Becker muscular dystrophy

Información en español Title

Other Names:

Benign pseudohypertrophic muscular dystrophy; Becker's muscular dystrophy; Muscular dystrophy, Becker type; Benign pseudohypertrophic muscular dystrophy; Becker's muscular dystrophy; Muscular dystrophy, Becker type; Muscular dystrophy pseudohypertrophic progressive, Becker type; Becker dystrophinopathy See More

Categories:

Congenital and Genetic Diseases; Heart Diseases; Nervous System Diseases; Congenital and Genetic Diseases; Heart Diseases; Nervous System Diseases; Newborn Screening See More

Summary Summary

Becker muscular dystrophy (BMD) is an inherited condition that causes progressive weakness and wasting of the skeletal and cardiac (heart) muscles. It primarily affects males.^[1]^[2] The age of onset and rate of progression can vary. Muscle weakness usually becomes apparent between the ages of 5 and 15. In some cases, heart involvement (cardiomyopathy) is the first sign.^[2] BMD is caused by a mutation in the DMD gene and is inherited in an X-linked recessive manner. BMD is very similar to Duchenne muscular dystrophy, except that in BMD, symptoms begin later and progress at a slower rate.^[1] There is no cure for this condition, but there is ongoing research that shows significant promise in treating the disease. Current treatment aims to relieve symptoms and improve quality of life.^[3] People with BMD may survive into their 40s or beyond.^[1]

Last updated: 9/3/2016

Symptoms Symptoms

The symptoms of Becker muscular dystrophy (BMD) may begin anywhere from childhood to a person's early 20s.^[4]^[5] Muscle weakness often affects the legs and pelvis, and slowly gets worse.^[4] Over time, affected people begin to have difficulty walking, frequent falls, difficulty with muscle skills (such as running, hopping, and jumping), and loss of muscle mass.^[3] Eventually, affected people require a wheelchair.^[5] The condition also affects the heart muscles, causing dilated cardiomyopathy. This form of heart disease enlarges and weakens the heart muscle, preventing it from pumping blood efficiently. Dilated cardiomyopathy progresses rapidly and is life-threatening in many cases.^[4] Other symptoms of BMD may include cognitive problems, fatigue, loss of balance and coordination, problems breathing, and muscle weakness in the arms, neck and other areas of the body.^[3]

Last updated: 9/3/2016

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	-
Arrhythmia	-
Calf muscle pseudohypertrophy	-
Cardiomyopathy	-
Elevated serum creatine phosphokinase	-
Hyporeflexia	-
Muscle weakness	-
Muscular dystrophy	-
Myalgia	-
X-linked recessive inheritance	-

Last updated: 9/1/2016

Cause Cause

Becker muscular dystrophy (BMD) is caused by specific mutations in the DMD gene. The DMD gene gives the body instructions to make a protein called dystrophin. This protein helps stabilize and protect muscle fibers and may play a role in chemical signaling within cells. Mutations that lead to an abnormal "version" of dystrophin that allow it to keep some of its function usually cause BMD. Muscle cells without fully functional dystrophin become damaged as muscles contract and relax with use. They then weaken and die over time, leading to the muscle weakness and heart problems in people with BMD.^[4]

Last updated: 9/3/2016

Inheritance Inheritance

Becker muscular dystrophy is inherited in an X-linked recessive manner. A condition is considered X-linked if the mutated gene that causes the condition is located on the X chromosome, one of the two sex chromosomes. In males (who have only one X chromosome), one mutated copy of the gene in each cell is enough to cause the condition. In females (who have two X chromosomes), a mutation must be present in both copies of the gene to cause the condition. Males are affected by X-linked recessive disorders much more frequently than females. A specific characteristic of X-linked inheritance is that fathers cannot pass X-linked traits to their sons.^[4]

In X-linked recessive inheritance, a female with one mutated copy of the gene in each cell is called a carrier. Female carriers of X-linked recessive conditions have a 50% (1 in 2) risk to pass on the mutated gene to each child. Male children have a 50% risk to be affected, and female children have a 50% risk to be a carrier. Female carriers usually do not have signs or symptoms of the condition. Occasionally, females who carry a DMD mutation may have muscle weakness and cramping. These symptoms are typically milder than the severe muscle weakness and wasting in affected males. Females who carry a DMD mutation also have an increased risk to develop heart problems, including dilated cardiomyopathy.^[4]

In about two thirds of cases, an affected male inherits the mutation from his mother who carries a mutated copy of the DMD gene. The other third of cases probably result from new mutations in the gene.^[4]

Last updated: 9/3/2016

Diagnosis Diagnosis

Becker muscular dystrophy (BMD) may first be suspected in a person with signs or symptoms of BMD. Healthcare providers will often conduct neurological and muscle exams, as well as order specific laboratory tests. A careful medical history is also important to differentiate between BMD and Duchenne muscular dystrophy.^[3]

Exams in a person with BMD may reveal:^[3]

Abnormally developed bones, leading to deformities of the chest and back (scoliosis)
Abnormality of heart muscle function (cardiomyopathy)
Congestive heart failure or irregular heartbeat (arrhythmias)
Muscle deformities
- Contractures of heels and legs
- Fat and connective tissue (pseudohypertrophy) in calf muscles
Muscle wasting that begins in the legs and pelvis, then progresses to the muscles of the shoulders, neck, arms, and respiratory system

Laboratory tests that help confirm the diagnosis include:^[3]

CPK
Electromyography (EMG)
Muscle biopsy or genetic testing

Last updated: 9/3/2016

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

There is currently no cure for Becker muscular dystrophy (BMD), and management aims to help with symptoms and improve the quality of life. Affected people are encouraged to remain active, because inactivity (such as bed rest) can make the muscle disease worse.^[3]

Physical therapy can help with stretching tight muscles and using assistive devices; occupational therapy can help with daily living skills; and speech therapy may help those with dysphagia (difficulty swallowing). Surgery may be needed for progressive scoliosis and development of contractures.^[6]

People with BMD should be monitored for orthopedic complications. Cardiac (heart) evaluations are recommended beginning at around 10 years old, or when symptoms first begin. Evaluations should be repeated at least every two years.^[7]

Some studies have shown that certain corticosteroids (such as prednisone or prednisolone) can slow the decline of muscle strength in people with Duchenne muscular dystophy; however, information about their use in people with BMD is limited.^[7] There are a number of additional therapies for BMD being studied.^[7] Potential future treatments for BMD may include gene therapy, exon skipping, ataluren, creatine, deacetylase inhibitors, myostatin inactivation, and cell therapy (myoblast treatment, and/or the use of stem cells).^[6]^[8]

Last updated: 9/3/2016

Management Guidelines

Section on Cardiology and Cardiac Surgery. Cardiovascular health supervision for individuals affected by Duchenne or Becker Muscular Dystrophy. Pediatrics 2006; 116: 1569-1573.
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.

Prognosis Prognosis

Becker muscular dystrophy (BMD) generally leads to slowly worsening disability, but the amount of disability can vary among affected people. Some men need a wheelchair, while others may only need walking aids such as canes or braces. The lifespan is often shorted due to heart disease and respiratory complications.^[9] Most people with BMD survive well into mid- to late adulthood. If the effects of the condition on the heart are mild, or if they are adequately controlled with medical intervention, a person can have a normal or nearly normal life span.^[10]

Last updated: 9/3/2016

Statistics Statistics

The incidence (rate of occurrence of new cases) of Becker muscular dystrophy (BMD) has been estimated to be between 1 in 18,000 and 1 in 30,000 male births.^[11]^[12]

Prevalence estimates (all the people affected with BMD at a given time) are relatively broad and the ranges differ depending on the source. According to Medscape Reference, the prevalence of BMD is estimated to be between 17 to 27 cases per million people.^[11] This means that at a given time, about 1 in 37,000 to 1 in 59,000 people are living with BMD. According to Orphanet, the prevalence is estimated to be between around 1 in 11,000 to 1 in 100,000.^[12]

Last updated: 11/4/2015

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 Becker muscular dystrophy. Click on the link to go to ClinicalTrials.gov to read descriptions of these studies.

Patient Registry

The DuchenneConnect Profile provides a patient registry, which gives people access to information about new treatments and trials, services like genetic testing and counseling, and regional and local resources for patients and their families.

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. Suggest an organization to add.

Organizations Supporting this Disease

Duchenne Connect
Telephone: 404-778-0553
Fax: 404-778-8559
E-mail: coordinator@duchenneconnect.org
Website: https://www.duchenneconnect.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 Foundation Australia
Suite 101, 5 Bay Drive
Meadowbank, 2114 Australia
Toll-free: 1-800-635-109
E-mail: info@mdnsw.org.au
Website: http://mdaustralia.org.au/
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/

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.

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 Becker muscular dystrophy. This website is maintained by the National Library of Medicine.
MedlinePlus was designed by the National Library of Medicine to help you research your health questions, and it provides more information about this topic.
The Merck Manuals Online Medical Library provides information on this condition for patients and caregivers.
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

Medscape Reference provides information on this topic. You may need to register to view the medical textbook, but registration is free.
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.
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 Becker muscular dystrophy. Click on the link to view a sample search on this topic.

News & Events News & Events

News

2016 Million Dollar Bike Ride Pilot Grant Program
August 15, 2016
GARD Information Navigator
May 10, 2016
Publication Highlights Release of Muscular Dystrophy Action Plan
April 8, 2016

NCATS Co-Sponsored Conferences

New Directions in Biology and Disease of Skeletal Muscle Sunday, June 29, 2014 - Wednesday, July 2, 2014
Location: Chicago, IL
Description: The goals of the New Directions conference are to: (1) provide a unique forum for presentation and sharing of unpublished data, (2) promote collaboration between industry and academic investigators, (3) provide an interactive forum for clinical trial planning and outcome measure development, (4) facilitate the identification of both common and unique targets for each neuromuscular disease, and (5) provide trainees and young investigators a forum in which to present data and to encourage trainees to remain studying neuromuscular disease.

Contact: Dr. John D. Porter, 301-496-5739,porterjo@ninds.nih.gov

Co-funding Institute(s): National Institute of Neurological Disorders and Stroke, Office of Rare Diseases Research

Related Diseases Related Diseases

The following diseases are related to Becker muscular dystrophy. If you have a question about any of these diseases, you can contact GARD.

Muscular dystrophy

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

What is the incidence of this disorder? See answer
My son was just diagnosed with BMD, he has always been a little slow in school and has a real hard time learning new things. Does BMD affect learning? See answer
Knowing that Becker's can occur at any time up until the person is 30, can a teen do strenuous exercises to possibly help prevent Becker's from becoming active later in life? If not, can strenuous exercises at least slow down the process of Becker's completely wiping out one's ability to use their muscles as they could before the process even started? See answer
I am a physician who frequently sees patients with Becker muscular dystrophy. Can you provide me with patient-friendly information about this condition? See answer
Several members of my husband's family are carriers of Duchenne and Becker muscular dystrophy. My husband does not have the disease. What are the chances of passing on this condition to any children we may have? See answer

References References

Duchenne and Becker muscular dystrophy. Genetics Home Reference. 2016; http://www.ghr.nlm.nih.gov/condition/duchenne-and-becker-muscular-dystrophy.
Duchenne and Becker muscular dystrophy. Orphanet. August, 2007; http://www.orpha.net/consor/cgi-bin/OC_Exp.php?Lng=EN&Expert=262.
Becker's muscular dystrophy. MedlinePlus. 2016; http://www.nlm.nih.gov/medlineplus/ency/article/000706.htm.
Duchenne and Becker muscular dystrophy. Genetics Home Reference (GHR). 2016; http://www.ghr.nlm.nih.gov/condition=duchenneandbeckermusculardystrophy.
Muscular Dystrophy, Becker. National Organization for Rare Disorders (NORD). 2007; http://rarediseases.org/rare-diseases/muscular-dystrophy-becker/.
Mandac BR. Becker Muscular Dystrophy. Medscape Reference. 2015; http://emedicine.medscape.com/article/313417-overview.
Darras BT, Miller DT & Urion DK. Dystrophinopathies. GeneReviews. 2014; http://www.ncbi.nlm.nih.gov/books/NBK1119/.
Darras BT. Treatment of Duchenne and Becker Muscular Dystrophy. UpToDate. Waltham, MA: UpToDate; 2016;
Becker Muscular Dystrophy. MedlinePlus. 2016; http://www.nlm.nih.gov/medlineplus/ency/article/000706.htm.
Becker Muscular Dystrophy. Muscular Dystrophy Association. http://mda.org/disease/becker-muscular-dystrophy/overview.
Benjamin R Mandac. Becker Muscular Dystrophy. Medscape Reference. September 3, 2015; http://emedicine.medscape.com/article/313417-overview#a6.
Rosaline Quinlivan. Becker muscular dystrophy. Orphanet. September, 2009; http://www.orpha.net/consor/cgi-bin/OC_Exp.php?lng=en&Expert=98895.