Treating pediatric neuromuscular disorders: The future is now

Effects of a neuropsychosocial teleassistance intervention on social cognition and health-related quality of life of pediatric patients with neuromuscular diseases

OBJECTIVE

This study aimed to determine the effects of a neuropsychosocial teleassistance group-based intervention on improving social cognitive functioning and health-related quality of life (HRQoL) in pediatric neuromuscular diseases (NMD).

METHODS

Thirty-five pediatric patients with NMD were assigned to the neuropsychosocial intervention program (n = 20) or waiting list control condition (n = 15). The intervention group received an integrative approach that combines training in social cognition with cognitive behavioral therapy. All participants completed a neuropsychological and clinical assessment at baseline and follow-up, which included tests of social cognition, both for emotion recognition and theory of mind, and HRQoL. Repeated-measures multivariate analysis of covariance was used to determine the effects of the teleassistance program.

RESULTS

Group × Time interactions revealed significant improvements in the intervention group as compared with the control group for different social cognition's indicators (AR NEPSY-II: p = .003, η2p = .24; TM NEPSY: p < .001, η2p = .35; Verbal task: p < .001, η2p = .35; Happé's Strange Stories: p = .049, η2p = .11) and HRQoL (Psychosocial health: p = .012, η2p = .18; Emotional functioning: p = .037, η2p = 0.13; Social functioning: p = .006, η2p = .21; Total: p = .013, η2p = .17), showing medium to large effects.

CONCLUSIONS

Patients receiving the neuropsychosocial intervention showed improvements in their social cognition performance and psychosocial HRQoL, providing evidence about the positive effects of the program in pediatric patients with NMD. This should be considered in further research and interventions in this field.

The severity of MUSK pathogenic variants is predicted by the protein domain they disrupt

Biallelic loss-of-function variants in the MUSK gene result in two allelic disorders: (1) congenital myasthenic syndrome (CMS; OMIM: 616325), a neuromuscular disorder that has a range of severity from severe neonatal-onset weakness to mild adult-onset weakness, and (2) fetal akinesia deformation sequence (OMIM: 208150), a form of pregnancy loss characterized by severe muscle weakness in the fetus. The MUSK gene codes for muscle-specific kinase (MuSK), a receptor tyrosine kinase involved in the development of the neuromuscular junction. Here, we report a case of neonatal-onset MUSK-related CMS in a patient harboring compound heterozygous deletions in the MUSK gene, including (1) a deletion of exons 2-3 leading to an in-frame MuSK protein lacking the immunoglobulin 1 (Ig1) domain and (2) a deletion of exons 7-11 leading to an out-of-frame, truncated MuSK protein. Individual domains of the MuSK protein have been elucidated structurally; however, a complete MuSK structure generated by machine learning algorithms has clear inaccuracies. We modify a predicted AlphaFold structure and integrate previously reported domain-specific structural data to suggest a MuSK protein that dimerizes in two locations (Ig1 and the transmembrane domain). We analyze known pathogenic variants in MUSK to discover domain-specific genotype-phenotype correlations; variants that lead to a loss of protein expression, disruption of the Ig1 domain, or Dok-7 binding are associated with the most severe phenotypes. A conceptual model is provided to explain the severe phenotypes seen in Ig1 variants and the poor response of our patient to pyridostigmine.

Application of whole exome sequencing in the diagnosis of muscular disorders: a study of Taiwanese pediatric patients

Background

Muscular dystrophies and congenital myopathies encompass various inherited muscular disorders that present diagnostic challenges due to clinical complexity and genetic heterogeneity.

Methods

This study aimed to investigate the use of whole exome sequencing (WES) in diagnosing muscular disorders in pediatric patients in Taiwan. Out of 161 pediatric patients suspected to have genetic/inherited myopathies, 115 received a molecular diagnosis through conventional tests, single gene testing, and gene panels. The remaining 46 patients were divided into three groups: Group 1 (multiplex ligation-dependent probe amplification-negative Duchenne muscular dystrophy) with three patients (6.5%), Group 2 (various forms of muscular dystrophies) with 21 patients (45.7%), and Group 3 (congenital myopathies) with 22 patients (47.8%).

Results

WES analysis of these groups found pathogenic variants in 100.0% (3/3), 57.1% (12/21), and 68.2% (15/22) of patients in Groups 1 to 3, respectively. WES had a diagnostic yield of 65.2% (30 patients out of 46), detecting 30 pathogenic or potentially pathogenic variants across 28 genes.

Conclusion

WES enables the diagnosis of rare diseases with symptoms and characteristics similar to congenital myopathies and muscular dystrophies, such as muscle weakness. Consequently, this approach facilitates targeted therapy implementation and appropriate genetic counseling.

Trends from two decades of orphan designations in paediatric rare neuromuscular diseases

Rare diseases are characterized by substantial unmet need mostly because the majority have limited, or no treatment options and a large number also affect children. Since the inception of EU orphan regulation in 2000 the European Medicines Agency Committee for Orphan Medicinal Products has received several applications for paediatric rare neuromuscular diseases (PERAN) however treatment options remain limited. Here we discuss the results form an observational, retrospective, cross-sectional study to characterize the currently authorised orphan medicinal products (OMP) and orphan designations (OD) given to products for PERAN in the last two decades. In the EU about half of PERAN diseases have at least one active OD approved since 2000, and about half of these are for Duchenne muscular dystrophy (DMD). The large majority of PERAN diseases do not have an authorised medicine with only 6 OMP currently authorised for Spinal muscular atrophy (3); DMD (1) and Myasthenia gravis (2). One in five products have inactive or discontinued regulatory development but clinical trials are ongoing for the vast majority of PERAN diseases, and more than half are in the final stage of clinical research with significantly more products with medical plausibility based in clinical data reaching advanced stages in clinical development.

A novel, patient-derived RyR1 mutation impairs muscle function and calcium homeostasis in mice

RYR1 is the most commonly mutated gene associated with congenital myopathies, a group of early-onset neuromuscular conditions of variable severity. The functional effects of a number of dominant RYR1 mutations have been established; however, for recessive mutations, these effects may depend on multiple factors, such as the formation of a hypomorphic allele, or on whether they are homozygous or compound heterozygous. Here, we functionally characterize a new transgenic mouse model knocked-in for mutations identified in a severely affected child born preterm and presenting limited limb movement. The child carried the homozygous c.14928C>G RYR1 mutation, resulting in the p.F4976L substitution. In vivo and ex vivo assays revealed that homozygous mice fatigued sooner and their muscles generated significantly less force compared with their WT or heterozygous littermates. Electron microscopy, biochemical, and physiological analyses showed that muscles from RyR1 p.F4976L homozygous mice have the following properties: (1) contain fewer calcium release units and show areas of myofibrillar degeneration, (2) contain less RyR1 protein, (3) fibers show smaller electrically evoked calcium transients, and (4) their SR has smaller calcium stores. In addition, single-channel recordings indicate that RyR1 p.F4976L exhibits higher Po in the presence of 100 μM [Ca2+]. Our mouse model partly recapitulates the clinical picture of the homozygous human patient and provides significant insight into the functional impact of this mutation. These results will help understand the pathology of patients with similar RYR1 mutations.

Neuromuscular disorders in the omics era

Neuromuscular disorders encompass a spectrum of conditions characterized by primary lesions within the peripheral nervous system, which include the anterior horn cell, peripheral nerve, neuromuscular junction, and muscle. In pediatrics, most of these disorders are linked to genetic causes. Despite the considerable progress, the diagnosis of these disorders remains a challenging due to wide clinical presentation, disease heterogeneity and rarity. It is noteworthy that certain neuromuscular disorders, once deemed untreatable, can now be effectively managed through novel therapies. Biomarkers emerge as indispensable tools, serving as objective measures that not only refine diagnostic accuracy but also provide guidance for therapeutic decision-making and the ongoing monitoring of long-term outcomes. Herein a comprehensive review of biomarkers in neuromuscular disorders is provided. We highlight the role of omics-based technologies that further characterize neuromuscular pathophysiology as well as identify potential therapeutic targets to guide treatment strategies.

Differential neuropsychological profiles in children and adolescents with motor disability in an inclusive educational setting

The aim of this study was to determine the potential cognitive impairment associated with motor disability in a group of children attending regular schools and to analyze whether there were different cognitive profiles according to the type of motor disability they presented. The study had 87 participants, 31 healthy and 56 with three types of motor disability: Neuromuscular Diseases (NMD Group), Cerebral Palsy-Hemiparesis (CP- HPx Group) and Cerebral Palsy-Diplegia (CP-DP). Ages ranged from 6 to 18 years and they had medium and medium-high socioeconomic and cultural levels. All participants attended regular state-funded and independent schools in an inclusive modality. The neuropsychological assessment included the following cognitive domains: processing speed, working memory, verbal and visual episodic memory, language, visuo-perception and constructive praxis and executive functioning. A second analysis was performed with the groups with CP: one based on the severity of gross motor impairment (GMFCS-E&R scale) and the other based on the levels of manual dexterity (MACS scale). ANCOVAs were performed controlling for age and processing speed in the three analyses. The group with CP-HPx was shown to be the most cognitively impaired of the three groups, with significant deficits in visuo-perception, verbal working memory, and visuo-spatial memory. Subjects with greater gross motor dysfunction (GMFCS-E&R) did not show the greatest cognitive impairment, while those with worse manual dexterity (MACS) exhibited greater cognitive impairment. Children and adolescents with motor disabilities, a priori cognitively normal, present different levels of cognitive impairment. This should be considered when planning educational adaptations for this infant-juvenile population.

Difficulties in social cognitive functioning among pediatric patients with muscular dystrophies

Introduction

Pediatric muscular dystrophies (MDs) are a heterogeneous group of rare neuromuscular diseases characterized by progressive muscle degeneration. A neuropsychosocial approach is crucial for these patients due to associated cognitive, behavioral, and psychiatric comorbidities; however, the social cognitive domain has not been adequately addressed.

Methods

This study aimed to analyze on social cognition performance in a pediatric MD patient cohort. This cross-sectional study included 32 pediatric patients with MD and 32 matched-healthy controls. The Social Perception Domain of the NEPSY-II, the Reading the Mind in the Eyes Test-Child and Happé's Strange Stories Test were administered. General intelligence and behavioral and emotional symptoms were controlled for to eliminate covariables' possible influence. The assessments were performed remotely.

Results

Children with MDs performed significantly worse on most of the social cognition tasks. The differences found between the groups could be explained by the level of general intelligence for some aspects more related to theory of mind (ToM) (TM NEPSY-II: F = 1.703, p = .197; Verbal task: F = 2.411, p = .125; RMET-C: F = 2.899, p = .094), but not for emotion recognition. Furthermore, these differences were also independent of behavioral and emotional symptoms.

Discussion

In conclusion, social cognition is apparently impaired in pediatric patients with MD, both for emotion recognition and ToM. Screening assessment in social cognition should be considered to promote early interventions aimed at improving these patient's quality of life.

Clinical and Genetic Aspects of Childhood-Onset Demyelinating Charcot-Marie-Tooth's Disease in Brazil

Charcot-Marie-Tooth's disease (CMT) represents the most common inherited neuropathy. Most patients are diagnosed during late stages of disease course during adulthood. We performed a review of clinical, neurophysiological, and genetic diagnoses of 32 patients with genetically defined childhood-onset demyelinating CMT under clinical follow-up in a Brazilian Center for Neuromuscular Diseases from January 2015 to December 2019. The current mean age was 33.1 ± 18.3 years (ranging from 7 to 71 years) and mean age at defined genetic diagnosis was 36.1 ± 18.3 years. The mean age at onset was 6.1 ± 4.4 years. The most common initial complaint was bilateral pes cavus. The genetic basis included PMP22 duplication (CMT1A) ( n  = 18), GJB1 (CMTX1) ( n  = 5), MPZ (CMT1B) ( n  = 3), FIG4 (CMT4J) ( n  = 3), SH3TC2 (CMT4C) ( n  = 1), PLEKHG5 (CMTRIC) ( n  = 1), and PRX (CMT4F) ( n  = 1). Almost all patients ( n  = 31) presented with moderate or severe compromise in the CMT neuropathy score 2 with the highest values observed in CMT1B. Medical history disclosed obstructive sleep apnea ( n  = 5), aseptic meningitis ( n  = 1/ MPZ ), akinetic-rigid parkinsonism ( n  = 1/ FIG4 ), and overlapping chronic inflammatory demyelinating polyneuropathy ( n  = 1/ MPZ ). Motor conduction block was detected in three individuals ( PMP22 , FIG4 , MPZ ). Acute denervation occurred in seven patients. Nonuniform demyelinating patterns were seen in four individuals (two CMT1A, one CMT1B, and one CMTX1). Abnormal cerebral white matter findings were detected in CMT1A and CMTX1, while hypertrophic roots were seen in CMT1A, CMT1B, and CMTX1. Our study emphasizes a relative oligogenic basis in childhood-onset demyelinating CMT and atypical findings may be observed especially in MPZ , PMP22 , and GJB1 gene variants.

Pediatric Neuromuscular Diseases

The diagnostic and referral workflow for children with neuromuscular disorders is evolving, particularly as newborn screening programs are expanding in tandem with novel therapeutic developments. However, for the children who present with symptoms and signs of potential neuromuscular disorders, anatomic localization, guided initially by careful history and physical examination, continues to be the cardinal initial step in the diagnostic evaluation. It is important to consider whether the localization is more likely to be in the lower motor neuron, peripheral nerve, neuromuscular junction, or muscle. After that, disease etiologies can be divided broadly into inherited versus acquired categories. Considerations of localization and etiologies will help generate a differential diagnosis, which in turn will guide diagnostic testing. Once a diagnosis is made, it is important to be aware of current treatment options, as a number of new therapies for some of these disorders have been approved in recent years. Families are also increasingly interested in clinical research, which may include natural history studies and interventional clinical trials. Such research has proliferated for rare neuromuscular diseases, leading to exciting advances in diagnostic and therapeutic technologies, promising dramatic changes in the landscape of these disorders in the years to come.

Understanding Challenges of Genetic Testing on Neuromuscular Disorders from the Parental Lens

Neuromuscular disorders, characterized by progressive muscle degeneration and weakness, present substantial challenges to both affected individuals and their families. Genetic testing assumes a pivotal role in facilitating early diagnosis, intervention, treatment, and informed family planning for these conditions. The objective of this qualitative study is to delve into the knowledge, awareness, and perceptions surrounding genetic testing within the cohort of parents caring for individuals with neuromuscular disorders in Malaysia. A semi-structured interview approach was employed to elicit data from parents of individuals diagnosed with neuromuscular disorders, encompassing those with clinical diagnoses and those diagnosed through genetic testing. Examination of the interview responses yielded nine overarching themes, which furnish invaluable insights into the perspectives of Malaysian parents concerning genetic testing. The study discerned several challenges associated with genetic testing, notably encompassing the limited awareness among parents, the financial constraints associated with genetic testing, and the perceived significance of genetic testing in the context of neuromuscular disorders. The findings suggest that the level of knowledge and awareness pertaining to genetic testing for neuromuscular disorders among parents in Malaysia varies, with initial levels of awareness ranging from relatively low to reasonably sufficient prior to and following the birth of an affected child. However, the investigation revealed that parents tended to cultivate more favorable perceptions regarding genetic testing subsequent to their experience with genetic counseling. This underscores the potential for heightened awareness and comprehension as a consequence of the personal experience of parenting an affected child confirmed through genetic testing and genetic counseling, ultimately influencing parental awareness.

Understanding caregiver experiences with disease-modifying therapies for spinal muscular atrophy: a qualitative study

OBJECTIVE

Spinal muscular atrophy (SMA) is a neuromuscular disorder that manifests with motor deterioration and respiratory complications. The paradigm of care is shifting as disease-modifying therapies including nusinersen, onasemnogene abeparvovec and risdiplam alter the disease trajectory of SMA. The objective of this study was to explore caregivers' experiences with disease-modifying therapies for SMA.

DESIGN

Qualitative study including semistructured interviews with caregivers of children with SMA who received disease-modifying therapies. Interviews were audio recorded, transcribed verbatim, coded and analysed using content analysis.

SETTING

The Hospital for Sick Children (Toronto, Canada).

RESULTS

Fifteen family caregivers of children with SMA type 1 (n=5), type 2 (n=5) and type 3 (n=5) participated. There were two emerging themes and several subthemes (in parentheses): (1) inequities in access to disease-modifying therapies (variable regulatory approvals, prohibitively expensive therapies and insufficient infrastructure) and (2) patient and family experience with disease-modifying therapies (decision making, hope, fear and uncertainty).

CONCLUSION

The caregiver experience with SMA has been transformed by the advent of disease-modifying therapies. Consistent and predictable access to disease-modifying therapies is a major concern for caregivers of children with SMA but is influenced by regulatory approvals, funding and eligibility criteria that are heterogenous across jurisdictions. Many caregivers described going to great lengths to access therapies, highlighting issues related to justice, such as equity and access. This diverse population reflects contemporary patients and families with SMA; their broad experiences may inform the healthcare delivery of other emerging orphan drugs.

A pilot study of an integrated, personalized, respiratory and motor telerehabilitation program for pediatric patients with hereditary neuromuscular disorders

INTRODUCTION

Telerehabilitation provides physical training to patients through telecommunication networks. We examined the feasibility, safety, and efficacy of an integrated, personalized, respiratory and motor telerehabilitation program for pediatric patients with hereditary neuromuscular disorders (NMDs).

METHODS

Stable pediatric patients were recruited for a 16-week home training program with personalized pulmonary, upper and lower limb exercises. Patients reviewed instructional videos at home and attended bi-weekly follow-ups through video or audio calls, text messages, or emails. The primary outcomes were respiratory function, Medical Research Council (MRC) grading, hand/pinch strength, 6-minute walk test, and Pediatric Quality-of-Life Inventory 3.0 Neuromuscular Module survey. The secondary outcomes were study compliance and user feedback.

RESULTS

Patients with spinal muscular atrophy (n = 4), congenital myasthenic syndrome (n = 2), and Duchenne muscular dystrophy (n = 2) completed the program. The median weekly exercise time was 101.3 min (range: 30.0-266.9). No extra face-to-face physiotherapy sessions were requested by the patients. No adverse events were reported. After the study, patients showed improvements in maximal expiratory pressure (35.0 vs. 47.5 cm H2O, p = .028) and maintained their MRC grade, hand/pinch strength, and walking distance. Patients also reported improvements in the Pediatric Quality-of-Life Inventory 3.0 Neuromuscular Module survey score (74.5 vs. 87.0, p = .036). Patients rated the overall program highly (mean: 4.00/5.00) and recommended it as a standard of care (mean: 4.38/5.00).

DISCUSSION

Our telerehabilitation program was feasible, safe, and possibly effective for this pilot cohort of stable pediatric patients with hereditary NMDs. Larger-scale studies for longer periods are warranted to confirm the results.

Gastrointestinal and nutritional care in pediatric neuromuscular disorders

Neuromuscular diseases (NMDs) affect the development and growth of the neuromuscular system in children. The pathology can occur anywhere along the neuromuscular pathway, from the brain to the nerves to the muscle fibers. These diseases have a profound impact on the quality of life not only of children but also of their families. The predominant manifestation in NMDs is hypotonia, which leads to muscle weakness and fatigue, reduced mobility, and decreased physical performance. However, multiple organ systems can be affected, with resulting orthopedic, cardiac, infectious, respiratory, and nutritional problems. Children with NMD present an increased risk for several dietary and feeding difficulties because of their neuromuscular diagnosis, presentation, and severity. These problems include chronic gastrointestinal issues (constipation, dysphagia, gastroesophageal reflux, and diarrhea), dysphagia, malnutrition, and body composition alterations. As a result, compared to the overall pediatric population, infants and children with NMD are more likely to be malnourished, ranging from failure to thrive to overweight or obesity. Disease-specific guidelines vary in level of detail and recommendations for dietary management. Overall, nutritional data available are sparse, with the exception of Duchenne muscular dystrophy, spinal muscular atrophy, and congenital muscular dystrophy. The purpose of this review is to describe the spectrum of nutritional challenges in children with NMD and to summarize the main dietary and gastrointestinal recommendations for each neuromuscular disorder to provide guidance for daily clinical practice.

Novel Radiological Brain Anomalies in a Patient with Congenital Muscular Dystrophy due to FKRP Mexican Founder Mutation c.1387A > G: Review of the Literature

Mutations in the FKRP gene result in phenotypes with severe forms of congenital muscular dystrophies (CMD) and limb-girdle muscular dystrophies. We present a Mexican patient with a pathogenic homozygous mutation in the FKRP gene (c.1387A > G, p.Asn463Asp) and CMD with radiological brain anomalies as disseminated hyperintensity lesions and discrete generalized cortical atrophy. These findings have not been reported to the best of our knowledge in other patients with the same mutation. The mutation c.1387A > G, p.Asn463Asp in the FKRP gene has been described to have a founder effect in central Mexico, since all the patients described to date are of Hispanic origin. Therefore, we emphasize studying mutations in the FKRP gene in Hispanic pediatric patients with clinical suspicion of CMD. Clinical and molecular diagnosis of specific CMD subtypes is needed to help clarify the prognosis, management, and genetic counseling to the patient and families.

Clinical and Demographic Characteristics of Families Attending the Epilepsy, Neuromuscular, and Child Wellbeing Clinics

Background Neurological diseases entail a broad spectrum of disorders. Among such ailments are epilepsy and neuromuscular disorders which impose a substantial burden on children and their families. Ensuring adequate access to outpatient services is crucial for these children regardless of the subclinical specialty, and clinicians can better comprehend the caregivers' perspectives by being aware of their backgrounds which can be aided using epidemiological studies. Methods In June 2023, a cross-sectional study was carried out in pediatric neurology clinics at a tertiary care center. The study included all families with a child or more (14 years and younger) diagnosed with neurological disorders. The study adopted a three-section survey delivered to participants recruited using a non-probability sampling technique to achieve a 95% confidence interval with a 5% margin of error. Results A total of 821 families participated in this study. The mean age of respondents was 40.46±8.72 years. Of the affected children, there were 600 (73.08%) children following up with the general neurology and epilepsy clinics, 164 (19.98%) were following up with the neuromuscular disorders clinics, and 57 (6.94%) were following up with the neurogenetic clinics. Familial status had no association with the type of clinic the patient was following up with p=0.0054. Single respondents had a significantly higher prevalence of children with epilepsy (p<0.0001). Parents with a high school level of education or lower had a significantly greater prevalence of epilepsy clinic follow-ups (p=0.0048). Conclusion The findings of this study contribute to the assessment of prevalent neurological disorders in children and shed light on the family dynamics surrounding these conditions. Through statistical analysis, the study establishes connections between certain demographic and clinical traits and specific neurological disorders among pediatric patients and their families. The study emphasizes the importance of socio-economic and socio-clinical support in promoting child health in such cases. Similar research would offer a more accurate portrayal of the challenges faced by families in these circumstances.

ATS Core Curriculum 2022. Pediatric Pulmonary Medicine: Updates in pediatric neuromuscular disease

The American Thoracic Society Core Curriculum updates clinicians annually in pediatric pulmonary disease. This is a concise review of the Pediatric Pulmonary Medicine Core Curriculum presented at the 2022 American Thoracic Society International Conference. Neuromuscular diseases (NMD) comprise a variety of conditions that commonly affect the respiratory system and cause significant morbidity including dysphagia, chronic respiratory failure, and sleep disordered breathing. Respiratory failure is the most common cause of mortality in this population. Substantial progress has been made in diagnosis, monitoring and treatment for NMD over the last decade. Pulmonary function testing (PFT) is utilized to objectively measure respiratory pump function and PFT milestones are utilized in NMD-specific pulmonary care guidelines. New disease modifying therapies are approved for the treatment of patients with Duchenne muscular dystrophy and spinal muscular atrophy (SMA), including the first ever approved systemic gene therapy, in the case of SMA. Despite extraordinary progress in the medical management of NMD, little is known regarding the respiratory implications and long-term outcomes for patients in the era of advanced therapeutics and precision medicine. The combination of technological and biomedical advancements has increased the complexity of the medical decision-making process for patients and families, thus emphasizing the importance of balancing respect for autonomy with the other foundational principles of medical ethics. This review features an overview of PFT, noninvasive ventilation strategies, novel and developing therapies, as well as the ethical considerations specific to the management of patients with pediatric NMD.

Use of Complementary and Alternative Medicine in Children with Neuromuscular Disorders Followed at Penn State Health Pediatric Muscular Dystrophy Association Care Center Clinic

The exact prevalence of complementary and alternative medicine (CAM) use is not known in pediatric patients with neuromuscular diseases followed by any of the 150 Muscular Dystrophy Association (MDA) Care Center Clinics nationwide. This study describes the prevalence and variety of CAM usage in this population, while also assessing the prevalence of caregiver disclosure of CAM use and caregiver perception of provider support for CAM. Fifty-two caregivers of pediatric patients seen at Penn State Health's Pediatric MDA Care Center Clinic completed our online survey. Overall, 19.2% of caregivers reported CAM use by their child. Less than half of caregivers reported discussing CAM use with their child's neurologist (41.5%); however, a majority of respondents reported interest in using CAM for their child in the future (52.8%). Understanding the prevalence of CAM usage and disclosure in pediatric MDA clinics may facilitate safer use of CAM in this community.

Ryanodine receptor 1 related myasthenia like myopathy responsive to pyridostigmine

Disease causing variants in the Ryanodine receptor 1 (RYR1) gene are a common cause for congenital myopathy and for malignant hyperthermia susceptibility. We report a 17 year old boy with congenital muscle weakness progressing to a myasthenia like myopathy with muscle weakness, fatigability, ptosis, and ophthalmoplegia. Muscle biopsy showed predominance and atrophy of type 1 fibers. Whole-exome trio sequencing revealed three variants in the RYR1-gene in the patient: c.6721C > T,p.(Arg2241*) and c.2122G > A,p.(Asp708Asn) in cis position, and the c.325C > T,p.(Arg109Trp) variant in trans. Treatment with pyridostigmine improved symptoms. This case supports that a myasthenia like phenotype is part of the phenotypic spectrum of RYR1 related disorders, and that treatment with pyridostigmine can be beneficial for patients with this phenotype.

Seroprevalence of Binding and Neutralizing Antibodies against 39 Human Adenovirus Types in Patients with Neuromuscular Disorders

High pre-existing antibodies against viral vectors reduce their functionality and may lead to adverse complications. To circumvent this problem in future gene therapy approaches, we tested the seroprevalence of a large range of human adenovirus types in patients with neuromuscular disorders (NMDs) to find appropriate viral vector candidates for gene replacement therapy for NMDs. Binding and neutralizing antibodies against 39 human adenovirus types were tested in the sera of 133 patients with NMDs and 76 healthy controls aged 17-92 years. The influence of age, sex, and NMDs on antibody levels was analyzed. The seroprevalence of different adenoviruses in the cohort varied widely. The highest levels of binding antibodies were detected against HAdV-D27, -C1, -D24, -D70, -B14, -C6, -D13, -B34, and -E4, whereas the lowest reactivity was detected against HAdV-F41, -A31, -B11, -D75, -D8, -D65, -D26, -D80, and -D17. The highest neutralizing reactivity was observed against HAdV-B3, -C2, -E4, -C1, -G52, -C5, and -F41, whereas the lowest neutralizing reactivity was observed against HAdV-D74, -B34, -D73, -B37, -D48, -D13, -D75, -D8, -B35, and -B16. We detected no influence of sex and only minor differences between different age groups. Importantly, there were no significant differences between healthy controls and patients with NMDs. Our data show that patients with NMDs have very similar levels of binding and neutralizing antibodies against HAdV compared to healthy individuals, and we identified HAdV-A31, -B16, -B34, -B35, -D8, -D37, -D48, -D73, -D74, -D75, and -D80 as promising candidates for future vector development due to their low binding and neutralizing antibody prevalence.

The COVID-19 pandemic restrictions affect the healthcare and health status of paediatric patients with neuromuscular diseases: a developing country perspective

PURPOSE

The COVID-19 pandemic has forced the rapid and unprecedented reorganisation of current practices in the treatment of neuromuscular disorders (NMD). Cessation of care and treatments can worsen the underlying condition, exacerbate symptoms, and increase anxiety, leading to a vicious circle and increased management concerns. This study aims to determine the changes in healthcare and health status of children with NMD from a developing country perspective.

MATERIALS AND METHODS

Forty-seven children with NMD were included in this cross-sectional study. The participants were contacted via phone call. The survey conducted for the study was included demographic data, changes and problems in healthcare, perceived health status change, and satisfaction with the services provided. Descriptive statistics were used to characterise the sample.

RESULTS

The mean age of the children was 7.86 ± 3.45 years. The participants encountered 24.83 ± 26.54% of difficulties in getting medication care, and there was 69.95 ± 24.47% disruption in accessing routine medical care. The participants' rehabilitation sessions were disrupted in the 78.54 ± 14.93%, and there were 95.83 ± 10.03% deficiencies in therapists' informing. Children with NMD indicated that their perceived health status decreased compared to before pandemic in all parameters.

CONCLUSION

This study highlights the unfavourable indirect effect of the COVID-19 pandemic restrictions on healthcare and health status of paediatric patients with NMD. Since the COVID-19 pandemic is an uncertain process, the solutions or modifications should be promptly put into effect to improve the healthcare and health status of children with NMD.

Modeling neuromuscular diseases in zebrafish

Neuromuscular diseases are a diverse group of conditions that affect the motor system and present some overlapping as well as distinct clinical manifestations. Although individually rare, the combined prevalence of NMDs is similar to Parkinson's. Over the past decade, new genetic mutations have been discovered through whole exome/genome sequencing, but the pathogenesis of most NMDs remains largely unexplored. Little information on the molecular mechanism governing the progression and development of NMDs accounts for the continual failure of therapies in clinical trials. Different aspects of the diseases are typically investigated using different models from cells to animals. Zebrafish emerges as an excellent model for studying genetics and pathogenesis and for developing therapeutic interventions for most NMDs. In this review, we describe the generation of different zebrafish genetic models mimicking NMDs and how they are used for drug discovery and therapy development.

The Presentation of Two Unrelated Clinical Cases from the Republic of North Ossetia-Alania with the Same Previously Undescribed Variant in the COL6A2 Gene

Here, we described three affected boys from two unrelated families of Ossetian-Digor origin from the Republic of North Ossetia-Alania who were admitted to the Research Centre for Medical Genetics with unspecified muscular dystrophy. High-throughput sequencing was performed and revealed two novel frameshift variants in the COL6A2 gene (NM_001849.3) in a heterozygous state each in both cases: c.508_535delinsCTGTGG and c.1659_1660del (case 1) and c.1689del and c.1659_1660del (case 2). In two cases, the same nucleotide variant in the COL6A2 gene (c.1659_1660del) was observed. We have suggested that the variant c.1659_1660del may be common in the Ossetian-Digor population because two analyzed families have the same ancestry from the same subethnic group of Ossetians). The screening for an asymptomatic carriage of the nucleotide variant c.1659_1660del in 54 healthy donors from Ossetian-Digor population revealed that the estimated carrier frequency is 0.0093 (CI: 0.0002–0.0505), which is high for healthy carriers of the pathogenic variant. Molecular genetic, anamnestic data and clinical examination results allowed us to diagnose Ullrich muscular dystrophy in those affected boys. Genetic heterogeneity and phenotypic diversity of muscular dystrophies complicate diagnosis. It is important to make a differential diagnosis of such conditions and use HTS methods to determine the most accurate diagnosis.

Sum-Frequency Vibrational Spectroscopic Study of the Cation-π Interaction: Amine and Guanidine

The cation-π interaction is an interaction between a positively charged cation and π electrons in an aromatic group of a molecule. It is considered to play key roles in signal transduction, stabilization of the protein structure, enzyme catalysis in biology, and wet adhesion and biomolecular condensation. In this study, octadecylguanidine hydrochloride (ODG) and octadecylamine (ODA) having guanidine and amine headgroups, respectively, are found to interact with π molecules (phenol or indole) as investigated by sum-frequency vibrational spectroscopy. ODG is unstable and does not form a neat monolayer on the water surface. However, after adding π molecules into subphase water, it becomes more stable against dissolution as evidenced by the appearance of its CH_x peaks and a CH peak of the aromatic ring in the sum-frequency spectrum. Unlike ODG, ODA forms a stable monolayer on the water surface at a neutral pH. After adding π molecules into the solution, the amine-π interaction promotes the protonation of the amine headgroup and the penetration of the π molecules makes the ODA monolayer more disordered. Indole is found to be more effective in binding with the ODG as compared to phenol.

New medicine for neuromuscular diseases: An evolving paradox for patient and family hopes and expectations

Recent developments in novel therapies for neuromuscular diseases offer parents new perspectives on their affected children's future. This article examines how the emergence of new therapies impacts the lives of parents of children with Duchenne muscular dystrophy or spinal muscular atrophy type 2, two genetic neuromuscular disorders characterized by progressive muscle degeneration. Aiming for a first-person perspective, fieldwork was conducted utilizing participant observation, semistructured interviews, and several internet sources. Six families with a total of 12 persons, all living in Denmark, were included in the interviews. Two types of parents were identified who were at opposite ends in dealing with the new therapies-the cure optimists and the cure pragmatists. Different hopes resulted in different narratives for their children's futures. The article raises questions about how and when children with chronic diseases should be involved in their parent's hopes for a cure and highlights the dilemmas facing health professionals working in the field of children with chronic diseases for which the prospects of a cure are improving. We conclude that health professionals must find a way to carefully balance guidance and information about experimental medicines, including the fact that experimental medicine sometimes fails, does not work as well as hoped for, or does not become available, with sustaining parental hopes for their children's future.

Illness Perceptions and Illness Identity in Adolescents and Emerging Adults With Neuromuscular Disorders

BACKGROUND

Neuromuscular disorders (NMD) are intrusive medical conditions with implications for psychosocial development.

OBJECTIVES

This paper explores illness perceptions and illness identity dimensions of youth with NMD. First, we compare illness identity outcomes and illness perceptions of NMD patients with a comparison group of adolescents with type 1 diabetes mellitus (DM). Second, we report about the relationships between NMD-related variables and illness perceptions and illness identity.

METHODS

Scores on the Brief Illness Perception Questionnaire and the Illness Identity Questionnaire were compared between a group of NMD patients (N = 59; 12-22 years) and an age- and gender-matched group of DM patients (N = 118). NMD-related variables included time since diagnosis, prognosis, wheelchair use, and physical limitations.

RESULTS

Youth with NMD scored significantly higher on two of the four illness identity dimensions than youth with DM. NMD patients reported significantly less positive illness perceptions, experienced more physical symptoms, and had a lower score on understanding of their illness. Within the NMD group, wheelchair-users have a better understanding of their disease than those who are not wheelchair-bound.

CONCLUSIONS

The present study is the first to investigate illness identity and illness perceptions in NMD. More research is needed to provide insight in the identity formation process of the growing group of adolescents with NMDs.

Congenital or Early Developing Neuromuscular Diseases Affecting Feeding, Swallowing and Speech – A Review of the Literature from January 1998 to August 2021

Background:

The knowledge about the impact of oral motor impairment in neuromuscular diseases (NMDs) is limited but increasing.

Objective:

The aim of this review was to collect and compile knowledge on how muscle weakness in congenital or early developing NMDs directly or indirectly affects feeding, swallowing, speech and saliva control.

Methods:

A literature search was performed in PubMed from January 1, 1998, to August 31, 2021. The keywords “feeding”, “dysphagia”, “swallowing”, “dysarthria”, “speech”, “drooling” and “sialorrhea” were used in combination with “paediatric neuromuscular disease” or specific diagnoses.

Results:

Sixty-five studies were selected for the review, 33 focused on feeding and swallowing, 11 on speech, four on a combination of feeding, swallowing, saliva control or speech and 17 general descriptions. Most of the studies reported on patients with a disorder affecting muscles. These studies show that muscle weakness and impaired motility affecting the muscles innervated by the cranial nerves may influence feeding, swallowing, and speech, and that respiratory function, general health and neurodevelopmental delay also influence these functions. Feeding impairment and breathing difficulties are common in NMDs. Lifesaving interventions such as tube feeding and ventilatory support are common in severe cases.

Conclusions:

Feeding impairment, dysphagia and dysarthria are prevalent in NMDs with congenital or early age of onset. Feeding and swallowing has been studied more than speech and saliva control. More children with NMD survive thanks to new treatment options and it is therefore urgent to follow up how these therapies may impact the development of feeding, swallowing, and speech.

The predictive value of models of neuromuscular disorders to potentiate clinical translation

Neuromuscular disorders (NMDs) are a heterogenous group of rare inherited diseases that compromise the function of peripheral nerves and/or muscles. With limited treatment options available, there is a growing need to design effective preclinical studies that can lead to greater success in clinical trials for novel therapeutics. Here, I discuss recent advances in modelling NMDs to improve preclinical studies as well as two articles from this issue that work in parallel to enable a deeper understanding of a particularly rare NMD, known as X-linked myotubular myopathy.

Effect of the COVID-19 pandemic on patients with inherited neuromuscular disorders

BACKGROUND

The COVID-19 pandemic has brought substantial challenges for current practices in treating hereditary neuromuscular disorders (hNMDs). However, this infection has not been the only concern for these patients. Social distancing has compromised multidisciplinary assistance and physical activity, and has brought about several mental health issues. We presented a follow-up on 363 patients with hNMDs at a Brazilian tertiary center during the peak of the COVID-19 pandemic.

OBJECTIVE

We aimed to show the frequency and severity of SARS-CoV-2 infection among hNMD patients and to demonstrate the effects of the pandemic on life habits, disease progression and multidisciplinary supportive care status.

METHODS

Three hundred and sixty-three patients (58% male and 42% female) were followed for three months through three teleconsultations during the peak of the COVID-19 pandemic in Brazil.

RESULTS

There were decreases in the numbers of patients who underwent physical, respiratory and speech therapies. For several patients, their appetite (33%) and sleep habits (25%) changed. Physical exercises and therapies were interrupted for most of the patients. They reported new onset/worsening of fatigue (17%), pain (17%), contractions (14%) and scoliosis (7%). Irritability and sleep, weight and appetite changes, and especially diminished appetite and weight loss, were more frequent in the group that reported disease worsening. There was a low COVID-19 contamination rate (0.8%), and all infected patients had a mild presentation.

CONCLUSION

The isolation by itself was protective from a COVID-19 infection perspective. However, this isolation might also trigger a complex scenario with life habit changes that are associated with an unfavorable course for the NMD.

Identification of Potential Biomarkers for Ryanodine Receptor 1 (RYR1) Mutation-Associated Myopathies Using Bioinformatics Approach

Background

Myopathies related to Ryanodine receptor 1 (RYR1) mutation are the most common nondystrophy muscle disorder in humans. Early detection and diagnosis of RYR1 mutation-associated myopathies may lead to more timely treatment of patients, which contributes to the management and preparation for malignant hyperthermia. However, diagnosis of RYR1 mutation-associated myopathies is delayed and challenging. The absence of diagnostic morphological features in muscle biopsy does not rule out the possibility of pathogenic variations in RYR1. Accordingly, it is helpful to seek biomarkers to diagnose RYR1 mutation-associated myopathies.

Methods

Skeletal muscle tissue microarray datasets of RYR1 mutation-associated myopathies or healthy persons were built in accordance with the gene expression synthesis (GEO) database. Differentially expressed genes (DEGs) were identified on the basis of R software. Genes specific to tissue/organ were identified through BioGPS. An enrichment analysis of DEGs was conducted in accordance with the Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Ontology (GO). We also built protein-protein interaction (PPI) networks to explore the function and enrichment pathway of DEGs and the identification of hub genes. Lastly, the ROC curve was drawn for hub genes achieving specific expressions within skeletal muscle. Moreover, the area under the curve (AUC) was obtained to calculate the predictive value of key genes. The transcription factors of hub genes achieving specific expressions within skeletal muscle were predicted with the use of the iRegulon plugin.

Results

We identified 170 DEGs among 11 muscle biopsy samples of healthy subjects and 17 muscle biopsy samples of RYR1 mutation-associated myopathy patients in the dataset. Among the above DEGs, 30 genes achieving specific expressions within tissues/organs were found. GO and KEGG enrichment analysis of DEGs mainly focused on muscle contraction, actin-mediated cell contraction, actin filament-based movement, and muscular sliding. 12 hub genes were identified with the use of Cytoscape. Four hub genes were specifically expressed in skeletal muscle tissue, including MYH1 (AUC: 0.856), TNNT3 (AUC: 0.840), MYLPF (AUC: 0.786), and ATP2A1 (AUC: 0.765). The iRegulon predicted results suggested that the transcription factor MYF6 was found with the highest reliability.

Conclusions

Four skeletal muscle tissue-specific genes were identified, including MYH1, TNNT3, MYLPF, and ATP2A1, as the potential biomarkers for diagnosing and treating RYR1 mutation-associated myopathies, which provided insights into the transcriptome-level development mechanism. The transcription factor MYF6 may be a vital upstream regulator of the above biomarkers.

Transcriptome-based variant calling and aberrant mRNA discovery enhance diagnostic efficiency for neuromuscular diseases

Background

Whole-exome sequencing-based diagnosis of rare diseases typically yields 40%–50% of success rate. Precise diagnosis of the patients with neuromuscular disorders (NMDs) has been hampered by locus heterogeneity or phenotypic heterogeneity. We evaluated the utility of transcriptome sequencing as an independent approach in diagnosing NMDs.

Methods

The RNA sequencing (RNA-Seq) of muscle tissues from 117 Korean patients with suspected Mendelian NMD was performed to evaluate the ability to detect pathogenic variants. Aberrant splicing and CNVs were inspected to identify additional causal genetic factors for NMD. Aberrant splicing events in Dystrophin (DMD) were investigated by using antisense oligonucleotides (ASOs). A non-negative matrix factorisation analysis of the transcriptome data followed by cell type deconvolution was performed to cluster samples by expression-based signatures and identify cluster-specific gene ontologies.

Results

Our pipeline called 38.1% of pathogenic variants exclusively from the muscle transcriptomes, demonstrating a higher diagnostic rate than that achieved via exome analysis (34.9%). The discovery of variants causing aberrant splicing allowed the application of ASOs to the patient-derived cells, providing a therapeutic approach tailored to individual patients. RNA-Seq data further enabled sample clustering by distinct gene expression profiles that corresponded to clinical parameters, conferring additional advantages over exome sequencing.

Conclusion

The RNA-Seq-based diagnosis of NMDs achieves an increased diagnostic rate and provided pathogenic status information, which is not easily accessible through exome analysis.

Aquatic Therapy for Persons with Neuromuscular Diseases - A Scoping Review

BACKGROUND

Aquatic exercise is among the most common physical activity modalities performed by people with disabilities.

OBJECTIVE

The present paper reviews currently-available research on aquatic therapy (AT) for persons with neuromuscular diseases (NMD).

METHODS

A scoping review of the existing literature was conducted on PubMed, Embase, Medline, Scopus, Web of Science, SPORTdiscus, CINAHL and Lilacs from the earliest date available until October 2020. It follows the methodological framework for conducting a scoping review proposed by the Joanna Briggs Institute.

RESULTS

A total of 28 articles were analyzed and the study parameters grouped by the topography of NMD; most of the studies (n = 16) addressed myopathies. A considerable increase in the number of studies was found over time, and heterogeneity was identified across and within AT interventions for persons with NMD; hence, to allow more effective interpretation of study results, there is a need to standardize the fundamental parameters and procedures for AT.

CONCLUSIONS

This scoping review provides a comprehensive outline of available literature; the findings could serve as a starting point for clinical studies on the effects of AT on persons with NMD, and encourage a more coherent approach to their design.

A case for genomic medicine in South African paediatric patients with neuromuscular disease

Paediatric neuromuscular diseases are under-recognised and under-diagnosed in Africa, especially those of genetic origin. This may be attributable to various factors, inclusive of socioeconomic barriers, high burden of communicable and non-communicable diseases, resource constraints, lack of expertise in specialised fields and paucity of genetic testing facilities and biobanks in the African population, making access to and interpretation of results more challenging. As new treatments become available that are effective for specific sub-phenotypes, it is even more important to confirm a genetic diagnosis for affected children to be eligible for drug trials and potential treatments. This perspective article aims to create awareness of the major neuromuscular diseases clinically diagnosed in the South African paediatric populations, as well as the current challenges and possible solutions. With this in mind, we introduce a multi-centred research platform (ICGNMD), which aims to address the limited knowledge on NMD aetiology and to improve genetic diagnostic capacities in South African and other African populations.

Pediatric Neuromuscular Disorders in Ile-Ife, Nigeria: Pattern and the Challenges with Management

The aim of this study was to describe the presentation pattern and challenges with the management of pediatric neuromuscular disorders (NMDs) in Ile-Ife, Nigeria through retrospective review of their clinical records. We recruited 24 children aged 14 days to 15 years with a male preponderance (male-to-female ratio = 2.4:1). Late presentation was a prominent feature which was highest among children with myopathies with a mean duration of symptoms of 46.5 ± 33.4 months before presentation. Peripheral neuropathy was the most common type of NMDs (63.0%). Among these, injection nerve palsy from the use of wrong site for intramuscular injections was the most common (60.0%). Nonavailability of electrophysiologic and genetic testing as well as appropriate medications was the major challenges. Acquired NMDs are common in our setting. There is a need to improve preventive measures of acquired NMDs and early diagnosis of the inherited types.

Evidence based position paper on Physical and Rehabilitation Medicine practice for people with muscular dystrophies

Muscular dystrophies present a group of inherited degenerative disorder that are characterized by progressive muscular weakness. This evidence-based position paper represents the official position of the European Union through the UEMS PRM Section. The aim of the paper is to evaluate the role of the physical and rehabilitation medicine (PRM) physician and PRM practice for people with muscular dystrophies. A systematic review of the literature and a consensus procedure by means of a Delphi process have been performed involving the delegates of all European countries represented in the UEMS PRM Section. The systematic literature review is reported together with thirty-three recommendations resulting from the Delphi procedure. The role of the PRM physician is to assess the functional status of persons with muscular dystrophy and to plan, monitor and lead PRM program in an interdisciplinary setting within a multiprofessional team.

Cardiopulmonary exercise testing in neuromuscular disease: a systematic review

INTRODUCTION

Cardiopulmonary exercise testing (CPET) is increasingly used to determine aerobic fitness in health and disability conditions. Patients with neuromuscular diseases (NMDs) often present with symptoms of cardiac and/or skeletal muscle dysfunction and fatigue that might impede the ability to deliver maximal cardiopulmonary effort. Although an increasing number of studies report on NMDs' physical fitness, the applicability of CPET remains largely unknown.

AREAS COVERED

This systematic review synthesized evidence about the quality and feasibility of CPET in NMDs and patient's aerobic fitness. The review followed the PRISMA guidelines (PROSPERO number CRD42020211068). Between September and October 2020 one independent reviewer searched the PubMed/MEDLINE, EMBASE, SCOPUS, and Web of Science databases. Excluding reviews and protocol description articles without baseline data, all study designs using CPET to assess adult or pediatric patients with NMDs were included. The methodological quality was assessed according to the American Thoracic Society/American College of Chest Physicians (ATS/ACCP) recommendations.

EXPERT OPINION

CPET is feasible for ambulatory patients with NMDs when their functional level and the exercise modality are taken into account. However, there is still a vast potential for standardizing and designing disease-specific CPET protocols for patients with NMDs. Moreover, future studies are urged to follow the ATS/ACCP recommendations.

Urine-Derived Stem Cells Express 571 Neuromuscular Disorders Causing Genes, Making Them a Potential in vitro Model for Rare Genetic Diseases

Background: Neuromuscular disorders (NMDs) are a heterogeneous group of genetic diseases, caused by mutations in genes involved in spinal cord, peripheral nerve, neuromuscular junction, and muscle functions. To advance the knowledge of the pathological mechanisms underlying NMDs and to eventually identify new potential drugs paving the way for personalized medicine, limitations regarding the availability of neuromuscular disease-related biological samples, rarely accessible from patients, are a major challenge. Aim: We characterized urinary stem cells (USCs) by in-depth transcriptome and protein profiling to evaluate whether this easily accessible source of patient-derived cells is suitable to study neuromuscular genetic diseases, focusing especially on those currently involved in clinical trials. Methods: The global transcriptomics of either native or MyoD transformed USCs obtained from control individuals was performed by RNA-seq. The expression of 610 genes belonging to 16 groups of disorders (http://www.musclegenetable.fr/) whose mutations cause neuromuscular diseases, was investigated on the RNA-seq output. In addition, protein expression of 11 genes related to NMDs including COL6A, EMD, LMNA, SMN, UBA1, DYNC1H1, SOD1, C9orf72, DYSF, DAG1, and HTT was analyzed in native USCs by immunofluorescence and/or Western blot (WB). Results: RNA-seq profile of control USCs shows that 571 out of 610 genes known to be involved in NMDs, are expressed in USCs. Interestingly, the expression levels of the majority of NMD genes remain unmodified following USCs MyoD transformation. Most genes involved in the pathogenesis of all 16 groups of NMDs are well represented except for channelopathies and malignant hyperthermia related genes. All tested proteins showed high expression values, suggesting consistency between transcription and protein representation in USCs. Conclusion: Our data suggest that USCs are human cells, obtainable by non-invasive means, which might be used as a patient-specific cell model to study neuromuscular disease-causing genes and that they can be likely adopted for a variety of in vitro functional studies such as mutation characterization, pathway identification, and drug screening.

Neonatal encephalopathy: Etiologies other than hypoxic-ischemic encephalopathy

Neonatal encephalopathy (NE) describes the clinical syndrome of a newborn with abnormal brain function that may result from a variety of etiologies. HIE should be distinguished from neonatal encephalopathy due to other causes using data gathered from the history, physical and neurological exam, and further investigations. Identifying the underlying cause of encephalopathy has important treatment implications. This review outlines conditions that cause NE and may be mistaken for HIE, along with their distinguishing clinical features, pathophysiology, investigations, and treatments. NE due to brain malformations, vascular causes, neuromuscular causes, genetic conditions, neurogenetic disorders and inborn errors of metabolism, central nervous system (CNS) and systemic infections, and toxic/metabolic disturbances are discussed.

Complexity of skeletal muscle degeneration: multi-systems pathophysiology and organ crosstalk in dystrophinopathy

Duchenne muscular dystrophy is a highly progressive muscle wasting disorder due to primary abnormalities in one of the largest genes in the human genome, the DMD gene, which encodes various tissue-specific isoforms of the protein dystrophin. Although dystrophinopathies are classified as primary neuromuscular disorders, the body-wide abnormalities that are associated with this disorder and the occurrence of organ crosstalk suggest that a multi-systems pathophysiological view should be taken for a better overall understanding of the complex aetiology of X-linked muscular dystrophy. This article reviews the molecular and cellular effects of deficiency in dystrophin isoforms in relation to voluntary striated muscles, the cardio-respiratory system, the kidney, the liver, the gastrointestinal tract, the nervous system and the immune system. Based on the establishment of comprehensive biomarker signatures of X-linked muscular dystrophy using large-scale screening of both patient specimens and genetic animal models, this article also discusses the potential usefulness of novel disease markers for more inclusive approaches to differential diagnosis, prognosis and therapy monitoring that also take into account multi-systems aspects of dystrophinopathy. Current therapeutic approaches to combat muscular dystrophy are summarised.

Peripheral nervous system manifestations of Shiga toxin-producing E. coli-induced haemolytic uremic syndrome in children

Background

The Neurological involvement is the most common extra-renal complication of Shiga toxin-producing E. coli-hemolytic uremic syndrome (HUS) or typical HUS. On brain magnetic resonance examination, main neurological signs encompass acute lesions of the basal ganglia and the white matter, which could usually regress after Eculizumab infusion. In contrast, peripheral nervous system (PNS) manifestations in typical HUS are very rare and, when occurring, they require a careful management of neurological sequelae and an intensive multidisciplinary neuro-rehabilitation program.

Case presentation

Here, we present two pediatric cases of severe and complicated typical HUS with PNS manifestations who required therapeutic treatment and an intensive multidisciplinary neuro-rehabilitation program.

In both cases, PNS manifestations were followed by the recovery from typical HUS-related severe central neurological damage and manifested mainly with marked bilateral motor deficit and hyporeflexia/areflexia in the lower limbs. The peripheral polyneuropathy was treated with immunosuppressive therapy (methylprednisolone boluses, i.v. immunoglobulins, plasma exchange), followed by a prolonged intensive neuro-rehabilitation program. After 8 months of rehabilitation, both patients gained complete functional recovery.

Conclusions

PNS manifestations during typical HUS are a rare event and potentially leading to severe disability. A timely clinical assessment is mandatory to set up a prompt therapeutic and rehabilitation program and to obtain a complete clinical and functional recovery.

Instruments to assess upper-limb function in children and adolescents with neuromuscular diseases: a systematic review

AIM

To synthesize clinical and scientific evidence regarding the instruments available to assess upper-limb function in paediatric patients with neuromuscular disease (NMD).

METHOD

This systematic review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses and COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN) guidelines (Prospective Registry of Systematic Reviews no. CRD42020140343). Two independent reviewers searched the PubMed/MEDLINE, LILACS, Embase, and Scopus databases. Inclusion criteria were cross-sectional or longitudinal studies or randomized controlled trials that used scales or questionnaires to assess upper-limb function in paediatric patients with NMDs. The COSMIN Risk of Bias checklist and criteria for good measurement properties were applied to assess the methodological quality of the instruments.

RESULTS

In total, 34 articles and 12 instruments were included. The Brooke Upper Extremity (n=16) and Performance of Upper Limb (PUL) (n=12) instruments were the most used tools. The PUL and Duchenne muscular dystrophy (DMD) Upper Limb patient-reported outcome measures (PROMs) tested more measurement properties and provided higher methodological quality scores for patients with DMD. Likewise, the Revised Upper Limb Module (RULM) was the most suitable instrument for patients with spinal muscular atrophy. No instrument has been devised to assess upper-limb function in patients with Charcot-Marie-Tooth disease and no other disease-specific instruments were found.

INTERPRETATION

The PUL, DMD Upper Limb PROM, and RULM are the most suitable instruments to assess upper-limb function in the two most prevalent paediatric NMDs. The identified gaps and methodological flaws of the available instruments indicate a need to develop high-quality instruments to assess other types of paediatric NMDs. What this paper adds The most suitable observer-rater instrument to assess upper-limb function in Duchenne muscular dystrophy (DMD) is the Performance of Upper Limb. The most suitable observer-rater instrument to assess upper-limb function in spinal muscular atrophy is the Revised Upper Limb Module. The DMD Upper Limb patient-reported outcome measure is recommended to assess the upper-limb performance of patients with DMD. Literature gaps and methodological flaws indicate the need to develop high-quality instruments to assess other types of paediatric neuromuscular disease.

How Inflammation Pathways Contribute to Cell Death in Neuro-Muscular Disorders

Neuro-muscular disorders include a variety of diseases induced by genetic mutations resulting in muscle weakness and waste, swallowing and breathing difficulties. However, muscle alterations and nerve depletions involve specific molecular and cellular mechanisms which lead to the loss of motor-nerve or skeletal-muscle function, often due to an excessive cell death. Morphological and molecular studies demonstrated that a high number of these disorders seem characterized by an upregulated apoptosis which significantly contributes to the pathology. Cell death involvement is the consequence of some cellular processes that occur during diseases, including mitochondrial dysfunction, protein aggregation, free radical generation, excitotoxicity and inflammation. The latter represents an important mediator of disease progression, which, in the central nervous system, is known as neuroinflammation, characterized by reactive microglia and astroglia, as well the infiltration of peripheral monocytes and lymphocytes. Some of the mechanisms underlying inflammation have been linked to reactive oxygen species accumulation, which trigger mitochondrial genomic and respiratory chain instability, autophagy impairment and finally neuron or muscle cell death. This review discusses the main inflammatory pathways contributing to cell death in neuro-muscular disorders by highlighting the main mechanisms, the knowledge of which appears essential in developing therapeutic strategies to prevent the consequent neuron loss and muscle wasting.

[Etiology, epidemiology, prognosis and biomechanical principles of neuromuscular scoliosis]

Deformity due to neuromuscular disease is often progressive and associated with reduced vital capacity. In general, all treatment should be performed in specialized centers, since invasive measures are associated with an increased morbidity compared to adolescent scoliosis. Derived from the etiology and the resulting biomechanical basis (characteristics), important aspects and considerations arise for all healthcare institutions from the examination interval to the duration of conservative therapy and initiation of surgical therapy. Proper monitoring and assessment are key components to identify curve progression and to achieve preservation or improvement of basic functions.

New diagnostic and therapeutic modalities in neuromuscular disorders in children

Pediatric neuromuscular disorders are a diverse group of conditions that affect how muscle and nerve function. They involve the motor neurons, nerves, neuromuscular junction and muscles. Pathology of any of these regions leads to the inability to perform voluntary movements. Over time, the natural progression of most of these disorders is followed by significant disability, and at the most extreme, almost complete paralysis and death secondary to complications. Diagnostic measures for pediatric neuromuscular disorders, like that of most medical conditions, relies heavily on clinical presentation, history and a detailed physical examination. Primary additional diagnostic measures have included serum creatine kinase (CK) levels, electromyography (EMG), nerve conduction studies (NCS) and muscle or nerve biopsies, which has historically been the gold standard. In the last several decades less invasive testing has become more common such as muscle magnetic resonance imaging (MRI) and genetic testing.  The advances of molecular genetics, such as next generation sequencing (NGS) which includes whole-exome sequencing (WES) and whole-genome sequencing (WGS), enable clinicians to pinpoint more accurately exact gene mutations. The advent of genetic testing enhances personalized medicine. The field of pediatric neuromuscular disorders is also undergoing a remarkable evolution in therapeutic modalities including novel targeted therapies such as exon skipping/inclusion and gene replacement therapies. This is a review of the initial approach to suspected neuromuscular disorders in children as well as up to date diagnostic and therapeutic modalities for the most common pediatric neuromuscular disorders. As the world enters the new decade, there are encouraging therapeutic results. However, there remain key challenges to these modalities including limitations in its applicability, optimization for delivery of gene replacement therapies and in its effectiveness.

Ion Channel Gene Mutations Causing Skeletal Muscle Disorders: Pathomechanisms and Opportunities for Therapy

Skeletal muscle ion channelopathies (SMICs) are a large heterogeneous group of rare genetic disorders caused by mutations in genes encoding ion channel subunits in the skeletal muscle mainly characterized by myotonia or periodic paralysis, potentially resulting in long-term disabilities. However, with the development of new molecular technologies, new genes and new phenotypes, including progressive myopathies, have been recently discovered, markedly increasing the complexity in the field. In this regard, new advances in SMICs show a less conventional role of ion channels in muscle cell division, proliferation, differentiation, and survival. Hence, SMICs represent an expanding and exciting field. Here, we review current knowledge of SMICs, with a description of their clinical phenotypes, cellular and molecular pathomechanisms, and available treatments.