Multifocal motor neuropathy

Title

Other Names:

MMN; MMNCB; Multifocal motor neuropathy with conduction block

Categories:

Nervous System Diseases

Summary Summary

Multifocal motor neuropathy (MMN) is a rare neuropathy characterized by progressive, asymmetric muscle weakness and atrophy (wasting).^[1] Signs and symptoms include weakness in the hands and lower arms; cramping; involuntary contractions or twitching; and atrophy of affected muscles.^[2] MMN is thought to be due to an abnormal immune response, but the underlying cause is not clear.^[1] Most people treated with intravenous immune globulin (IVIG) have rapid improvement in weakness, but maintenance IVIG is usually required for sustained improvement.^[1]

Last updated: 3/2/2016

Symptoms Symptoms

Signs and symptoms of multifocal motor neuropathy (MMN) may include weakness; cramping; involuntary contractions or twitching; and wasting (atrophy) of affected muscles.^[2] Atrophy occurs late in the course of the condition.^[1] Muscles of the hands and lower arms are most commonly affected, but muscles of the lower limbs may also be involved. The symptoms are often asymmetrical, meaning that they differ on the right and left side of the body.^[3]^[2]

Last updated: 3/2/2016

Cause Cause

The exact underlying cause of multifocal motor neuropathy (MMN) is poorly understood. It is considered an immune-mediated disorder (due to an abnormal immune system response), both because IVIG therapy improves symptoms, and many patients have anti-GM1 antibodies. Research to further understand the cause of MMN is underway.^[4]^[5]

Last updated: 3/7/2016

Inheritance Inheritance

We are not aware of any evidence that multifocal motor neuropathy (MMN) is inherited or of any reports of familial cases (occurring in more than one person in a family). Furthermore, to our knowledge, no specific genes known to be associated with MMN have been identified.

Last updated: 3/7/2016

Treatment Treatment

Multifocal motor neuropathy (MMN) is considered treatable with intravenous immune globulin (IVIG). Early treatment shortly after symptoms begin is recommended.^[5] Most people have a fairly rapid improvement in weakness with IVIG, but the improvement generally does not last beyond a few months. Maintenance IVIG infusions are usually needed every two to six weeks. For those with severe disease whose symptoms don't respond to IVIG (or for those who become resistant), treatment options are limited. Several reports have suggested that cyclophosphamide may be partially effective.^[4]

Last updated: 3/7/2016

Management Guidelines

The National Guideline Clearinghouse (NGC) is a public resource for evidence-based clinical practice guidelines. The NGC was originally created by the Agency for Healthcare Research and Quality (AHRQ) in partnership with the American Medical Association and the American Association of Health Plans.

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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

ClinicalTrials.gov lists trials that are studying or have studied Multifocal motor neuropathy. Click on the link to go to ClinicalTrials.gov to read descriptions of these studies.

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

Neuropathy Action Foundation
1950 Old Tustin Avenue
Santa Ana, CA 92705
Toll-free: (877) 512-7262
E-mail: info@NeuropathyAction.org
Website: http://www.neuropathyaction.org/

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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 GBS/CIDP Foundation International provides information about this condition. The GBS|CIDP Foundation International is a global non-profit organization supporting individuals and families affected by Guillain-Barré syndrome, chronic inflammatory demyelinating polyneuropathy (CIDP), and related syndromes through a commitment to support, education, research, and advocacy.
The National Institute of Neurological Disorders and Stroke (NINDS) collects and disseminates research information related to neurological disorders. Click on the link to view information on this topic.
The Neuropathy Action Foundation (NAF) provides an online brochure about Multifocal motor neuropathy. The NAF is dedicated to ensuring neuropathy patients obtain resources, information and tools to access individualized treatment to improve their quality of life.

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.
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 Multifocal motor neuropathy. Click on the link to view a sample search on this topic.

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

Is multifocal motor neuropathy hereditary? We have no family history that I know of. My son was diagnosed with MMN at age 29, if he has children are they at risk? See answer

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References References

Dale Lange and Jessica Robinson-Papp. Multifocal motor neuropathy. UpToDate. Waltham, MA: UpToDate; January, 2015;
NINDS Multifocal Motor Neuropathy Information Page. National Institute of Neurological Disorders and Stroke. http://www.ninds.nih.gov/disorders/multifocal_neuropathy/multifocal_neuropathy.htm. Accessed 5/1/2013.
Guimarães-Costa R, Bombelli F, Léger JM. Multifocal motor neuropathy. Presse Med. 2013 Apr 24; http://www.ncbi.nlm.nih.gov/pubmed/?term=23623583. Accessed 5/1/2013.
Lange D, Robinson-Papp J. Multifocal motor neuropathy. UpToDate. Waltham, MA: UpToDate; February, 2016;
MMN Overview. GBS/CIDP Foundation International. 2016; http://www.gbs-cidp.org/variants/mmn-overview/.