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Myotonia congenita


Información en español Title




Other Names:
Thomsen and Becker disease
Categories:
Congenital and Genetic Diseases; Nervous System Diseases

Summary Summary


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Myotonia congenita is a genetic disease characterized by the inability of the skeletal muscles to quickly relax after voluntary movements. Symptoms typically begin in childhood and vary from person to person. They may include muscle stiffness, muscle weakness, and attacks of weakness brought on by movement after rest. There are two forms of myotonia congenita: Becker disease, which is the most common and severe, generalized form; and Thomsen disease, which is a rare and milder form.[1] Both forms are caused by mutations in the CLCN1 gene. The Becker type is inherited in an autosomal recessive manner, and the Thomsen type is inherited in an autosomal dominant manner.[2] Treatment may include medication for muscle stiffness,  such as mexiletine, carbamazepine, or phenytoin. Exercise may temporarily alleviate myotonia. People with myotonia congenita may be at increased risk for harmful side effects of anesthesia. Therefore, it is recommended that relatives of a person with the disease are tested during childhood.[3]
Last updated: 3/22/2017

Symptoms Symptoms


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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.

Showing of 16 |
Medical Terms Other Names
Learn More:
HPO ID
80%-99% of people have these symptoms
EMG abnormality 0003457
Myotonia 0002486
5%-29% of people have these symptoms
Myalgia
Muscle ache
Muscle pain
[ more ]
0003326
1%-4% of people have these symptoms
Muscle stiffness 0003552
Muscle weakness
Muscular weakness
0001324
Myotonia with warm-up phenomenon 0003740
Percussion myotonia 0010548
Skeletal muscle hypertrophy
Increased skeletal muscle cells
0003712
Percent of people who have these symptoms is not available through HPO
Autosomal dominant inheritance 0000006
Autosomal recessive inheritance 0000007
Childhood onset
Symptoms begin in childhood
0011463
Dysphagia
Poor swallowing
Swallowing difficulties
Swallowing difficulty
[ more ]
0002015
EMG: myotonic runs 0003730
Handgrip myotonia 0012899
Lid lag on downgaze 0025605
Muscle hypertrophy of the lower extremities 0008968
Showing of 16 |
Do you have more information about symptoms of this disease? We want to hear from you.
Last updated: 2/1/2021
Do you have updated information on this disease? We want to hear from you.

Diagnosis Diagnosis


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Making a diagnosis for a genetic or rare disease can often be challenging. Healthcare professionals typically look at a person’s medical history, symptoms, physical exam, and laboratory test results in order to make a diagnosis. The following resources provide information relating to diagnosis and testing for this condition. If you have questions about getting a diagnosis, you should contact a healthcare professional.

Testing Resources

  • The Genetic Testing Registry (GTR) provides information about the genetic tests for this condition. The intended audience for the GTR is health care providers and researchers. Patients and consumers with specific questions about a genetic test should contact a health care provider or a genetics professional.

Treatment Treatment


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Treatment for myotonia congenita depends on the symptoms and severity in each person. People with mild symptoms may just need to modify their activities. Those with more severe muscle stiffness might consider or need sodium channel blockers or other medications to relieve symptoms. Medication options may include:
  • Mexiletine - this is a sodium channel blocker and is the best documented treatment option. It may significantly reduce muscle stiffness.
  • Phenytoin or carbamazepine - these are anticonvulsants that have been reported to help symptoms in some people.
  • Quinine (an antimalarial), dantrolene (a muscle relaxant), or acetazolamide (a diuretic) may help symptoms in some cases.
Exercise is known to temporarily relieve myotonia. Some people with myotonia congenita have reported more long-term relief with gymnastics, but this has not been studied in controlled trials. Anesthesia should be used with caution in people with myotonia congenita.[3]
Last updated: 12/4/2017

Management Guidelines

  • Project OrphanAnesthesia is a project whose aim is to create peer-reviewed, readily accessible guidelines for patients with rare diseases and for the anesthesiologists caring for them. The project is a collaborative effort of the German Society of Anesthesiology and Intensive Care, Orphanet, the European Society of Pediatric Anesthesia, anesthetists and rare disease experts with the aim to contribute to patient safety.

Find a Specialist Find a Specialist


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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

  • To find a medical professional who specializes in genetics, you can ask your doctor for a referral or you can search for one yourself. Online directories are provided by the American College of Medical Genetics and the National Society of Genetic Counselors. If you need additional help, contact a GARD Information Specialist. You can also learn more about genetic consultations from MedlinePlus Genetics.

Related Diseases Related Diseases


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Related diseases are conditions that have similar signs and symptoms. A health care provider may consider these conditions in the table below when making a diagnosis. Please note that the table may not include all the possible conditions related to this disease.

Conditions with similar signs and symptoms from Orphanet
Steinert myotonic dystrophy, proximal myotonic myopathy and sodium channel channelopathies should be always considered in the differential diagnosis. Steinert myotonic dystrophy and proximal myotonic myopathy represent the most relevant differential diagnosis; these diseases present with fixed muscle weakness and wasting, and multisystem involvement, which are usually not associated to Thomsen and Becker disease, and occasionally may present with only myotonia. In addition, some degree of weakness may be observed in Thomsen and Becker disease, especially in later disease stages. Sodium muscle channelopathies may present with myotonia, which may be very similar to that reported in Thomsen and Becker disease or characterized by worsening with exercise, the so-called ''paradoxical myotonia'' (paramyotonia congenita).
Visit the Orphanet disease page for more information.

Organizations Organizations


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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

  • European Alliance of Neuromuscular Disorders Associations
    MDG Malta 4
    Gzira Road
    Gzira, Intl GAR 04
    Malta
    Telephone: 003-56 -21 346688
    E-mail: eamda@hotmail.com
    Website: http://www.eamda.eu/
  • Neuromuscular Disease Foundation
    269 South Beverly Drive, Suite 1206
    Beverly Hills, CA 90212
    Telephone: 310-736-2978
    Website: https://curehibm.org/

Organizations Providing General Support

  • Muscular Dystrophy Association (MDA)
    222 S Riverside Plaza
    Suite 1500
    Chicago, IL 60606
    Toll-free: 1-833-275-6321 (Helpline)
    E-mail: resourcecenter@mdausa.org
    Website: https://www.mda.org
Do you know of an organization? We want to hear from you.

Learn More Learn More


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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.

Where to Start

  • MedlinePlus was designed by the National Library of Medicine to help you research your health questions, and it provides more information about this topic.
  • Muscular Dystrophy Association has information and resources about Myotonia congenita. Please click on the link to access this resource.
  • The National Organization for Rare Disorders (NORD) has a report for patients and families about this condition. NORD is a patient advocacy organization for individuals with rare diseases and the organizations that serve them.

In-Depth Information

  • GeneReviews provides current, expert-authored, peer-reviewed, full-text articles describing the application of genetic testing to the diagnosis, management, and genetic counseling of patients with specific inherited conditions.
  • Medscape Reference provides information on this topic. You may need to register to view the medical textbook, but registration is free.
  • 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. 
    Myotonia congenita, autosomal recessive (Becker disease)
    Myotonia congenita, autosomal dominant (Thomsen disease)
  • Orphanet is a European reference portal for information on rare diseases and orphan drugs. Access to this database is free of charge.

GARD Answers GARD Answers


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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.

Have a question? Contact a GARD Information Specialist.

References References


  1. NINDS Myotonia Congenita Information Page. National Institute of Neurological Disorders and Stroke (NINDS). October 18, 2015; https://www.ninds.nih.gov/Disorders/All-Disorders/Myotonia-Congenita-Information-Page.
  2. Myotonia congenita. Genetics Home Reference (GHR). April 2007; http://ghr.nlm.nih.gov/condition/myotonia-congenita.
  3. Dunø M & Colding-Jørgensen E. Myotonia Congenita. GeneReviews. 2015; https://www.ncbi.nlm.nih.gov/books/NBK1355/.
Do you know of a review article? We want to hear from you.
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rare disease research!
You can help advance rare disease research!
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