CGG repeat expansion in LRP12 in amyotrophic lateral sclerosis.

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disorder characterized by the degeneration of motor neurons. Although repeat expansion in C9orf72 is its most common cause, the pathogenesis of ALS isn't fully clear. In this study, we show that repeat expansion in LRP12, a causative variant of oculopharyngodistal myopathy type 1 (OPDM1), is a cause of ALS. We identify CGG repeat expansion in LRP12 in five families and two simplex individuals. These ALS individuals (LRP12-ALS) have 61-100 repeats, which contrasts with most OPDM individuals with repeat expansion in LRP12 (LRP12-OPDM), who have 100-200 repeats. Phosphorylated TDP-43 is present in the cytoplasm of iPS cell-derived motor neurons (iPSMNs) in LRP12-ALS, a finding that reproduces the pathological hallmark of ALS. RNA foci are more prominent in muscle and iPSMNs in LRP12-ALS than in LRP12-OPDM. Muscleblind-like 1 aggregates are observed only in OPDM muscle. In conclusion, CGG repeat expansions in LRP12 cause ALS and OPDM, depending on the length of the repeat. Our findings provide insight into the repeat length-dependent switching of phenotypes.

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.

The SYNGAP1 3'UTR Variant in ALS Patients Causes Aberrant SYNGAP1 Splicing and Dendritic Spine Loss by Recruiting HNRNPK.

Fused in sarcoma (FUS) is a pathogenic RNA-binding protein in amyotrophic lateral sclerosis (ALS). We previously reported that FUS stabilizes Synaptic Ras-GTPase activating protein 1 (Syngap1) mRNA at its 3' untranslated region (UTR) and maintains spine maturation. To elucidate the pathologic roles of this mechanism in ALS patients, we identified the SYNGAP1 3'UTR variant rs149438267 in seven (four males and three females) out of 807 ALS patients at the FUS binding site from a multicenter cohort in Japan. Human-induced pluripotent stem cell (hiPSC)-derived motor neurons with the SYNGAP1 variant showed aberrant splicing, increased isoform α1 levels, and decreased isoform γ levels, which caused dendritic spine loss. Moreover, the SYNGAP1 variant excessively recruited FUS and heterogeneous nuclear ribonucleoprotein K (HNRNPK), and antisense oligonucleotides (ASOs) blocking HNRNPK altered aberrant splicing and ameliorated dendritic spine loss. These data suggest that excessive recruitment of RNA-binding proteins, especially HNRNPK, as well as changes in SYNGAP1 isoforms, are crucial for spine formation in motor neurons.SIGNIFICANCE STATEMENT It is not yet known which RNAs cause the pathogenesis of amyotrophic lateral sclerosis (ALS). We previously reported that Fused in sarcoma (FUS), a pathogenic RNA-binding protein in ALS, stabilizes synaptic Ras-GTPase activating protein 1 (Syngap1) mRNA at its 3' untranslated region (UTR) and maintains dendritic spine maturation. To elucidate whether this mechanism is crucial for ALS, we identified the SYNGAP1 3'UTR variant rs149438267 at the FUS binding site. Human-induced pluripotent stem cell (hiPSC)-derived motor neurons with the SYNGAP1 variant showed aberrant splicing, which caused dendritic spine loss along with excessive recruitment of FUS and heterogeneous nuclear ribonucleoprotein K (HNRNPK). Our findings that dendritic spine loss is because of excess recruitment of RNA-binding proteins provide a basis for the future exploration of ALS-related RNA-binding proteins.

Genetic factors affecting survival in Japanese patients with sporadic amyotrophic lateral sclerosis: a genome-wide association study and verification in iPSC-derived motor neurons from patients.

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 imputed genotype data of 7 908 526 variants. We used Cox proportional hazards regression analysis with an additive model adjusted for sex, age at onset and the first two principal components calculated from genotyped data to conduct a genome-wide association study. We further analysed messenger RNA (mRNA) and phenotype expression in motor neurons derived from induced pluripotent stem cells (iPSC-MNs) of patients with ALS. RESULTS: Three novel loci were significantly associated with the survival of patients with sporadic ALS-FGF1 at 5q31.3 (rs11738209, HR=2.36 (95% CI, 1.77 to 3.15), p=4.85×10-9), THSD7A at 7p21.3 (rs2354952, 1.38 (95% CI, 1.24 to 1.55), p=1.61×10-8) and LRP1 at 12q13.3 (rs60565245, 2.18 (95% CI, 1.66 to 2.86), p=2.35×10-8). FGF1 and THSD7A variants were associated with decreased mRNA expression of each gene in iPSC-MNs and reduced in vitro survival of iPSC-MNs obtained from patients with ALS. The iPSC-MN in vitro survival was reduced when the expression of FGF1 and THSD7A was partially disrupted. The rs60565245 was not associated with LRP1 mRNA expression. CONCLUSIONS: We identified three loci associated with the survival of patients with sporadic ALS, decreased mRNA expression of FGF1 and THSD7A and the viability of iPSC-MNs from patients. The iPSC-MN model reflects the association between patient prognosis and genotype and can contribute to target screening and validation for therapeutic intervention.

Far-field potential of the compound muscle action potential as a reliable marker in amyotrophic lateral sclerosis.

INTRODUCTION/AIMS: Reliable neurophysiological markers in amyotrophic lateral sclerosis (ALS) are of great interest. The compound muscle action potential (CMAP) amplitude has been a conventional marker, although it is greatly influenced by the electrode position. We propose the far-field potential of the CMAP (FFP-CMAP) as a new neurophysiological marker in ALS. METHODS: Patients with ALS and age-matched healthy controls were enrolled. We used a proximal reference (pref) in addition to the conventional distal reference (dref). Routine CMAP was recorded from the belly-dref lead and FFP-CMAP from the dref-pref lead for the ulnar and tibial nerves. Multiple point stimulation motor unit number estimation (MUNE) was also examined in the ulnar nerve. Inter-rater reproducibility was evaluated by two examiners, and some patients were followed up every 3 mo for 1 y. RESULTS: We tested 17 patients with ALS and 10 controls. The amplitudes of routine CMAP and FFP-CMAP in the ulnar and tibial nerves, and hypothenar MUNE value in the ulnar nerve were significantly decreased in ALS compared to controls. Ulnar FFP-CMAP achieved the highest inter-rater intraclass correlation coefficient (ICC) value (0.942) when compared with routine CMAP (0.880) and MUNE (0.839). The tibial FFP-CMAP had a higher ICC value (0.986) than the routine CMAP (0.697). In this way, the FFP-CMAP showed high inter-rater reproducibility because its shape was not much influenced by the electrode position. During 1-y follow-up, decline of CMAP, FFP, and MUNE showed significant correlations with the Amyotrophic Lateral Sclerosis Functional Rating Scale - Revised (ALSFRS-R). DISCUSSION: The FFP-CMAP shows promise as a reliable marker for ALS.

Correlation of muscle ultrasound with clinical and pathological findings in idiopathic inflammatory myopathies.

INTRODUCTION/AIMS: In idiopathic inflammatory myopathies (IIMs), the change in muscle echogenicity and its histopathological basis are not well understood. We quantitatively measured muscle echogenicity in patients with IIMs and evaluated its correlation with disease activity and histopathological findings. METHODS: This study involved patients with IIMs who underwent both ultrasonography (US) and muscle biopsy, as well as age- and sex-matched rheumatoid arthritis patients as inflammatory disease controls. On US, axial images of the right biceps brachii and vastus medialis were obtained. Standardized histopathological scoring was used to quantitatively measure each pathological domain. RESULTS: Forty-two patients (17 with inclusion body myositis [IBM] and 25 with IIMs other than IBM) and 25 controls were included. The muscle echo intensity (EI) of patients with IIMs was significantly higher than that of controls. Muscle EI showed significant correlations with creatine kinase (r = 0.66, p < .001) and muscle strength (r = -0.73, p < .0001) in patients with non-IBM IIMs. In patients with IBM, moderate correlation was found between muscle EI and quadriceps muscle strength (r = -0.53, p = .028). Histopathologically, the number of infiltrating CD3+ inflammatory cells correlated with muscle EI in the non-IBM group (r = 0.56, p = .017), but not in the IBM group. DISCUSSION: Muscle EI may be useful as a surrogate marker of muscle inflammation in non-IBM IIM. Increased muscle EI may be difficult to interpret in patients with long-standing IBM, which has advanced and complex histopathology.

Genetic and clinical landscape of childhood cerebellar hypoplasia and atrophy.

PURPOSE: Cerebellar hypoplasia and atrophy (CBHA) in children is an extremely heterogeneous group of disorders, but few comprehensive genetic studies have been reported. Comprehensive genetic analysis of CBHA patients may help differentiating atrophy and hypoplasia and potentially improve their prognostic aspects. METHODS: Patients with CBHA in 176 families were genetically examined using exome sequencing. Patients with disease-causing variants were clinically evaluated. RESULTS: Disease-causing variants were identified in 96 of the 176 families (54.5%). After excluding 6 families, 48 patients from 42 families were categorized as having syndromic associations with CBHA, whereas the remaining 51 patients from 48 families had isolated CBHA. In 51 patients, 26 aberrant genes were identified, of which, 20 (76.9%) caused disease in 1 family each. The most prevalent genes were CACNA1A, ITPR1, and KIF1A. Of the 26 aberrant genes, 21 and 1 were functionally annotated to atrophy and hypoplasia, respectively. CBHA+S was more clinically severe than CBHA-S. Notably, ARG1 and FOLR1 variants were identified in 2 families, leading to medical treatments. CONCLUSION: A wide genetic and clinical diversity of CBHA was revealed through exome sequencing in this cohort, which highlights the importance of comprehensive genetic analyses. Furthermore, molecular-based treatment was available for 2 families.

Comparison of two families with and without ataxia harboring novel variants in PRKCG.

Spinocerebellar ataxia type 14 (SCA14) is an autosomal dominant SCA caused by variants of the PRKCG encoding protein kinase C gamma (PKCγ). Although the toxic gain-of-function mechanism is the main cause of SCA14, its molecular pathophysiology remains unclear. To elucidate the molecular pathogenesis of SCA14, we analyzed two families with the variants in PRKCG. Clinical symptoms and neurological findings of two Japanese families were evaluated by neurologists. Exome sequencing was performed using the BGI platform. GFP-tagged PRKCGs harboring the identified variants were transfected into the HeLa cells, and aggregation of PKCγ was analyzed using confocal laser microscopy. Solubility of PKCγ was evaluated by assessing the proportion of insoluble fraction present in1% Triton-X. Patients in family 1 presented with only cerebellar atrophy without ataxia; however, patients in family 2 exhibited cerebellar ataxia, dystonia, and more severe cerebellar atrophy than those in family 1. Exome sequencing identified two novel missense variants of PRKCG:c.171 G > C,p.W57C (family 1), and c.400 T > C,p.C134R (family 2). Both the mutant PKCγ aggregated in the cytoplasm. Although the solubility of PKCγ of the C134R variant was lower than that of the wild-type, PKCγ of W57C retained its solubility. In conclusion, we identified two novel variants of PRKCG. The difference in severity between the two families may be due to the difference in solubility changes observed between the two variants. Decreased solubility of the PKCγ may play an important role in the pathogenesis of SCA14.

Prediction Model of Amyotrophic Lateral Sclerosis by Deep Learning with Patient Induced Pluripotent Stem Cells.

In amyotrophic lateral sclerosis (ALS), early diagnosis is essential for both current and potential treatments. To find a supportive approach for the diagnosis, we constructed an artificial intelligence-based prediction model of ALS using induced pluripotent stem cells (iPSCs). Images of spinal motor neurons derived from healthy control subject and ALS patient iPSCs were analyzed by a convolutional neural network, and the algorithm achieved an area under the curve of 0.97 for classifying healthy control and ALS. This prediction model by deep learning algorithm with iPSC technology could support the diagnosis and may provide proactive treatment of ALS through future prospective research. ANN NEUROL 2021;89:1226-1233.

Serum NfL and CHI3L1 for ALS and parkinsonian disorders in the process of diagnosis.

Serum neurofilament light chain (NfL) and chitinase 3-like 1 (CHI3L1, also called YKL-40) concentrations are attractive candidate biomarkers for neurodegenerative disorders, which include amyotrophic lateral sclerosis (ALS) and parkinsonian disorders. We aimed to assess the diagnostic power of serum NfL and CHI3L1 concentrations with regard to the early diagnosis of ALS and Parkinson's disease (PD). We studied 157 individuals, which included 41 healthy controls, 8 patients with ALS mimics, 18 patients initially diagnosed with ALS (ID-ALS), 32 patients late-diagnosed with ALS (LD-ALS), 29 patients with PD, 12 patients with PD mimics, and 17 patients initially diagnosed with atypical parkinsonian disorders (ID-APDs) at the initial stage of diagnosis. Electrochemiluminescence was used to measure the concentrations of serum NfL and CHI3L1, the diagnostic performance of which was assessed using the area under the receiver operating curves (AUCs). The AUCs of serum NfL were 0.90 for discriminating ALS mimics from LD-ALS at the initial stage of diagnosis and 0.89 for discriminating ALS mimics from ALS (LD/ID-ALS). The AUCs of serum NfL were 0.76 for discriminating PD from PD mimics at the initial stage of diagnosis, and 0.80 for discriminating PD from APD. No significant difference existed in serum CHI3L1 concentrations between individuals with suspected ALS or parkinsonism (p = 0.14, and p = 0.44, respectively). Serum NfL had excellent and almost good diagnostic performances for patients with ALS and PD, respectively, at the initial stage of diagnosis, whereas no significant difference existed in serum CHI3L1 between any groups.

Ultrasound assessment of sarcopenia in patients with rheumatoid arthritis.

OBJECTIVES: To evaluate the efficacy of ultrasound (US) as a diagnostic tool for sarcopenia in patients with rheumatoid arthritis (RA). METHODS: Female RA patients aged >50 years and matched controls were cross-sectionally assessed. Sarcopenia was diagnosed based on the 2019-updated Asian Working Group for Sarcopenia definition. The cross-sectional area (CSA) and echo intensity (EI) of the biceps brachii, rectus femoris, and EI of the vastus lateralis were examined bilaterally. Correction for subcutaneous fat and calculation of the recorrected EI (rcEI) were performed. We performed logistic regression using both muscle rcEI and CSA with receiver operating curve analysis to evaluate the discriminative performance per muscle group. RESULTS: Seventy-eight consecutive RA patients and 15 age-and sex-matched controls were assessed. Sarcopenia was diagnosed in 34 RA patients (43.6%). The rcEI of examined muscles were significantly higher, whereas CSA were significantly lower in sarcopenic RA patients than in non-sarcopenic patients and matched controls. The combined discriminative performance of rcEI and CSA was superior to those of rcEI or CSA alone. CONCLUSIONS: This study suggests the use of US for the diagnosis of sarcopenia in RA patients. The diagnostic performance increases when both echogenicity and CSA are considered together rather than individually.

Analysis of genetic risk factors in Japanese patients with Parkinson's disease.

Parkinson's disease (PD) is caused by a combination of genetic and environmental factors. Notably, genetic risk factors vary according to ethnicity and geographical regions, and few studies have analyzed the frequency of PD causative genes in Japanese patients. Therefore, we performed genetic analyses of Japanese patients with PD. We recruited 221 participants, including 26 patients with familial PD. Genetic risk factors were evaluated by target sequencing and gene dosage analysis. We detected the genetic risk factors in 58 cases (26.2%) and classified patients into three groups to clarify the differences in genetic risk factors by age at onset (AAO). The early-onset group (AAO < 50 years) included 18 cases (44.7%), who tended to have a larger number of genetic risk factors than the later-onset groups. Regarding the AAO for each causative gene, patients with PRKN variants were significantly younger at onset than those bearing LRRK2 variants. LRRK2 variants showed similar frequency in each AAO group. Of note, we identified two novel variants. Patients with early-onset PD have more genetic risk factors than patients with late-onset PD. In Japanese patients with PD, PRKN, and LRRK2 were the major PD-related genes. Particularly, LRRK2 was a common genetic factor in all age groups because of the presence of the Asian-specific variant such as LRRK2 p.G2385R. Accumulation of genetic and clinical data can contribute to the development of treatments for PD.

Diagnostic usefulness of denervation edema in the multifidus muscles using 3-Tesla magnetic resonance imaging in cervical radiculopathy.

BACKGROUND: Diagnosing cervical radiculopathy (CR) can be difficult because of symptomatic overlap with peripheral neuropathies. In this retrospective observational study, we aimed to determine whether short-tau inversion recovery (STIR) magnetic resonance imaging (MRI) sequences are useful for detecting signs of denervation in the multifidus muscles in patients with CR. METHODS: We analyzed the data of 18 patients with CR who developed arm weakness within 1 year. We also included 10 patients with sensorimotor symptoms involving the upper extremities who did not have intervertebral foraminal stenosis on MRI as controls. For each patient with CR, the signal intensity (SI) of the affected multifidus muscles was measured and compared to that on the contralateral side (signal intensity ratio: SIR). RESULTS: Control patients without CR did not exhibit STIR signal abnormalities in the multifidus muscles. Most of the 18 patients with CR were male (83.3%), and the mean age was 59.4 years. Thirteen of 18 CR patients (72.2%) were determined to have STIR signal abnormalities by a radiologist. The mean SIR in the 13 patients with increased SI was significantly higher than that in the five patients without signal abnormalities (1.23 vs 0.97, P = .004), supporting the radiologist's diagnosis. The distribution of signal abnormalities closely followed those identified via clinical and electrophysiological tests, especially severe weakness (P = .044). CONCLUSIONS: Denervation edema of the multifidus muscles can be detected in CR and correlates with clinical/electrophysiological tests and weakness severity, which may aid in CR diagnostics.

MR spectroscopy and imaging-derived measurements in the supplementary motor area for biomarkers of amyotrophic lateral sclerosis.

The diagnosis of amyotrophic lateral sclerosis (ALS) requires both upper and lower motor neuron signs. However, quite a few patients with ALS lack the upper motor neuron sign during the disease. This study sought to investigate whether metabolites, including glutamate (Glu), N-acetyl aspartate (NAA), and gamma aminobutyric acid (GABA), in the supplementary motor area (SMA) measured by magnetic resonance spectroscopy (MRS), could be a surrogate biomarker for ALS. Twenty-five patients with ALS and 12 controls underwent 3.0-T MR scanning, which measured Glu, NAA, and GABA. Finally, receiver operating characteristic (ROC) curves were created and the area under curve (AUC) was calculated to assess the diagnostic power. Logistic regression analysis revealed the usefulness of both Glu and NAA for the differentiation of ALS from controls (Glu, P = 0.009; NAA, P = 0.033). The ratio of Glu to NAA or GABA was significantly increased in patients with ALS (Glu/NAA, P = 0.027; Glu/GABA, P = 0.003). Both the AUCs were more than 0.7, with high specificity but low sensitivity. The present findings might indicate that both the Glu/NAA and the Glu/GABA ratios in the SMA could be potential biomarkers for the diagnosis of ALS.

An autopsy report of a familial amyotrophic lateral sclerosis case carrying VCP Arg487His mutation with a unique TDP-43 proteinopathy.

We here report an autopsy case of familial amyotrophic lateral sclerosis (ALS) with p.Arg487His mutation in the valosin-containing protein (VCP) gene (VCP), in which upper motor neurons (UMNs) were predominantly involved. Moreover, our patient developed symptoms of frontotemporal dementia later in life and pathologically exhibited numerous phosphorylated transactivation response DNA-binding protein of 43 kDa (p-TDP-43)-positive neuronal cytoplasmic inclusions and short dystrophic neurites with a few lentiform neuronal intranuclear inclusions, sharing the features of frontotemporal lobar degeneration with TDP-43 pathology type A pattern. A review of previous reports of ALS with VCP mutations suggests that our case is unique in terms of its UMN-predominant lesion pattern and distribution of p-TDP-43 pathology. Thus, this case report effectively expands the clinical and pathological phenotype of ALS in patients with a VCP mutation.

"Burnt-out" progressive multifocal leukoencephalopathy in idiopathic CD4+ lymphocytopenia.

Progressive multifocal leukoencephalopathy (PML) is a fatal disease caused by John Cunningham virus (JCV) infection; however, a growing number of PML patients now survive longer and achieve remission, largely due to the advent of combination antiretroviral therapy. Several reports have suggested that the pathology in such patients presents only chronic demyelination without characteristic cellular changes, being referred to as "burnt-out" PML. On the other hand, our knowledge of "burnt-out" PML is still substantially limited, especially in patients with non-human immunodeficiency virus infection. Here, we report a case of PML associated with idiopathic CD4+ lymphocytopenia (ICL) who presented with spontaneous remission and survived for 11 years after onset. Notably, postmortem examination revealed surprisingly broad "burnt-out" lesions lacking the classic histopathological findings. However, pathogenic JCV-specific DNA sequences was still present in the autopsied brain tissue. This case suggests that complete remission can be achieved with a persistent presence of JCV-specific pathogenic sequences, even after a catastrophic infection. Considering that there have been a few reported cases of PML with ICL with long survival, the long-term survival of our case may share a favorable immunological response that is unique to a subgroup of ICL.

Detection of nerve enlargement with ultrasound and correlation with skin biopsy findings in painful sensory neuropathy associated with Sjögren's syndrome.

OBJECTIVES: We evaluated usefulness of peripheral nerve ultrasound (US) in detecting abnormality in painful sensory neuropathy (PSN) associated with primary Sjögren's syndrome (pSS), and associations among various clinical factors, US findings, and intraepidermal nerve fiber density (IENFD). METHODS: We conducted a retrospective, single-center, observational study of patients with pSS-PSN. US image was obtained to measure cross sectional area (CSA) of peripheral nerves and compared with matched pSS control. RESULTS: We included 11 patients with pSS-PSN (10 women; age 70.5 ± 5.66) and 17 pSS controls (15 women; age 62.5 ± 16.7). Sural nerve CSA were significantly increased in pSS-PSN group (3.48 ± 1.0 mm2 vs 2.05 ± 0.65 mm2, p = .001). US of sural nerve showed the area under the ROC curve of 0.872 (95% CI, 0.732 - 1). Sural nerve CSA and IENFD of lower leg showed positive correlation. Compared with pSS-PSN patients with abnormal IENFD, those with normal IENFD showed significantly larger sural nerve CSA, and trends toward less systemic disease activity and small fiber impairment with sparing of large fibers. CONCLUSION: US was useful in discriminating pSS patients with PSN from those without. Additionally, US may disclose distinct subsets of pSS-PSN with different clinical findings and IENFD.

Prognosis of amyotrophic lateral sclerosis patients undergoing tracheostomy invasive ventilation therapy in Japan.

OBJECTIVE: The aim of this study is to describe and clarify the factors affecting the prognosis of Japanese patients with amyotrophic lateral sclerosis (ALS) undergoing tracheostomy invasive ventilation (TIV) therapy. METHODS: We conducted a prospective longitudinal observational case-control study using a multicentre registry. ALS patients who started TIV therapy after registration (TIV group) and those who did not receive TIV (non-TIV group) were included. We compared the survival time between the TIV group and the non-TIV group using a propensity score matching analysis and evaluated the prognostic factors in the TIV group. RESULTS: From February 2006 to January 2018, 190 patients in the TIV group and 1093 patients in the non-TIV group were included in this study. The mean age of disease onset and usage rate of gastrostomy and non-invasive ventilation therapy differed between the groups. In the propensity score matching analysis using known prognostic factors, the median overall survival time of the TIV group was significantly greater than that of the non-TIV group (11.33 years vs 4.61 years; p<0.001). Analysis using the Cox proportional hazard model suggested that older age of onset and respiratory onset was an independent factor for poor prognosis after starting TIV therapy. CONCLUSION: We showed that there was a significant difference of approximately 7 years in life expectancy between Japanese ALS patients who did and did not receive TIV therapy.

MiR-33a is a therapeutic target in SPG4-related hereditary spastic paraplegia human neurons.

Recent reports, including ours, have indicated that microRNA (miR)-33 located within the intron of sterol regulatory element binding protein (SREBP) 2 controls cholesterol homeostasis and can be a potential therapeutic target for the treatment of atherosclerosis. Here, we show that SPAST, which encodes a microtubule-severing protein called SPASTIN, was a novel target gene of miR-33 in human. Actually, the miR-33 binding site in the SPAST 3'-UTR is conserved not in mice but in mid to large mammals, and it is impossible to clarify the role of miR-33 on SPAST in mice. We demonstrated that inhibition of miR-33a, a major form of miR-33 in human neurons, via locked nucleic acid (LNA)-anti-miR ameliorated the pathological phenotype in hereditary spastic paraplegia (HSP)-SPG4 patient induced pluripotent stem cell (iPSC)-derived cortical neurons. Thus, miR-33a can be a potential therapeutic target for the treatment of HSP-SPG4.

Classification of needle-EMG resting potentials by machine learning.

INTRODUCTION: The diagnostic importance of audio signal characteristics in needle electromyography (EMG) is well established. Given the recent advent of audio-sound identification by artificial intelligence, we hypothesized that the extraction of characteristic resting EMG signals and application of machine learning algorithms could help classify various EMG discharges. METHODS: Data files of 6 classes of resting EMG signals were divided into 2-s segments. Extraction of characteristic features (384 and 4,367 features each) was used to classify the 6 types of discharges using machine learning algorithms. RESULTS: Across 841 audio files, the best overall accuracy of 90.4% was observed for the smaller feature set. Among the feature classes, mel-frequency cepstral coefficients (MFCC)-related features were useful in correct classification. CONCLUSIONS: We showed that needle EMG resting signals were satisfactorily classifiable by the combination of feature extraction and machine learning, and this can be applied to clinical settings. Muscle Nerve 59:224-228, 2019.