Miyoshi myopathy

Title

Other Names:

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

Categories:

Congenital and Genetic Diseases; Nervous System Diseases

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.^[1] It is caused by mutations in the DYSF gene and is inherited in an autosomal recessive manner.^[2] Management may include physical therapy, use of mechanical aids, surgical intervention for orthopedic complications, respiratory aids, and social and emotional support.^[1]

Last updated: 4/5/2011

Symptoms Symptoms

The onset of signs and symptoms is typically in mid to late childhood or early-adulthood, with an average age at onset of 19 years. Young adults typically have muscle weakness and atrophy (wasting), most marked in the distal parts of the legs, especially the gastrocnemius (calf) and soleus (Achilles tendon) muscles. Early on, affected individuals are not able to stand on tiptoe, but retain the ability to stand on the heels. Over a period of years, the weakness and atrophy spread to the thighs and gluteal muscles, at which time climbing stairs, standing, and walking become difficult. The forearms may become mildly atrophic with decrease in grip strength; the small muscles of the hands are not affected. The weakness may eventually include the shoulder girdle muscles. The weakness and atrophy may be asymmetric (occurring more on one side than the other). Progression of the condition is typically slow.^[1]

Last updated: 4/5/2011

The Human Phenotype Ontology (HPO) provides the following list of features that have been reported in people with this condition. Much of the information in the HPO comes from Orphanet, a European rare disease database. If available, the list includes a rough estimate of how common a feature is (its frequency). Frequencies are based on a specific study and may not be representative of all studies. You can use the MedlinePlus Medical Dictionary for definitions of the terms below.

Signs and Symptoms	Approximate number of patients (when available)
Adult onset	75%
Deposits immunoreactive to beta-amyloid protein	5%
Autosomal recessive inheritance	-
Decreased Achilles reflex	-
Decreased/absent ankle reflexes	-
Difficulty climbing stairs	-
Difficulty running	-
Distal amyotrophy	-
Distal muscle weakness	-
Elevated serum creatine phosphokinase	-
Heterogeneous	-
Lower limb muscle weakness	-
Muscle fibrillation	-
Muscular dystrophy	-
Quadriceps muscle atrophy	-
Variable expressivity	-

Last updated: 9/1/2016

Cause Cause

Miyoshi myopathy is caused by 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).

Last updated: 4/5/2011

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: 6/6/2011

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

Yes, genetic testing for this condition is available. GeneTests lists the names of laboratories that are performing genetic testing for Miyoshi myopathy. To view the contact information for the clinical laboratories conducting testing, click here. To access the contact information for the research laboratories performing genetic testing, click here.

Please note: Most of the laboratories listed through GeneTests do not accept direct contact from patients and their families; therefore, if you are interested in learning more, you will need to work with a health care provider or a genetics professional.

Last updated: 4/5/2011

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 should be tailored to each individual, depending on his/her specific signs and symptoms. A general approach to appropriate management can prolong survival and improve quality of life.^[1] This approach may include:

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 and stimulation to maximize a sense of social involvement and productivity and to reduce the sense of social isolation common in these disorder^[1]

Last updated: 4/5/2011

Management Guidelines

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.

Do you have updated information on this condition? Let us know.

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 studying or have studied Miyoshi myopathy. Click on the link to go to ClinicalTrials.gov to read descriptions of these studies.
The Jain Foundation provides information on clinical trials and research studies for dysferlinopathy.

Patient Registry

The Jain Foundation offers a patient registry for individuals with dysferlinopathy.

Organizations Organizations

Nonprofit support and advocacy groups bring together patients, families, medical professionals, and researchers. These groups often raise awareness, provide support, and develop patient-centered information. Many are the driving force behind research for better treatments and possible cures. They can direct people to research, resources, and services. Many groups also have experts who serve as medical advisors. Visit their 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
2310 130th Ave., NE
Suite B101
Bellevue, WA 98005
Telephone: 425-882-1492
E-mail: dysferlinopathy@jain-foundation.org
Website: https://www.jain-foundation.org/
Muscular Dystrophy Association (MDA)
222 S Riverside Plaza
Suite 1500
Chicago, IL 60606
Toll-free: 800-572-1717
TTY: 1-800-572-1717
E-mail: mda@mdausa.org
Website: http://www.mdausa.org/
Muscular Dystrophy Family Foundation
P.O. Box 776
Carmel, IN 46082
Toll-free: 800-544-1213
Telephone: 317-615-9140
E-mail: http://mdff.org/contact-us/
Website: http://www.mdff.org
Muscular Dystrophy UK
61A Great Suffolk Street
London SE1 0BU
United Kingdom
Telephone: 0800 652 6352; (+44) 0 020 7803 4800
E-mail: info@musculardystrophyuk.org
Website: http://www.musculardystrophyuk.org/
Parent Project Muscular Dystrophy
1012 North University Boulevard
Middletown, OH 45042
Toll-free: 800-714-5437
Telephone: 513-424-0696
Fax: 513-425-9907
E-mail: pat@parentprojectmd.org
Website: http://www.parentprojectmd.org

Do you know of an organization? Send us your suggestions.

Living With Living With

Living with a genetic or rare disease can impact the daily lives of patients and families. These resources can help families navigate various aspects of living with a rare disease.

Healthcare Resources

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

Genetics 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 GeneTests, 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.

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

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

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.
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

Masashi Aoki. Dysferlinopathy. GeneReviews. April 22, 2010; http://www.ncbi.nlm.nih.gov/books/NBK1303/. Accessed 4/4/2011.
I. Pénisson-Besnier. Miyoshi myopathy. Orphanet. April 2004; http://www.orpha.net/consor/cgi-bin/OC_Exp.php?lng=EN&Expert=45448. Accessed 4/4/2011.

Do you know of a review article? Send us your suggestions.