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Ravi B, Antonellis A, Sumner CJ, Lieberman AP. Genetic approaches to the treatment of inherited neuromuscular diseases. Hum Mol Genet 2020; 28:R55-R64. [PMID: 31227836 DOI: 10.1093/hmg/ddz131] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2019] [Revised: 04/29/2019] [Accepted: 06/07/2019] [Indexed: 12/17/2022] Open
Abstract
Inherited neuromuscular diseases are a heterogeneous group of developmental and degenerative disorders that affect motor unit function. Major challenges toward developing therapies for these diseases include heterogeneity with respect to clinical severity, age of onset and the primary cell type that is affected (e.g. motor neurons, skeletal muscle and Schwann cells). Here, we review recent progress toward the establishment of genetic therapies to treat inherited neuromuscular disorders that affect both children and adults with a focus on spinal muscular atrophy, Charcot-Marie-Tooth disease and spinal and bulbar muscular atrophy. We discuss clinical features, causative mutations and emerging approaches that are undergoing testing in preclinical models and in patients or that have received recent approval for clinical use. Many of these efforts employ antisense oligonucleotides to alter pre-mRNA splicing or diminish target gene expression and use viral vectors to replace expression of mutant genes. Finally, we discuss remaining challenges for optimizing the delivery and effectiveness of these approaches. In sum, therapeutic strategies for neuromuscular diseases have shown encouraging results, raising hope that recent strides will translate into significant clinical benefits for patients with these disorders.
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Cortese MM, Kambhampati AK, Schuster JE, Alhinai Z, Nelson GR, Guzman Perez-Carrillo GJ, Vossough A, Smit MA, McKinstry RC, Zinkus T, Moore KR, Rogg JM, Candee MS, Sejvar JJ, Hopkins SE. A ten-year retrospective evaluation of acute flaccid myelitis at 5 pediatric centers in the United States, 2005-2014. PLoS One 2020; 15:e0228671. [PMID: 32053652 PMCID: PMC7018000 DOI: 10.1371/journal.pone.0228671] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Accepted: 01/20/2020] [Indexed: 12/18/2022] Open
Abstract
Background Acute flaccid myelitis (AFM) is a severe illness similar to paralytic poliomyelitis. It is unclear how frequently AFM occurred in U.S. children after poliovirus elimination. In 2014, an AFM cluster was identified in Colorado, prompting passive US surveillance that yielded 120 AFM cases of unconfirmed etiology. Subsequently, increased reports were received in 2016 and 2018. To help inform investigations on causality of the recent AFM outbreaks, our objective was to determine how frequently AFM had occurred before 2014, and if 2014 cases had different characteristics. Methods We conducted a retrospective study covering 2005–2014 at 5 pediatric centers in 3 U.S. regions. Possible AFM cases aged ≤18 years were identified by searching discharge ICD-9 codes and spinal cord MRI reports (>37,000). Neuroradiologists assessed MR images, and medical charts were reviewed; possible cases were classified as AFM, not AFM, or indeterminate. Results At 5 sites combined, 26 AFM cases were identified from 2005–2013 (average annual number, 3 [2.4 cases/100,000 pediatric hospitalizations]) and 18 from 2014 (12.6 cases/100,000 hospitalizations; Poisson exact p<0.0001). A cluster of 13 cases was identified in September–October 2014 (temporal scan p = 0.0001). No other temporal or seasonal trend was observed. Compared with cases from January 2005–July 2014 (n = 29), cases from August–December 2014 (n = 15) were younger (p = 0.002), more frequently had a preceding respiratory/febrile illness (p = 0.03), had only upper extremities involved (p = 0.008), and had upper extremity monoplegia (p = 0.03). The cases had higher WBC counts in cerebrospinal fluid (p = 0.013). Conclusion Our data support emergence of AFM in 2014 in the United States, and those cases demonstrated distinctive features compared with preceding sporadic cases.
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Abstract
This article serves as a guide for the pediatric orthopedic physical examination for newborn, children, and adolescents. The newborn physical examination is very unique and therefore is classified separately from the children and adolescent examination. The following pages should be used as an overview of the pediatric orthopedic physical examination and to provide normal parameters, guide a more focused approach that will improve proper diagnoses, and aid in developing a proper management plan. The art of examining a pediatric patient comes with time, and some helpful hints (look for the ♠) can improve the experience.
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Sansone VA. Episodic Muscle Disorders. Continuum (Minneap Minn) 2019; 25:1696-1711. [PMID: 31794467 DOI: 10.1212/con.0000000000000802] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
PURPOSE OF REVIEW This article reviews the episodic muscle disorders, including benign cramp-fasciculation syndrome, the periodic paralyses, and the nondystrophic myotonias. The core diagnostic criteria for a diagnosis of primary periodic paralysis, including clues to distinguish between the hypokalemic and hyperkalemic forms, and the distinctive elements that characterize Andersen-Tawil syndrome are discussed. Management of patients with these disorders is also discussed. RECENT FINDINGS Childhood presentations of periodic paralysis have recently been described, including atypical findings. Carbonic anhydrase inhibitors, such as dichlorphenamide, have recently been approved by the US Food and Drug Administration (FDA) for the treatment of both hypokalemic and hyperkalemic forms of periodic paralysis. Muscle MRI may be a useful outcome measure in pharmacologic trials in periodic paralysis. Genetic research continues to identify additional gene mutations responsible for periodic paralysis. SUMMARY This article will help neurologists diagnose and manage episodic muscle disorders and, in particular, the periodic paralyses and the nondystrophic myotonias.
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Abstract
The peripheral nervous system (PNS) is composed of motor neurons, nerve roots, plexuses, peripheral nerves (motor, sensory and autonomic), neuromuscular junction, and skeletal muscles. Disorders of the PNS in neonates most frequently cause weakness, hypotonia, and contractures, which may be generalized or focal. Since these findings may also occur with brain and spinal cord lesions, key features of the history and neurologic exam, together with diagnostic testing, are helpful in reaching a diagnosis. This review covers the diagnostic approach to PNS disorders in the neonate and includes a discussion of representative diseases of the motor neuron, brachial plexus, peripheral nerves, neuromuscular junction, and muscles. The importance of reaching a precise genetic diagnosis is highlighted with a discussion of current and emerging treatments for neonatal PNS diseases, particularly spinal muscular atrophy.
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Abstract
PURPOSE OF REVIEW Weakness is a common reason patients are seen in neurologic consultation. This article reviews the differential diagnosis of neuromuscular disorders in the intensive care unit (ICU), discusses the intensive care needs and evaluation of respiratory failure in patients with neuromuscular disorders, and provides a practical guide for management. RECENT FINDINGS Although primary neuromuscular disorders used to be the most common cause for weakness from peripheral nervous system disease in the ICU, a shift toward ICU-acquired weakness is observed in today's clinical practice. Therefore, determining the cause of weakness is important and may have significant prognostic implications. Guillain-Barré syndrome and myasthenia gravis remain the most common primary neuromuscular disorders in the ICU. In patients with myasthenia gravis, it is important to be vigilant with the airway and institute noninvasive ventilation early in the course of the disease to attempt to avoid the need for intubation. On the other hand, patients with Guillain-Barré syndrome should be intubated without delay if the airway is at risk to avoid further complications. In patients with ICU-acquired weakness, failure to wean from the ventilator is usually the challenge. Early mobility, glucose control, minimizing sedation, and avoiding neuromuscular blocking agents remain the only therapeutic regimen available for ICU-acquired weakness. SUMMARY Critical care management of neuromuscular disorders requires a multidisciplinary approach engaging members of the ICU and consultative teams. Developing an airway management protocol could have implications on outcome and length of stay for patients with neuromuscular disorders in the ICU. Tending to the appropriate nuances of each patient who is critically ill with a neuromuscular disorder through evidence-based medicine can also have implications on length of stay and outcome.
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Moline H, Kalaskar A, Pomputius WF, Lopez A, Routh J, Kenyon C, Griffith J. Notes from the Field: Six Cases of Acute Flaccid Myelitis in Children - Minnesota, 2018. MMWR-MORBIDITY AND MORTALITY WEEKLY REPORT 2019; 68:356-358. [PMID: 30998669 PMCID: PMC6476059 DOI: 10.15585/mmwr.mm6815a4] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Lipnick SL, Agniel DM, Aggarwal R, Makhortova NR, Finlayson SG, Brocato A, Palmer N, Darras BT, Kohane I, Rubin LL. Systemic nature of spinal muscular atrophy revealed by studying insurance claims. PLoS One 2019; 14:e0213680. [PMID: 30870495 PMCID: PMC6417721 DOI: 10.1371/journal.pone.0213680] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Accepted: 02/26/2019] [Indexed: 12/27/2022] Open
Abstract
Objective We investigated the presence of non-neuromuscular phenotypes in patients affected by Spinal Muscular Atrophy (SMA), a disorder caused by a mutation in the Survival of Motor Neuron (SMN) gene, and whether these phenotypes may be clinically detectable prior to clinical signs of neuromuscular degeneration and therefore independent of muscle weakness. Methods We utilized a de-identified database of insurance claims to explore the health of 1,038 SMA patients compared to controls. Two analyses were performed: (1) claims from the entire insurance coverage window; and (2) for SMA patients, claims prior to diagnosis of any neuromuscular disease or evidence of major neuromuscular degeneration to increase the chance that phenotypes could be attributed directly to reduced SMN levels. Logistic regression was used to determine whether phenotypes were diagnosed at significantly different rates between SMA patients and controls and to obtain covariate-adjusted odds ratios. Results Results from the entire coverage window revealed a broad spectrum of phenotypes that are differentially diagnosed in SMA subjects compared to controls. Moreover, data from SMA patients prior to their first clinical signs of neuromuscular degeneration revealed numerous non-neuromuscular phenotypes including defects within the cardiovascular, gastrointestinal, metabolic, reproductive, and skeletal systems. Furthermore, our data provide evidence of a potential ordering of disease progression beginning with these non-neuromuscular phenotypes. Conclusions Our data point to a direct relationship between early, detectable non-neuromuscular symptoms and SMN deficiency. Our findings are particularly important for evaluating the efficacy of SMN-increasing therapies for SMA, comparing the effectiveness of local versus systemically delivered therapeutics, and determining the optimal therapeutic treatment window prior to irreversible neuromuscular damage.
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Malbec R, Chami B, Aeschbach L, Ruiz Buendía GA, Socol M, Joseph P, Leïchlé T, Trofimenko E, Bancaud A, Dion V. µLAS: Sizing of expanded trinucleotide repeats with femtomolar sensitivity in less than 5 minutes. Sci Rep 2019; 9:23. [PMID: 30631115 PMCID: PMC6328573 DOI: 10.1038/s41598-018-36632-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Accepted: 11/23/2018] [Indexed: 11/09/2022] Open
Abstract
We present µLAS, a lab-on-chip system that concentrates, separates, and detects DNA fragments in a single module. µLAS speeds up DNA size analysis in minutes using femtomolar amounts of amplified DNA. Here we tested the relevance of µLAS for sizing expanded trinucleotide repeats, which cause over 20 different neurological and neuromuscular disorders. Because the length of trinucleotide repeats correlates with the severity of the diseases, it is crucial to be able to size repeat tract length accurately and efficiently. Expanded trinucleotide repeats are however genetically unstable and difficult to amplify. Thus, the amount of amplified material to work with is often limited, making its analysis labor-intensive. We report the detection of heterogeneous allele lengths in 8 samples from myotonic dystrophy type 1 and Huntington disease patients with up to 750 CAG/CTG repeats in five minutes or less. The high sensitivity of the method allowed us to minimize the number of amplification cycles and thus reduce amplification artefacts without compromising the detection of the expanded allele. These results suggest that µLAS can speed up routine molecular biology applications of repetitive sequences and may improve the molecular diagnostic of expanded repeat disorders.
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Andersson E, Persson AL, Carlsson CP. Are Auricular Maps Reliable for Chronic Musculoskeletal Pain Disorders?: A Double-Blind Evaluation. Acupunct Med 2018; 25:72-9. [PMID: 17906600 DOI: 10.1136/aim.25.3.72] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Aim To examine the proposed somatotopic relation between the regions in which patients report musculoskeletal pain and tender points located on the external ears according to a map based on commonly used auricular acupuncture maps. Methods Twenty-five patients (16 women) from a chronic pain clinic were included. Patients were asked, before examination of the external ears, if they had past or present musculoskeletal pain in any of 11 body regions. An ear map, collapsed into 11 zones representing the musculoskeletal system, was used. The ear examiner was blinded to the patients’ pain conditions, medical history and ongoing treatment. Patients communicated with the examiner only to express if tenderness was present in the external ear on palpation using a spring-loaded pressure stylus commonly used for auricular acupuncture. The degree of tenderness was registered on a 5-point scale and dichotomised (no tenderness or tenderness). Agreements between the patients’ painful body regions and tenderness in the external ear zones were presented as percentage, kappa values, sensitivity and specificity. Results The 25 patients reported 116 past or present musculoskeletal pain regions and had 110 tender ear zones. No statistically significant agreements were found between the painful body regions and the corresponding tender ear zones. Conclusions Our results did not show agreements between patients’ reported musculoskeletal pain regions and tender zones in the external ears assessed according to commonly used maps in auricular acupuncture using a pressure stylus. However, very tender points occur on the external ear in a population with chronic musculoskeletal pain.
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Sagath L, Lehtokari VL, Välipakka S, Udd B, Wallgren-Pettersson C, Pelin K, Kiiski K. An Extended Targeted Copy Number Variation Detection Array Including 187 Genes for the Diagnostics of Neuromuscular Disorders. J Neuromuscul Dis 2018; 5:307-314. [PMID: 30040739 PMCID: PMC6087456 DOI: 10.3233/jnd-170298] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
BACKGROUND Our previous array, the Comparative Genomic Hybridisation design (CGH-array) for nemaline myopathy (NM), named the NM-CGH array, revealed pathogenic copy number variation (CNV) in the genes for nebulin (NEB) and tropomyosin 3 (TPM3), as well as recurrent CNVs in the segmental duplication (SD), i.e. triplicate, region of NEB (TRI, exons 82-89, 90-97, 98-105). In the light of this knowledge, we have designed and validated an extended CGH array, which includes a selection of 187 genes known to cause neuromuscular disorders (NMDs). OBJECTIVE Our aim was to develop a reliable method for CNV detection in genes related to neuromuscular disorders for routine mutation detection and analysis, as a much-needed complement to sequencing methods. METHODS We have developed a novel custom-made 4×180 k CGH array for the diagnostics of NMDs. It includes the same tiled ultra-high density coverage of the 12 known or putative NM genes as our 8×60 k NM-CGH-array but also comprises a selection of 175 additional genes associated with NMDs, including titin (TTN), at a high to very high coverage. The genes were divided into three coverage groups according to known and potential pathogenicity in neuromuscular disorders. RESULTS The array detected known and putative CNVs in all three gene coverage groups, including the repetitive regions of NEB and TTN. CONCLUSIONS The targeted neuromuscular disorder 4×180 k array-CGH (NMD-CGH-array v1.0) design allows CNV detection for a broader spectrum of neuromuscular disorders at a high resolution.
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Abstract
PURPOSE OF REVIEW This article provides a review of the clinical phenotypes and evaluation of peripheral nerve hyperexcitability syndromes. These rare diagnoses include cramp-fasciculation syndrome, Isaacs syndrome, and Morvan syndrome. Recent investigations have led to an understanding of the autoimmune underpinnings of these conditions and their specific associated antibodies. As the presentation of peripheral nerve hyperexcitability syndromes includes muscle stiffness, twitches, and spasms, which are also shared with certain central nervous system and myopathic conditions, the differential diagnosis of peripheral nerve hyperexcitability syndromes is reviewed. RECENT FINDINGS Peripheral nerve hyperexcitability syndromes share clinical and electrodiagnostic evidence of motor nerve instability; however, their clinical presentations are varied. Case reviews have helped us understand the spectrum of symptoms associated with the three peripheral nerve hyperexcitability syndromes reviewed here: cramp-fasciculation syndrome, Isaacs syndrome, and Morvan syndrome. More recently, research has focused on understanding the voltage-gated potassium channel complex antibodies as well as neoplasms associated with these conditions. SUMMARY The diagnosis of peripheral nerve hyperexcitability syndromes requires a high index of suspicion, support from the physical examination, familiarity with the spectrum of symptoms associated with peripheral nerve hyperexcitability syndromes, and recognition of diagnostic EMG features. Voltage-gated potassium channel complex antibodies are associated with these conditions. Optimum treatment and autoimmune pathogenesis remain areas of active research.
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Rodríguez-Torres D, Jiménez-Jáimez J, Macías-Ruiz R, Álvarez-López M, Tercedor L. Cardiac Manifestations of Neuromuscular Disease. REVISTA ESPANOLA DE CARDIOLOGIA (ENGLISH ED.) 2018; 71:580-582. [PMID: 28601412 DOI: 10.1016/j.rec.2017.03.033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2016] [Accepted: 03/14/2017] [Indexed: 06/07/2023]
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Finsterer J, Stöllberger C. Reasons for missing noncompaction in myopathies and vice versa. Cardiovasc Pathol 2018; 35:20-22. [PMID: 29730526 DOI: 10.1016/j.carpath.2018.04.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Revised: 02/20/2018] [Accepted: 04/03/2018] [Indexed: 11/18/2022] Open
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Dowling JJ, D. Gonorazky H, Cohn RD, Campbell C. Treating pediatric neuromuscular disorders: The future is now. Am J Med Genet A 2018; 176:804-841. [PMID: 28889642 PMCID: PMC5900978 DOI: 10.1002/ajmg.a.38418] [Citation(s) in RCA: 74] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Accepted: 07/31/2017] [Indexed: 12/12/2022]
Abstract
Pediatric neuromuscular diseases encompass all disorders with onset in childhood and where the primary area of pathology is in the peripheral nervous system. These conditions are largely genetic in etiology, and only those with a genetic underpinning will be presented in this review. This includes disorders of the anterior horn cell (e.g., spinal muscular atrophy), peripheral nerve (e.g., Charcot-Marie-Tooth disease), the neuromuscular junction (e.g., congenital myasthenic syndrome), and the muscle (myopathies and muscular dystrophies). Historically, pediatric neuromuscular disorders have uniformly been considered to be without treatment possibilities and to have dire prognoses. This perception has gradually changed, starting in part with the discovery and widespread application of corticosteroids for Duchenne muscular dystrophy. At present, several exciting therapeutic avenues are under investigation for a range of conditions, offering the potential for significant improvements in patient morbidities and mortality and, in some cases, curative intervention. In this review, we will present the current state of treatment for the most common pediatric neuromuscular conditions, and detail the treatment strategies with the greatest potential for helping with these devastating diseases.
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Girabent-Farres M, Monne-Guasch L, Bagur-Calafat C, Fagoaga J. [Spanish translation and validation of the neuromuscular module of the Pediatric Quality of Life Inventory (PedsQL): evaluation of the quality of life perceived by the parents of 2-4-year-old children with neuromuscular diseases]. Rev Neurol 2018; 66:81-88. [PMID: 29368326] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
INTRODUCTION Paediatric neuromuscular disorders, which negatively impact on children's health-related quality of life (HRQoL), are a frequent cause of parental consultation with a physiotherapist. Parents' stress overload triggers a poor perception of their children's HRQoL. For this reason, it is essential to have psychometrically sound instrument to measure parent's perceptions such as the Pediatric Quality of Life Inventory (PedsQL) Neuromuscular Module. AIM To assess the validity and reliability of the Spanish version of PedsQL Neuromuscular Module for parent perceived quality of life of children aged 2-4 with neuromuscular disorders. SUBJECTS AND METHODS The cognitive validity of the Spanish version of PedsQL was carried out with Mapi Research Trust permission. Subsequently, a test-retest was performed with 42 parent volunteers of children aged 2-4 with paediatric neuromuscular disorders. This allowed an evaluation of PedsQL intra-observer concordance and internal consistency. Finally, construct validity was evaluated through factor analysis. RESULTS The Cronbach alpha and all correlation intra-observer coefficients were higher than 0.8, indicating excellent validity and reliability. The construct validity analysis presented 63.5% variability and such analysis suggested that a seven-dimension construct might be a better fit than three. CONCLUSIONS The Spanish version of PedsQL Neuromuscular Module for parent perceived quality of life of children aged 2-4 presented excellent validity and reliability.
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Kaminska M, Noel F, Petrof BJ. Optimal method for assessment of respiratory muscle strength in neuromuscular disorders using sniff nasal inspiratory pressure (SNIP). PLoS One 2017; 12:e0177723. [PMID: 28520769 PMCID: PMC5433762 DOI: 10.1371/journal.pone.0177723] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Accepted: 05/02/2017] [Indexed: 11/30/2022] Open
Abstract
Background The ability to accurately determine respiratory muscle strength is vitally important in patients with neuromuscular disorders (NMD). Sniff nasal inspiratory pressure (SNIP), a test of inspiratory muscle strength, is easier to perform for many NMD patients than the more commonly used determination of maximum inspiratory pressure measured at the mouth (MIP). However, due to an inconsistent approach in the literature, the optimal technique to perform the SNIP maneuver is unclear. Therefore, we systematically evaluated the impact of performing the maneuver with nostril contralateral to the pressure-sensing probe open (SNIPOP) versus closed (SNIPCL), on determination of inspiratory muscle strength in NMD patients as well as control subjects with normal respiratory muscle function. Methods NMD patients (n = 52) and control subjects without respiratory dysfunction (n = 52) were studied. SNIPOP, SNIPCL, and MIP were measured during the same session and compared using ANOVA. Agreement and bias were assessed with intraclass correlation coefficients (ICC) and Bland-Altman plots. Results Mean MIP values were 58.2 and 94.0 cmH2O in NMD and control subjects, respectively (p<0.001). SNIPCL was greater than SNIPOP in NMD (51.9 ±31.0 vs. 36.9 ±25.4 cmH2O; p<0.001) as well as in controls (89.2 ±28.1 vs. 69.2 ±29.2 cmH2O; p<0.001). In both populations, the ICC between MIP and SNIPCL (NMD = 0.78, controls = 0.35) was higher than for MIP and SNIPOP (NMD = 0.53, controls = 0.06). In addition, SNIPCL was more often able to exclude inspiratory muscle weakness than SNIPOP. Conclusions SNIPCL values are systematically higher than SNIPOP in both normal subjects and NMD patients. Therefore, SNIPCL is a useful complementary test for ruling out inspiratory muscle weakness in individuals with low MIP values.
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Sardone V, Zhou H, Muntoni F, Ferlini A, Falzarano MS. Antisense Oligonucleotide-Based Therapy for Neuromuscular Disease. Molecules 2017; 22:molecules22040563. [PMID: 28379182 PMCID: PMC6154734 DOI: 10.3390/molecules22040563] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Revised: 02/28/2017] [Accepted: 03/14/2017] [Indexed: 02/06/2023] Open
Abstract
Neuromuscular disorders such as Duchenne Muscular Dystrophy and Spinal Muscular Atrophy are neurodegenerative genetic diseases characterized primarily by muscle weakness and wasting. Until recently there were no effective therapies for these conditions, but antisense oligonucleotides, a new class of synthetic single stranded molecules of nucleic acids, have demonstrated promising experimental results and are at different stages of regulatory approval. The antisense oligonucleotides can modulate the protein expression via targeting hnRNAs or mRNAs and inducing interference with splicing, mRNA degradation, or arrest of translation, finally, resulting in rescue or reduction of the target protein expression. Different classes of antisense oligonucleotides are being tested in several clinical trials, and limitations of their clinical efficacy and toxicity have been reported for some of these compounds, while more encouraging results have supported the development of others. New generation antisense oligonucleotides are also being tested in preclinical models together with specific delivery systems that could allow some of the limitations of current antisense oligonucleotides to be overcome, to improve the cell penetration, to achieve more robust target engagement, and hopefully also be associated with acceptable toxicity. This review article describes the chemical properties and molecular mechanisms of action of the antisense oligonucleotides and the therapeutic implications these compounds have in neuromuscular diseases. Current strategies and carrier systems available for the oligonucleotides delivery will be also described to provide an overview on the past, present and future of these appealing molecules.
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Kamali T, Stashuk DW. A Density-Based Clustering Approach to Motor Unit Potential Characterizations to Support Diagnosis of Neuromuscular Disorders. IEEE Trans Neural Syst Rehabil Eng 2017; 25:956-966. [PMID: 28252410 DOI: 10.1109/tnsre.2017.2673664] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Electrophysiological muscle classification involves characterization of extracted motor unit potentials (MUPs) followed by the aggregation of these MUP characterizations. Existing techniques consider three classes (i.e., myopathic, neurogenic, and normal) for both MUP characterization and electrophysiological muscle classification. However, diseased-induced MUP changes are continuous in nature, which make it difficult to find distinct boundaries between normal, myopathic, and neurogenic MUPs. Hence, MUP characterization based on more than three classes is better able to represent the various effects of disease. Here, a novel, electrophysio- logical muscle classification system is proposed, which considers a dynamic number of classes for characterizing MUPs. To this end, a clustering algorithm called neighbor- hood distances entropy consistency is proposed to find clusters with arbitrary shapes and densities in an MUP feature space. These clusters represent several concepts of MUP normality and abnormality and are used for MUP characterization instead of the conventional three classes. An examined muscle is then classified by embedding its MUP characterizations in a feature vector fed to an ensemble of support vector machine and nearest neighbor classifiers. For 103 sets of MUPs recorded in tibialis anterior muscles, the proposed system had a 97% electro-physiological muscle classification accuracy, which is significantly higher than in previous works.
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Abstract
The motor unit comprises the anterior horn cell, its axon, and the muscle fibers that it innervates. Although the true number of motor units is unknown, the number of motor units appears to vary greatly between different muscles and between different individuals. Assessment of the number and function of motor units is needed in diseases of the anterior horn cell and other motor nerve disorders. Amyotrophic lateral sclerosis is the most important disease of anterior horn cells. The need for an effective biomarker for assessing disease progression and for use in clinical trials in amyotrophic lateral sclerosis has stimulated the study of methods to measure the number of motor units. Since 1970 a number of different methods, including the incremental, F-wave, multipoint, and statistical methods, have been developed but none has achieved widespread applicability. Two methods (MUNIX and the multipoint incremental method) are in current use across multiple centres and are discussed in detail in this review, together with other recently published methods. Imaging with magnetic resonance and ultrasound is increasingly being applied to this area. Motor unit number estimates have also been applied to other neuromuscular diseases such as spinal muscular atrophy, compression neuropathies, and prior poliomyelitis. The need for an objective measure for the assessment of motor units remains tantalizingly close but unfulfilled in 2016.
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Sanchez B, Rutkove SB. Electrical Impedance Myography and Its Applications in Neuromuscular Disorders. Neurotherapeutics 2017; 14:107-118. [PMID: 27812921 PMCID: PMC5233633 DOI: 10.1007/s13311-016-0491-x] [Citation(s) in RCA: 61] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Electrical impedance myography (EIM) refers to the specific application of electrical bioimpedance techniques for the assessment of neuromuscular disorders. In EIM, a weak, high-frequency electrical current is applied to a muscle or muscle group of interest and the resulting voltages measured. Among its advantages, the technique can be used noninvasively across a variety of disorders and requires limited subject cooperation and evaluator training to obtain accurate and repeatable data. Studies in both animals and human subjects support its potential utility as a primary diagnostic tool, as well as a biomarker for clinical trial or individual patient use. This review begins by providing an overview of the current state and technological advances in electrical impedance myography and its specific application to the study of muscle. We then provide a summary of the clinical and preclinical applications of EIM for neuromuscular conditions, and conclude with an evaluation of ongoing research efforts and future developments.
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Thompson R, Robertson A, Lochmüller H. Natural History, Trial Readiness and Gene Discovery: Advances in Patient Registries for Neuromuscular Disease. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 1031:97-124. [PMID: 29214567 DOI: 10.1007/978-3-319-67144-4_5] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Inherited neuromuscular diseases (NMDs) are genetic disorders that affect the skeletal muscles or the nerves controlling muscle function. With a new generation of diagnostic options and recent advances in translational research improving the opportunities for therapy development for these rare conditions, capturing patient information in databases collecting a range of clinical and genetic data together with contact details has assumed an increasingly important role in trial planning and recruitment as well as natural history data collection. Here we provide an overview of a decade of patient registration activities in the NMD field, with a particular focus on patient registries set up with trial readiness in mind. A summary is provided of databases collecting precise genetic information focused on confirming the causative mutation and their evolution into registries that combine genetic data with additional clinical information useful for trial feasibility and recruitment. Use of these systems for a range of purposes beyond trial recruitment, including natural history assessment, care standards monitoring, genotype-phenotype correlation and disease burden evaluation is also described within the context of research networks (TREAT-NMD) and European Reference Networks (ERN-EURO-NMD). New initiatives including registries using controlled vocabularies for computational accessibility that focus on phenotypic data capture for gene discovery are analysed, and examples of the lessons learned at every stage are provided in order to allow new patient registration initiatives to benefit from the extensive experience gained.
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Abstract
PURPOSE OF REVIEW Neuromuscular diseases are clinically and genetically heterogeneous and probably contain the greatest proportion of causative Mendelian defects than any other group of conditions. These disorders affect muscle and/or nerves with neonatal, childhood or adulthood onset, with significant disability and early mortality. Along with heterogeneity, unidentified and often very large genes require complementary and comprehensive methods in routine molecular diagnosis. Inevitably, this leads to increased diagnostic delays and challenges in the interpretation of genetic variants. RECENT FINDINGS The application of next-generation sequencing, as a research and diagnostic strategy, has made significant progress into solving many of these problems. The analysis of these data is by no means simple, and the clinical input is essential to interpret results. SUMMARY In this review, we describe using examples the recent advances in the genetic diagnosis of neuromuscular disorders, in research and clinical practice and the latest developments that are underway in next-generation sequencing. We also discuss the latest collaborative initiatives such as the Genomics England (Department of Health, UK) genome sequencing project that combine rare disease clinical phenotyping with genomics, with the aim of defining the vast majority of rare disease genes in patients as well as modifying risks and pharmacogenomics factors.
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Posa A, Zierz S. [Postvaccinal complication and medical malpractice law]. VERSICHERUNGSMEDIZIN 2016; 69:67-69. [PMID: 27483686] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The case report involves a 38-year-old female patient with muscular atrophy, paresis and sensory deficits in the right upper limb following several vaccinations. A legal dispute ensued over whether medical malpractice could have caused the neurological deficits. Medical malpractice could not be confirmed. Even vaccinations administered correctly can lead to neurological impairment.
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