Duchenne muscular dystrophy (DMD) is a progressive form of muscular dystrophy that occurs primarily in males, though in rare cases may affect females. DMD causes progressive weakness and loss (atrophy) of skeletal and heart muscles. Early signs of DMD may include delayed ability to sit, stand, or walk and difficulties learning to speak. Muscle weakness is usually noticeable by 3 or 4 years of age and begins in the hips, pelvic area, upper legs, and shoulders. The calves may be enlarged. Children with DMD may have an unusual walk and difficulty running, climbing stairs, and getting up from the floor. DMD may also affect learning and memory, as well as communication and certain social emotional skills. Muscle weakness worsens with age and progresses to the arms, legs and trunk. Most children with DMD use a wheelchair full time by age 13. Heart and respiratory muscle problems begin in the teen years and lead to serious, life threatening complications.
DMD is caused by changes (mutations) in the DMD gene. The DMD gene codes for the protein dystrophin. Dystrophin is mainly made in skeletal and heart muscle cells, but a small amount is also made in nerve cells (neurons) in specific parts of the brain. DMD is inherited in an X-linked recessive pattern; however, it may also occur in people who do not have a family history of DMD. While there is no known cure for DMD, there are treatments that can help control symptoms. Due to the advancement of medical treatment, boys with DMD may now live into young adulthood.
Becker muscular dystrophy (BMD) is also caused by mutations in the DMD gene. People with BMD have less severe symptoms than DMD. In addition, symptoms start later in childhood or in adolescence and progress more slowly.
Symptoms of Duchenne muscular dystrophy (DMD) are usually noticed in boys between 1 to 6 years of age. There is a steady decline in muscle strength between the ages of 6 and 11 years. By age 10, braces may be needed for walking. By age 13, most boys with DMD are using a wheelchair full-time. The signs and symptoms include:
- Taking longer to learn to sit, stand, or walk on own, which is known as delayed motor development. The average age for walking in boys with DMD is 18 months.
- Having a waddling walk and difficulty climbing stairs or running.
- Difficulty getting up from the floor. Children may walk their hands up their legs to stand which is known as the Gower maneuver.
- Enlarged calf muscles due to the calf muscle cells being replaced by fat and connective tissue (pseudohypertrophy). This may also cause calf pain.
- Muscle weakness first affecting the muscles of the hips, pelvic area, thighs and shoulders, and later the skeletal (voluntary) muscles in the arms, legs and trunk.
- Tight or rigid joints (also known as contractures) may develop as muscle loss progresses. If not treated, these will become severe, causing discomfort and restricting mobility and flexibility. Contractures can affect the knees, hips, feet, elbows, wrists and fingers.
- Scoliosis may develop within several years of full-time wheelchair use.
- By the early teens, the respiratory and heart muscles are also affected.
- Breathing problems due to weakness of the diaphragm and the other muscles around the lungs. Skeletal changes, such as scoliosis, may also increase breathing problems. Breathing problems may become life-threatening.
- Progressive enlargement of the heart (cardiomyopathy) that stops the heart from pumping blood efficiently, and becomes life-threatening in many cases.
- Learning and memory issues (cognitive impairment) may occur in some cases, but do not worsen as DMD progresses.
- Communication may be more difficult for some.
- Social behavior may be affected, as well as the ability to read facial cues.
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.
Duchenne muscular dystrophy (DMD) is caused by mutations in the DMD gene. The DMDgene provides instructions for making a protein called dystrophin. Dystophin is primarily made in the muscle cells of the heart and skeletal muscle. The main job of dystrophin in muscle cells is to help stabilize and protect muscle fibers.
Small amounts of dystrophin are also made in nerve cells (neurons) in specific parts of the brain, including the hippocampus. The hippocampus is the part of the brain involved in learning and memory, as well as emotions. Scientists do not yet understand the job of dystrophin in neurons.
DMD is caused by genetic changes in the DMD gene that stop any functional dystrophin from being made. When dystrophin is missing, the muscle cells become damaged more easily. In response to the damage, inflammation occurs, which only worsens the process. Over time, the muscle cells without dystrophin weaken and die, leading to the muscle weakness and heart problems seen in DMD. The non-progressive memory and learning problems, as well as social behavioral problems, in some boys with DMD are most likely linked to loss of dystrophin in the neurons of the hippocampus and other parts of the brain where dystrophin is normally produced in small amounts, but at this point it is not known why this occurs and why only some people with DMD have these problems.
Different genetic changes in the DMD gene can cause a spectrum of disorders known as dystrophinopathies. The dystrophinopathies can range from very mild symptoms to the more severe symptoms seen in people with DMD. Other dystrophinopathies include Becker muscular dystrophy (BMD) and DMD-associated dilated cardiomyopathy (DCM).
Genetic changes causing Duchenne muscular dystrophy (DMD) can be passed down in families. The DMD gene is located on the X chromosome, one of the two types of sex chromosomes. Males have an X and a Y chromosome; whereas females have two X chromosomes. Since males only have one X chromosome, they also only have one copy of the DMD gene. If this copy has a genetic change that causes DMD, the male will have DMD. Males get their X chromosome from their mother and the Y chromosome from their father.
Since females have two X chromosomes, they have two copies of the DMD gene. Having two changed copies of the DMD gene that can cause DMD is unlikely, but would cause DMD in females. A female with only one changed copy of the DMD gene is called a “carrier”. She can pass on the changed gene, but usually does not have symptoms of DMD. Carriers of changes in the DMD gene that can cause DMD are at an increased risk of developing heart problems, including cardiomyopathy. In addition, due to a process called X-inactivation, in rare cases, female carriers may have mild, moderate, or severe DMD.[
If a man with DMD has children, all of his daughters will be carriers. Since boys inherit the Y chromosome from their father, sons will not inherit DMD from their fathers, even if the father has DMD.
Women who are carriers of a change in the DMD gene that can cause DMD have a 50% chance of passing it on to each child, whether the child is a boy or a girl. In other words, each daughter will have a 50% risk of being a carrier. Each son will have a 50% risk of having DMD.[
In some cases, a child is the first person in his family to be diagnosed with DMD. This can happen if the change in the DMD gene happened by mistake during the making of the egg or sperm. When this happens it is called a new or de novo mutation. In this case, the risk that the mother would have another child with DMD is low. However, sometimes, the boy’s mother is a carrier of DMD, but is the first person in her family with the change in the DMDgene. This means the change in the DMD gene happened by mistake during the making of the egg or the sperm that came together to form the fertilized egg that developed into her. In this case, the mother is a carrier and would have a 50% risk that each son will have DMD and also a 50% risk that each daughter will be a carrier. To complicate the inheritance even more, a woman may not have the change in the DMD gene in all of her cells. She may only have the change in the gene in some of the cells of her body, including her eggs, or even just in some of her eggs. This can happen if the mistake happens after the egg is fertilized, but sometime early in development of the fetus. In these cases the risk of passing the changed gene to her children depends on how many of her eggs are affected.
Since the inheritance of DMD can be complicated, a family with a newly diagnosed child with DMD should speak with a genetic counselor or other genetic specialist to understand if there is a risk of having more children with DMD and to understand the available genetic testing options.
A child’s doctor may suspect Duchenne muscular dystrophy (DMD) in young boys who have the signs and symptoms of DMD, including progressive muscle weakness. Family history is also important. Blood tests can be used to check for increased levels of certain special proteins called muscle enzymes in the blood which can leak from damaged muscles. Most commonly, the blood level of the enzyme creatine phosphokinase (CPK or CK) is checked, but a doctor may also check the blood levels of transaminases such as aspartate transaminase and alanine transaminase. Finding a change in the DMD genethat can cause DMD through genetic testing confirms the diagnosis of DMD. Testing for DMD may include:
- Blood test which measures the levels of serum creatine phosphokinase(CK or CPK). Very high CK levels indicate muscle damage is causing the muscle weakness, rather than nerve damage.
- Molecular genetic testing (usually blood cells are used) to see whether there is a change or mutation in the DMD gene that can cause DMD or one of the related dystrophinopathies.
- Electromyography can be used to distinguish conditions that only impact the muscles (myotonic) from those that involve that brain and muscles (neurogenic).
- Muscle biopsy is rarely used to diagnose DMD due to the decreased cost and higher accuracy of genetic testing.
There is no known cure for Duchenne muscular dystrophy (DMD) but research is ongoing. The goal of treatment is to control the symptoms of DMD and related complications caused by severe progressive muscle weakness and loss in order to maximize the quality of life. An enlarged, weakened heart (dilated cardiomyopathy) may be treated with medications, but in severe cases a heart transplant may be necessary. Assistive devices for breathing difficulties may be needed, especially at night and as the disease progresses.
Gentle exercise is encouraged for people with DMD. Physical inactivity (such as bed rest) can worsen the muscle disease, but so can overexertion. Physical therapy may be helpful to maintain muscle strength and function. Orthopedic devices (such as braces and wheelchairs) may improve the ability to move and take care of oneself.
Steroids (corticosteroids) may improve the strength and function of muscles in people with DMD, including lung function. Steroid options include:
- Prednisone is a steroid that has been shown to extend the ability to walk by 2 to 5 years. However, the possible side effects of prednisone include weight gain, high blood pressure, behavior changes, and delayed growth.
- Deflazacort (another form of prednisone), is used in Europe and believed to have fewer side effects and was recently approved in the United States by the FDA.
- Oxandrolone, a medication used in a research study, also has similar benefits to prednisone, but with fewer side effects.
The U.S. Food and Drug Administration of United States approved Exondys 51 (eteplirsen) injection to treat people with DMD who have a change in the DMD gene that will allow a shortened form of dystrophin to be made if exon 51 is skipped. An exon is the part of the gene that actually codes for the protein. The DMD gene has 79 exons. About 13% of those with DMD may be helped by Exondys 51.
Because chronic use of corticosteroids can lead to side effects, and rapid withdrawal of corticosteroids can result in life-threatening complications, there are recommended guidelines on how to proceed with withdrawal. The PJ Nicholoff Protocol guides withdrawal from corticosteroids following long term treatment.
The Muscular Dystrophy Association (MDA) has current information about the medical management of DMD.
- Section on Cardiology and Cardiac Surgery. Cardiovascular health supervision for individuals affected by Duchenne or Becker Muscular Dystrophy.Pediatrics 2006; 116: 1569-1573.
- Orphanet Emergency Guidelines is an article which is expert-authored and peer-reviewed that is intended to guide health care professionals in emergency situations involving this condition.
- 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.
The medication(s) listed below have been approved by the Food and Drug Administration (FDA) as orphan products for treatment of this condition.
- Deflazacort (Brand name: Emflaza) – Manufactured by Marathon Pharmaceuticals
FDA-approved indication: Treatment of Duchenne Muscular Dystrophy in patients 5 years of age and older.
- Eteplirsen (Brand name: Exondys 51) – Manufactured by Sarepta Therapeutics, Inc.
FDA-approved indication: Treatment of Duchenne muscular dystrophy (DMD) in patients who have a confirmed mutation of the DMD gene that is amenable to exon 51 skipping.
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.
- 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.
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
- gov lists trials that are related to Duchenne muscular dystrophy. 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.
- Orphanet lists European clinical trials, research studies, and patient registries enrolling people with this condition.
- 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.
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.
Where to Start
- Genetics Home Reference (GHR) contains information on Duchenne 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 National Human Genome Research Institute’s (NHGRI) website has an information page on this topic. NHGRI is part of the National Institutes of Health and supports research on the structure and function of the human genome and its role in health and disease.
- 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.
- 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.
- 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 Duchenne muscular dystrophy. Click on the link to view a sample search on this topic.
Resources for Kids
- BrainPOP presents the topic of Duchenne muscular dystrophy in a short, animated movie that is available on CheckOrphan’s Web site. BrainPOP produced this video in partnership with Parent Project Muscular Dystrophy, this four minute video strives to provide kids of all ages with a clear understanding of Duchenne.
Advocacy Groups and Nonprofit Organizations
A national nonprofit organization that raises awareness and funds to find a cure for Duchenne muscular dystrophy. The funds raised support the most promising research programs aimed at treating and curing the disease. CureDuchenne Cares provides outreach and education to parents and caregivers, as well as professional training and certification to physical therapists that treat Duchenne patients.
The mission of the Jett Foundation is to build awareness of Duchenne muscular dystrophy and fulfill the unmet needs in our community through programming, education, support, and research.
Muscular Dystrophy Association (MDA)
The MDA is leading the fight to free individuals – and the families who love them – from the harm of muscular dystrophy, ALS and related muscle-debilitating diseases that take away physical strength, independence and life. The MDA uses its collective strength to help kids and adults live longer and grow stronger by finding research breakthroughs across diseases, caring for individuals from day one and empowering families with services and support in hometowns across America.
Parent Project Muscular Dystrophy (PPMD)
The largest and most comprehensive nonprofit organization in the United States focused on ending Duchenne. Its goal is to accelerate research efforts, catalyze advocacy, demand optimal care for all young men with Duchenne, and educate the global community.
Rare Disease Organizations
A non-governmental patient-driven alliance of patient organizations representing 724 rare disease patient organizations in 64 countries.
National Organization for Rare Disorders
Provides a unified voice for the 30 million people who wake up every day to fight the battle with a rare disease, including parents and caregivers.
Rare Disease Legislative Advocates
A program of the EveryLife Foundation for Rare Diseases designed to support the advocacy of all rare disease patients and organizations.
A nonprofit health advocacy organization that engages individuals, families, and communities to transform health. They create ways to make it easier to find or build solutions in health services and research.
A rare disease patient advocacy organization that aims to build awareness, educate the global community and provide critical connections and resources that equip advocates to become activists for their disease.
A comprehensive registry that connects the entire Duchenne community. This central hub brings together those living with the disease, along with their families, friends, and caregivers—and connects them with medical research, clinical care, clinical trials, and each other. Duchenne Connect is a program of Parent Project Muscular Dystrophy.
A network for the neuromuscular field that provides an infrastructure to ensure that the most promising new therapies reach patients as quickly as possible. Its focus is on the development of tools that industry, clinicians, and scientists need to bring novel therapeutic approaches through preclinical development and into the clinic, and on establishing best-practice care for neuromuscular patients worldwide.
An online database of publicly and privately supported clinical studies conducted around the world. ClinicalTrials.gov currently lists thousands of studies with locations in all 50 states and in 191 countries.
Genetics Home Reference
An online resource from the National Institutes of Health. The website provides easy-to-understand information about genetic conditions and a range of topics. You’ll find basic explanations of how genes work and how mutations cause disorders. It also includes current information about genetic testing, gene therapy, and the Human Genome Project.
National Society of Genetic Counselors
Provides a helpful, easy-to-use online directory to help connect physicians, patients, and other genetic counselors. Search by state, city, counselor’s name, institution, work setting, type of specialty, or zip code.
Provides free genetic testing, interpretation, and counseling to people with Duchenne or Becker muscular dystrophy who meet certain eligibility criteria and who have been unable to access genetic testing in the past due to financial barriers, such as cost or lack of insurance coverage. Decode Duchenne is administered by DuchenneConnect, a program of Parent Project Muscular Dystrophy.
Resources for Families and Caregivers
A website of the National Task Force for Early Identification of Childhood Neuromuscular Disorders. The site provides information and tools to help parents and healthcare professionals identify the early signs of muscle weakness and neuromuscular disease.
A unique social hub building communities for patients, families, and healthcare professionals affected by rare disorders.
Caregiver Action Network (CAN)
The nation’s leading family caregiver organization working to improve the quality of life for the more than 90 million Americans who care for loved ones with chronic conditions, disabilities, disease, or the frailties of old age. CAN (formerly the National Family Caregivers Association) is a nonprofit organization providing education, peer support, and resources to family caregivers across the United States free of charge.
Center for Parent Information & Resources
A central resource of information and products to the community of Parent Training Information Centers and the Community Parent Resource Centers so they can focus their efforts on serving families of children with disabilities.
Cyberbullying Research Center
Dedicated to providing up-to-date information about the nature, extent, causes, and consequences of cyberbullying, it is intended to be a resource for parents, educators, law enforcement officers, counselors, and others who work with youth. You will find facts, figures, and detailed stories from those who have been directly affected by online aggression. In addition, the site includes numerous resources to help you prevent and respond to cyberbullying incidents.
Family Caregiver Alliance (FCA)
A community-based nonprofit organization that that aims to illuminate the caregivers’ daily challenges to better the lives of caregivers nationally, provide them the assistance they need, and champion their cause through education, services, research and advocacy. FCA offers programs at national, state, and local levels to support and sustain caregivers.
Family Voices aims to achieve family-centered care for all children and youth with special health care needs and/or disabilities. Throughout their national grassroots network, they provide families resources and support to make informed decisions, advocate for improved public and private policies, build partnerships among families and professionals, and serve as a trusted resource on health care.
An email list of family of parents, caregivers and others who are working with children with physical and/or mental disabilities and delays.
Parent to Parent USA
Programs offering parent-to-parent support as a core resource for families with children who have a special health care need, disability, or mental health issue. Through a one-to-one “match,” experienced support parents provide emotional support to families and assist them in finding information and resources.
Sibling Support Project
A national program dedicated to the lifelong and ever-changing concerns of the millions of brothers and sisters of people with special health, developmental and mental health concerns.
A website providing information from various government agencies on what bullying is, what cyberbullying is, who is at risk, and how you can prevent and respond to bullying.
The Bully Project
Inspired by the award-winning film BULLY, this social action campaign includes tools for educators to spark meaningful conversations about bullying.
The Parent Advocacy Center for Educational Rights (PACER Center)
PACER Center is a parent training and information center for families of children and youth with all disabilities from birth to young adults. Parents can find publications, workshops, and other resources to help make decisions about education, vocational training, employment, and other services for their children with disabilities. PACER’s National Bullying Prevention Center provides resources designed to benefit all students, including those with disabilities.
The Washington State Fathers Network (WSFN)
The Washington State Fathers Network (WSFN) connects men with other dads, resources, information and education, plus opportunities for “all family” celebrations. Focus is on assisting fathers as they become more competent and compassionate caregivers for their children with special needs. WSFN is the only regional program in the US and Canada fully devoted to fathers of children with special health care needs and developmental disabilities. Since 1986 it has opened new doors of hope for thousands of men and their families, providing them with support and resources to be effective, nurturing dads.
General Health Resources
Agency for Healthcare & Research Quality (AHRQ)
Aims to provide evidence to make health care safer, higher quality, more accessible, equitable and affordable, and to work with the US Department of Health and Human Services and with other partners to ensure that the evidence is used and understood.
Health Hotlines (National Library of Medicine)
A community service to help the public locate health-related information.
Social Security Administration Compassionate Allowances Program
Provides a way of quickly identifying diseases and other medical conditions that may qualify for financial assistance.
Center on Technology & Disability
Designed to increase the capacity of families and providers to advocate for, acquire, and implement effective assistive and instructional technology practices, devices, and services for those who suffer from disabilities.
National Human Genome Research Institute
Developed with the goal of mapping the human genome, the group provides a list of resources for financial assistance with genetic testing.
National Library of Medicine
Provides guidance on how to find reliable information online regarding human genetics.
Patient Advocate Foundation
Provides professional case management services to individuals facing barriers to healthcare access for chronic and disabling disease, medical debt crisis, and employment-related issues at no cost.