). However, the changes in body composition after nutritional intervention remain unclear. We herein present a patient with ALS who experienced an increased weight and muscle mass owing to nutritional therapy and physical exercise. Case Presentation An 86-year-old man presented with dysphagia and dysarthria. The patient was diagnosed with bulbar-type ALS. As weight loss progressed, a gastrostomy was performed. After 21 months of disease onset, gastrointestinal bleeding due to a bumper ulcer led to further weight loss (from 40.2 kg to 36.8 kg). The patient experienced difficulty walking and ingesting food orally. Although the total daily energy expenditure (TDEE) was estimated to be 1,122 kcal/day, an intake of 1,500 kcal/day beyond the calculated TDEE was administered. The patient continued to perform daily voluntary exercises in addition to his usual rehabilitation. After 5 months, his weight increased from 36.8 kg to 40.4 kg. Muscle mass increased from 25.1 kg to 30.1 kg, as measured using a multifrequency bioelectrical impedance device. Muscle strength improved from 8.5/10.0 kg to 15.0/18.0 kg in grip strength and from 15.2 kPa to 20.4 kPa in tongue pressure. The patient's physical and swallowing functions also improved. Conclusion In patients with ALS, a decreased body weight and muscle mass due to acute disease may be improved by appropriate nutritional therapy and physical exercise.

[Paraneoplastic Disorders of Peripheral Nervous System].

Paraneoplastic disorders of the peripheral nervous system are immune-mediated neurological syndromes associated with tumors. Several clinical phenotypes have been associated with these disorders. Sensory neuronopathy is the most well-known clinical phenotype, and is caused by neuronal cell injury to the dorsal root ganglia. Symptoms of the peripheral nervous system usually lead to the discovery of tumors. Antineuronal antibodies are occasionally identified in the serum and/or cerebrospinal fluid of these patients. The prevalence of small-cell lung cancer is notable in these patients. Early tumor resection, coupled with the initiation of immunotherapy, may prove effective in improving and stabilizing clinical symptoms.

Complete nanopore repeat sequencing of SCA27B (GAA-FGF14 ataxia) in Japanese.

BACKGROUND: Although pure GAA expansion is considered pathogenic in SCA27B, non-GAA repeat motif is mostly mixed into longer repeat sequences. This study aimed to unravel the complete sequencing of FGF14 repeat expansion to elucidate its repeat motifs and pathogenicity. METHODS: We screened FGF14 repeat expansion in a Japanese cohort of 460 molecularly undiagnosed adult-onset cerebellar ataxia patients and 1022 controls, together with 92 non-Japanese controls, and performed nanopore sequencing of FGF14 repeat expansion. RESULTS: In the Japanese population, the GCA motif was predominantly observed as the non-GAA motif, whereas the GGA motif was frequently detected in non-Japanese controls. The 5'-common flanking variant was observed in all Japanese GAA repeat alleles within normal length, demonstrating its meiotic stability against repeat expansion. In both patients and controls, pure GAA repeat was up to 400 units in length, whereas non-pathogenic GAA-GCA repeat was larger, up to 900 units, but they evolved from different haplotypes, as rs534066520, located just upstream of the repeat sequence, completely discriminated them. Both (GAA)≥250 and (GAA)≥200 were enriched in patients, whereas (GAA-GCA)≥200 was similarly observed in patients and controls, suggesting the pathogenic threshold of (GAA)≥200 for cerebellar ataxia. We identified 14 patients with SCA27B (3.0%), but their single-nucleotide polymorphism genotype indicated different founder alleles between Japanese and Caucasians. The low prevalence of SCA27B in Japanese may be due to the lower allele frequency of (GAA)≥250 in the Japanese population than in Caucasians (0.15% vs 0.32%-1.26%). CONCLUSIONS: FGF14 repeat expansion has unique features of pathogenicity and allelic origin, as revealed by a single ethnic study.

Distal oesophageal spasm in a patient with multiple system atrophy: A case report.

A 74-year-old man developed orthostatic syncope, a feeling of food stuck in his chest, and postprandial vomiting 3 years before presentation. Examination revealed severe orthostatic hypotension and cerebellar ataxia, and he was diagnosed with multiple system atrophy (MSA) with predominant cerebellar ataxia. Videofluoroscopic examination of swallowing showed lower oesophageal stricture and barium stagnation within the oesophagus. Oesophagogastroduodenoscopy revealed hypercontraction of the lower oesophagus, and high-resolution oesophageal manometry showed premature contractions of the lower oesophagus and decreased oesophageal peristalsis. The median integrated relaxation pressure in the lower oesophageal sphincter was normal, and achalasia was therefore excluded. Based on the Chicago classification version 4.0, his oesophageal dysmotility was classified as distal oesophageal spasm (DES). The stuck feeling in his chest and vomiting improved following endoscopic balloon dilation. This case suggests that DES can cause oesophageal food stagnation and postprandial vomiting in patients with MSA.

Case report: Atypical case of autoimmune glial fibrillary acidic protein astrocytopathy following COVID-19 vaccination refractory to immunosuppressive treatments.

A 54-year-old Japanese man presented with headache and fever the day after SARS-CoV-2 vaccination. He became deeply unconscious within a week. Brain MRI showed periventricular linear enhancements and a few spotty lesions in the cerebral white matter. Cerebrospinal fluid (CSF) testing showed mild pleocytosis. He was treated with intravenous methylprednisolone and plasma exchange. However, the white matter lesions enlarged to involve the brainstem and cerebellum, and long cord spinal lesions appeared. Anti-glial fibrillary acidic protein (GFAP) antibody was positive in the CSF and serum, and he was therefore diagnosed as autoimmune GFAP-astrocytopathy (GFAP-A). In addition, high-dose immunoglobulin therapy was administered twice, but his symptoms did not improve; the white matter lesions enlarged further, and modified Rankin Scale score increased to 5. A brain biopsy specimen showed infiltration of macrophages and CD4 + lymphocytes together with neuron and oligodendrocytic injuries and glial scar. Although GFAP-A generally responds well to steroids, the present case developed GFAP-A following SARS-CoV-2 vaccination, with refractory to intensive immunosuppressive therapy and atypical pathologic findings of infiltration of CD4 + lymphocytes and demyelination.

HLA-DQB1*05 subtypes and not DRB1*10:01 mediates risk in anti-IgLON5 disease.

Anti-IgLON5 disease is a rare and likely underdiagnosed subtype of autoimmune encephalitis. The disease displays a heterogeneous phenotype that includes sleep, movement and bulbar-associated dysfunction. The presence of IgLON5-antibodies in CSF/serum, together with a strong association with HLA-DRB1*10:01∼DQB1*05:01, supports an autoimmune basis. In this study, a multicentric human leukocyte antigen (HLA) study of 87 anti-IgLON5 patients revealed a stronger association with HLA-DQ than HLA-DR. Specifically, we identified a predisposing rank-wise association with HLA-DQA1*01:05∼DQB1*05:01, HLA-DQA1*01:01∼DQB1*05:01 and HLA-DQA1*01:04∼DQB1*05:03 in 85% of patients. HLA sequences and binding cores for these three DQ heterodimers were similar, unlike those of linked DRB1 alleles, supporting a causal link to HLA-DQ. This association was further reflected in an increasingly later age of onset across each genotype group, with a delay of up to 11 years, while HLA-DQ-dosage dependent effects were also suggested by reduced risk in the presence of non-predisposing DQ1 alleles. The functional relevance of the observed HLA-DQ molecules was studied with competition binding assays. These proof-of-concept experiments revealed preferential binding of IgLON5 in a post-translationally modified, but not native, state to all three risk-associated HLA-DQ receptors. Further, a deamidated peptide from the Ig2-domain of IgLON5 activated T cells in two patients, compared with one control carrying HLA-DQA1*01:05∼DQB1*05:01. Taken together, these data support a HLA-DQ-mediated T-cell response to IgLON5 as a potentially key step in the initiation of autoimmunity in this disease.

[Adult-onset COVID-19-associated Fulminant Acute Encephalopathy with Elevated Cerebrospinal Fluid Interleukin-8: A Case Report].

A 26-year-old woman receiving immunosuppressive therapy for polymyositis was infected with COVID-19 (an omicron mutant strain) and presented with fever. On the second day after the onset, she was admitted to our hospital and developed status epilepticus. Brain magnetic resonance imaging on admission revealed abnormal symmetric hyperintensities in the bilateral putamen and around the dorsal horns of the lateral ventricle. Three days after admission, brain computed tomography revealed marked cerebral edema and herniation. The cerebrospinal fluid (CSF) cell count was normal, and the reverse transcription polymerase chain reaction for severe acute respiratory syndrome coronavirus 2 was negative. Interleukin (IL)-2, 6, and 10 levels were within the normal range in both serum and CSF, whereas IL-8 levels in the CSF were markedly higher compared to serum levels. She had fulminant acute encephalopathy, suspected to be in the early stages of acute necrotizing encephalopathy (ANE). Steroid pulse therapy and intravenous infusions of remdesivir were ineffective, and the patient died of sepsis on the 26th day after admission. We demonstrated that ANE may occur even in patients infected with Omicron strains and speculated that the pathogenesis in this case might be associated with intrathecal IL-8 production by microglial activation.

Anti-IgLON5 Disease Showing an Improvement in Dysautonomia, Including Vocal Cord Palsy, via Combined Immunotherapy.

Anti-IgLON5 disease shows various neurological manifestations, of which dysautonomia is one of the major symptoms and is rarely improved by immunotherapy. We herein report a patient with anti-IgLON5 disease who showed several autonomic failures, including vocal cord palsy for four months. The patient presented with cognitive impairments, bulbar symptoms accompanied by myorhythmia in the pharynx and tongue, cerebellar ataxia with tremor, motor neuron symptoms in the limbs, gastrointestinal dysfunction, orthostatic hypotension, non-rapid eye movement sleep disorder on polysomnography, and severe vocal cord palsy. Combined immunotherapy improved his symptoms, including vocal cord palsy, suggesting that combined immunotherapy might improve dysautonomia in anti-IgLON5 disease.

[Clinical features and effects of shunt surgery in patients with progressive supranuclear palsy and idiopathic normal pressure hydrocephalus].

This study aimed to retrospectively review the frequency and clinical features of 13 patients with progressive supranuclear palsy (PSP) and idiopathic normal pressure hydrocephalus (iNPH). All patients were found to have PSP-Richardson's syndrome (PSP-RS). Shunt surgery was effective in 5 of 11 patients (45.5%). A comparison of these 5 patients who responded to shunt surgery versus the remaining 6 patients revealed a significant difference in the reduction of frontal lobe blood flow on cerebral perfusion single-photon emission computed tomography (SPECT) (P = 0.018). These results suggest that PSP-RS is common in patients with PSP and iNPH and indicate the usefulness of cerebral perfusion SPECT in estimating the effect of shunt surgery.

Balamuthia mandrillaris amoebic encephalitis mimicking tuberculous meningitis.

A 76-year-old female with no apparent immunosuppressive conditions and no history of exposure to freshwater and international travel presented with headache and nausea 3 weeks before the presentation. On admission, her consciousness was E4V4V6. Cerebrospinal fluid analysis showed pleocytosis with mononuclear cell predominance, elevated protein, and decreased glucose. Despite antibiotic and antiviral therapy, her consciousness and neck stiffness gradually worsened, right eye-movement restriction appeared, and the right direct light reflex became absent. Brain magnetic resonance imaging revealed hydrocephalus in the inferior horn of the left lateral ventricle and meningeal enhancement around the brainstem and cerebellum. Tuberculous meningitis was suspected, and pyrazinamide, ethambutol, rifampicin, isoniazid, and dexamethasone were started. In addition, endoscopic biopsy was performed from the white matter around the inferior horn of the left lateral ventricle to exclude brain tumor. A brain biopsy specimen revealed eosinophilic round cytoplasm with vacuoles around blood vessels, and we diagnosed with amoebic encephalitis. We started azithromycin, flucytosine, rifampicin, and fluconazole, but her symptoms did not improve. She died 42 days after admission. In autopsy, the brain had not retained its structure due to autolysis. Hematoxylin and eosin staining of her brain biopsy specimen showed numerous amoebic cysts in the perivascular brain tissue. Analysis of the 16S ribosomal RNA region of amoebas from brain biopsy and autopsy specimens revealed a sequence consistent with Balamuthia mandrillaris. Amoebic meningoencephalitis can present with features characteristic of tuberculous meningitis, such as cranial nerve palsies, hydrocephalus, and basal meningeal enhancement. Difficulties in diagnosing amoebic meningoencephalitis are attributed to the following factors: (1) excluding tuberculous meningitis by microbial testing is difficult, (2) amoebic meningoencephalitis has low incidence and can occur without obvious exposure history, (3) invasive brain biopsy is essential in diagnosing amoebic meningoencephalitis. We should recognize the possibility of amoebic meningoencephalitis when evidence of tuberculosis meningitis cannot be demonstrated.

Autoimmune Glial Fibrillary Acidic Protein Astrocytopathy Following SARS-CoV-2 Infection.

We herein report the first case of autoimmune glial fibrillary acidic protein (GFAP) astrocytopathy after coronavirus disease 2019 (COVID-19). A 23-year-old man experienced fatigue, a fever, and headache 14 days after the resolution of COVID-19. He was severely disoriented and admitted to our hospital. On admission, the patient exhibited disorientation, headache, neck stiffness, myoclonus of both upper limbs, dysuria, and pyramidal signs. A blood examination revealed hyponatremia, and a cerebrospinal fluid (CSF) analysis showed lymphocytic pleocytosis. The CSF test results were positive for anti-GFAPα antibodies. The patient was treated with methylprednisolone pulse therapy, followed by oral prednisolone, which quickly ameliorated his neurological abnormalities.