Congenital myopathies
RSS feedThe SH3 domain interactome of amphiphysin 2 in centronuclear myopathies
While amphiphysin 2 uses its BAR domain to anchor to cell membranes and cause them to bend, it also has an SH3 domain at the other end that enables it to interact with other proteins, in particular dynamin 2, cavin 4 or another amphiphysin 2 molecule. Using a new approach to studying the interactome, the … [Read more]
The MYOCAPTURE project improves molecular understanding of congenital myopathies
Between 2009 and 2018, whole exome sequencing of 310 families affected by congenital myopathy as part of the MYOCAPTURE project, supported by the AFM-TĂ©lĂ©thon, identified 14 new genes: four linked to other neuromuscular diseases or cardiomyopathy (ASCC1, HSPB8, CACNA1S, MYPN), ten never implicated in a genetic neuromuscular disease (ACTN2, CASQ1, GGPS1, MAP3K20/ZAK, ORAI1, MYO18B, PYROXD1, … [Read more]
Congenital myopathy linked to the STAC3 gene is a frequent cause of early hypotonia in South Africa
South African researchers report the clinical and biological data from a cohort of 127 young children with congenital hypotonia: they had been previously excluded for SMA and Prader-Willi syndrome, the homozygous variant identified in STAC3 by high-throughput DNA sequencing in 31 children is the same as that found in patients from Africa, additional haplotyping studies … [Read more]
Dominant CACNA1S mutations: pure myopathic forms are possible
Dominant mutations of the CACNA1S gene most often cause hypokalemic periodic paralysis or malignant hyperthermia. The team at the Brussels Neuromuscular Reference Centre reports the case of a 65-year-old man with progressive proximal muscle weakness that began at the age of 35, without any transient paralysis: his mother, who had been in a wheelchair since … [Read more]
Overview of neuromuscular diseases
After a brief reminder of the structure of the motor unit and the various modes of inheritance, this document provides short descriptions of the neuromuscular diseases that are part of our scope at AFM-TĂ©lĂ©thon, as well as how to manage and treat them. For each group of diseases, as well as in the motor unit … [Read more]
A biallelic SOX8 variant causes a new syndrome combining myopathy, bone deformities, intellectual impairment and ovarian dysfunction
A Canadian team reports the case of a skinny, short 27-year-old woman with a diminished head circumference, non-progressive proximal and distal muscle weakness, moderate intellectual impairment and oligomenorrhea. She also presented with facial paralysis, significant dysphagia and severe dysphonia, as well as elbow, knee and ankle retractions and long, thin, hyperlaxed fingers. From birth, there … [Read more]
Muscle hypertonicity linked to TPM2 and TPM3 variants
A Finnish team has described a congenital myopathy linked to atypical TPM2 or TPM3 in seven patients from three families. In contrast to the phenotype of nemalin myopathy with weakness and hypotonia usually associated with TPM2 or TPM3 mutations, the patients presented with muscular hypertonia that could go as far as trismus and/or lead to … [Read more]
Histopathology of THOC2 splice-site arthrogryposis shows filamentous cytoplasmic inclusions
Following the description in 2021 of a family with X-linked arthrogryposis due to a mutation in the THOC2 gene, a French team reports : another family with the same mutation responsible for arthrogryposis. Muscle biopsy showed a wide variation in the size of muscle fibres, as well as the presence of cytoplasmic bodies in almost … [Read more]
A natural history of paediatric RYR1-related congenital myopathies
Two major London paediatric neuromuscular centres carried out a retrospective study of 69 children with RYR1-related myopathy followed up between 1992 and 2019: 29 presented a dominant form of myopathy linked to RYR1, 31 a recessive form, six a de novo dominant form and three a form of transmission as yet undefined; Onset ranged from … [Read more]
Sporadic nemalin myopathy with atypical skin involvement responding to immunoglobulins
A Danish team presents the case of a 59-year-old woman with atypical sporadic late-onset nemaline myopathy (SLONM): skin manifestations (redness and phlyctenes on the extremities and trunk) preceded the onset of neuromuscular symptoms by one year; the residual thymus showed follicular hyperplasia; Muscle biopsy revealed rods and abnormal mitochondria; the electromyogram revealed not only myopathic … [Read more]
