GTR Home > Conditions/Phenotypes > Myopathy, centronuclear, 1

Summary

Autosomal dominant centronuclear myopathy is a congenital myopathy characterized by slowly progressive muscular weakness and wasting (Bitoun et al., 2005). The disorder involves mainly limb girdle, trunk, and neck muscles but may also affect distal muscles. Weakness may be present during childhood or adolescence or may not become evident until the third decade of life, and some affected individuals become wheelchair-bound in their fifties. Ptosis and limitation of eye movements occur frequently. The most prominent histopathologic features include high frequency of centrally located nuclei in a large number of extrafusal muscle fibers (which is the basis of the name of the disorder), radial arrangement of sarcoplasmic strands around the central nuclei, and predominance and hypotrophy of type 1 fibers. Genetic Heterogeneity of Centronuclear Myopathy Centronuclear myopathy is a genetically heterogeneous disorder. See also X-linked CNM (CNMX; 310400), caused by mutation in the MTM1 gene (300415); CNM2 (255200), caused by mutation in the BIN1 gene (601248) on chromosome 2q14; CNM3 (614408), caused by mutation in the MYF6 gene (159991) on chromosome 12q21; and CNM4 (614807), caused by mutation in the CCDC78 gene (614666) on chromosome 16p13. In addition, some patients with mutation in the RYR1 gene (180901) can have findings of centronuclear myopathy on skeletal muscle biopsy (see 255320). [from OMIM]

Associated genes

  • Also known as: CMT2M, CMTDI1, CMTDIB, DI-CMTB, DYN2, DYNII, LCCS5, DNM2
    Summary: dynamin 2

  • Also known as: C3orf29, MTMR14
    Summary: myotubularin related protein 14

Clinical features

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  • Areflexia
  • Easy fatigability
  • Muscle hypertrophy
  • Ptosis
  • External ophthalmoplegia
  • Motor delay
  • Flexion contracture
  • Centrally nucleated skeletal muscle fibers
  • Proximal muscle weakness
  • Sleepy facial expression
  • Facial palsy
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