Blog Archives

Sweet dysgeusia, a rare taste disorder, may be encountered in severe anti-acetylcholine receptor antibody (AChRAb)-myasthenia gravis (MG). A 42 year-old man reported progressive loss of sweet taste evolving for almost 10 weeks, revealing an AChRAb-positive MG with thymoma. Improvement of sweet perception paralleled reduction of the MG composite score during the 15 months follow-up period, … [Read more]

Clinicians are faced with unprecedented opportunities to identify the genetic aetiologies of hitherto molecularly uncharacterised conditions via the use of high-throughput sequencing. Access to genomic technology and resultant data is no longer limited to clinicians, geneticists and bioinformaticians, however; ongoing commercialisation gives patients themselves ever greater access to sequencing services. The authors report an increasingly … [Read more]

A 61-year-old woman with a five-year history of progressive muscle weakness and atrophy had a muscle biopsy characterized by a combination of dystrophic features (necrotic fibers and endomysial fibrosis) and mitochondrial alterations [ragged-red cytochrome c oxidase (COX)-negative fibers]. Sequencing of the whole mtDNA, assessment of the mutation load in muscle and in accessible non-muscle tissues, … [Read more]

Nemaline myopathy (NM) is a genetically heterogeneous disorder characterized by early onset muscular weakness and sarcoplasmatic or intranuclear inclusions of rod-shaped Z-disk material in muscle fibers. Thus far, mutations in seven genes have been identified as the cause of NM. Only one singleTNNT1 nonsense mutation has been previously described that causes autosomal recessive NM in … [Read more]

Mutations affecting skeletal muscle isoforms of the tropomyosin genes may cause nemaline myopathy (NM), cap myopathy, core-rod myopathy, congenital fibre-type disproportion, distal arthrogryposes and Escobar syndrome. This study correlates the clinical picture of these diseases with novel (16) and previously reported (31) mutations of the TPM2 and TPM3 genes. Altogether 93 families are included: 53 … [Read more]

A working hypothesis for the pathogenesis of myotonic dystrophy type 1 (DM1) involves the aberrant sequestration of an alternative splicing regulator, MBNL1, by expanded CUG repeats, r(CUG)exp. It has been suggested that a reversal of the myotonia and potentially other symptoms of the DM1 disease can be achieved by inhibiting the toxic MBNL1-r(CUG)exp interaction. Using … [Read more]

Mutations in the survival motor neuron (SMN1) gene lead to the neuromuscular disease spinal muscular atrophy (SMA). Although SMA is primarily considered a motor neuron disease, the importance of muscle defects in its pathogenesis has not been fully examined. Here, the authors used both primary cell culture and two different SMA model mice to demonstrate … [Read more]

Nemaline myopathy (NM) is a rare congenital myopathy characterised by hypotonia, muscle weakness, and often skeletal muscle deformities with the presence of nemaline bodies (rods) in the muscle biopsy. The nebulin (NEB) gene is the most commonly mutated and is thought to account for approximately 50% of genetically diagnosed cases of NM. In this study, … [Read more]

Fibro-adipogenic progenitors (FAPs) are important components of the skeletal muscle regenerative environment. Whether FAPs support muscle regeneration or promote fibro-adipogenic degeneration is emerging as a key determinant in the pathogenesis of muscular diseases, including Duchenne muscular dystrophy (DMD). However, the molecular mechanism that controls FAP lineage commitment and activity is currently unknown. Here, the authors … [Read more]

While transfer of a protein encoded by a single nucleus to nearby nuclei in multinucleated cells has been known for almost 25 years, the biological consequences for gain-of-function diseases have not been considered. Here, the authors have investigated nuclear protein spreading and its potential consequences in two of the three most prevalent neuromuscular diseases. By … [Read more]