Treatment of cryptogenic new-onset refractory status epilepticus (C-NORSE) with tocilizumab: A case report

A 35-year-old woman with no prior history of epilepsy developed status epilepticus (SE), which was highly resistant to multiple antiseizure medications and sedatives. The etiology of SE was not identified despite extensive investigation, and the patient was diagnosed with cryptogenic new-onset refractory status epilepticus (C-NORSE). Although first-line immunotherapies such as high-dose corticosteroids and plasma exchange were ineffective, the patient manifested a resolution of SE after the administration of tocilizumab, which inhibits interleukin-6. Non-antibody-mediated inflammation has been hypothesized to be a probable pathophysiology of C-NORSE in recent studies, and tocilizumab may be a plausible second-line treatment.

Protective effect of scallop-derived plasmalogen against vascular dysfunction, via the pSTAT3/PIM1/NFATc1 axis, in a novel mouse model of Alzheimer's disease with cerebral hypoperfusion

A strong relationship between Alzheimer's disease (AD) and vascular dysfunction has been the focus of increasing attention in aging societies. In the present study, we examined the long-term effect of scallop-derived plasmalogen (sPlas) on vascular remodeling-related proteins in the brain of an AD with cerebral hypoperfusion (HP) mouse model. We demonstrated, for the first time, that cerebral HP activated the axis of the receptor for advanced glycation endproducts (RAGE)/phosphorylated signal transducer and activator of transcription 3 (pSTAT3)/provirus integration site for Moloney murine leukemia virus 1 (PIM1)/nuclear factor of activated T cells 1 (NFATc1), accounting for such cerebral vascular remodeling. Moreover, we also found that cerebral HP accelerated pSTAT3-mediated astrogliosis and activation of the nucleotide-binding domain and leucine-rich repeat protein 3 (NLRP3) inflammasome, probably leading to cognitive decline. On the other hand, sPlas treatment attenuated the activation of the pSTAT3/PIM1/NFATc1 axis independent of RAGE and significantly suppressed NLRP3 inflammasome activation, demonstrating the beneficial effect on AD.

Adrenomyeloneuropathy with Later Development of Cerebral Form Caused by a Hemizygous Splice-site Variant in ABCD1

Adrenomyeloneuropathy (AMN)/adrenoleukodystrophy (ALD) is an X-linked genetic disorder caused by pathogenic variants in ABCD1. We treated a 54-year-old man with slowly progressive spastic paraparesis with later development of the cerebral form. A pathogenic splice-site variant of ABCD1 (c.1489-1G>A, p.Val497Alafs*51) and elevated levels of very long-chain fatty acids were found, leading to the diagnosis of AMN. Detailed ABCD1 mRNA expression analyses revealed decreased levels of ABCD1 mRNA accompanied by deletion of the first 31 bp in exon 6. The altered mRNA transcriptional patterns associated with splice site variants are diverse and may provide important insights into ALD pathogenesis.

SPTLC2 variants are associated with early-onset ALS and FTD due to aberrant sphingolipid synthesis

OBJECTIVE

Amyotrophic lateral sclerosis (ALS) is a devastating, incurable neurodegenerative disease. A subset of ALS patients manifests with early-onset and complex clinical phenotypes. We aimed to elucidate the genetic basis of these cases to enhance our understanding of disease etiology and facilitate the development of targeted therapies.

METHODS

Our research commenced with an in-depth genetic and biochemical investigation of two specific families, each with a member diagnosed with early-onset ALS (onset age of <40 years). This involved whole-exome sequencing, trio analysis, protein structure analysis, and sphingolipid measurements. Subsequently, we expanded our analysis to 62 probands with early-onset ALS and further included 440 patients with adult-onset ALS and 1163 healthy controls to assess the prevalence of identified genetic variants.

RESULTS

We identified heterozygous variants in the serine palmitoyltransferase long chain base subunit 2 (SPTLC2) gene in patients with early-onset ALS. These variants, located in a region closely adjacent to ORMDL3, bear similarities to SPTLC1 variants previously implicated in early-onset ALS. Patients with ALS carrying these SPTLC2 variants displayed elevated plasma ceramide levels, indicative of increased serine palmitoyltransferase (SPT) activity leading to sphingolipid overproduction.

INTERPRETATION

Our study revealed novel SPTLC2 variants in patients with early-onset ALS exhibiting frontotemporal dementia. The combination of genetic evidence and the observed elevation in plasma ceramide levels establishes a crucial link between dysregulated sphingolipid metabolism and ALS pathogenesis. These findings expand our understanding of ALS's genetic diversity and highlight the distinct roles of gene defects within SPT subunits in its development.

Late-onset Myoclonic Seizure in a 78-year-old Woman with Gaucher Disease

We herein report a 78-year-old woman with Gaucher disease (GD) who was initially diagnosed with GD type 1, had been receiving long-term enzyme replacement therapy since 58 years old, and developed neurological manifestations in her 70s. The neurological manifestations included myoclonic seizures and progressive cognitive decline. Although it is rare for GD patients to first develop neurologic manifestations at such an advanced age, physicians engaged in long-term care for GD patients should be alert for this possibility.

Neuroprotective effect of, a flavonoid, sudachitin in mice stroke model

A flavonoid, sudachitin, has been reported to show some beneficial health effects, including as an anti-inflammatory in LPS-stimulated macrophages, as well as improving glucose and lipid metabolism in mice fed a high-fat diet. In this study, we investigated the neuroprotective effect of sudachitin in the transient middle cerebral artery occlusion (tMCAO) mouse model. After daily pre-treatment of vehicle or sudachitin (5 or 50 mg/kg) for 14 days, mice (n = 76) were subjected to a sham operation or tMCAO for 45 min, and on the following days, they were treated daily with vehicle or sudachitin. The administration of sudachitin significantly reduced (p < 0.05) cerebral infarct volume and attenuated apoptosis, 5 days after tMCAO. Neurological impairment improved, the expression of an oxidative stress marker, 4-HNE, decreased, and the Sirt1/PGC-1α pathway was activated 5 days after tMCAO in the sudachitin-treated group. This is the first report to demonstrate the neuroprotective effect of sudachitin in cerebral ischemia/reperfusion injury mice model, probably by activating the Sirt1/PGC-1α axis. Sudachitin may be a promising supplement or therapeutic agent for reducing injury caused by ischemic strokes.

Anti-neurofascin 155 Antibody-positive Neuropathy in a Human Immunodeficiency Virus-infected Patient

Human immunodeficiency virus (HIV)-associated neuropathy is a common complication of HIV infection and has several clinical subtypes. HIV-associated chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is a demyelinating neuropathy whose clinical features are known to differ from those of CIDP in the HIV-uninfected population. We herein report a case of CIDP in an HIV-infected patient who was finally diagnosed with anti-neurofascin 155 (NF155) antibody-positive neuropathy. The clinical features, including clinical findings and therapeutic responses, were typical of paranodal antibody-mediated neuropathy. To our knowledge, this is the first case of anti-NF155 antibody-associated neuropathy in an HIV-infected patient.

CGG repeat expansion in LOC642361/NUTM2B-AS1 typically presents as oculopharyngodistal myopathy

CGG repeat expansions in LOC642361/NUTM2B-AS1 have recently been identified as a cause of oculopharyngeal myopathy with leukoencephalopathy. However, since only three patients from a single family were reported, it remains unknown whether their clinicopathological features are typical for CGG repeat expansions in LOC642361/NUTM2B-AS1. Here, using repeat-primed-polymerase chain reaction and long-read sequencing, we identify 12 individuals from 3 unrelated families with CGG repeat expansions in LOC642361/NUTM2B-AS1, typically presenting with oculopharyngodistal myopathy. The CGG repeat expansions range from 161 to 669 repeat units. Most of the patients present with ptosis, restricted eye movements, dysphagia, dysarthria, and diffuse limb muscle weakness. Only one patient shows T2-weighted hyperintensity in the cerebellar white matter surrounding the deep cerebellar nuclei on brain magnetic resonance imaging. Muscle biopsies from three patients show a myopathic pattern and rimmed vacuoles. Analyses of muscle biopsies suggest that CGG repeat expansions in LOC642361/NUTM2B-AS1 may deleteriously affect aggrephagic capacity, suggesting that RNA toxicity and mitochondrial dysfunction may contribute to pathogenesis. Our study thus expands the phenotypic spectrum for the CGG repeat expansion of LOC642361/NUTM2B-AS1 and indicates that this genetic variant typically manifests as oculopharyngodistal myopathy with chronic myopathic changes with rimmed vacuoles and filamentous intranuclear inclusions in muscle fibers.

Clinical and Genetic Features of Multiplex Families with Multiple System Atrophy and Parkinson's Disease

While multiple system atrophy (MSA) has been considered a sporadic disease, there were previously reported multiplex families with MSA. Furthermore, several families with multiple patients with MSA and Parkinson's disease (PD) have been reported. As genetic risk factors for MSA, functionally impaired variants in COQ2 and Gaucher-disease-causing GBA variants have been reported. While it has been established that GBA variants are associated with PD, COQ2 may also be associated with PD. In 672 patients with MSA, we identified 12 multiplex families of patients with MSA and PD in first-degree relatives. We conducted a detailed analysis of the clinical presentations of these patients and genetic analyses of GBA and COQ2. In the multiplex families, a patient with MSA with predominant parkinsonism (MSA-P) was observed in nine families, while a patient with MSA cerebellar subtype (MSA-C) was observed in three families. Six families had siblings with MSA and PD, five families had a parent-offspring pair with MSA and PD, and in one family, a sibling and a parent of an MSA patient had PD. In genetic analyses of these patients, GBA variants were identified in one of the 12 MSA patients and two of the seven PD patients. Functionally impaired variants of COQ2 were identified in two of the 12 MSA patients and not identified in the seven PD patients. This study further emphasizes the occurrence of MSA and PD in first-degree relatives, raising the possibility that a common genetic basis underlies MSA and PD. Even though variants of COQ2 and GBA were identified in some patients in multiplex families with MSA and PD, it is necessary to further explore as yet unidentified genetic risk factors shared by MSA and PD.

Recovery after Prolonged Disturbance of Consciousness and Repeated Cerebral Perfusion Changes in Neuronal Intranuclear Inclusion Disease

Encephalitic episodes are a clinical manifestation of neuronal intranuclear inclusion disease (NIID) and often show transient disturbance of consciousness. We herein report a genetically confirmed patient with NIID who initially presented progressive dementia and showed prolonged disturbance of consciousness preceded by an acute-onset headache. During that time, we performed N-isopropyl-p-[123I] iodoamphetamine single-photon-emission computed tomography twice and found that the blood flow increased in different regions. Prolonged disturbance of consciousness following an encephalitic episode may be associated with repeated hyperperfusion in various regions resulting from mitochondrial dysfunction. NIID patients presenting with encephalitic episodes can recover gradually and spontaneously even after prolonged disturbances of consciousness.

Injection of exogenous amyloid-β oligomers aggravated cognitive deficits, and activated necroptosis, in APP23 transgenic mice

Alzheimer's disease (AD) is a neurodegenerative disease that is characterized by the loss of synapses and neurons in the brain, and the accumulation of amyloid plaques. Aβ oligomers (AβO) play a critical role in the pathogenesis of AD. Although there is increasing evidence to support the involvement of necroptosis in the pathogenesis of AD, the exact mechanism remains elusive. In the present study, we explored the effect of exogenous AβO injection on cell necroptosis and cognitive deficits in APP23 transgenic mice. We found that intrahippocampal injection of AβO accelerated the development of AD pathology and caused cognitive impairment in APP23 mice. Specifically, AβO injection significantly accelerated the accumulation of AβO and increased the expression level of phosphorylated-tau, and also induced necroptosis. Behavioral tests showed that AβO injection was associated with cognitive impairment. Furthermore, necroptosis induced by AβO injection occurred predominantly in microglia of the AD brain. We speculate that AβO increased necroptosis by activating microglia, resulting in cognitive deficits. Our results may aid in an understanding of the role played by AβO in AD from an alternative perspective and provide new ideas and evidence for necroptosis as a potential intervention and therapeutic target for AD.

A Novel de novo KIF1A Mutation in a Patient with Ataxia, Intellectual Disability and Mild Foot Deformity

Early-onset ataxias are often difficult to diagnose due to the genetic and phenotypic heterogeneity of patients. Whole exome sequencing (WES) is a powerful method for determining causative mutations of early-onset ataxias. We report a case in which a novel de novo KIF1A mutation was identified in a patient with ataxia, intellectual disability and mild foot deformity.A patient presented with sporadic forms of ataxia with mild foot deformity, intellectual disability, peripheral neuropathy, pyramidal signs, and orthostatic hypotension. WES was used to identify a novel de novo mutation in KIF1A, a known causative gene of neurodegeneration and spasticity with or without cerebellar atrophy or cortical visual impairment syndrome (NESCAVS).We report a novel phenotype of NESCAVS that is associated with a novel de novo missense mutation in KIF1A, which provides valuable information for the diagnosis of NESCAVS even in the era of WES. Early rehabilitation of patients with NESCAVS may prevent symptom worsening and improve the disease course.

Case Report: Intraventricular Cerliponase Alfa Treatment in a Patient with Advanced Neuronal Ceroid Lipofuscinosis Type 2

Neuronal ceroid lipofuscinosis type 2 (CLN2) is an autosomal recessive lysosomal disease caused by decreased activity of the enzyme tripeptidyl peptidase 1 (TPP1) due to pathogenic variants in the TPP1 gene. Cerliponase alfa, a recombinant proenzyme form of TPP1, has shown efficacy in preventing motor and language function decline in early-stage CLN2. However, the safety and effects of this therapy in advanced-stage CLN2 are unclear. We herein report a case of intraventricular cerliponase alfa treatment for over a year in a patient with advanced-stage CLN2. The results suggest the safety and potential efficacy of treatment at an advanced stage of CLN2.

The Myocardial Accumulation of Aggregated Desmin Protein in a Case of Desminopathy with a de novo DES p.R406W Mutation

Desminopathy is a cardiac and skeletal myopathy caused by disease-causing variants in the desmin (DES) gene and represents a subgroup of myofibrillar myopathies, where cytoplasmic desmin-postive immunoreactivity is the pathological hallmark. We herein report a 28-year-old Japanese man who was initially diagnosed with sporadic hypertrophic cardiomyopathy with atrioventricular block at 9 years old and developed weakness in the soft palate and extremities. The myocardial tissue dissected during implantation of the ventricular-assisted device showed a dilated phase of hypertrophic cardiomyopathy and intracellular accumulation of proteinase K-resistant desmin aggregates. Genetic testing confirmed a de novo mutation of DES, which has already been linked to desminopathy. As the molecular diagnosis of desminopathy is challenging, particularly if patients show predominantly cardiac signs and a routine skeletal muscle biopsy is unavailable, these characteristic pathological findings of endomyocardial proteinase K-resistant desmin aggregates might aid in clinical practice.

Noncanonical splice-site variant in peripheral myelin protein 22 gene (PMP22) in a patient with hereditary neuropathy with liability to pressure palsies

AIM

Hereditary neuropathy with liability to pressure palsies (HNPP) is a peripheral neuropathy with autosomal dominant inheritance. Diagnosis can be made from the characteristic abnormalities determined by nerve conduction studies (NCS), including subclinical deficits at physiological compression sites. Heterozygous deletion of the chromosome 17p11.2-p12 region including the peripheral myelin protein 22 gene (PMP22) is the cause in the majority of cases. However, the loss of function of PMP22 due to frameshift-causing insertion/deletion, missense, nonsense, or splice-site disrupting variants cause HNPP in some patients. We report a case of a patient diagnosed with HNPP on the basis of clinical features and the results of NCS. No deletions of PMP22 were detected by fluorescence in situ hybridization.

METHODS

We performed direct nucleotide sequence analysis and identified a heterozygous variant, c.78 + 3G > T, in PMP22. Since this variant is located outside the canonical splice site at the exon 2-intron 2 junction, we investigated whether the variant causes aberrant splicing and leads to the skipping of exon 2 of PMP22 by in vitro minigene splicing assay.

RESULTS

We demonstrated that the c.78 + 3G > T variant causes the skipping of exon 2 and leads to loss of function of the mutant allele.

CONCLUSION

Searching for sequence variants located outside the canonical splice sites should also be considered even when deletion of PMP22 is not found in a patient with a clinical diagnosis suggesting HNPP.

Nine Hereditary Movement Disorders First Described in Asia: Their History and Evolution

Clinical case studies and reporting are important to the discovery of new disorders and the advancement of medical sciences. Both clinicians and basic scientists play equally important roles leading to treatment discoveries for both cures and symptoms. In the field of movement disorders, exceptional observation of patients from clinicians is imperative, not just for phenomenology but also for the variable occurrences of these disorders, along with other signs and symptoms, throughout the day and the disease course. The Movement Disorders in Asia Task Force (TF) was formed to help enhance and promote collaboration and research on movement disorders within the region. As a start, the TF has reviewed the original studies of the movement disorders that were preliminarily described in the region. These include nine disorders that were first described in Asia: Segawa disease, PARK-Parkin, X-linked dystonia-parkinsonism, dentatorubral-pallidoluysian atrophy, Woodhouse-Sakati syndrome, benign adult familial myoclonic epilepsy, Kufor-Rakeb disease, tremulous dystonia associated with mutation of the calmodulin-binding transcription activator 2 gene, and paroxysmal kinesigenic dyskinesia. We hope that the information provided will honor the original researchers and help us learn and understand how earlier neurologists and basic scientists together discovered new disorders and made advances in the field, which impact us all to this day.

Clinical features of a family with late-onset distal hereditary motor neuropathy harboring p.Pro39Leu variant of HSPB1

BACKGROUND AND AIMS

Pathogenic variants of HSPB1, the gene encoding the small heat shock protein 27, have been reported to cause autosomal dominant distal hereditary motor neuropathy (dHMN) type II and autosomal dominant Charcot-Marie-Tooth (CMT) disease with minimal sensory involvement (CMT2F). This study aimed to describe the clinical features of patients in a family with late-onset dHMN carrying the Pro39Leu variant of HSPB1.

METHODS

Whole-exome sequence analysis identified a heterozygous pathogenic variant (Pro39Leu) of HSPB1 in the proband. The presence of the HSPB1 Pro39Leu variant in two affected individuals was confirmed using direct nucleotide sequence analysis.

RESULTS

Both patients exhibited distal muscle weakness with lower extremity predominance and no obvious sensory deficits, leading to a clinical diagnosis of late-onset dHMN. Nerve conduction studies (NCSs) revealed a subclinical complication of sensory disturbance in one of the patients. The clinical and electrophysiological findings of patients with the HSPB1 Pro39Leu variant in this study and previous reports are summarized.

INTERPRETATION

This study suggests that the clinical spectrum of patients carrying HSPB1 Pro39Leu variants, especially the disease onset, might be broader than expected, and HSPB1 variants should be considered in patients diagnosed with late-onset dHMN. Furthermore, patients with dHMN may have concomitant sensory deficits that should be evaluated using NCSs.

Neurofilament light chain levels in cerebrospinal fluid as a sensitive biomarker for cerebral adrenoleukodystrophy

OBJECTIVE

Adrenoleukodystrophy (ALD) has a poor prognosis when it progresses to the cerebral form (CALD). The aim of this study is to investigate whether cerebrospinal fluid (CSF) neurofilament light chain (cNfL) is a sensitive biomarker for detecting CALD and assessing response to hematopoietic stem cell transplantation (HSCT).

METHODS

We conducted a cross-sectional study of 41 male ALD patients. The cNfL levels in patients with the cerebral form of ALD (CALD) or the cerebello-brainstem form of ALD were compared with those in patients with adrenomyeloneuropathy (AMN). The correlation between cNfL levels and MRI-based Loes severity scores was investigated. A longitudinal analysis was performed on patients who underwent multiple CSF examinations.

RESULTS

The cNfL levels in 22 patients with CALD were significantly higher than those in 14 patients with AMN (median, 5545 vs. 1490 pg/mL; p < 0.001). The cutoff cNfL level of 1930 pg/mL showed good sensitivity (95.5%) and specificity (85.7%) for distinguishing CALD from AMN. The cNfL levels were positively correlated with Loes scores (p < 0.001). The cNfL levels in three AMN patients who later converted to CALD increased above the cutoff level during the conversion period, while the cNfL levels in four patients who remained in AMN were consistently below the cutoff. In 10 ALD patients who underwent HSCT, their cNfL levels decreased 3-24 months after HSCT. Two patients whose cNfL increased after HSCT showed deterioration in cognitive functions.

INTERPRETATION

The cNfL level is useful for evaluating the disease activities of ALD and the response to HSCT.

Genome-wide association study identifies a new susceptibility locus in PLA2G4C for Multiple System Atrophy

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 association ( P = 6.5 × 10 ^-7 ) that was replicated in additional Japanese samples ( P = 2.9 × 10 ^-6 . OR = 1.58; 95% confidence interval, 1.30 to 1.91), and then confirmed as highly significant in a meta-analysis of East Asian population data ( P = 5.0 × 10 ^-15 . Odds ratio= 1.49; 95% CI 1.35 to 1.72). The association of rs2303744 with MSA remained significant in combined European/North American samples ( P =0.023. Odds ratio=1.14; 95% CI 1.02 to 1.28) despite allele frequencies being quite different between these populations. rs2303744 leads to an amino acid substitution in PLA2G4C that encodes the cPLA2γ lysophospholipase/transacylase. The cPLA2γ-Ile143 isoform encoded by the MSA risk allele has significantly decreased transacylase activity compared with the alternate cPLA2γ-Val143 isoform that may perturb membrane phospholipids and α-synuclein biology.

The clinical and molecular spectrum of ZFYVE26-associated hereditary spastic paraplegia: SPG15

In the field of hereditary spastic paraplegia (HSP), progress in molecular diagnostics needs to be translated into robust phenotyping studies to understand genetic and phenotypic heterogeneity and to support interventional trials. ZFYVE26-associated hereditary spastic paraplegia (HSP-ZFYVE26, SPG15) is a rare, early-onset complex HSP, characterized by progressive spasticity and a variety of other neurological symptoms. While prior reports, often in populations with high rates of consanguinity, have established a general phenotype, there is a lack of systematic investigations and a limited understanding of age-dependent manifestation of symptoms. Here we delineate the clinical, neuroimaging and molecular features of 44 individuals from 36 families, the largest cohort assembled to date. Median age at last follow-up was 23.8 years covering a wide age range (11-61 years). While symptom onset often occurred in early childhood [median: 24 months, interquartile range (IQR) = 24], a molecular diagnosis was reached at a median age of 18.8 years (IQR = 8), indicating significant diagnostic delay. We demonstrate that most patients present with motor and/or speech delay or learning disabilities. Importantly, these developmental symptoms preceded the onset of motor symptoms by several years. Progressive spasticity in the lower extremities, the hallmark feature of HSP-ZFYVE26, typically presents in adolescence and involves the distal lower limbs before progressing proximally. Spasticity in the upper extremities was seen in 64%. We found a high prevalence of extrapyramidal movement disorders including cerebellar ataxia (64%) and dystonia (11%). Parkinsonism (16%) was present in a subset and showed no sustained response to levodopa. Cognitive decline and neurogenic bladder dysfunction progressed over time in most patients. A systematic analysis of brain MRI features revealed a common diagnostic signature consisting of thinning of the anterior corpus callosum, signal changes of the anterior forceps and non-specific cortical and cerebellar atrophy. The molecular spectrum included 45 distinct variants, distributed across the protein structure without mutational hotspots. Spastic Paraplegia Rating Scale scores, SPATAX Disability Scores and the Four Stage Functional Mobility Score showed moderate strength in representing the proportion of variation between disease duration and motor dysfunction. Plasma neurofilament light chain levels were significantly elevated in all patients (Mann-Whitney U-test, P < 0.0001) and were correlated inversely with age (Spearman's rank correlation coefficient r = -0.65, P = 0.01). In summary, our systematic cross-sectional analysis of HSP-ZFYVE26 patients across a wide age-range, delineates core clinical, neuroimaging and molecular features and identifies markers of disease severity. These results raise awareness to this rare disease, facilitate an early diagnosis and create clinical trial readiness.

High-dose ubiquinol supplementation in multiple-system atrophy: a multicentre, randomised, double-blinded, placebo-controlled phase 2 trial

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-blinded, placebo-controlled phase 2 trial. Patients with MSA were randomly assigned (1:1) to either ubiquinol (1500 mg/day) or placebo. The primary efficacy outcome was the change in the unified multiple system atrophy rating scale (UMSARS) part 2 at 48 weeks. Efficacy was assessed in all patients who completed at least one efficacy assessment (full analysis set). Safety analyses included patients who completed at least one dose of investigational drug. This trial is registered with UMIN-CTR (UMIN000031771), where the drug name of MSA-01 was used to designate ubiquinol.

Findings

Between June 26, 2018, and May 27, 2019, 139 patients were enrolled and randomly assigned to the ubiquinol group (n = 69) or the placebo group (n = 70). A total of 131 patients were included in the full analysis set (63 in the ubiquinol group; 68 in the placebo group). This study met the primary efficacy outcome (least square mean difference in UMSARS part 2 score (-1.7 [95% CI, -3.2 to -0.2]; P = 0.023)). The ubiquinol group also showed better secondary efficacy outcomes (Barthel index, Scale for the Assessment and Rating of Ataxia, and time required to walk 10 m). Rates of adverse events potentially related to the investigational drug were comparable between ubiquinol (n = 15 [23.8%]) and placebo (n = 21 [30.9%]).

Interpretation

High-dose ubiquinol was well-tolerated and led to a significantly smaller decline of UMSARS part 2 score compared with placebo.

Funding

Japan Agency for Medical Research and Development.

A case of intravascular lymphoma presenting with a lesion in the splenium of the corpus callosum

Intravascular lymphoma (IVL) is difficult to diagnose because its clinical presentation and laboratory and imaging findings are nonspecific. Herein, we report a case of IVL presenting as a lesion in the splenium of the corpus callosum. A 52-year-old man attended the emergency department with a 2-week history of progressively worsening abnormal behavior and gait disturbance. Magnetic resonance imaging on admission revealed an oval lesion in the splenium of the corpus callosum. The follow-up magnetic resonance imaging performed 2 months after disease onset revealed multiple high-signal areas in the bilateral cerebral white matter on T2-weighted images and diffusion-weighted images. The blood test results showed an elevated level of lactate dehydrogenase and serum-soluble interleukin-2 receptor. These findings were compatible with the diagnosis of IVL. IVL is often difficult to diagnose due to a wide variety of clinical presentations and imaging findings.

Favorable outcome of hematopoietic stem cell transplantation in late-onset Krabbe disease

BACKGROUND

Late-onset Krabbe disease is a disorder with autosomal recessive inheritance caused by a deficiency in galactocerebrosidase (GALC) activity. Its late-onset form usually shows slow disease progression with atypical symptoms including spastic paresis. The efficacy of hematopoietic stem cell transplantation (HSCT) in late-onset Krabbe disease has not been fully established.

CASE REPORT

We describe the case of a patient with late-onset Krabbe disease showing progressive spastic paraparesis. At the age of 18, one and a half years after the development of symptoms, the patient underwent HSCT. After HSCT, the patient's GALC activity returned to a normal level and the lesions in the brain and spinal cord became faint on images. Over two and a half years after the HSCT, the patient's gait remained spastic, however, an improvement in gait speed and modified Rankin Scale score was observed. No severe adverse events occurred during this period.

CONCLUSION

Our experience reported herein provides additional evidence for a favorable course in HSCT conducted in the early course of late-onset Krabbe disease.

Copper Deficiency in Wilson's Disease with a Normal Zinc Value

Copper deficiency (CD) is a rare complication of long-term treatment of Wilson's disease (WD) and is usually accompanied by high serum zinc levels. A 57-year-old woman with WD presented with limb weakness and sensory disturbance due to myeloneuropathy and macrocytic anemia after 36 years of treatment. Markedly reduced serum free copper values confirmed CD, which was considered to be caused by progressive dysphagia and severe diarrhea rather than zinc overdose because of the normal serum zinc levels. Discontinuing copper-reducing therapy and increasing copper intake improved her symptoms. Physicians should be alert for the risk of CD in WD patients, especially those with dysphagia.

CSF P-Tau181 and Other Biomarkers in Patients With Neuronal Intranuclear Inclusion Disease

BACKGROUND AND OBJECTIVES

CSF tau phosphorylated at threonine 181 (p-tau181) is a widely used biomarker for Alzheimer disease (AD) and has recently been regarded to reflect β-amyloid and/or p-tau deposition in the AD brain. Neuronal intranuclear inclusion disease (NIID) is a neurodegenerative disease characterized by intranuclear inclusions in neurons, glial cells, and other somatic cells. Symptoms include dementia, neuropathy, and others. CSF biomarkers were not reported. The objective of this study was to investigate whether CSF biomarkers including p-tau181 are altered in patients with NIID.

METHODS

This was a retrospective observational study. CSF concentrations of p-tau181, total tau, amyloid-beta 1-42 (Aβ42), monoamine metabolites homovanillic acid (HVA), and 5-hydroxyindole acetic acid (5-HIAA) were compared between 12 patients with NIID, 120 patients with Alzheimer clinical syndrome biologically confirmed based on CSF biomarker profiles, and patients clinically diagnosed with other neurocognitive disorders (dementia with Lewy bodies [DLB], 24; frontotemporal dementia [FTD], 13; progressive supranuclear palsy [PSP], 21; and corticobasal syndrome [CBS], 13). Amyloid PET using Pittsburgh compound B (PiB) was performed in 6 patients with NIID.

RESULTS

The mean age of patients with NIID, AD, DLB, FTD, PSP, and CBS was 71.3, 74.6, 76.8, 70.2, 75.5, and 71.9 years, respectively. CSF p-tau181 was significantly higher in NIID (72.7 ± 24.8 pg/mL) compared with DLB, PSP, and CBS and was comparable between NIID and AD. CSF p-tau181 was above the cutoff value (50.0 pg/mL) in 11 of 12 patients with NIID (91.7%). Within these patients, only 2 patients showed decreased CSF Aβ42, and these patients showed negative or mild local accumulation in PiB PET, respectively. PiB PET scans were negative in the remaining 4 patients tested. The proportion of patients with increased CSF p-tau181 and normal Aβ42 (A-T+) was significantly higher in NIID (75%) compared with DLB, PSP, and CBS (4.2%, 4.8%, and 7.7%, respectively). CSF HVA and 5-HIAA concentrations were significantly higher in patients with NIID compared with disease controls.

DISCUSSION

CSF p-tau181 was increased in patients with NIID without amyloid accumulation. Although the deposition of p-tau has not been reported in NIID brains, the molecular mechanism of tau phosphorylation or secretion of p-tau may be altered in NIID.

A novel homozygous nonsense variant of LMF1 in pregnancy-induced hypertriglyceridemia with acute pancreatitis

Hypertriglyceridemia (HTG)-induced pancreatitis during pregnancy could lead to maternal and fetal death. However, its genetic bases are not fully understood, and its treatment strategies are yet to be established. Here we report a case with a novel homozygous nonsense variant of LMF1 in pregnancy-associated HTG with acute pancreatitis. Our patient had childhood-onset severe HTG that had been well-controlled by dietary management in the non-pregnant period with plasma triglyceride (TG) levels at around 200 mg/dL. Milky plasma was noted at the first-trimester pregnancy checkup, followed by a severe increase in plasma TG (10,500 mg/dL) that resulted in pancreatitis in the last trimester. The implementation of strict dietary fat restriction (less than 4 grams per day) reduced plasma TG levels and led to successful delivery. Exome sequencing revealed a novel homozygous nonsense variant in LMF1 (c.697C>T, p.Arg233Ter). The activities of lipoprotein lipase (LPL) and hepatic lipase in post-heparin plasma were not abolished but reduced. The use of pemafibrate decreased plasma TG levels with a concomitant increase in LPL activity. HTG in childhood or early pregnancy is commonly assumed to be polygenic in origin but should be regarded as a feature suggestive of monogenic hyperchylomicronemia. Adequate TG monitoring and dietary fat restriction should be implemented to prevent potentially lethal events of pancreatitis.

Recent advances in CGG repeat diseases and a proposal of fragile X-associated tremor/ataxia syndrome, neuronal intranuclear inclusion disease, and oculophryngodistal myopathy (FNOP) spectrum disorder

While whole genome sequencing and long-read sequencing have become widely available, more and more focuses are on noncoding expanded repeats. Indeed, more than half of noncoding repeat expansions related to diseases have been identified in the five years. An exciting aspect of the progress in this field is an identification of a phenomenon called repeat motif-phenotype correlation. Repeat motif-phenotype correlation in noncoding repeat expansion diseases is first found in benign adult familial myoclonus epilepsy. The concept is extended in the research of CGG repeat expansion diseases. In this review, we focus on newly identified CGG repeat expansion diseases, update the concept of repeat motif-phenotype correlation in CGG repeat expansion diseases, and propose a clinical concept of FNOP (fragile X-associated tremor/ataxia syndrome, neuronal intranuclear inclusion disease, and oculopharyngodistal myopathy)-spectrum disorder, which shares clinical features and thus probably share some common disease pathophysiology, to further facilitate discussion and progress in this field.

Proteomic profile of nuclei containing p62-positive inclusions in a patient with neuronal intranuclear inclusion disease

Neuronal intranuclear inclusion disease (NIID) is a neurodegenerative disease characterized by eosinophilic hyaline intranuclear inclusions in the neurons, glial cells, and other somatic cells. Although CGG repeat expansions in NOTCH2NLC have been identified in most East Asian patients with NIID, the pathophysiology of NIID remains unclear. Ubiquitin- and p62-positive intranuclear inclusions are the pathological hallmark of NIID. Targeted immunostaining studies have identified several other proteins present in these inclusions. However, the global molecular changes within nuclei with these inclusions remained unclear. Herein, we analyzed the proteomic profile of nuclei with p62-positive inclusions in a NIID patient with CGG repeat expansion in NOTCH2NLC to discover candidate proteins involved in the NIID pathophysiology. We used fluorescence-activated cell sorting and liquid chromatography-tandem mass spectrometry (LC-MS/MS) to quantify each protein identified in the nuclei with p62-positive inclusions. The distribution of increased proteins was confirmed via immunofluorescence in autopsy brain samples from three patients with genetically confirmed NIID. Overall, 526 proteins were identified, of which 243 were consistently quantified using MS. A 1.4-fold increase was consistently observed for 20 proteins in nuclei with p62-positive inclusions compared to those without. Fifteen proteins identified with medium or high confidence in the LC-MS/MS analysis were further evaluated. Gene ontology enrichment analysis showed enrichment of several terms, including poly(A) RNA binding, nucleosomal DNA binding, and protein binding. Immunofluorescence studies confirmed that the fluorescent intensities of increased RNA-binding proteins identified by proteomic analysis, namely hnRNP A2/B1, hnRNP A3, and hnRNP C1/C2, were higher in the nuclei with p62-positive inclusions than in those without, which were not confined to the intranuclear inclusions. We identified several increased proteins in nuclei with p62-positive inclusions. Although larger studies are needed to validate our results, these proteomic data may form the basis for understanding the pathophysiology of NIID.

Insights into familial adult myoclonus epilepsy pathogenesis: How the same repeat expansion in six unrelated genes may lead to cortical excitability

Familial adult myoclonus epilepsy (FAME) results from the same pathogenic TTTTA/TTTCA pentanucleotide repeat expansion in six distinct genes encoding proteins with different subcellular localizations and very different functions, which poses the issue of what causes the neurobiological disturbances that lead to the clinical phenotype. Postmortem and electrophysiological studies have pointed to cortical hyperexcitability as well as dysfunction and neurodegeneration of both the cortex and cerebellum of FAME subjects. FAME expansions, contrary to the same expansion in DAB1 causing spinocerebellar ataxia type 37, seem to have no or limited impact on their recipient gene expression, which suggests a pathophysiological mechanism independent of the gene and its function. Current hypotheses include toxicity of the RNA molecules carrying UUUCA repeats, or toxicity of polypeptides encoded by the repeats, a mechanism known as repeat-associated non-AUG translation. The analysis of postmortem brains of FAME1 expansion (in SAMD12) carriers has revealed the presence of RNA foci that could be formed by the aggregation of RNA molecules with abnormal UUUCA repeats, but evidence is still lacking for other FAME subtypes. Even when the expansion is located in a gene ubiquitously expressed, expression of repeats remains undetectable in peripheral tissues (blood, skin). Therefore, the development of appropriate cellular models (induced pluripotent stem cell-derived neurons) or the study of affected tissues in patients is required to elucidate how FAME repeat expansions located in unrelated genes lead to disease.

Protective Effects of Rivaroxaban on White Matter Integrity and Remyelination in a Mouse Model of Alzheimer's Disease Combined with Cerebral Hypoperfusion

BACKGROUND

Alzheimer's disease (AD) is characterized by cognitive dysfunction and memory loss that is accompanied by pathological changes to white matter. Some clinical and animal research revealed that AD combined with chronic cerebral hypoperfusion (CCH) exacerbates AD progression by inducing blood-brain barrier dysfunction and fibrinogen deposition. Rivaroxaban, an anticoagulant, has been shown to reduce the rates of dementia in atrial fibrillation patients, but its effects on white matter and the underlying mechanisms are unclear.

OBJECTIVE

The main purpose of this study was to explore the therapeutic effect of rivaroxaban on the white matter of AD+CCH mice.

METHODS

In this study, the therapeutic effects of rivaroxaban on white matter in a mouse AD+CCH model were investigated to explore the potential mechanisms involving fibrinogen deposition, inflammation, and oxidative stress on remyelination in white matter.

RESULTS

The results indicate that rivaroxaban significantly attenuated fibrinogen deposition, fibrinogen-related microglia activation, oxidative stress, and enhanced demyelination in AD+CCH mice, leading to improved white matter integrity, reduced axonal damage, and restored myelin loss.

CONCLUSIONS

These findings suggest that long-term administration of rivaroxaban might reduce the risk of dementia.

Somatic GJA4 gain-of-function mutation in orbital cavernous venous malformations

Orbital cavernous venous malformation (OCVM) is a sporadic vascular anomaly of uncertain etiology characterized by abnormally dilated vascular channels. Here, we identify a somatic missense mutation, c.121G > T (p.Gly41Cys) in GJA4, which encodes a transmembrane protein that is a component of gap junctions and hemichannels in the vascular system, in OCVM tissues from 25/26 (96.2%) individuals with OCVM. GJA4 expression was detected in OCVM tissue including endothelial cells and the stroma, through immunohistochemistry. Within OCVM tissue, the mutation allele frequency was higher in endothelial cell-enriched fractions obtained using magnetic-activated cell sorting. Whole-cell voltage clamp analysis in Xenopus oocytes revealed that GJA4 c.121G > T (p.Gly41Cys) is a gain-of-function mutation that leads to the formation of a hyperactive hemichannel. Overexpression of the mutant protein in human umbilical vein endothelial cells led to a loss of cellular integrity, which was rescued by carbenoxolone, a non-specific gap junction/hemichannel inhibitor. Our data suggest that GJA4 c.121G > T (p.Gly41Cys) is a potential driver gene mutation for OCVM. We propose that hyperactive hemichannel plays a role in the development of this vascular phenotype.

Expanded clinical spectrum of oculopharyngodistal myopathy type 1

INTRODUCTION/AIMS

Heterozygous CGG repeat expansions in low-density lipoprotein receptor-related protein 12 (LRP12) have recently been identified as a cause of oculopharyngodistal myopathy (OPDM), and the disease is designated as OPDM type 1 (OPDM1). In contrast to broadening of our knowledge on the genetic background of OPDM, what we know of the clinical phenotype of genetically confirmed OPDM1 remains limited.

METHODS

This investigation was a single-center case series study of OPDM consisting of ten patients from seven families. Repeat-primed polymerase chain reaction and Southern blot analyses were performed to confirm the CGG repeat expansions in LRP12. Clinical findings were retrospectively reviewed.

RESULTS

Seven patients from five families were identified as having CGG repeat expansions in LRP12. We found a high prevalence of axial muscle involvement, such as neck muscle weakness (6/7) and fatty infiltration in the rectus abdominis muscle, as revealed by computed tomography (5/5). We identified patients with very subtle oculopharyngeal symptoms, mimicking isolated distal myopathy. Muscle specimens were collected from the biceps brachii and tibialis anterior muscles of three patients. Myopathic changes were more severe with more atrophic fibers forming clusters in the tibialis anterior than the biceps brachii muscles of these three patients. No rimmed vacuoles were observed in the biceps brachii muscles in two of the three patients.

DISCUSSION

This study shows the expanded clinical spectrum of OPDM1, highlighting the importance of axial muscle evaluation in OPDM1. Considering patients with very subtle oculopharyngeal symptoms, genetic analysis of LRP12 should be considered in patients with isolated distal myopathy.

Valosin-containing protein Asp395Gly mutation in a patient with frontotemporal dementia: a case report

Background

Variants in the valosin-containing protein (VCP) gene were identified as one of the causes for inclusion body myopathy associated with Paget disease of the bone and frontotemporal dementia (FTD). Previously identified pathogenic variants in VCP are associated with frontotemporal lobar degeneration with TDP-43 inclusions (FTLD-TDP) pathologically, but p.Asp395Gly VCP was recently reported to cause familial FTD with tauopathy characterized by neurofibrillary tau tangles (NFT) and not FTLD-TDP. We describe the clinical and genetic findings of a patient with p.Asp395Gly valosin-containing protein (VCP), who was diagnosed with FTD without a family history and in the absence of muscle or bone disease comorbidity.

Case presentation

The patient was a 62-year-old man, who developed atypical depression at the age of 37 years. Subsequently, he presented with self-centered behavior at the age of 45 years. The self-centered behavior intensified from around the age of 50 years, which was accompanied by the development of executive dysfunction; therefore, he visited our hospital at 52 years of age. Magnetic resonance imaging revealed bilateral frontal lobe atrophy. Brain perfusion single-photon emission computed tomography revealed bilateral frontal lobe hypoperfusion. The patient fulfilled the diagnostic criteria for behavioral variant of FTD. Ten years after the diagnosis, computed tomography of the trunk and limbs, muscle biopsy, and bone scintigraphy revealed the absence of concomitant muscle and bone disease. The concentrations of cerebrospinal fluid (CSF) total tau and phosphorylated tau proteins were 389 pg/mL and 53.2 pg/mL (cut-off: 50 pg/mL), respectively. Genetic analyses were performed using the whole-exome and Sanger sequencing methods. We identified p.Asp395Gly VCP in this patient with pure FTD.

Conclusions

p.Asp395Gly VCP was identified in a patient with likely sporadic FTD without concomitant muscle and bone disease. The CSF analysis suggested that our patient may have FTD due to NFT accumulation similar to the familial FTD patients with p.Asp395Gly VCP recently reported. Our findings suggest that a genetic search for the pathogenic variants of VCP should be considered not only for familial FTD, but also for patients with sporadic FTD, even in the absence of comorbid muscle or bone disease.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12883-022-02951-4.

APOE Alleles With Tau and Aβ Pathology In Patients With Amyotrophic Lateral Sclerosis and Parkinsonism-Dementia Complex in the Kii Peninsula

BACKGROUND AND OBJECTIVES

To examine the association of the apolipoprotein E gene (APOE) ε4 and ε2 alleles with the pathological features of patients with amyotrophic lateral sclerosis and Parkinsonism-dementia complex cases in the Kii peninsula of Japan (Kii ALS/PDC) METHODS: We analyzed APOE polymorphisms in 18 autopsy patients with ALS/PDC, consisting of nine, eight, and one patient with PDC, ALS, and PDC followed by ALS, respectively. Moreover, we revealed the relationship between APOE polymorphisms and Aβ and tau pathologies, respectively.

RESULTS

The frequency of the ε4 allele was not different between patients with Kii ALS/PDC and control participants. APOE ε4 was associated with increased Aβ pathology (p=0.005 by χ² test) but not with increased tau pathology (p=0.984). The frequency of the ε2 allele was apparently higher than that of control participants (p=0.254). APOE ε2 allele was associated with increased tau pathology (p=0.009) and not with reduced Aβ pathology (p=0.383) in patients with Kii ALS/PDC.

DISCUSSION

Although there was no overrepresentation of the frequency of the ε4 or ε2 allele, our findings suggest that the ε2 allele is associated with increased tau pathology and not with reduced Aβ pathology in patients with Kii ALS/PDC.

Nonsyndromic arteriopathy and aortopathy and vascular Ehlers-Danlos syndrome causing COL3A1 variants

Vascular Ehlers-Danlos syndrome (vEDS) is an autosomal dominant genetic disorder characterized by soft connective tissue vulnerability due to dysfunction of Type III collagen and caused by the pathogenic variants in COL3A1 gene. In the era of next-generation sequencing, multiple genes including COL3A1 can be simultaneously analyzed, and among patients suffering from aortopathy even without any other clinical features suggestive of vEDS, pathogenic COL3A1 variants have been increasingly identified. Here, we briefly summarize the characteristics of 12 Japanese patients from 11 families with arteriopathy and pathogenic or likely pathogenic COL3A1 variants in our hospital. Five patients did not have any extra-arterial clinical features, however, the multigene panel testing for hereditary thoracic aortic aneurysm and dissection unexpectedly revealed that two had glycine substitutions in the triple-helical region and three had haploinsufficient type variants in the COL3A1 gene, whose pathogenicities were all classified as pathogenic or likely pathogenic. Further genetic screening and identification of pathogenic variants in patients with nonsyndromic arteriopathy and aortopathy will enable us to develop risk-stratification and management based on the genetic diagnosis.

Multi-type RFC1 repeat expansions as the most common cause of hereditary sensory and autonomic neuropathy

Non-coding repeat expansions within RFC1 and NOTCH2NLC genes have lately been linked to multisystem neurodegenerative diseases, which also shed light on yet undiagnosed patients with inherited peripheral neuropathies. The aim of this study was to identify the genetic basis of patients with hereditary sensory and autonomic neuropathy (HSAN). We collected 79 unrelated DNA samples clinically suspected with HSAN from multiple regions of Japan. Mutation screening was first performed using gene panel sequencing and whole-exome sequencing. Pathogenic/likely pathogenic variants were identified from genes of WNK1/HSN2 (6 cases), SCN9A (3 cases), NTRK1 (3 cases), and DNMT1 (2 cases). Subsequently, long-range flanking PCR and repeat-primed PCR were applied to analyze repeat expansions in RFC1 and NOTCH2NLC. Bi-allelic RFC1 repeat expansions were detected from 20 adult-onset HSAN patients, consisting of [(AAGGG)exp/(AAGGG)exp] (8 cases), [(ACAGG)exp/(ACAGG)exp] (8 cases), and [(AAGGG)exp/(ACAGG)exp] (4 cases). GGC repeat expansion in NOTCH2NLC was found in 1 case. Single-nucleotide variant-based haplotype analysis of patients harboring disease-associated repeat expansions in RFC1 revealed distinguishable haplotypes among subgroups with different repeat genotypes. These findings substantially redefine the genetic spectrum of HSAN, where multi-type RFC1 repeat expansions account for 25.3% of all patients, highlighting the necessity of genetic screening, particularly for adult-onset patients.

Diagnostic Values of Venous Peak Lactate, Lactate-to-pyruvate Ratio, and Fold Increase in Lactate from Baseline in Aerobic Exercise Tests in Patients with Mitochondrial Diseases

Objective Although aerobic exercise tests on cycle ergometry have long been used for initial assessments of cases of suspected mitochondrial disease, the test parameters in patients with final diagnoses of other diseases via the widely used 15 W for 15 minutes exercise protocol have not been fully characterized. Methods We retrospectively reviewed all patients who underwent the test at our institution. We classified the patients with genetic diagnoses or those who met previously reported clinical criteria as having mitochondrial diseases and those with a final diagnosis of another disease as having other diseases. Results were available from 6 patients with mitochondrial disease and 15 with other diseases. Results During the test, elevated venous peak lactate above the upper normal limit of healthy controls at rest [19.2 mg/dL (2.13 mM)] was observed in 3 patients with mitochondrial diseases (50.0%) and 5 with other diseases (33.3%). In the group of patients with elevated venous peak lactate, a lactate-to-pyruvate ratio of >20 was observed in all 3 patients with mitochondrial disease but in only 1 of the 5 with other diseases. More than a 2-fold increase in venous lactate from baseline was observed in 4 patients with mitochondrial disease (66.7%) and 1 with another disease (6.7%). Conclusion Elevated venous peak lactate levels were observed in patients with final diagnoses of other diseases, even under a low 15-minute workload at 15 W. The lactate-to-pyruvate ratio and increase in lactate level from baseline may add diagnostic value to venous peak lactate levels alone.

Comprehensive Genetic Analyses of Inherited Peripheral Neuropathies in Japan: Making Early Diagnosis Possible

Various genomic variants were linked to inherited peripheral neuropathies (IPNs), including large duplication/deletion and repeat expansion, making genetic diagnosis challenging. This large case series aimed to identify the genetic characteristics of Japanese patients with IPNs. We collected data on 2695 IPN cases throughout Japan, in which PMP22 copy number variation (CNV) was pre-excluded. Genetic analyses were performed using DNA microarrays, next-generation sequencing-based gene panel sequencing, whole-exome sequencing, CNV analysis, and RFC1 repeat expansion analysis. The overall diagnostic rate and the genetic spectrum of patients were summarized. We identified 909 cases with suspected IPNs, pathogenic or likely pathogenic variants. The most common causative genes were MFN2, GJB1, MPZ, and MME. MFN2 was the most common cause for early-onset patients, whereas GJB1 and MPZ were the leading causes of middle-onset and late-onset patients, respectively. Meanwhile, GJB1 and MFN2 were leading causes for demyelinating and axonal subtypes, respectively. Additionally, we identified CNVs in MPZ and GJB1 genes and RFC1 repeat expansions. Comprehensive genetic analyses explicitly demonstrated the genetic basis of our IPN case series. A further understanding of the clinical characteristics of IPN and genetic spectrum would assist in developing efficient genetic testing strategies and facilitate early diagnosis.

[Recommendations (Proposal) for promoting research for overcoming neurological diseases 2020]

The Japanese Society of Neurology discusses research, education, and medical care in the field of neurology and makes recommendations to the national government. Dr. Mizusawa, the former representative director of the Japanese Society of Neurology, selected committee members and made "Recommendations for Promotion of Research for Overcoming Neurological Diseases" in 2013. After that, the Future Vision Committee was established in 2014, and these recommendations have been revised once every few years by the committee. This time, the Future Vision Committee made the latest recommendations from 2020 to 2021. In this section I, we will discuss clinical and research topics of neurology categorized by the methodology, including genetic research, translational research, nucleic acid therapies, iPS research, and nursing/welfare.

[Recommendations (Proposal) for promoting research for overcoming neurological diseases 2020]

The Japanese Society of Neurology discusses research, education, and medical care in the field of neurology and makes recommendations to the national government. Dr. Mizusawa, the former representative director of the Japanese Society of Neurology, selected committee members and made "Recommendations for Promotion of Research for Overcoming Neurological Diseases" in 2013. After that, the Future Vision Committee was established in 2014, and these recommendations have been revised once every few years by the committee. This time, the Future Vision Committee made the latest recommendations from 2020 to 2021. In this section II, we will discuss clinical and research topics of neurology categorized by the diseases. In each field, the hot topic of the disease was described by the expert.

Novel de novo POLR3B mutations responsible for demyelinating Charcot-Marie-Tooth disease in Japan

Background

Biallelic POLR3B mutations cause a rare hypomyelinating leukodystrophy. De novo POLR3B heterozygous mutations were recently associated with afferent ataxia, spasticity, variable intellectual disability, and epilepsy, and predominantly demyelinating sensorimotor peripheral neuropathy.

Methods

We performed whole‐exome sequencing (WES) of DNA samples from 804 Charcot–Marie–Tooth (CMT) cases that could not be genetically diagnosed by DNA‐targeted resequencing microarray using next‐generation sequencers. Using WES data, we analyzed the POLR3B mutations and confirmed their clinical features.

Results

We identified de novo POLR3B heterozygous missense mutations in two patients. These patients presented with early‐onset demyelinating sensorimotor neuropathy without ataxia, spasticity, or cognitive impairment. Patient 1 showed mild cerebellar atrophy and spinal cord atrophy on magnetic resonance imaging and eventually died of respiratory failure in her 50s. We classified these mutations as pathogenic based on segregation studies, comparison with control database, and in silico analysis.

Conclusion

Our study is the third report on patients with demyelinating CMT harboring heterozygous POLR3B mutations and verifies the pathogenicity of POLR3B mutations in CMT. Although extremely rare in our large Japanese case series, POLR3B mutations should be added to the CMT‐related gene panel for comprehensive genetic screening, particularly for patients with early‐onset demyelinating CMT.

Efficacy of canakinumab on AA amyloidosis in late-onset NLRP3-associated autoinflammatory disease with an I574F somatic mosaic mutation

There have been hundreds of reports on mutations in the NLRP3 gene related to NLRP3-associated autoinflammatory disease, but few of these mutations have occurred as both germline and somatic mosaic mutations. In this case-based review, we report a 68-year-old man with an NLRP3-associated autoinflammatory disease. He developed secondary amyloidosis, including a renal and colorectal presentation in his 50 s. Sequencing of the NLRP3 gene revealed an I574F somatic mosaic mutation, which has up to now only been reported in germline mutations. The patient was treated with canakinumab, which had great efficacy not only on the NLRP3-mediated inflammation, but also on the chronic renal failure and proteinuria provoked by secondary renal amyloidosis. To evaluate the effectiveness of canakinumab, we conducted a literature research on renal amyloidosis related to NLRP3-associated autoinflammatory disease treated with canakinumab. Although our patient had a relatively long medical history and greater amounts of proteinuria than other reported cases, canakinumab had great efficacy on renal impairment, in similar to other reported cases. Along with the first report of a late-onset I574F somatic mosaic mutation in NLRP3-associated autoinflammatory disease, this report demonstrates the effectiveness of canakinumab on renal amyloidosis, probably through the way that IL-1β blockade minimizes podocyte injury.