National Center for Advancing and Translational Sciences Genetic and Rare Diseases Information Center, a program of the National Center for Advancing and Translational Sciences

Muscular dystrophy, congenital, merosin-positive



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

This table lists symptoms that people with this disease may have. For most diseases, symptoms will vary from person to person. People with the same disease may not have all the symptoms listed. This information comes from a database called the Human Phenotype Ontology (HPO) . The HPO collects information on symptoms that have been described in medical resources. The HPO is updated regularly. Use the HPO ID to access more in-depth information about a symptom.

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Medical Terms Other Names
Learn More:
HPO ID
Percent of people who have these symptoms is not available through HPO
Autosomal recessive inheritance 0000007
Congenital muscular dystrophy 0003741
Congenital onset
Symptoms present at birth
0003577
Decreased fetal movement
Less than 10 fetal movements in 12 hours
0001558
Delayed ability to walk 0031936
Facial palsy
Bell's palsy
0010628
Flexion contracture
Flexed joint that cannot be straightened
0001371
Increased variability in muscle fiber diameter 0003557
Joint laxity
Joint instability
Lax joints
Loose-jointedness
Loosejointedness
[ more ]
0001388
Mildly elevated creatine kinase 0008180
Myopathy
Muscle tissue disease
0003198
Neck muscle weakness
Floppy neck
0000467
Neonatal hypotonia
Low muscle tone, in neonatal onset
0001319
Proximal muscle weakness
Weakness in muscles of upper arms and upper legs
0003701
Respiratory insufficiency due to muscle weakness
Decreased lung function due to weak breathing muscles
0002747
Scoliosis 0002650
Shoulder girdle muscle weakness
Weak shoulder muscles
0003547
Variable expressivity 0003828
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Last updated: 7/1/2020

If you need medical advice, you can look for doctors or other healthcare professionals who have experience with this disease. You may find these specialists through advocacy organizations, clinical trials, or articles published in medical journals. You may also want to contact a university or tertiary medical center in your area, because these centers tend to see more complex cases and have the latest technology and treatments.

If you can’t find a specialist in your local area, try contacting national or international specialists. They may be able to refer you to someone they know through conferences or research efforts. Some specialists may be willing to consult with you or your local doctors over the phone or by email if you can't travel to them for care.

You can find more tips in our guide, How to Find a Disease Specialist. We also encourage you to explore the rest of this page to find resources that can help you find specialists.

Healthcare Resources


Research helps us better understand diseases and can lead to advances in diagnosis and treatment. This section provides resources to help you learn about medical research and ways to get involved.

Patient Registry

  • A registry supports research by collecting of information about patients that share something in common, such as being diagnosed with Muscular dystrophy, congenital, merosin-positive. The type of data collected can vary from registry to registry and is based on the goals and purpose of that registry. Some registries collect contact information while others collect more detailed medical information. Learn more about registries.

    Registries for Muscular dystrophy, congenital, merosin-positive:
    Congenital Muscle Disease International Registry
     

Support and advocacy groups can help you connect with other patients and families, and they can provide valuable services. Many develop patient-centered information and are the driving force behind research for better treatments and possible cures. They can direct you to research, resources, and services. Many organizations also have experts who serve as medical advisors or provide lists of doctors/clinics. Visit the group’s website or contact them to learn about the services they offer. Inclusion on this list is not an endorsement by GARD.

Organizations Supporting this Disease


These resources provide more information about this condition or associated symptoms. The in-depth resources contain medical and scientific language that may be hard to understand. You may want to review these resources with a medical professional.

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. 

Questions sent to GARD may be posted here if the information could be helpful to others. We remove all identifying information when posting a question to protect your privacy. If you do not want your question posted, please let us know.


  1. Darras BT. Oculopharyngeal, distal, and congenital muscular dystrophies. UpToDate. June 3, 2015; http://www.uptodate.com/contents/topic.do?topicKey=PEDS/6180.
  2. MUSCULAR DYSTROPHY, CONGENITAL, MEROSIN-POSITIVE. OMIM. July 22, 2005; http://omim.org/entry/609456?search=Congenital%20Muscular%20Dystrophy%2C%20Merosin%20Positive&highlight=congenital%20positive%20dystrophy%20merosin%20muscular. Accessed 6/19/2015.