Congenital muscular dystrophy

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Congenital muscular dystrophy (CMD) is the term used to describe muscular dystrophy that is present at birth. CMD describes a number of autosomal recessive diseases of muscle weakness and possible joint deformities, present at birth and slowly progressing. Life expectancies for affected individuals vary, although some forms of CMD do not affect life span at all.

All such known dystrophies are genetically recessive and result from mutations in a variety of different genes, including those encoding the laminin-α2 chain, fukutin-related protein, LARGE and fukutin, amongst others. Currently there is no cure. Physical and occupational therapy, surgery, wheelchairs and other assistive technology may be helpful.

Classification

A classification for CMDs had been proposed in 2004 by Muntoni and Voit, based on genetic mutation.^[1]

• Genes encoding for structural proteins of the basal membrane or extracellular matrix of the skeletal muscle fibres.
  • Laminin-α2–deficient CMD (MDC1A)
  • Ullrich CMD (UCMDs 1, 2 and 3)
  • Integrin-α7 deficiency (ITGA7)

• Genes encoding for putative or demonstrated glycosyltransferases, that in turn affect the glycosylation of dystroglycan, an external membrane protein of the basal membrane.
  • Walker-Warburg syndrome
  • MEB disease
  • Fukuyama CMD (FCMD)
  • CMD plus secondary laminin deficiency 1 (MDC1B)
  • CMD plus secondary laminin deficiency 2 (mutation in fukitin-related protein, MDC1C)
  • CMD with mental retardation and pachygyria (mutation in LARGE, MDC1D)

• Rigid spine with muscular dystrophy Type 1 (RSMD1): deficiency of selenoprotein-N, an endoplasmic reticulum protein of unknown function.

References