Ichiro Yabe

• MD, PhD
• Professor at Hokkaido University

In Japan, there are no nationwide guidelines for presymptomatic testing for hereditary neuromuscular diseases. Although each institution has been dealing with this situation by using their own procedures to date, it is necessary to develop a standardized guidelines based on the Japanese medical system, because the development of disease-modifying t...

Background Pose estimation algorithms applied to two‐dimensional videos evaluate gait disturbances; however, a few studies have used this method to evaluate ataxic gait. Objective The aim was to assess whether a pose estimation algorithm can predict the severity of cerebellar ataxia by applying it to gait videos. Methods We video‐recorded 66 pati...

Background Tau aggregation is the major cause of several neurodegenerative tauopathies. Tau interaction with other proteins affects the formation of tau aggregates with seeding activity but less is known about its effects on tau‐seed properties. Our previous study revealed that Bassoon (BSN), a presynaptic protein, interacts with tau‐seed, exacerba...

An 82-year-old man presented with acute progressive disturbance of consciousness. We suspected autoimmune limbic encephalitis because of abnormal magnetic resonance imaging findings in the bilateral temporal lobes and cerebrospinal fluid pleocytosis. The patient tested positive for anti-Tr/Delta/Notch-like epidermal growth factor-related receptor (...

Polymyalgia rheumatica (PMR) is a common inflammatory disorder characterized by myalgia/stiffness in proximal hip and shoulder girdle, elevated C reactive protein, and erythrocyte sedimentation rate, but its pathogenesis is not fully elucidated. We report three cases of PMR who do not respond adequately to standard treatment. Those patients had typ...

Most cases of dementia with Lewy bodies (DLB) follow a chronic course. However, some cases of rapidly progressive dementia (RPD) are difficult to distinguish from other diseases. Herein, we report how to differentiate DLB presenting with RPD from other diseases and its pathological features, with examples from our own experience. A 70‐year‐old man...

Multiple system atrophy (MSA) is a neurodegenerative disorder characterized by autonomic nervous system dysfunction and cerebellar ataxia or parkinsonism. Recently, expanded GAA repeats (≥250 repeat units) in intron 1 of FGF14 have been shown to be responsible for spinocerebellar ataxia type 27B (SCA27B), a late-onset ataxia with an autosomal domin...

Introduction Alzheimer disease (AD) is the most common type of dementia, affecting 70% of patients with dementia. In Japan, over 5 million people aged 65 years and older had dementia in 2018, and this figure is expected to rise to 25% to 30% of this age group by 2045. In Japan, lecanemab, which was approved in 2023, is expected to be a new treatmen...

The Japanese Society of Neurology’s Special Committee on Measures for Transition from Pediatric to Adult Health Care held a workshop to discuss the activities of the transitional care support centers (TCSCs). The following points were addressed: (1) from Kanagawa Prefecture, the activities of the TCSC, which is set up alongside the Intractable Dise...

Clinical diagnosis of progressive supranuclear palsy (PSP) is difficult due to various phenotypes. Neuropathologically, PSP is defined by neuronal loss in the basal ganglia and brainstem with widespread occurrence of neurofibrillary tangles (NFTs) and accumulation of phosphorylated tau protein in neurons and glial cells in the brain. We previously...

Background/Objectives: Sporadic Creutzfeldt–Jakob disease (sCJD) is a fatal neurodegenerative disorder traditionally diagnosed based on the World Health Organization (WHO) criteria in 1998. Recently, Hermann et al. proposed updated diagnostic criteria incorporating advanced biomarkers to enhance early detection of sCJD. This study aimed to evaluate...

Background Chronic lymphoproliferative disorder of natural killer cells (CLPD-NK) is a rare disease characterized by a persistent increase in NK cells in peripheral blood and is generally asymptomatic. If present, symptoms may include fatigue, B symptoms (fever, night sweats, and unintentional weight loss), autoimmune-associated diseases, splenomeg...

POEMS syndrome is often associated with a poor prognosis. Elevated serum vascular endothelial growth factor (sVEGF) is a useful diagnostic marker with high sensitivity and specificity. However, the relationship between sVEGF elevation and polyneuropathy in POEMS syndrome remains controversial. We herein report a case of polyneuropathy without sVEGF...

Tauopathy is known to be a major pathognomonic finding in important neurodegenerative diseases such as progressive supranuclear palsy (PSP) and corticobasal degeneration. However, the mechanism by which tauopathy is triggered remains to be elucidated. We previously identified the point mutation c.11596C > G, p.Pro3866Ala in the Bassoon gene (BSN) i...

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 inve...

Spinocerebellar ataxia type 10 (SCA10) is a rare autosomal dominant ataxia caused by a large expansion of the (ATTCT)n repeat in ATXN10. SCA10 was described in Native American and Asian individuals which prompted a search for an expanded haplotype to confirm a common ancestral origin for the expansion event. All patients with SCA10 expansions in ou...

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 molecula...

Spinocerebellar ataxia type 6 (SCA6) is a polyglutamine disorder caused by the expansion of CAG repeats in the gene encoding voltage‐gated calcium channel subunit alpha1 A ( CACNA1A ). The clinical features of SCA6 include slowly progressive cerebellar ataxia and downbeat positioning nystagmus. The clinical significance of 19 CAG repeats is unclear...

Paraneoplastic neurological syndromes (PNS) are neurological disorders that occur in close association with tumors without direct metastasis or invasion of the tumors and in which anti-neural antibodies may be present. Cerebellar ataxia is a common form of PNS in patients with breast cancer. However, reports of symptom improvement with breast cance...

Objective This study aimed to describe the usefulness of our teleconsultation system for managing multiple sclerosis (MS) in regions without specialists. Methods A cross‐sectional questionnaire survey involving 11 MS patients and their primary neurologists was carried out between May and December 2023. Real‐time video conferences were conducted be...

Better understanding of the earliest molecular pathologies of all neurodegenerative diseases is expected to improve human therapeutics. We investigated the earliest molecular pathology of spinocerebellar ataxia type 1 (SCA1), a rare familial neurodegenerative disease that primarily induces death and dysfunction of cerebellum Purkinje cells. Extensi...

Background Multiple system atrophy (MSA) is a neurodegenerative disorder characterized by autonomic failure and various motor symptoms. While MSA‐C (cerebellar type) predominates in East Asia, MSA‐P (parkinsonian type) predominates in Europe and North America. This nationwide patient registry aimed to (1) conduct a prospective natural history study...

Objective In 2022, Wenning et al. proposed the Movement Disorder Society Criteria (MDS Criteria) for the Diagnosis of Multiple System Atrophy (MSA). These criteria were expected to provide useful alternatives to the second consensus statement. We examined trends in these diagnostic criteria. Methods We used patient data registered with the Hokkaido...

Spinocerebellar degeneration (SCD) is a neurodegenerative disorder characterized by cerebellar ataxia and other multisystem manifestations, such as Parkinsonism and pyramidal tract symptoms. No effective treatment is available for SCD. Approximately one-third of the cases of SCD are inherited, and the remaining two-third are sporadic, including mul...

Background Tau aggregation is the underlying cause of several neurodegenerative tauopathies. Formation of tau aggregates with seeding activity involves interactions with other proteins, but with unknown effects on tau‐seed properties. Our previous study found that Bassoon (BSN), a presynaptic protein, interacts with tau‐seed, exacerbating its toxic...

Assessing dysarthria features in patients with neurodegenerative diseases helps diagnose underlying pathologies. Although deep neural network (DNN) techniques have been widely adopted in various audio processing tasks, few studies have tested whether DNNs can help differentiate neurodegenerative diseases using patients’ speech data. This study eval...

The clinical presentation of corticobasal degeneration is diverse, while the background pathology of corticobasal syndrome is also heterogeneous. Therefore, predicting the pathological background of corticobasal syndrome is extremely difficult. Herein, we investigated the clinical findings and course in patients with pathologically, genetically and...

To elucidate the molecular basis of multiple system atrophy (MSA), a neurodegenerative disease, we conducted a genome-wide association study (GWAS) in a Japanese MSA case/control series followed by replication studies in Japanese, Korean, Chinese, European, and North American samples. In the GWAS stage, rs2303744 on chromosome 19 showed a suggestiv...

Background The diagnosis of Parkinson’s disease (PD) and evaluation of its symptoms require in-person clinical examination. Remote evaluation of PD symptoms is desirable, especially during a pandemic such as the coronavirus disease 2019 pandemic. One potential method to remotely evaluate PD motor impairments is video-based analysis. In this study,...

A 35-year-old male patient had been repeatedly involved in car accidents since the age of 34 years, had difficulty in tidying his room, and developed speech and gait disorders. At the first examination, he had a hypophonia and poor gait, but he could talk and walk by himself. His Mini-Mental State Examination (MMSE) score was 23 and mild cognitive...

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 (C...

We retrospectively reviewed the medical histories, examination results, treatments, and prognoses of nine patients with cryptococcal meningitis who were diagnosed and treated at Hokkaido University Hospital and its affiliated hospitals over the past 10 years. Cryptococcal meningitis can develop even in immunocompetent hosts, and its prognosis is po...

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 f...

Purpose: To develop a method for predicting amyloid positron emission tomography (PET) positivity based on multiple regression analysis of quantitative susceptibility mapping (QSM). Materials and methods: This prospective study included 39 patients with suspected dementia from four centers. QSM images were obtained through a 3-T, three-dimension...

Background: This study aimed to investigate medication prescriptions for patients with myelomeningocele (MMC) across different age groups, particularly in adulthood and after middle age. Methods: The Japan Medical Data Center (JMDC) database, based on medical claims data, was utilized for this analysis. Patients were divided into 10-year age gro...

Comprehensive genomic profiling (CGP) tests have been covered by public insurance in Japan for patients with advanced solid tumors who have completed or are completing standard treatments or do not have them. Therefore, genotype-matched drug candidates are often unapproved or off-label, and improving clinical trial access is critical, involving the...

Background Several genetic factors are associated with the pathogenesis of sporadic amyotrophic lateral sclerosis (ALS) and its phenotypes, such as disease progression. Here, in this study, we aimed to identify the genes that affect the survival of patients with sporadic ALS. Methods We enrolled 1076 Japanese patients with sporadic ALS with impute...

Among the different forms of cerebellar ataxia, autoimmune cerebellar ataxia (ACA) or immune‐mediated cerebellar ataxia (IMCA), which appears to be based on an autoimmune mechanism, has long been considered important from the viewpoint of paraneoplastic syndrome. With the expansion of the concept of immune‐mediated neurological diseases and the ide...

To elucidate the molecular basis of multiple system atrophy (MSA), a neurodegenerative disease, we conducted a genome-wide association study (GWAS) in a Japanese MSA case/control series followed by replication studies in Japanese, Korean, Chinese, European and North American samples. In the GWAS stage rs2303744 on chromosome 19 showed a suggestive...

No disease-modifying therapy has been established for spinocerebellar degeneration and multiple system atrophy, and only symptomatic therapy is currently available. Taltirelin and protirelin are drugs covered by health insurance for cerebellar ataxia symptoms, and are expected to suppress the progression of symptoms. Muscle relaxants are used for s...

A man in his 50s presented with a 2-month history of paresthesia and hypoesthesia of the extremities and B symptoms including low-grade fever, weight loss, and night sweats. He also reported a 3-year history of skin discoloration in cold weather. Laboratory test results showed a high white blood cell count and elevated serum C-reactive protein and...

Background Functionally impaired variants of COQ2, encoding an enzyme in biosynthesis of coenzyme Q10 (CoQ10), were found in familial multiple system atrophy (MSA) and V393A in COQ2 is associated with sporadic MSA. Furthermore, reduced levels of CoQ10 have been demonstrated in MSA patients. Methods This study was a multicentre, randomised, double-...

The N-terminus of the PRNP gene normally contains a 5-octapeptide repeat (R1-R2-R2-R3-R4), and insertions at this locus can cause hereditary prion diseases. In the present study, we found a 5-octapeptide repeat insertion (5-OPRI) in a sibling case of frontotemporal dementia. Consistent with previous literature, 5-OPRI rarely met the diagnostic crit...

Background: CSF1R-related leukoencephalopathy is an adult-onset leukoencephalopathy caused by mutations in CSF1R. The present study aimed to explore the broader genetic spectrum of CSF1R-related leukoencephalopathy in association with clinical and imaging features. Methods: Mutational analysis of CSF1R was performed for 100 consecutive patients...

Chronic lymphocytic inflammation with pontine perivascular enhancement responsive to steroids (CLIPPERS) is an inflammatory disease of the central nervous system that predominantly affects the brainstem. Apart from corticosteroids, there are few reported treatment options for CLIPPERS, and there is no standard therapy. A 77-year-old man presented w...

Neuronal intranuclear inclusion disease (NIID) is a progressive neurodegenerative condition. Skin biopsies taken from the lower leg were reported to be a standard diagnostic procedure for NIID; however, no studies have addressed the optimal skin biopsy locations. We retrospectively analyzed 12 cases in which skin biopsies were performed for diagnos...

The newly revised diagnostic criteria for multiple system atrophy (MSA) have reduced the criteria for diagnosing orthostatic hypotension compared to the conventional diagnostic criteria, but require tests such as MRI and residual urine measurement. Under the new diagnostic criteria, cases that were previously classified as possible MSA with low dia...

The patient was a 45-year-old man. Since 2019, he had exhibited repeated steroid-improved dysuria and long spinal cord lesions. At the time of recurrence in June 2020, he exhibited a marked increase in serum IgM levels, suggesting hematopoietic disease. We found an MYD88 L265P mutation in cerebrospinal fluid cells, which subsequently led to the dia...

Smoking is a known risk factor for the development and progression of several autoimmune diseases. Previous studies have pointed out the association of smoking with the development and worsening of symptoms in myasthenia gravis (MG), but further investigation is necessary to confirm this association. Smoking history was investigated in a cross-sect...

Background Since COVID-19 vaccination was introduced, various adverse effects have been linked to the vaccines. In patients with hypopituitarism, adrenal insufficiency due to the side reactions including fever of COVID-19 vaccination is concerned. Clinical Case A 33-year woman was on medical therapy including hydrocortisone (HC) for panhypopituita...

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...

To clarify the prevalence, clinical features, treatment outcome, and severity determinants of anti-mitochondrial M2 antibody-positive myositis (AMA-M2-positive myositis). Clinical data for AMA-M2-positive myositis patients who were treated at Hokkaido University Hospital and other participating facilities from 2012 to 2021 were retrospectively eval...

As therapies for hereditary neuromuscular diseases are developed, the need for presymptomatic genetic testing and genetic counseling for early treatment is expected to increase. In Japan, there is no uniformly recommended protocol for presymptomatic genetic testing. In order to provide basic data for the establishment of a presymptomatic genetic te...

The aim of this study was to clarify the roles of the cerebellum and basal ganglia for temporal integration. We studied 39 patients with spinocerebellar ataxia (SCA), comprising SCA6, SCA31, Machado–Joseph disease (MJD, also called SCA3), and multiple system atrophy (MSA). Thirteen normal subjects participated as controls. Participants were instruc...

Objectives Complement component 6 (C6) deficiency is a very rare genetic defect that leads to significantly diminished synthesis, secretion, or function of C6. In the current report, we demonstrate a previously undescribed, homozygous missense mutation in exon 17 of the C6 gene (c.2545A>G p.Arg849Gly) in a 35-year-old Japanese woman with moyamoya d...

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 my...

Background Little is known about the real-world status of neurosurgical treatment of myelomeningocele patients. Objective To investigate the real-world status of neurosurgical treatment of myelomeningocele patients, medical claims data provided by the Japan Medical Data Center (JMDC) were analyzed. Methods The health claims data of 556 patients w...

Objectives Smoking is a known risk factor for the development and progression of autoimmune diseases. Previous studies in ocular myasthenia gravis (MG) patients showed that smoking is associated with the severity of symptoms and progression to generalized MG. However, whether smoking affects MG symptoms in patients with a broader clinical spectrum...

Background Many genetic counseling (GC) studies have focused on anxiety status because clients of GC often feel anxious during their visits. Metacognition is known to be one of the causes of having an inappropriate thinking style. In this study, we examined the relationship between anxiety and the metacognitive status of GC clients according to the...

Introduction: Autoimmune glial fibrillary acidic protein (GFAP) astrocytopathy is a recently described steroid-responsive meningoencephalomyelitis positive for cerebrospinal fluid (CSF) anti-GFAP antibody. Area postrema syndrome (APS) involves intractable hiccups, nausea, and vomiting, which is caused by medulla oblongata (MO) impairment. APS is a...

Cat scratch disease (CSD) is a zoonotic infection caused by Bartonella henselae typically resulting in self-limited regional lymphadenopathy. Encephalitis is a complication with a supposedly benign prognosis, but we encountered an exceptional case. A 19-year-old Japanese woman presented with status epilepticus. She was diagnosed with CSD-associated...

Purpose: Studies on quantitative susceptibility mapping (QSM) have reported an increase in magnetic susceptibilities in patients with Alzheimer's disease (AD). Despite the pathological importance of the brain surface areas, they are sometimes excluded in QSM analysis. This study aimed to reveal the efficacy of QSM analysis with brain surface corre...

Background: Human immunodeficiency virus (HIV)-associated vasculopathy can cause ischemic cerebral stroke; however, there is limited evidence on optimal management. Herein, we report a case of acute ischemic stroke due to progressive internal carotid artery (ICA) stenosis in an HIV-positive patient. Superficial temporal artery to middle cerebral a...

Objectives: Voxel-based morphometry (VBM) is widely used to quantify the progression of Alzheimer's disease (AD), but improvement is still needed for accurate early diagnosis. We evaluated the feasibility of a novel diagnosis index for early diagnosis of AD based on quantitative susceptibility mapping (QSM) and VBM. Methods: Thirty-seven patient...

Objective To evaluate the efficacy and safety of perampanel in patients with sporadic amyotrophic lateral sclerosis (SALS). Methods This randomized, double-blind, placebo-controlled, multicenter, phase 2 clinical study was conducted at 12 sites. Patients with probable or definite ALS as defined by revised El Escorial criteria were enrolled. Sixty-...

OBJECTIVE Patients with myelomeningocele often require multiple surgeries, but no study has clarified the kind of treatment given to these patients throughout their lives. The authors analyzed the type of surgery that was performed and at what age for Japanese patients with myelomeningoceles. METHODS The Japanese health claims data of 556 patients...

Background and aims: Some hereditary transthyretin (ATTRv) amyloidosis patients are misdiagnosed as Charcot-Marie-Tooth disease (CMT) at onset. We assess the findings to identify ATTRv amyloidosis among patients with suspected CMT to screen transthyretin gene variants for treatments. Methods: We assessed clinical, cerebrospinal fluid, and electr...

The appearance of slides and posters is important to allow an effective and easy-to-understand presentation. It is desirable to limit the amount of information shown on one slide, paying attention to the layout, colors, fonts, etc., and to create easy-to-read slides. At the beginning of the presentation, it is recommended to show the outline of the...

Disease sites of female genital tract cancers of BRCA1 / 2 -associated hereditary breast and ovarian cancer (HBOC) are less understood than non-hereditary cancers. We aimed to elucidate the disease site distribution of genital cancers in women with the germline BRCA1 and BRCA2 pathogenic variants (BRCA1 + and BRCA2 +) of HBOC. For the primary disea...

DNAJC7 has recently been identified as an amyotrophic lateral sclerosis (ALS) gene via large-scale exome analysis, and its involvement in ALS is still unclear in various populations. This study aimed to determine the frequencies and characteristics of the DNAJC7 variants in a Japanese ALS cohort. A total of 807 unrelated Japanese patients with spor...

The aim of this study was to evaluate the feasibility of kinetic analysis of cerebrospinal fluid (CSF) using ¹⁷O-labeled water tracer. Four subjects (two idiopathic normal pressure hydrocephalus (iNPH) and two possible AD dementia patients) were prospectively included. Injectable formulation of ¹⁷O-labeled water containing 10 mol% of H2¹⁷O (PSO17),...

An 81-year-old man presented with limb weakness and dysesthesia approximately 10 days after eating pork liver. His neurological examination revealed muscle weakness predominantly centered in the lower limbs and absence of deep tendon reflex, and cerebrospinal fluid analysis showed elevated proteins with normal cell counts. Furthermore, his nerve co...

Autoimmune encephalitis (AE) is a group of inflammatory brain diseases that are characterized by prominent neuropsychiatric symptoms. Early therapeutic intervention is important for AE. Therefore, without waiting for autoantibody test results, clinicians must consider the possibility of AE based solely on clinical symptoms and conventional test res...

Introduction Recently, unilateral cortical fluid-attenuated inversion recovery-hyperintense lesions in anti-myelin oligodendrocyte glycoprotein (MOG)-associated encephalitis with seizures (FLAMES) have been revealed as one of the clinical types of anti-MOG antibody-associated diseases (MOGAD). To date, no neuropathological study on FLAMES has demon...