Miyoshi myopathy

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Other Names:

Muscular dystrophy, distal, late onset, autosomal recessive; MM; Miyoshi distal myopathy

Categories:

Congenital and Genetic Diseases; Nervous System Diseases

This disease is grouped under:

Dysferlinopathy

Summary Summary

Miyoshi myopathy is a type of muscular dystrophy characterized by muscle weakness and atrophy (wasting), mainly in the distal parts of the legs.^[1] The first symptoms typically begin in young adulthood (on average 20 years of age) and include weakness and atrophy of the calves (sometimes asymmetrically), leading to inability to jump, run or walk on tiptoes. Over a period of years, the weakness and atrophy typically spread to the thighs and gluteal muscles. The forearms may become mildly atrophic with decrease in grip strength. Blood exams show an elevation of the creatine kinase (CK) often 10-100 times above the normal values.^[1] It is caused by variations (mutations) in the DYSF gene. Inheritance is autosomal recessive.^[2] Management may include physical therapy, use of mechanical aids, surgical intervention for orthopedic complications, respiratory aids, and social and emotional support.^[1]

Miyoshi myopathy is part of the group of diseases known as "Dysferlinopathies", which are caused by DYSF pathogenic variants.

Last updated: 7/2/2018

Symptoms Symptoms

The disease have slow progression. Onset of signs and symptoms is typically in mid to late childhood or early-adulthood, (average age at onset of 19 years), and may include:^[1]

Muscle weakness and atrophy (wasting), most marked in the distal parts of the legs, especially the gastrocnemius (calf) and soleus (Achilles tendon) muscles, specially in young adults
Inability to stand on tiptoe, retaining the ability to stand on the heels
Slow progression of weakness and atrophy spreading to the thighs and gluteal muscles, at which time climbing stairs, standing, and walking become difficult
Mildly loss of muscular mass in forearms with decrease in grip strength; the small muscles of the hands are not affected
Weakness of the shoulder girdle muscles, which may occur on one side than the other.

Last updated: 7/2/2018

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
30%-79% of people have these symptoms
Adult onset	Symptoms begin in adulthood	0003581
Difficulty standing	Difficulty in standing	0003698
Difficulty walking	Difficulty in walking	0002355
Distal upper limb amyotrophy		0007149
Exercise-induced myalgia	Exercise-induced muscle pain Muscle pain on exercise Muscle pain with exercise Muscle pain, exercise-induced [ more ]	0003738
Pelvic girdle muscle weakness		0003749
Proximal amyotrophy	Wasting of muscles near the body	0007126
Quadriceps muscle weakness	Quadriceps weakness	0003731
Shoulder girdle muscle weakness	Weak shoulder muscles	0003547
Tibialis atrophy		0011399
Tibialis muscle weakness		0008963
5%-29% of people have these symptoms
Calf muscle hypertrophy	Increased size of calf muscles	0008981
Decreased/absent ankle reflexes		0200101
Deposits immunoreactive to beta-amyloid protein		0003791
Foot dorsiflexor weakness	Foot drop	0009027
Loss of ability to walk		0006957
Toe walking	Toe-walking	0040083
Triceps weakness		0031108
Percent of people who have these symptoms is not available through HPO
Autosomal recessive inheritance		0000007
Decreased Achilles reflex		0009072
Difficulty climbing stairs	Difficulty walking up stairs	0003551
Difficulty running		0009046
Distal amyotrophy	Distal muscle wasting	0003693
Distal muscle weakness	Weakness of outermost muscles	0002460
Elevated serum creatine kinase	Elevated blood creatine phosphokinase Elevated circulating creatine phosphokinase Elevated creatine kinase Elevated serum CPK Elevated serum creatine phosphokinase High serum creatine kinase Increased CPK Increased creatine kinase Increased creatine phosphokinase Increased serum CK Increased serum creatine kinase Increased serum creatine phosphokinase [ more ]	0003236
Lower limb muscle weakness	Lower extremity weakness Lower limb weakness Muscle weakness in lower limbs [ more ]	0007340
Muscle fibrillation		0010546
Muscular dystrophy		0003560
Quadriceps muscle atrophy	Wasting of quad muscles	0009050
Variable expressivity		0003828

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Do you have more information about symptoms of this disease? We want to hear from you.

Last updated: 1/1/2021

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Cause Cause

Miyoshi myopathy is caused by pathogenic variants (mutations) in the DYSF gene, which encodes the dysferlin protein, a component of muscular fiber membranes. The presence and/or activity of the dysferlin protein is decreased or absent in individuals who have Miyoshi myopathy.^[2] This leads to abnormalities in the integrity of the muscle fiber membrane and problems with membrane repair. Mutations in the same gene are also involved in autosomal recessive limb-girdle muscular dystrophy type 2B (LGMD2B) and other diseases. The group of diseases caused by mutations in the DYSF gene are referred as "Dysferlinopathy".^[1]

Last updated: 7/2/2018

Inheritance Inheritance

Miyoshi myopathy is inherited in an autosomal recessive manner.^[1] Individuals have two copies of each gene (one copy inherited from each parent). In an individual affected with an autosomal recessive condition, both copies of the responsible gene have mutations. This means that each of the parents of an affected individual carry one mutated copy of the gene, and are therefore referred to as "carriers." Carriers of an autosomal recessive condition typically do not show signs or symptoms of the condition. When two carriers for the same condition have children together, each child has a 1 in 4 (25%) risk to have the condition, a 1 in 2 (50%) risk to be a carrier like each of the parents, and a 1 in 4 chance to not have the condition and not be a carrier. Carrier testing for at-risk relatives and prenatal diagnosis for pregnancies at increased risk are possible if the disease-causing mutations in the family are known.

Last updated: 7/2/2018

Diagnosis Diagnosis

Characteristics that may make the diagnosis of Miyoshi myopathy likely are:

Mid- to late-childhood or early-adult onset of signs and symptoms
Early and predominant involvement of the calf muscles
Slow progression
Elevation of serum creatine kinase (CK) concentration, often 10-100 times normal
Primarily myogenic pattern on EMG (electromyography)
Biopsy evidence of a chronic, active myopathy without rimmed vacuoles^[1]

Diagnosis typically depends on a combination of muscle biopsy and genetic testing. Muscle biopsy almost always indicates a primary dysferlinopathy (a disorder involving dysferlin, the protein absent or decreased in individuals with Miyoshi myopathy and limb-girdle muscular dystrophy type 2B). Molecular genetic testing of DYSF, the only gene associated with dysferlinopathy, is clinically available.^[1]

Last updated: 6/6/2011

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.
The Jain Foundation sponsors genetic testing to confirm the diagnosis of dysferlinopathy.

Treatment Treatment

There is currently no cure or definitive treatment for Miyoshi myopathy. Management depend on the specific signs and symptoms, and is aimed to prolong survival and improve quality of life:.^[1]

Physical therapy and stretching exercises to promote mobility and prevent contractures
Use of mechanical aids such as canes, walkers, orthotics, and wheelchairs as needed to help ambulation and mobility
Surgical intervention as needed for orthopedic complications such as foot deformity and scoliosis
Use of respiratory aids when indicated
Social and emotional support

Because dysferlinopathies are progressive conditions, rehabilitative interventions should be focused on slowing down the of muscle weakness and wasting progression, rather than increasing muscle strength and walking capacity at the risk of causing irreversible muscle damage. Gene therapies are under investigation.^[3]

Last updated: 7/2/2018

Find a Specialist Find a Specialist

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 Genetics Home Reference.
The Jain Foundation provides a list of doctors who are knowledgeable about diagnosing dysferlinopathy.

Related Diseases Related Diseases

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
Differential diagnosis includes autosomal recessive limb-girdle muscular dystrophy type 2L (LGMD2L), LGMD2B and qualitative or quantitative defects of caveolin-3. Visit the Orphanet disease page for more information.

Research Research

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.

Clinical Research Resources

The Centers for Mendelian Genomics program is working to discover the causes of rare genetic disorders. For more information about applying to the research study, please visit their website.
ClinicalTrials.gov lists trials that are related to Miyoshi myopathy. Click on the link to go to ClinicalTrials.gov to read descriptions of these studies.

Please note: Studies listed on the ClinicalTrials.gov website are listed for informational purposes only; being listed does not reflect an endorsement by GARD or the NIH. We strongly recommend that you talk with a trusted healthcare provider before choosing to participate in any clinical study.
The Jain Foundation provides information on clinical trials and research studies for dysferlinopathy.

Patient Registry

A registry supports research by collecting of information about patients that share something in common, such as being diagnosed with Miyoshi myopathy. 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 Miyoshi myopathy:
Dysferlin Registry

Organizations Organizations

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

Jain Foundation
9706 4th Ave NE
Ste 101
Seattle, WA 98115
Telephone: 425-882-1492
E-mail: patients@jain-foundation.org
Website: https://www.jain-foundation.org/
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
Muscular Dystrophy Family Foundation
P.O. Box 776
Carmel, IN 46082
Telephone: +1-317-615-9140
E-mail: info@mdff.org
Website: https://mdff.org/
MDFF provides financial assistance, quality programs and services for the Muscular Dystrophy community in Indiana.
Muscular Dystrophy UK
61A Great Suffolk Street
London, SE1 0BU United Kingdom
Toll-free: 0800 652 6352 (Helpline)
Telephone: (+44) 0 020 7803 4800
E-mail: info@musculardystrophyuk.org
Website: https://www.musculardystrophyuk.org/

Do you know of an organization? We want to hear from you.

Learn More Learn More

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

The Jain Foundation Learning Center provides basic information on this condition.
Genetics Home Reference (GHR) contains information on Miyoshi myopathy. This website is maintained by the National Library of Medicine.

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.
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.
http://www.ncbi.nlm.nih.gov/omim/254130
http://www.ncbi.nlm.nih.gov/omim/613318
http://www.ncbi.nlm.nih.gov/omim/613319
Orphanet is a European reference portal for information on rare diseases and orphan drugs. Access to this database is free of charge.
PubMed is a searchable database of medical literature and lists journal articles that discuss Miyoshi myopathy. Click on the link to view a sample search on this topic.

News & Events News & Events

Other Conferences

The Jain Foundation holds an annual conference dedicated to dysferlinopathy research.

GARD Answers GARD Answers

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. Submit a new question

My brother and I have similar symptoms and I was recently informed that it was Miyoshi distal myopathy. Could you please provide some of the latest information on this disease? See answer

Have a question? Contact a GARD Information Specialist.

References References

Aoki M. Dysferlinopathy. GeneReviews. 2015; http://www.ncbi.nlm.nih.gov/books/NBK1303/.
Miyoshi myopathy. Orphanet. 2015; http://www.orpha.net/consor/cgi-bin/OC_Exp.php?lng=EN&Expert=45448.
Begam M, Collier AF, Mueller AL, Roche R, Galen SS & Roche JA. Diltiazem improves contractile properties of skeletal muscle in dysferlin-deficient BLAJ mice, but does not reduce contraction-induced muscle damage. Physiological Reports. 2018; 6(11):e13727. https://www-ncbi-nlm-nih-gov.ezproxy.nihlibrary.nih.gov/pmc/articles/PMC5995314/.

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