The Classification, Natural History and Treatment of the Limb Girdle Muscular Dystrophies.

Over sixty years ago John Walton and Frederick Nattrass defined limb girdle muscular dystrophy (LGMD) as a separate entity from the X-linked dystrophinopathies such as Duchenne and Becker muscular dystrophies. LGMD is a highly heterogeneous group of very rare neuromuscular disorders whose common factor is their autosomal inheritance. Sixty years later, with the development of increasingly advanced molecular genetic investigations, a more precise classification and understanding of the pathogenesis is possible.

Development and Application of an Ultrasensitive Hybridization-Based ELISA Method for the Determination of Peptide-Conjugated Phosphorodiamidate Morpholino Oligonucleotides.

Antisense oligonucleotide (AON)-induced exon skipping is one of the most promising strategies for treating Duchenne muscular dystrophy (DMD) and other rare monogenic conditions. Phosphorodiamidate morpholino oligonucleotides (PMOs) and 2'-O-methyl phosphorothioate (2'OMe) are two of the most advanced AONs in development. The next generation of peptide-conjugated PMO (P-PMO) is also showing great promise, but to advance these therapies it is essential to determine the pharmacokinetic and biodistribution (PK/BD) profile using a suitable method to detect AON levels in blood and tissue samples.

Recent advances in the management of Duchenne muscular dystrophy.

Duchenne muscular dystrophy (DMD) is the commonest inherited neuromuscular disorder of childhood and mainly affects males. Over the course of the last century, the average life expectancy of these patients has doubled and now stands at ∼25 years. This progress has been made possible through advances in the diagnosis, treatment and long-term care of patients with DMD.

Short stature and pubertal delay in Duchenne muscular dystrophy.

Children with Duchenne muscular dystrophy (DMD) are shorter than their healthy peers. The introduction of corticosteroid (CS) has beneficial effects on muscle function but slows growth further and is associated with pubertal delay. In contrast to CS usage in most children and adolescents, weaning glucocorticoid is not a key objective of management in DMD.

The TREAT-NMD advisory committee for therapeutics (TACT): an innovative de-risking model to foster orphan drug development.

Despite multiple publications on potential therapies for neuromuscular diseases (NMD) in cell and animal models only a handful reach clinical trials. The ability to prioritise drug development according to objective criteria is particularly critical in rare diseases with large unmet needs and a limited numbers of patients who can be enrolled into clinical trials. TREAT-NMD Advisory Committee for Therapeutics (TACT) was established to provide independent and objective guidance on the preclinical and development pathway of potential therapies (whether novel or repurposed) for NMD.

Phenotypic variability of TRPV4 related neuropathies.

Mutations in the transient receptor potential vanilloid 4 (TRPV4) gene have been associated with autosomal dominant skeletal dysplasias and peripheral nervous system syndromes (PNSS). PNSS include Charcot-Marie-Tooth disease (CMT) type 2C, congenital spinal muscular atrophy and arthrogryposis and scapuloperoneal spinal muscular atrophy. We report the clinical, electrophysiological and muscle biopsy findings in two unrelated patients with two novel heterozygous missense mutations in the TRPV4 gene.

Absence of Cardiac Benefit with Early Combination ACE Inhibitor and Beta Blocker Treatment in mdx Mice.

Most patients with Duchenne muscular dystrophy (DMD) will develop cardiomyopathy; however, the evidence for prophylactic treatment of children with cardiac medications is limited. We have used the mdx mouse model of DMD to assess if early combination treatment with beta blocker (BB) and ACE inhibitor (AI) is superior to single treatment with either one of these drugs. Mice were assessed with cardiac MRI (ventricular structure and function, in vivo calcium influx (manganese-enhanced MRI)), pressure-volume loops, and histopathology.

Conserved expression of truncated telethonin in a patient with limb-girdle muscular dystrophy 2G.

Limb-girdle muscular dystrophy 2G is caused by mutations in the TCAP gene that encodes for telethonin. Here we describe a 49 year-old male patient of Indian descent presenting a classical LGMD phenotype. He had normal motor milestones but became noticeably slower in his early teens and was wheelchair bound by age 44.

The TREAT-NMD DMD Global Database: analysis of more than 7,000 Duchenne muscular dystrophy mutations.

Analyzing the type and frequency of patient-specific mutations that give rise to Duchenne muscular dystrophy (DMD) is an invaluable tool for diagnostics, basic scientific research, trial planning, and improved clinical care. Locus-specific databases allow for the collection, organization, storage, and analysis of genetic variants of disease. Here, we describe the development and analysis of the TREAT-NMD DMD Global database (http://umd.

Improving highly accelerated fat fraction measurements for clinical trials in muscular dystrophy: origin and quantitative effect of R2* changes.

Purpose To investigate the effect of R2* modeling in conventional and accelerated measurements of skeletal muscle fat fraction in control subjects and patients with muscular dystrophy. Materials and Methods Eight patients with Becker muscular dystrophy and eight matched control subjects were recruited with approval from the Newcastle and North Tyneside 2 Research Ethics Committee and with written consent. Chemical-shift images with six widely spaced echo times (in 3.

Validation of genetic modifiers for Duchenne muscular dystrophy: a multicentre study assessing SPP1 and LTBP4 variants.

Objective: Duchenne muscular dystrophy (DMD) is characterised by progressive muscle weakness. It has recently been reported that single nucleotide polymorphisms (SNPs) located in the SPP1 and LTBP4 loci can account for some of the inter-individual variability observed in the clinical disease course. The validation of genetic association in large independent cohorts is a key process for rare diseases in order to qualify prognostic biomarkers and stratify patients in clinical trials.

Assessment of ventricular function in mouse models of muscular dystrophy: a comparison of MRI with conductance catheter.

Outcomes of clinical trials depend on the quality of preceding preclinical research, yet functional assays and outcome measures for mouse models of disease are often poorly standardized or inappropriate. Muscular dystrophies are associated with cardiomyopathy so preclinical research requires reliable measures of cardiac function in animal models of the disease. MRI and conductance catheter were compared as preclinical tools to detect cardiomyopathy in two mouse models of muscular dystrophy.

Safety and efficacy of drisapersen for the treatment of Duchenne muscular dystrophy (DEMAND II): an exploratory, randomised, placebo-controlled phase 2 study.

Background: Duchenne muscular dystrophy is caused by dystrophin deficiency and muscle deterioration and preferentially affects boys. Antisense-oligonucleotide-induced exon skipping allows synthesis of partially functional dystrophin. We investigated the efficacy and safety of drisapersen, a 2'-O-methyl-phosphorothioate antisense oligonucleotide, given for 48 weeks.

Improving recognition of Duchenne muscular dystrophy: a retrospective case note review.

Background: Over the last 30 years, there has been little improvement in the age of diagnosis of Duchenne muscular dystrophy (DMD) (mean age of 4.5-4.11 years).

The burden of Duchenne muscular dystrophy: an international, cross-sectional study.

Objective: The objective of this study was to estimate the total cost of illness and economic burden of Duchenne muscular dystrophy (DMD).

Methods: Patients with DMD from Germany, Italy, United Kingdom, and United States were identified through Translational Research in Europe-Assessment & Treatment of Neuromuscular Diseases registries and invited to complete a questionnaire online together with a caregiver. Data on health care use, quality of life, work status, informal care, and household expenses were collected to estimate costs of DMD from the perspective of society and caregiver households.

Affinity proteomics within rare diseases: a BIO-NMD study for blood biomarkers of muscular dystrophies.

Despite the recent progress in the broad-scaled analysis of proteins in body fluids, there is still a lack in protein profiling approaches for biomarkers of rare diseases. Scarcity of samples is the main obstacle hindering attempts to apply discovery driven protein profiling in rare diseases. We addressed this challenge by combining samples collected within the BIO-NMD consortium from four geographically dispersed clinical sites to identify protein markers associated with muscular dystrophy using an antibody bead array platform with 384 antibodies.

Two recurrent mutations are associated with GNE myopathy in the North of Britain.

Objective: GNE myopathy is a rare recessive myopathy associated with inclusion bodies on muscle biopsy. The clinical phenotype is associated with distal muscle weakness with quadriceps sparing. Most of the current information on GNE myopathy has been obtained through studies of Jewish and Japanese patient cohorts carrying founder mutations in the GNE gene.

Novel mutations widen the phenotypic spectrum of slow skeletal/β-cardiac myosin (MYH7) distal myopathy.

Laing early onset distal myopathy and myosin storage myopathy are caused by mutations of slow skeletal/β-cardiac myosin heavy chain encoded by the gene MYH7, as is a common form of familial hypertrophic/dilated cardiomyopathy. The mechanisms by which different phenotypes are produced by mutations in MYH7, even in the same region of the gene, are not known. To explore the clinical spectrum and pathobiology, we screened the MYH7 gene in 88 patients from 21 previously unpublished families presenting with distal or generalized skeletal muscle weakness, with or without cardiac involvement.

Quantitative magnetic resonance imaging in limb-girdle muscular dystrophy 2I: a multinational cross-sectional study.

We conducted a prospective multinational study of muscle pathology using magnetic resonance imaging (MRI) in patients with limb-girdle muscular dystrophy 2I (LGMD2I). Thirty eight adult ambulant LGMD2I patients (19 male; 19 female) with genetically identical mutations (c.826C>A) in the fukutin-related protein (FKRP) gene were recruited.

Fibronectin is a serum biomarker for Duchenne muscular dystrophy.

Purpose: To identify and validate serum biomarkers for the progression of Duchenne muscular dystrophy (DMD) using a MS-based bottom-up pipeline.

Experimental Design: We used a bottom-up proteomics approach, including a protein concentration equalization step, different proteolytic digestions, and MS detection schemes, to identify candidate biomarkers in serum samples from control subjects and DMD patients. Fibronectin was chosen for follow-up based on the differences in peptide spectral counts and sequence coverage observed between the DMD and control groups.

Mutations in the Mitochondrial Citrate Carrier SLC25A1 are Associated with Impaired Neuromuscular Transmission.

Background And Objective: Congenital myasthenic syndromes are rare inherited disorders characterized by fatigable weakness caused by malfunction of the neuromuscular junction. We performed whole exome sequencing to unravel the genetic aetiology in an English sib pair with clinical features suggestive of congenital myasthenia.

Methods: We used homozygosity mapping and whole exome sequencing to identify the candidate gene variants.