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Genetic and Rare Diseases Information Center (GARD)

Muscular dystrophy, congenital, merosin-positive

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The congenital muscle dystrophies are currently classified according to the genetic defects. Historically, congenital muscular dystrophies were classified in two broad groups: Classic CMD (which included the Merosin-deficient CMD and the Merosin-positive CMD) and the CMD with central nervous system (CNS) abnormalities (Fukuyama CMD, muscle-eye-brain disease and Walker-Warburg syndrome). Therefore, merosin-positive congenital muscle dystrophy (CMD) is now considered an old term which refers to a group of diseases without structural brain abnormalities that are caused by a variety of gene mutations, resulting in protein defects that do not affect the merosin protein. It usually has a milder phenotype than the merosin-negative CMD dystrophy group and includes, among others:[1]

Classic CMD without distinguishing features
Rigid spine syndrome associated with mutations in the selenoprotein N1 gene (SEPN1)
CMD with hyperextensible distal joints (Ullrich type)
CMD with intellectual disability or sensory abnormalities.

The pattern of muscle weakness and wasting in the patients within this group of congenital muscular dystrophy conditions is worse in the proximal upper limb-girdle and trunk muscles. Lower limb muscles may be mildly involved. Muscle biopsy shows a dystrophic pattern with normal staining for dystrophin, laminin alpha-2 of merosin and the sarcoglycans.[2]
Last updated: 6/19/2015


  1. Darras BT. Oculopharyngeal, distal, and congenital muscular dystrophies. UpToDate. June 3, 2015;
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In Depth Information

  • The Monarch Initiative brings together data about this condition from humans and other species to help physicians and biomedical researchers. Monarch’s tools are designed to make it easier to compare the signs and symptoms (phenotypes) of different diseases and discover common features. This initiative is a collaboration between several academic institutions across the world and is funded by the National Institutes of Health. Visit the website to explore the biology of this condition.
  • Online Mendelian Inheritance in Man (OMIM) is a catalog of human genes and genetic disorders. Each entry has a summary of related medical articles. It is meant for health care professionals and researchers. OMIM is maintained by Johns Hopkins University School of Medicine. 
See Disclaimer regarding information on this site. Some links on this page may take you to organizations outside of the National Institutes of Health.