Myology research highlights

Duchenne and Becker muscular dystrophies are caused by mutations in dystrophin. Cardiac manifestations vary broadly, making prognosis difficult. Current dystrophin genotype-cardiac phenotype correlations are limited. For skeletal muscle, the reading-frame rule suggests in-frame mutations tend to yield milder phenotypes. The authors performed dystrophin genotype-cardiac phenotype correlations using a protein-effect model and cardiac magnetic resonance imaging. … [Read more]

The effects of voluntary activity initiated in adult mdx (C57BL/10ScSc-DMDmdx /J) mice on skeletal and cardiac muscle function have not been studied extensively. Here, the authors studied the effects of 3 months of voluntary wheel running initiated at age 7 months on hindlimb muscle weakness, increased susceptibility to muscle contraction-induced injury, and left ventricular function … [Read more]

Quantitative muscle ultrasound (QUS) in boys with Duchenne Muscular Dystrophy (DMD) shows increased echointensity as muscle is replaced with fat and fibrosis. Studies of quantitative ultrasound in infants/young boys with DMD over time have not been reported. Calibrated muscle backscatter (cMB), a reproducible measure of ultrasound echointensity,was used to quantify muscle pathology in 5 young … [Read more]

Receptor-activator of NF-κB, its ligand RANKL, and the soluble decoy receptor osteoprotegerin are the key regulators of osteoclast differentiation and bone remodeling. Although there is a strong association between osteoporosis and skeletal muscle atrophy/dysfunction, the functional relevance of a particular biological pathway that synchronously regulates bone and skeletal muscle physiopathology still is elusive. Here, the … [Read more]

Protein aggregate myopathies (PAMs) define muscle disorders characterised by protein accumulation in muscle fibres. The authors describe a new PAM in a patient with proximal muscle weakness and hypertrophic cardiomyopathy, whose muscle fibres contained inclusions containing myosin and myosin-associated proteins, and aberrant distribution of microtubules. These lesions appear as intact A- and M-bands lacking thin … [Read more]

PTC Therapeutics has started a safety and tolerability study in adult and pediatric patients with spinal muscular atrophy (SMA). The investigational compound developed by PTC in collaboration with corporate partner Roche and other entities, RG7800, is designed to increase levels of the SMN (survival of motor neuron) protein. A deficiency of full-length, fully functional SMN … [Read more]

Sporadic late-onset nemaline myopathy (SLONM) is a rare, late-onset myopathy that progresses subacutely. If associated with a monoclonal gammopathy of unknown significance (MGUS), the outcome is unfavorable: the majority of these patients die within 1 to 5 years of respiratory failure. This study aims to qualitatively assess the long-term treatment effect of high-dose melphalan (HDM) … [Read more]

Neuromuscular diseases (NMDs) are a group of over 200 highly genetically as well as clinically heterogeneous inherited genetic disorders that affect the peripheral nervous and muscular systems, resulting in gross motor disability. The clinical and genetic heterogeneities of NMDs make disease diagnosis complicated and expensive, often involving multiple tests. To expedite the molecular diagnosis of … [Read more]

McArdle disease (Glycogen Storage Disease type V) is caused by an absence of muscle phosphorylase leading to exercise intolerance, myoglobinuria rhabdomyolysis and acute renal failure. This update of a review first published in 2004, systematically examined the evidence from randomised controlled trials (RCTs) of pharmacological or nutritional treatments for improving exercise performance and quality of … [Read more]

This study aimed to identify and characterize the molecular basis of a syndrome associated with myasthenia, cortical hyperexcitability, cerebellar ataxia, and intellectual disability. The authors performed in vitro microelectrode studies of neuromuscular transmission, performed exome and Sanger sequencing, and analyzed functional consequences of the identified mutation in expression studies. Neuromuscular transmission at patient endplates was … [Read more]