ABSTRACT
BACKGROUND AND OBJECTIVES: Vamorolone is a dissociative agonist of the glucocorticoid receptor that has shown similar efficacy and reduced safety concerns in comparison with prednisone in Duchenne muscular dystrophy (DMD). This study was conducted to determine the efficacy and safety of vamorolone over 48 weeks and to study crossover participants (prednisone to vamorolone; placebo to vamorolone). METHODS: A randomized, double-blind, placebo-controlled and prednisone-controlled clinical trial of 2 doses of vamorolone was conducted in participants with DMD, in the ages from 4 years to younger than 7 years at baseline. The interventions were 2 mg/kg/d of vamorolone and 6 mg/kg/d of vamorolone for 48 weeks (period 1: 24 weeks + period 2: 24 weeks) and 0.75 mg/kg/d of prednisone and placebo for the first 24 weeks (before crossover). Efficacy was evaluated through gross motor outcomes and safety through adverse events, growth velocity, body mass index (BMI), and bone turnover biomarkers. This analysis focused on period 2. RESULTS: A total of 121 participants with DMD were randomized. Vamorolone at a dose of 6 mg/kg/d showed maintenance of improvement for all motor outcomes to week 48 (e.g., for primary outcome, time to stand from supine [TTSTAND] velocity, week 24 least squares mean [LSM] [SE] 0.052 [0.0130] rises/s vs week 48 LSM [SE] 0.0446 [0.0138]). After 48 weeks, vamorolone at a dose of 2 mg/kg/d showed similar improvements as 6 mg/kg/d for North Star Ambulatory Assessment (NSAA) (vamorolone 6 mg/kg/d-vamorolone 2 mg/kg/d LSM [SE] 0.49 [1.14]; 95% CI -1.80 to 2.78, p = 0.67), but less improvement for other motor outcomes. The placebo to vamorolone 6 mg/kg/d group showed rapid improvements after 20 weeks of treatment approaching benefit seen with 48-week 6 mg/kg/d of vamorolone treatment for TTSTAND, time to run/walk 10 m, and NSAA. There was significant improvement in linear growth after crossover in the prednisone to vamorolone 6 mg/kg/d group, and rapid reversal of prednisone-induced decline in bone turnover biomarkers in both crossover groups. There was an increase in BMI after 24 weeks of treatment that then stabilized for both vamorolone groups. DISCUSSION: Improvements of motor outcomes seen with 6 mg/kg/d of vamorolone at 24 weeks of treatment were maintained to 48 weeks of treatment. Vamorolone at a dose of 6 mg/kg/d showed better maintenance of effect compared with vamorolone at a dose of 2 mg/kg/d for most (3/5) motor outcomes. Bone morbidities of prednisone (stunting of growth and declines in serum bone biomarkers) were reversed when treatment transitioned to vamorolone. TRIAL REGISTRATION INFORMATION: ClinicalTrials.gov Identifier: NCT03439670. CLASSIFICATION OF EVIDENCE: This study provides Class I evidence that for boys with DMD, the efficacy of vamorolone at a dose of 6 mg/kg/d was maintained over 48 weeks.
Subject(s)
Muscular Dystrophy, Duchenne , Pregnadienediols , Humans , Male , Biomarkers , Muscular Dystrophy, Duchenne/drug therapy , Prednisone/adverse effects , Pregnadienediols/adverse effects , Child, Preschool , ChildABSTRACT
BACKGROUND: Utrophin, a dystrophin homolog, is consistently upregulated in muscles of patients with Duchenne muscular dystrophy (DMD) and is believed to partially compensate for the lack of dystrophin in dystrophic muscle. Even though several animal studies support the idea that utrophin can modulate DMD disease severity, human clinical data are scarce. METHODS: We describe a patient with the largest reported in-frame deletion in the DMD gene, including exons 10-60 and thus encompassing the entire rod domain. FINDINGS: The patient presented with an unusually early and severe progressive weakness, initially suggesting congenital muscular dystrophy. Immunostaining of his muscle biopsy showed that the mutant protein was able to localize at the sarcolemma and stabilize the dystrophin-associated complex. Strikingly, utrophin protein was absent from the sarcolemmal membrane despite the upregulation of utrophin mRNA. CONCLUSIONS: Our results suggest that the internally deleted and dysfunctional dystrophin lacking the entire rod domain may exert a dominant-negative effect by preventing upregulated utrophin protein from reaching the sarcolemmal membrane and thus blocking its partial rescue of muscle function. This unique case may set a lower size limit for similar constructs in potential gene therapy approaches. FUNDING: This work was supported by a grant from MDA USA (MDA3896) and by grant number R01AR051999 from NIAMS/NIH to C.G.B.
Subject(s)
Dystrophin , Muscular Dystrophy, Duchenne , Animals , Humans , Dystrophin/genetics , Dystrophin/metabolism , Utrophin/genetics , Utrophin/metabolism , Utrophin/therapeutic use , Muscular Dystrophy, Duchenne/genetics , Muscular Dystrophy, Duchenne/pathology , Muscles/metabolism , Muscles/pathology , Sarcolemma/metabolism , Sarcolemma/pathologyABSTRACT
OBJECTIVE: To examine whether telemedicine remains safe and of high quality despite rapid expansion of services by comparing telemedicine encounters before and during the COVID-19 pandemic. METHODS: Pre-post study investigating 2,999 telemedicine encounters: February 1, 2020-May 15, 2020, was performed. A total of 2,919 completed visits before and after strict social distancing implementation were analyzed for patient and provider characteristics, encounter characteristics (e.g., history and physical examination), and quality and safety metrics (phone calls ≤ 7 days postvisit, visit-cause-specific hospital admission or mortality ≤ 30 days after visit). Stratified analysis of 3 groups for outcomes (young age, neuromuscular diagnosis, and new encounters) was performed. RESULTS: Patients ranging from 1 month to 33 years of age were seen. Rural patients were less likely to be seen during the pandemic compared with urban patients (8% vs 90%; p < 0.0001); teaching clinic and specialty clinic encounters increased significantly during the pandemic (8% vs 3%; p = 0.005), and documentation of at least 2 systems on examination was noted significantly more frequently during the pandemic (13% vs 7%; p = 0.009). No deaths were reported. There were no differences before/during the pandemic in safety or telemedicine failure metrics within the entire group and high-risk subgroups. CONCLUSIONS: Despite a markedly and rapidly expanded scope of ambulatory telemedicine care during the COVID-19 pandemic, telemedicine remained a safe and high-quality option for pediatric neurology patients. In addition, populations perceived as high risk for telemedicine (the very young, new patients, and those with neuromuscular diagnoses) can benefit from telemedicine visits, particularly when access to in-person care is limited.
ABSTRACT
BACKGROUND: Duchenne muscular dystrophy is associated with progressive cardiorespiratory failure, including left ventricular dysfunction. METHODS AND RESULTS: Males with probable or definite diagnosis of Duchenne muscular dystrophy, diagnosed between 1 January, 1982 and 31 December, 2011, were identified from the Muscular Dystrophy Surveillance Tracking and Research Network database. Two non-mutually exclusive groups were created: patients with ≥2 echocardiograms and non-invasive positive pressure ventilation-compliant patients with ≥1 recorded ejection fraction. Quantitative left ventricular dysfunction was defined as an ejection fraction <55%. Qualitative dysfunction was defined as mild, moderate, or severe. Progression of quantitative left ventricular dysfunction was modelled as a continuous time-varying outcome. Change in qualitative left ventricle function was assessed by the percentage of patients within each category at each age. Forty-one percent (n = 403) had ≥2 ejection fractions containing 998 qualitative assessments with a mean age at first echo of 10.8 ± 4.6 years, with an average first ejection fraction of 63.1 ± 12.6%. Mean age at first echo with an ejection fraction <55 was 15.2 ± 3.9 years. Thirty-five percent (140/403) were non-invasive positive pressure ventilation-compliant and had ejection fraction information. The estimated rate of decline in ejection fraction from first ejection fraction was 1.6% per year and initiation of non-invasive positive pressure ventilation did not change this rate. CONCLUSIONS: In our cohort, we observed that left ventricle function in patients with Duchenne muscular dystrophy declined over time, independent of non-invasive positive pressure ventilation use. Future studies are needed to examine the impact of respiratory support on cardiac function.
Subject(s)
Muscular Dystrophy, Duchenne/pathology , Muscular Dystrophy, Duchenne/physiopathology , Ventricular Dysfunction, Left/pathology , Ventricular Dysfunction, Left/physiopathology , Adolescent , Adult , Child , Child, Preschool , Cohort Studies , Echocardiography , Glucocorticoids/therapeutic use , Humans , Infant , Infant, Newborn , Male , Muscular Dystrophy, Duchenne/complications , Muscular Dystrophy, Duchenne/drug therapy , Stroke Volume , Young AdultABSTRACT
PURPOSE: Individuals with X-linked myotubular myopathy (XLMTM) who survive infancy require extensive supportive care, including ventilator assistance, wheelchairs and feeding tubes. Half die before 18 months of age. We explored respiratory support and associated mortality risk in RECENSUS, particularly among patients ≤5 years old who received respiratory support at birth; this subgroup closely matches patients in the ASPIRO trial of gene therapy for XLMTM. DESIGN: RECENSUS is an international, retrospective study of patients with XLMTM. Descriptive and time-to-event analyses examined survival on the basis of age, respiratory support, tracheostomy use, predicted mutational effects and life-sustaining care. RESULTS: Outcomes for 145 patients were evaluated. Among 126 patients with respiratory support at birth, mortality was 47% overall and 59% among those ≤5 years old. Median survival time was shorter for patients ≤5 years old than for those >5 years old (2.2 years (IQR 0.7-5.6) vs 30.2 years (IQR 19.4-30.2)). The most common cause of death was respiratory failure (66.7%). Median survival time was longer for patients with a tracheostomy than for those without (22.8 years (IQR 8.7-30.2) vs 1.8 years (IQR 0.2-not estimable)). The proportion of patients living without a tracheostomy was 50% at age 6 months and 28% at age 2 years. Median survival time was longer with provision of life-sustaining care than without (19.4 years (IQR 3.1-not estimable) vs 0.2 years (IQR 0.1-2.1)). CONCLUSIONS: High mortality, principally due to respiratory failure, among patients with XLMTM ≤5 years old despite respiratory support underscores the need for early diagnosis, informed decision-making and disease-modifying therapies. TRIAL REGISTRATION NUMBER: NCT02231697.
Subject(s)
Myopathies, Structural, Congenital/mortality , Respiration, Artificial/statistics & numerical data , Age Factors , Child , Child, Preschool , Female , Humans , Infant , Infant, Newborn , Male , Myopathies, Structural, Congenital/physiopathology , Myopathies, Structural, Congenital/therapy , Premature Birth/epidemiology , Retrospective StudiesABSTRACT
We previously reported a pathogenic de novo p.R342W mutation in the transcriptional corepressor CTBP1 in four independent patients with neurodevelopmental disabilities [1]. Here, we report the clinical phenotypes of seven additional individuals with the same recurrent de novo CTBP1 mutation. Within this cohort, we identified consistent CtBP1-related phenotypes of intellectual disability, ataxia, hypotonia, and tooth enamel defects present in most patients. The R342W mutation in CtBP1 is located within a region implicated in a high affinity-binding cleft for CtBP-interacting proteins. Unbiased proteomic analysis demonstrated reduced interaction of several chromatin-modifying factors with the CtBP1 W342 mutant. Genome-wide transcriptome analysis in human glioblastoma cell lines expressing -CtBP1 R342 (wt) or W342 mutation revealed changes in the expression profiles of genes controlling multiple cellular processes. Patient-derived dermal fibroblasts were found to be more sensitive to apoptosis during acute glucose deprivation compared to controls. Glucose deprivation strongly activated the BH3-only pro-apoptotic gene NOXA, suggesting a link between enhanced cell death and NOXA expression in patient fibroblasts. Our results suggest that context-dependent relief of transcriptional repression of the CtBP1 mutant W342 allele may contribute to deregulation of apoptosis in target tissues of patients leading to neurodevelopmental phenotypes.
Subject(s)
Alcohol Oxidoreductases/genetics , DNA-Binding Proteins/genetics , Mutation, Missense , Adolescent , Alcohol Oxidoreductases/metabolism , Alleles , Apoptosis , Ataxia/complications , Ataxia/genetics , Brain Neoplasms/genetics , Cell Line, Tumor , Child , Child, Preschool , Chromatin/chemistry , DNA-Binding Proteins/metabolism , Female , Fibroblasts/metabolism , Glioblastoma/genetics , Humans , Intellectual Disability/complications , Intellectual Disability/genetics , Male , Muscle Hypotonia/complications , Muscle Hypotonia/genetics , Phenotype , Protein Binding , Proteomics , Tooth Abnormalities/complications , Tooth Abnormalities/genetics , Young AdultABSTRACT
Introduction: As the proportion of males with Duchenne muscular dystrophy (DMD) surviving into adulthood increases, more information is needed regarding their health care transition planning, an essential process for adolescents and young adults with DMD. The objective of this study was to describe the health care transition experiences of a population of males living with Duchenne or Becker muscular dystrophy (DBMD). Methods: The eligible participants, identified through the Muscular Dystrophy Surveillance Tracking and Research Network (MD STARnet) surveillance project, were 16-31 years old and lived in Arizona, Colorado, Georgia, Iowa, or western New York (n=258). The MD STARnet Health Care Transitions and Other Life Experiences Survey was conducted in 2013 and administered online or in a telephone interview. Sixty-five males (25%) completed the survey. Among non-ambulatory males, response differences were compared by age group. Statistical comparisons were conducted using Fisher's exact test, or when appropriate, the Chisquare test. Results: Twenty-one percent of non-ambulatory males aged 16-18 years, 28% of non-ambulatory males aged 19-23 years, 25% of non-ambulatory males aged 24-30 years, and 18 ambulatory males had a written transition plan. Nineteen percent of non-ambulatory males aged 24-30 years had delayed or gone without needed health care in the past 12 months. Among non-ambulatory males aged 24-30 years, 75% had cardiology providers and 69% had pulmonology providers involved in their care in the past 12 months. Twentyeight percent of non-ambulatory males aged 19-23 years and 25% of non-ambulatory males aged 24-30 years reported that they did not receive health care or other services at least once because they were unable to leave their home. Non-ambulatory males aged 16-18 years (29%) were less likely to have ever discussed how to obtain or keep health insurance as they get older compared to non-ambulatory males aged 24-30 years (69%) (p <0.01). Discussion: This study identified potential barriers to the successful health care transition of males with DBMD. The results of this study may indicate a lack of targeted informational resources and education focused on supporting the transition of young men with DBMD as they age from adolescence into adulthood within the healthcare system. Future studies could determine the reasons for the potential barriers to health care and identify the optimal transition programs for males with DBMD. There are a few online resources on transition available to adolescents and young adults with special health care needs.
ABSTRACT
INTRODUCTION: X-linked myotubular myopathy (XLMTM), characterized by severe hypotonia, weakness, respiratory distress, and early mortality, is rare and natural history studies are few. METHODS: RECENSUS is a multicenter chart review of male XLMTM patients characterizing disease burden and unmet medical needs. Data were collected between September 2014 and June 2016. RESULTS: Analysis included 112 patients at six clinical sites. Most recent patient age recorded was ≤18 months for 40 patients and >18 months for 72 patients. Mean (SD) age at diagnosis was 3.7 (3.7) months and 54.3 (77.1) months, respectively. Mortality was 44% (64% ≤18 months; 32% >18 months). Premature delivery occurred in 34/110 (31%) births. Nearly all patients (90%) required respiratory support at birth. In the first year of life, patients underwent an average of 3.7 surgeries and spent 35% of the year in the hospital. DISCUSSION: XLMTM is associated with high mortality, disease burden, and healthcare utilization. Muscle Nerve 57: 550-560, 2018.
Subject(s)
Myopathies, Structural, Congenital/mortality , Premature Birth/epidemiology , Respiration, Artificial/statistics & numerical data , Surgical Procedures, Operative/statistics & numerical data , Adolescent , Age Factors , Child , Child, Preschool , Humans , Infant , Infant, Newborn , Male , Mortality , Retrospective Studies , Young AdultABSTRACT
OBJECTIVE: We describe long-term functional, neurodiagnostic, and psychosocial outcomes of a cohort of 12 children from Colorado diagnosed with acute flaccid myelitis (AFM) in 2014. METHODS: Children were assessed every 3 months for 1 year or until clinical resolution. Assessments included neurologic examination, MRI, EMG/nerve conduction studies (NCS), functional measures (Assisting Hand Assessment, Hammersmith Functional Motor Scale), and Patient-Reported Outcomes Measurement Information System questionnaires. RESULTS: Eight of 12 children completed the study. Six of 8 had persistent motor deficits at 1 year; 2 demonstrated full recovery. Four were not enrolled, 2 of whom reported full recovery. The 6 affected were weakest in proximal muscles, showing minimal to no improvement and significant atrophy at 1 year. All patients improved in distal muscle groups. Cranial nerve dysfunction resolved in 2 of 5 and improved in all. Four of 5 showed progressive functional improvement at 6 and 12 months. Two of 8 reported pain at 1 year. Three of 8 reported depressive symptoms. Repeat MRI was performed in 7 of 8 children a median of 7 months after onset and showed significant improvement or normalization in all but one child. Repeat EMG/NCS was performed on 4 children a median of 8 months after onset and showed ongoing denervation and chronic reinnervation in 3 children with persistent deficits. CONCLUSIONS: At 1 year, children with AFM demonstrated functional gains but weakness persisted. EMG changes correlated with persistent deficits better than imaging. Despite improvements, AFM had substantial long-term functional effects on affected children.
Subject(s)
Cranial Nerve Diseases/diagnosis , Movement Disorders/diagnosis , Muscle, Skeletal/physiopathology , Muscular Diseases/diagnosis , Myelitis/diagnosis , Outcome Assessment, Health Care/methods , Adolescent , Atrophy/pathology , Child , Child, Preschool , Colorado , Cranial Nerve Diseases/diagnostic imaging , Cranial Nerve Diseases/etiology , Cranial Nerve Diseases/physiopathology , Electromyography , Female , Follow-Up Studies , Humans , Magnetic Resonance Imaging , Male , Movement Disorders/diagnostic imaging , Movement Disorders/etiology , Movement Disorders/physiopathology , Muscular Diseases/diagnostic imaging , Muscular Diseases/etiology , Muscular Diseases/physiopathology , Myelitis/complications , Myelitis/diagnostic imaging , Myelitis/physiopathology , Neural Conduction/physiology , Patient Reported Outcome MeasuresABSTRACT
OBJECTIVE: To assess the effect of nutritional interventions on growth and on respiratory status in patients with congenital myopathy (CM), congenital muscular dystrophy (CMD), and congenital myasthenic syndrome (CMS). METHODS: Retrospective cohort study based on case-note review of 18 patients affected by CM, CMD, and CMS, followed at a single pediatric neuromuscular center, between 2006 and 2014. RESULTS: Seventy-two percent of patients required placement of a gastrostomy tube for bulbar weakness or for growth failure. Of those patients, 10 had 1 year follow up anthropometric data and 6 had 2 year follow up anthropometric data. Height percentiles and z-scores were significantly improved in patients after 1 year, while weight and BMI percentiles and z-scores were not. Weight and height percentiles and z-scores were significantly improved in patients at 2 year follow up, while BMI percentiles and z-scores were not. The number of respiratory illnesses was not significantly different before or after placement of the feeding tube. Of the patients who did not have placement of a gastrostomy tube, 4 had 1 year follow up anthropometric data and 3 had 2 year follow up anthropometric data. Gastrostomy tube fed patients had significantly higher mean weight percentiles and z-scores compared to orally fed patients. There was no significant difference in height or BMI between the gastrostomy fed and orally fed groups. Individual growth curves highlight the effect of intervention on weight and height. CONCLUSIONS: This is a single multidisciplinary center experience describing the effect of nutritional interventions on growth in patients with congenital neuromuscular disorders. While the number of patients and their data in this report are limited, it highlights that the growth in this group of patients is unique but that the low weight and short stature respond to nutritional interventions with changes typically seen after 2 years of intervention.
Subject(s)
Body Height , Body Mass Index , Body Weight , Child Development , Neuromuscular Diseases/rehabilitation , Child, Preschool , Cohort Studies , Enteral Nutrition , Female , Follow-Up Studies , Gastrostomy , Humans , Infant , Infant, Newborn , Male , Neuromuscular Diseases/complications , Respiration Disorders/complications , Retrospective Studies , Weight GainABSTRACT
IMPORTANCE: New genomic strategies can now be applied to identify a diagnosis in patients and families with previously undiagnosed rare genetic conditions. The large family evaluated in the present study was described in 1966 and now expands the phenotype of a known neuromuscular gene. OBJECTIVE: To determine the genetic cause of a slowly progressive, autosomal dominant, scapuloperoneal neuromuscular disorder by using linkage and exome sequencing. DESIGN, SETTING, AND PARTICIPANTS: Fourteen affected individuals in a 6-generation family with a progressive scapuloperoneal disorder were evaluated. Participants were examined at pediatric, neuromuscular, and research clinics from March 1, 2005, to May 31, 2014. Exome and linkage were performed in genetics laboratories of research institutions. MAIN OUTCOMES AND MEASURES: Examination and evaluation by magnetic resonance imaging, ultrasonography, electrodiagnostic studies, and muscle biopsies (n = 3). Genetic analysis included linkage analysis (n = 17) with exome sequencing (n = 7). RESULTS: Clinical findings included progressive muscle weakness in an initially scapuloperoneal and distal distribution, including wrist extensor weakness, finger and foot drop, scapular winging, mild facial weakness, Achilles tendon contractures, and diminished or absent deep tendon reflexes. Both age at onset and progression of the disease showed clinical variability within the family. Muscle biopsy specimens demonstrated type I fiber atrophy and trabeculated fibers without nemaline rods. Analysis of exome sequences within the linkage region (4.8 megabases) revealed missense mutation c.591C>A p.Glu197Asp in a highly conserved residue in exon 4 of ACTA1. The mutation cosegregated with disease in all tested individuals and was not present in unaffected individuals. CONCLUSIONS AND RELEVANCE: This family defines a new scapuloperoneal phenotype associated with an ACTA1 mutation. A highly conserved protein, ACTA1 is implicated in multiple muscle diseases, including nemaline myopathy, actin aggregate myopathy, fiber-type disproportion, and rod-core myopathy. To our knowledge, mutations in Glu197 have not been reported previously. This residue is highly conserved and located in an exposed position in the protein; the mutation affects the intermolecular and intramolecular electrostatic interactions as shown by structural modeling. The mutation in this residue does not appear to lead to rod formation or actin accumulation in vitro or in vivo, suggesting a different molecular mechanism from that of other ACTA1 diseases.
Subject(s)
Actins/genetics , Muscular Dystrophy, Emery-Dreifuss/genetics , Muscular Dystrophy, Emery-Dreifuss/physiopathology , Adult , Age of Onset , Child , Disease Progression , Exome/genetics , Genetic Linkage , Humans , Male , Muscular Dystrophy, Emery-Dreifuss/pathology , Mutation, Missense/genetics , Myopathies, Nemaline , Pedigree , PhenotypeABSTRACT
BACKGROUND: Cytoplasmic dynein provides the main motor force for minus-end-directed transport of cargo on microtubules. Within the vertebrate central nervous system (CNS), proliferation, neuronal migration, and retrograde axon transport are among the cellular functions known to require dynein. Accordingly, mutations of DYNC1H1, which encodes the heavy chain subunit of cytoplasmic dynein, have been linked to developmental brain malformations and axonal pathologies. Oligodendrocytes, the myelinating glial cell type of the CNS, migrate from their origins to their target axons and subsequently extend multiple long processes that ensheath axons with specialized insulating membrane. These processes are filled with microtubules, which facilitate molecular transport of myelin components. However, whether oligodendrocytes require cytoplasmic dynein to ensheath axons with myelin is not known. RESULTS: We identified a mutation of zebrafish dync1h1 in a forward genetic screen that caused a deficit of oligodendrocytes. Using in vivo imaging and gene expression analyses, we additionally found evidence that dync1h1 promotes axon ensheathment and myelin gene expression. CONCLUSIONS: In addition to its well known roles in axon transport and neuronal migration, cytoplasmic dynein contributes to neural development by promoting myelination.
Subject(s)
Axonal Transport/physiology , Axons/metabolism , Brain/embryology , Cytoplasmic Dyneins/metabolism , Myelin Sheath/metabolism , Zebrafish Proteins/metabolism , Zebrafish/embryology , Animals , Brain/cytology , Cytoplasmic Dyneins/genetics , Gene Expression Regulation, Developmental/physiology , Mutation , Myelin Sheath/genetics , Oligodendroglia/cytology , Oligodendroglia/metabolism , Zebrafish/genetics , Zebrafish Proteins/geneticsABSTRACT
INTRODUCTION: The purpose of this study was to measure and analyze motor unit number estimation (MUNE) values longitudinally in spinal muscular atrophy (SMA). METHODS: Sixty-two children with SMA types 2 and 3 were observed prospectively for up to 42 months. Longitudinal electrophysiological data were collected, including compound motor action potential (CMAP), single motor unit action potential (SMUP), and MUNE. RESULTS: Significant motor neuron loss and compensatory collateral reinnervation were noted at baseline. Over time, there was a significant mean increase in MUNE (4.92 units/year, P = 0.009), a mean decrease in SMUP amplitude (-6.32 µV/year, P = 0.10), and stable CMAP amplitude. CONCLUSIONS: The unexpected longitudinal results differ from findings in amyotrophic lateral sclerosis studies, perhaps indicating that compensatory processes in SMA involve new motor unit development. A better understanding of the mechanisms of motor unit decline and compensation in SMA is important for assessing novel therapeutic strategies and for providing key insights into disease pathophysiology.
Subject(s)
Action Potentials/physiology , Adaptation, Physiological/physiology , Motor Neurons/physiology , Muscle, Skeletal/physiopathology , Spinal Muscular Atrophies of Childhood/genetics , Survival of Motor Neuron 1 Protein/genetics , Adolescent , Adult , Child , Child, Preschool , Cohort Studies , Disease Progression , Electromyography , Exons , Female , Gene Deletion , Homozygote , Humans , Infant , Linear Models , Longitudinal Studies , Male , Middle Aged , Muscle, Skeletal/innervation , Prospective Studies , Spinal Muscular Atrophies of Childhood/physiopathology , Young AdultABSTRACT
OBJECTIVE: To provide weight-for-age, height-for-age, and body mass index-for-age growth reference standards for ambulatory, steroid-naïve males, ages 2-12 years, with Duchenne muscular dystrophy (DMD) and to compare these growth curves to the 2000 Centers for Disease Control and Prevention growth charts for boys, which serve as references of physical size and growth for the general male pediatric population in the US. STUDY DESIGN: Through a multi-state population-based surveillance of individuals with muscular dystrophy, a total of 1877 weight and 1544 height measurements ascertained during 1985-2010 from 513 males with DMD were obtained retrospectively from medical record review. Cases were classified as DMD if loss of ambulation occurred before the 12th birthday or, if younger than 12 years and still ambulating, the earliest symptoms of dystrophinopathy occurred before the 6th birthday. Each growth chart was constructed using 5 percentiles: 10th, 25th, 50th, 75th, and 90th. Smoothing procedures were applied in 2 stages to the irregular plots of the empirical percentile values. RESULTS: A set of growth curves, derived from a large cohort of male youth with DMD, are presented. These curves demonstrate that DMD males are shorter and tend to the extremes of weight and body mass index compared with the general male pediatric population in the US. CONCLUSION: Charts representing the pattern of growth in ambulatory, steroid-naïve males with DMD can facilitate monitoring of growth and early detection of unusual growth patterns. Use of these growth standards also will assist in monitoring responses to corticosteroid treatment.
Subject(s)
Growth , Muscular Dystrophy, Duchenne/physiopathology , Body Height , Body Mass Index , Body Weight , Child , Child, Preschool , Humans , Male , Retrospective StudiesABSTRACT
OBJECTIVE: To characterize the natural history of spinal muscular atrophy type 2 and type 3 (SMA 2/3) beyond 1 year and to report data on clinical and biological outcomes for use in trial planning. METHODS: We conducted a prospective observational cohort study of 79 children and young adults with SMA 2/3 who participated in evaluations for up to 48 months. Clinically, we evaluated motor and pulmonary function, quality of life, and muscle strength. We also measured SMN2 copy number, hematologic and biochemical profiles, muscle mass by dual x-ray absorptiometry (DXA), and the compound motor action potential (CMAP) in a hand muscle. Data were analyzed for associations between clinical and biological/laboratory characteristics cross-sectionally, and for change over time in outcomes using all available data. RESULTS: In cross-sectional analyses, certain biological measures (specifically, CMAP, DXA fat-free mass index, and SMN2 copy number) and muscle strength measures were associated with motor function. Motor and pulmonary function declined over time, particularly at time points beyond 12 months of follow-up. CONCLUSION: The intermediate and mild phenotypes of SMA show slow functional declines when observation periods exceed 1 year. Whole body muscle mass, hand muscle compound motor action potentials, and muscle strength are associated with clinical measures of motor function. The data from this study will be useful for clinical trial planning and suggest that CMAP and DXA warrant further evaluation as potential biomarkers.
Subject(s)
Motor Skills/physiology , Muscle Strength/physiology , Respiratory Mechanics/physiology , Spinal Muscular Atrophies of Childhood/physiopathology , Adolescent , Child , Child, Preschool , Cohort Studies , Female , Follow-Up Studies , Humans , Infant , Longitudinal Studies , Male , Prospective Studies , Quality of Life , Spinal Muscular Atrophies of Childhood/genetics , Young AdultABSTRACT
The transaminases alanine aminotransferase (ALT) and aspartate aminotransferase (AST) are markers of hepatocellular injury but are highly concentrated in muscle cells. Consequently, muscular dystrophies such as Duchenne muscular dystrophy, lead to hypertransaminasemia. Elevation in ALT and AST is most striking during the early stages of disease, before onset of or when only subtle signs of muscle disease are present. Thus, the incidental finding of elevated ALT/AST may be the presenting sign of muscle disease in many children and provides an opportunity for early diagnosis. Many physicians, however, pursue extensive workup for liver disease in children who present with the incidental finding of elevated ALT/AST. This results in delayed diagnosis and initiation of treatment and increased expense and may lead to unnecessary invasive procedures. We report 12 patients with muscle disease who presented with a variety of symptoms and were found to have an incidental finding of elevated ALT/AST. We propose a rapid screening process for evaluating children with the incidental finding of elevated ALT/AST to shorten the time to diagnosis of muscle disease.
Subject(s)
Alanine Transaminase/blood , Aspartate Aminotransferases/blood , Muscular Dystrophies/diagnosis , Biomarkers/blood , Child , Child, Preschool , Clinical Enzyme Tests , Early Diagnosis , Female , Humans , Incidental Findings , Infant , Male , Muscle Weakness/diagnosis , Unnecessary ProceduresABSTRACT
Psoriatic arthritis (PA) occurs in about 30% of patients with psoriasis. Although polyneuropathy is described in association with many connective tissue diseases, it is rarely reported in the autoimmune dermatoses. We describe 3 patients with polyneuropathy associated with PA. The clinical and electrophysiologic features are consistent with a chronic distal symmetric sensorimotor axonal process. PA-associated neuropathy should be considered in the differential diagnosis of chronic length-dependent axonal polyneuropathies.
Subject(s)
Arthritis, Psoriatic/complications , Polyneuropathies/complications , Action Potentials/physiology , Adult , Aged , Electromyography/methods , Female , Humans , Male , Neural Conduction/physiology , Retrospective StudiesABSTRACT
PURPOSE: Infantile masturbation (gratification behavior) is not commonly identified as a cause of recurrent paroxysmal movements. Extensive and fruitless investigations may be pursued before establishing this diagnosis. Sparse literature is available regarding masturbatory behavior as a whole, but literature available as case reports describes common features. The purpose of this case series is to describe consistent features in young children with posturing accompanying masturbation. METHODS: Twelve patients presenting to a pediatric movement disorders clinic with a suspected movement disorder were determined to have postures and movements associated with masturbation. We reviewed the clinical history, examination, and home videotapes of these patients. RESULTS: Our patients had several features in common: (1) onset after the age of 3 months and before 3 years; (2) stereotyped episodes of variable duration; (3) vocalizations with quiet grunting; (4) facial flushing with diaphoresis; (5) pressure on the perineum with characteristic posturing of the lower extremities; (6) no alteration of consciousness; (7) cessation with distraction; (8) normal examination; and (9) normal laboratory studies. CONCLUSIONS: The identification of these common features by primary care providers should assist in making this diagnosis and eliminate the need for extensive, unnecessary testing. Direct observation of the events is crucial, and the video camera is a useful tool that may help in the identification of masturbatory behavior.