Muscular Dystrophy

Muscular dystrophy is a group of genetic conditions that causes your muscles to weaken over time. It happens because gene changes affect proteins that your muscles need to work and stay strong.

This condition can affect your movement and strength. Some types can also affect breathing and heart function. How quickly symptoms progress varies based on the type.

This is a relatively rare condition without a cure. But therapy and medications may help you manage symptoms and support daily life.

Types of muscular dystrophy

There are more than 30 types of muscular dystrophy. Some of the more common ones include:

• Duchenne muscular dystrophy (DMD): This is the most common type. DMD causes progressive muscle weakness that also affects your heart and lungs.
• Becker muscular dystrophy (BMD): A milder form of Duchenne, BMD causes muscle weakness that progresses slowly.
• Myotonic dystrophy: This is the most common adult form. It causes muscle weakness and trouble relaxing muscles (myotonia) after use.
• Facioscapulohumeral muscular dystrophy (FSHD): This type affects the muscles of your face, shoulders and upper arms. It often begins in your teens.
• Limb-girdle muscular dystrophy (LGMD): This affects the muscles in your shoulders, upper arms, hips and thighs. It can begin at any age.
• Oculopharyngeal muscular dystrophy (OPMD): This usually weakens your eyelids and throat, causing droopy eyelids and trouble swallowing.
• Emery-Dreifuss muscular dystrophy (EDMD): This type of muscular dystrophy often begins in childhood. It causes muscle weakness in your shoulders and lower legs, along with heart issues.

Muscular dystrophy symptoms

The main symptom is muscle weakness that gets worse over time. Other symptoms can vary depending on the type you have. Each type can affect different muscles and parts of your body.

Muscle- and movement-related symptoms may include:

• Irregular walking pattern, like waddling or toe walking
• Trouble with balance, walking, climbing stairs or running
• Muscle stiffness
• Muscle pain or cramping
• Loss of muscle size (muscle atrophy)
• Facial muscle weakness or reduced facial expressions
• Permanent tightening of muscles, tendons or skin (contractures)

Other symptoms may include:

• Breathing problems
• Fatigue
• Trouble swallowing

Some types cause mild symptoms that progress slowly. Other types lead to faster muscle weakness and more physical disability.

What are usually the first signs of muscular dystrophy?

The first signs often appear in childhood, especially in types like Duchenne muscular dystrophy. Parents often notice changes before a provider does.

In young children, early signs may include:

• Delayed milestones, like sitting, standing or walking later than expected
• Trouble keeping up with other kids during play
• Difficulty running, jumping or climbing stairs
• Frequent falls or seeming clumsy
• A different walking pattern, like waddling or toe walking
• Trouble standing up from the floor (using hands to push on their legs)
• Enlarged calf muscles (even though their muscles are weak)

In milder or later-onset types, early signs may be less obvious. They could include:

• Getting tired more easily or during exercise
• Mild muscle weakness, especially in your hips or thighs
• Muscle cramps or stiffness

If you notice these signs, especially muscle weakness that doesn’t improve, see a healthcare provider for an evaluation.

Causes of muscular dystrophy

Changes in genes that are important for keeping muscles healthy and strong cause muscular dystrophy.

When these genes don’t work as they should, your body makes little or none of the needed proteins. Without enough protein, muscle cells damage more easily. Over time, muscles weaken, shrink and lose strength.

This condition can run in biological families, depending on the gene involved:

• Autosomal dominant: A child can develop the condition if they inherit one changed gene from either parent.
• Autosomal recessive: A child must inherit two changed genes, one from each parent, to develop the condition.
• X-linked: The changed gene is on the X chromosome. It affects boys more often because they have only one X chromosome.

In rare cases, muscular dystrophy can happen randomly, without a history of a gene change in your family history.

Risk factors

Risk factors are mostly genetic. Having a family history of the condition or inheriting a gene change that affects your muscles raises the risk.

Some types affect males more often because the changed gene is on the X chromosome. Males have only one X chromosome, so if it carries the gene change, they’re more likely to develop symptoms.

Complications

Muscular dystrophy may affect more than your muscles over time. Possible complications include:

• Bone problems: Weaker muscles and less movement might lead to low bone strength. This raises the risk of fractures and spine curvature (scoliosis).
• Heart issues: Some types could affect your heart muscle, causing an irregular heartbeat or a weakened heart (cardiomyopathy).
• Breathing challenges: Weak chest muscles may make breathing harder and raise the risk of lung infections.
• Sleep-related breathing issues: You may develop sleep apnea or shallow breathing during sleep.
• Loss of mobility: Muscle weakness and joint tightening could lead to disability and the need for walking aids or a wheelchair.
• Intellectual disability: Some types may affect learning and thinking skills. This may impact school performance and daily functioning.

How doctors diagnose muscular dystrophy

To diagnose muscular dystrophy, a healthcare provider starts with a medical history, physical exam and neurological exam. They’ll ask about symptoms like walking issues, frequent falls or trouble climbing stairs. They’ll also ask about your known biological family history.

If they suspect the condition, the next steps may include:

• Creatine kinase (CK) blood test: You may have elevated CK levels (sometimes very high in some types).
• Genetic testing: This is the main test that confirms the diagnosis. It checks for gene changes.
• Muscle biopsy: If genetic testing is unclear, your provider may test a small muscle sample to look for missing or abnormal proteins.

An electromyography (EMG), heart tests (EKG/ECG) or breathing tests may also check how your muscles, heart and lungs are working.

Muscular dystrophy treatment

There’s no cure for muscular dystrophy. But treatment may help slow muscle weakness and manage symptoms.

Common treatments vary by type and could include:

• Corticosteroids: These medicines may slow muscle damage and help you stay stronger and walk longer.
• Gene therapy: Young children with Duchenne muscular dystrophy and specific gene changes can receive gene therapies.
• Heart medications: Drugs like ACE inhibitors or beta-blockers may protect your heart and help treat cardiomyopathy. You might also need treatment for rhythm problems.
• Breathing support: Providers monitor your lung function and recommend breathing devices, like BiPAP, especially during sleep.
• Braces and mobility aids: Ankle-foot braces, walkers or wheelchairs help with balance and movement and support independence.
• Surgery: If needed, surgery could treat severe scoliosis or place a pacemaker for heart rhythm problems.

Some newer genetic treatments are available for certain types. Your provider will let you know if these options are a good fit for you.

Therapy for muscular dystrophy

Therapies play an important role in daily care and long-term function. Your provider might recommend:

• Physical therapy: Helps maintain strength, flexibility and movement while preventing joint stiffness
• Occupational therapy: Teaches ways to make daily tasks easier and safer
• Respiratory therapy: Supports breathing strength and helps prevent lung infections
• Speech therapy: Helps with swallowing or speech problems
• Mental health therapy: Provides emotional support

What can I expect if I have muscular dystrophy?

Muscular dystrophy is a lifelong condition. Muscle weakness slowly worsens over time. How it changes depends on the type and how it affects your body.

In your day-to-day life and activities, weakness may make it harder to move around and keep up your energy. You may have trouble with tasks like walking long distances, climbing stairs, lifting objects or getting up from the floor. You might need mobility aids like braces or a wheelchair. And you may need regular check-ups to monitor your heart and breathing, as some types affect these parts of your body, too.

Living with muscular dystrophy may mean changing how you do daily tasks, using devices for support and planning ahead. With the right care team and therapies, you can continue to do the things that are meaningful to you with some modification.

Muscular dystrophy life expectancy

Life expectancy varies depending on the type and the level of heart and lung involvement. For example:

• Duchenne muscular dystrophy: DMD is more severe. You may live into early adulthood. But improved heart and breathing care is helping many people live longer than in the past.
• Becker muscular dystrophy: This type is usually milder. Many people live into mid-adulthood or longer.
• Facioscapulohumeral muscular dystrophy: Most people have a near-normal life expectancy.

Every person’s experience is different. And advances in medical care continue to improve survival for many people with this condition. If you have questions about your life expectancy, talk to your healthcare provider.

Can muscular dystrophy be prevented?

There’s no way to prevent this condition because a genetic change causes it. But some steps might help you understand your risk and allow for earlier care:

• Genetic counseling: If you have a history of muscular dystrophy, you can meet with a genetic counselor to understand your risk and discuss family planning options.
• Early detection: Finding the condition early doesn’t prevent it. But it may help you start treatment sooner to reduce complications.