What Is Muscular Dystrophy? A Plain-Language Guide to the Group of Diseases That Weaken Muscles
Updated: 3 days ago
Medically reviewed by Dr. Baraa Alnahhal, MD · Last reviewed: October 17, 2026
Quick Answer
Muscular dystrophy is a group of more than 30 diseases that make muscles progressively weaker and lose mass, caused by changes in genes that make muscle-protecting proteins. [1] [2] The most common type, Duchenne, usually starts in early childhood and mostly affects boys. [1] Treatments can manage symptoms and slow the course [1], and complications need close monitoring by a care team.
What the research says
Duchenne and Becker muscular dystrophy affect roughly 5 and 2 in every 100,000 people worldwide. A meta-analysis of 25 studies covering about 901.6 million people estimated a global prevalence of 4.8 per 100,000 for Duchenne (95% CI 3.6–6.3) and 1.6 per 100,000 for Becker (95% CI 1.1–2.4). (Salari et al., Journal of Orthopaedic Surgery and Research, 2022 [5])
In Duchenne, corticosteroid treatment is linked to walking for longer. Pooling 59 studies, corticosteroid use was associated with a delayed loss of walking ability (pooled hazard ratio 0.42, 95% CI 0.23–0.75), better lung function tests, and delayed heart-muscle disease — though results varied widely between studies. (Weber et al., Muscle & Nerve, 2022 [6])
Knowing the exact type changes the care plan. A Lancet seminar explains that muscular dystrophies result from mutations in more than 40 genes, and because heart and breathing complications vary greatly between subtypes, an accurate genetic diagnosis lets care teams plan ahead for each type, with improved survival and quality of life in recent years. (Mercuri et al., The Lancet, 2019 [7])
What Is Muscular Dystrophy?
Muscular dystrophy is a group of diseases that causes muscles to become weaker and lose mass over time. [1] The condition is caused by changes in the genes that make proteins needed to form healthy muscles. [1]
There are many types of muscular dystrophy. Symptoms of the most common type start in childhood, mostly in boys. [1] Other types sometimes don't start until adulthood. [1]
The good news: medicines and other treatments can help manage the symptoms and slow the course of muscular dystrophy. [1]
Healthy muscles depend on proteins made by healthy genes. In muscular dystrophy, a gene change means those proteins can't do their job — and muscles gradually weaken and lose mass.
What Are the Main Symptoms?
The main symptom of muscular dystrophy is muscle weakness that becomes worse over time. [1] This makes everyday tasks harder to do. The type of muscular dystrophy a person has determines three things: the exact symptoms, the age range at which the symptoms start, and the muscle groups that are affected. [1]
There are over 30 types of muscular dystrophy. [1] [2] Here are the main ones and their key symptoms.
Duchenne Type Muscular Dystrophy
This is the most common form. Girls can carry the gene change that causes the disease, and some have symptoms. But Duchenne muscular dystrophy is much more common in boys. [1]
Most often, the symptoms start in early childhood. They can include challenges with movement, such as late walking, frequent falls, trouble rising from the floor or a lying or seated position, trouble running or jumping or climbing stairs, a waddling gait, and walking on the toes or the balls of the feet. [1]
Other symptoms can include large calf muscles, muscle pain and stiffness, learning or behavior-related challenges, and delayed growth. [1]
Becker Muscular Dystrophy
The symptoms of this type are like those of Duchenne muscular dystrophy, but Becker muscular dystrophy tends to be milder, and it becomes worse more slowly. [1] In general, symptoms start in the teens or early adulthood. They might not occur until the mid-20s or later. [1]
Other Types of Muscular Dystrophy
Some types of muscular dystrophy are defined by a certain feature, or by where in the body the symptoms start.
Eight of the main types — each defined by a specific gene change, the age it usually starts, and the body areas it affects most.
Type | When It Usually Starts | Key Features |
Duchenne | Early childhood | Most common; mostly boys; late walking, frequent falls, waddling gait, toe-walking, large calves |
Becker | Teens to adulthood (sometimes mid-20s or later) | Like Duchenne but milder and slower to worsen [1] |
Emery-Dreifuss | Often by age 10 | Stiff joints, toe-walking, trouble bending elbows, muscle wasting in shoulders/upper arms/calves, heart conditions [1] |
Myotonic (Steinert's) | Often ages 20–30, sometimes birth to childhood | Muscles can't relax at will; face and neck affected first; heart rhythm problems; breathing weakness [1] |
Facioscapulohumeral (FSHD) | Teenage years | Face, shoulders, upper arms; often one side more than the other; trouble closing eyelids; shoulder blades sticking out [1] |
Congenital | At birth or before age 2 | "Floppy" babies with low muscle tone; slow to roll over, sit up, or walk [1] |
Limb-girdle | Varies | Shoulders and hips; mild to serious trouble using arms and legs [1] |
Oculopharyngeal | 40s and 50s | Eyelids and throat muscles; trouble swallowing; drooping eyelids; worsens slowly [1] |
Nine complications to watch for — and how a healthcare team manages them.
What Causes Muscular Dystrophy?
Certain genes are involved in making proteins that protect muscle fibers. [1] Most muscular dystrophy happens when one of these genes goes through an irregular change. [1] You might hear this called a gene mutation.
Each type of muscular dystrophy is caused by a gene change that is particular to that type of the disease. [1] Most of these gene changes are passed from parent to child — also called inherited.
Who Is at Higher Risk?
Muscular dystrophy occurs in people of all ages and ethnic groups. [1] But the most common type, Duchenne, usually affects young boys. [1] People with a family history of muscular dystrophy have a higher risk of getting the disease or passing it on to their children. [1]
What Complications Can Happen?
Muscular dystrophy can lead to serious health issues. Here is what a healthcare team watches for.
Complication | What Happens | How It Is Managed |
Trouble walking | Over time, some people use a wheelchair for mobility [1] | Mobility support from the healthcare team |
Trouble using arms | Daily activities become harder if arm and shoulder muscles are affected | Supportive strategies and therapy |
Contractures | Muscles or tendons around joints shorten; less range of motion limits walking and arm use [1] | Monitoring of joints and range of motion |
Trouble breathing or coughing | Breathing muscles weaken; serious cases may need devices that keep airways open or assist breathing; weak cough makes it hard to clear mucus [1] | Breathing assistance; cough techniques and treatments |
Scoliosis (curved spine) | Most likely in a growing child who can't walk; curving can worsen breathing and positioning | Sometimes surgery to correct the curving [1] |
Heart problems | Harder for the heart to pump well or beat with a regular rhythm [1] | Close heart monitoring |
Swallowing problems | Trouble getting enough nutrition; raises risk of aspiration pneumonia (lung infection from breathing food or liquid into the airways) | Feeding tube to deliver nutrition when needed [1] |
Brain-related differences | Some children have challenges with learning, intelligence, or social skills; Duchenne has higher rates of autism spectrum disorder, ADHD, OCD, and anxiety [1] | School accommodations to help the child learn more easily |
Weakening bones | Low bone density (fewer minerals in bones); weaker bones over time, especially for children who use wheelchairs; higher fracture risk | Medicines to help strengthen weak bones [1] |
When Should I See a Doctor?
Get medical advice if you notice symptoms of muscle weakness in yourself or your child. Symptoms could include delays in development, more clumsiness than usual, and falling. [1]
What is the bottom line on muscular dystrophy?
Muscular dystrophy is not one disease — it is a group of more than 30, all sharing the same core problem: a gene change that stops muscle-protecting proteins from doing their job, leaving muscles weaker and smaller over time. The most common type, Duchenne, usually starts in early childhood and mostly affects boys, while other types — like Becker, limb-girdle, myotonic, FSHD, Emery-Dreifuss, congenital, and oculopharyngeal — arrive at different ages and target different muscle groups. The main symptom is muscle weakness that gets progressively worse, and the complications can reach beyond the muscles to the heart, breathing, swallowing, spine, and bones. Because medicines and other treatments can manage symptoms and slow the course, the single most important step is getting medical advice early — when you notice weakness, unusual clumsiness, falls, or developmental delays in yourself or a child.
Take the Next Step
If you've noticed muscle weakness, frequent falls, unusual clumsiness, or developmental delays in yourself or your child, don't wait to see whether it passes. Muscular weakness that worsens over time is the hallmark of this group of diseases, and the earlier a healthcare team is involved, the more it can do — medicines and other treatments can manage symptoms and slow the course, while breathing support, feeding tubes, heart monitoring, bone-strengthening medicines, and school accommodations can protect against the complications. Write down what you've noticed and when it started, and bring your family health history, since most of these gene changes are inherited. A healthcare provider can start the conversation about which type might be involved, what tests come next, and what a long-term care plan looks like for your situation. Explore more of Rinnit.com's plain-language guides to understand your symptoms, prepare for your appointment, and know exactly what to ask.
Early notice matters: children with certain types of muscular dystrophy can have learning, intellectual, or mental health challenges. If your child is affected, talk with your child's school and ask for accommodations — changes that can help your child learn more easily.
Frequently Asked Questions
What is muscular dystrophy?
Muscular dystrophy is a group of diseases that causes muscles to become weaker and lose mass over time. It is caused by changes in the genes that make proteins needed to form healthy muscles.
How many types are there?
There are over 30 types of muscular dystrophy. Each type is caused by a gene change that is particular to that type of the disease.
What is the main symptom?
Muscle weakness that becomes worse over time, making everyday tasks harder. The exact symptoms, the age they start, and the muscle groups affected depend on the type.
Who gets muscular dystrophy?
Muscular dystrophy occurs in people of all ages and ethnic groups. The most common type, Duchenne, usually affects young boys, while other types sometimes don't start until adulthood. People with a family history have a higher risk of getting the disease or passing it on.
Is muscular dystrophy inherited?
In most cases, yes. The gene changes that cause it are usually passed from parent to child — also called inherited.
What is the difference between Duchenne and Becker muscular dystrophy?
Both cause similar symptoms, but Becker muscular dystrophy tends to be milder and becomes worse more slowly. Becker symptoms usually start in the teens or early adulthood, sometimes not until the mid-20s or later, while Duchenne usually starts in early childhood.
Can muscles that can't relax at will be a sign of muscular dystrophy?
Yes — with myotonic muscular dystrophy (also called Steinert's disease), muscles can't relax at will. For example, it might be hard to let go of someone's hand after shaking it. Facial and neck muscles are often affected first.
What complications can muscular dystrophy cause?
Trouble walking, trouble using the arms, contractures (shortening of muscles or tendons around joints), trouble breathing or coughing, a curved spine (scoliosis), heart problems, swallowing problems, brain-related differences such as learning challenges, and weakening bones from low bone density.
Can muscular dystrophy be treated?
Medicines and other treatments can help manage the symptoms and slow the course of muscular dystrophy.
When should I see a doctor?
Get medical advice if you notice symptoms of muscle weakness in yourself or your child — including delays in development, more clumsiness than usual, and falling.
Related Reading
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Learn more in our guide to Creatine Kinase (CK) Test: What It Is, Normal Levels and High CK Causes.
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References
Mayo Clinic Staff. Muscular dystrophy - Symptoms & causes. Mayo Clinic. May 17, 2025. https://www.mayoclinic.org/diseases-conditions/muscular-dystrophy/symptoms-causes/syc-20375388
National Institute of Neurological Disorders and Stroke. Muscular Dystrophy. NINDS. March 13, 2026. https://www.ninds.nih.gov/health-information/disorders/muscular-dystrophy
American Academy of Orthopaedic Surgeons. Muscular Dystrophy. OrthoInfo. Accessed October 15, 2026. https://www.orthoinfo.org/diseases--conditions/muscular-dystrophy/
Centers for Disease Control and Prevention. About Muscular Dystrophy. CDC. January 7, 2025. https://www.cdc.gov/muscular-dystrophy/about/
Salari N, et al. Global prevalence of Duchenne and Becker muscular dystrophy: a systematic review and meta-analysis. J Orthop Surg Res. 2022;17(1):96. PMID 35168641. https://doi.org/10.1186/s13018-022-02996-8
Weber FJ, et al. Prognostic factors, disease course, and treatment efficacy in Duchenne muscular dystrophy: A systematic review and meta-analysis. Muscle Nerve. 2022;66(4):462-470. PMID 35860996. https://doi.org/10.1002/mus.27682
Mercuri E, et al. Muscular dystrophies. Lancet. 2019;394(10213):2025-2038. PMID 31789220. https://doi.org/10.1016/S0140-6736(19)32910-1
Medical disclaimer
This article is for general informational purposes only and does not constitute medical advice. Always consult a qualified healthcare professional for diagnosis and treatment decisions.
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