Autosomal recessive centronuclear myopathy

Autosomal recessive centronuclear myopathy (ARCNM) is a rare inherited muscle disorder belonging to the group of centronuclear myopathies, characterized by the abnormal central positioning of nuclei within muscle fibers, which are normally located at the periphery. This condition is caused by mutations in the BIN1 (amphiphysin 2) gene or the TTN (titin) gene, among others. It primarily affects skeletal muscles, leading to progressive muscle weakness and wasting. The disease typically presents in infancy or early childhood with generalized hypotonia (reduced muscle tone), facial weakness, ophthalmoplegia (impaired eye movements), ptosis (drooping eyelids), and progressive limb weakness, particularly affecting proximal muscles. Respiratory insufficiency may develop and can be a significant source of morbidity. Motor milestones are often delayed, and affected individuals may have difficulty with ambulation. The severity of autosomal recessive centronuclear myopathy can vary considerably, ranging from severe neonatal presentations with significant respiratory compromise to milder childhood-onset forms with slower progression. Muscle biopsy is a key diagnostic tool, revealing the characteristic centrally placed nuclei in a significant proportion of muscle fibers, along with type 1 fiber predominance and radial arrangement of sarcoplasmic strands. Diagnosis is confirmed through genetic testing. There is currently no cure or disease-specific treatment for ARCNM. Management is supportive and multidisciplinary, including physical therapy to maintain mobility and prevent contractures, respiratory support (including non-invasive ventilation when needed), orthopedic interventions for scoliosis or other skeletal complications, and regular monitoring of cardiac and respiratory function. Research into potential gene therapies and other targeted treatments is ongoing.

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