Muscular dystrophy is a group of conditions that damage and weaken your muscles over time. Symptoms, age of onset, and outlook depend on the type of muscular dystrophy you have.

Muscular dystrophy refers to a group of genetic conditions characterized by progressive muscle weakness and loss, which can significantly impact mobility and function.

Researchers have identified over 30 types of muscular dystrophies. Combined, they affect around 1 in 5,000 to 10,000 people globally.

Most diagnoses occur in childhood, although they can occur at any age. Muscular dystrophies are also more common in people assigned male at birth, but they can affect anyone.

Keep reading to learn more about the most common types of muscular dystrophy and their symptoms, as well as treatments, life expectancy, and when to see a doctor.

There are several types of muscular dystrophy, which vary in symptoms and severity.

1. Duchenne muscular dystrophy (DMD)

Duchenne muscular dystrophy (DMD) is the most common among children. Most individuals affected are children assigned male at birth. It’s rare for children assigned female at birth to develop DMD.

Studies estimate the incidence of DMD to be about 1 in 3,600 male infants born in the United States. The U.S. prevalence rate may be as high as 2 per 10,000 people.

Symptoms typically begin between ages 2 and 3 years, and may include:

  • trouble walking
  • loss of reflexes
  • difficulty standing up
  • slouching posture
  • bone thinning
  • scoliosis
  • learning differences
  • breathing difficulties
  • swallowing problems
  • lung and heart weakness

According to the Muscular Dystrophy Association (MDA), most people with DMD require an assistive device, such as a wheelchair, before their teenage years.

In the past, people lived with DMD into their late teens or 20s. However, it’s now more common for people to live into their 30s. This is due in part to advances in medical treatment, including cardiac and respiratory care.

2. Becker muscular dystrophy (BMD)

Both Becker muscular dystrophy (BMD) and DMD are caused by a lack of the protein dystrophin, which plays a key role in muscle function.

In BMD, the body’s skeletal muscles produce insufficient dystrophin, whereas in DMD, it’s completely absent.

As a result, BMD is similar in symptoms to DMD but less severe. Muscle weakness occurs mostly in the arms, shoulders, legs, and pelvis, with symptoms appearing between ages 11 and 25 years.

Other BMD symptoms may include:

According to the MDA, up to 7 in 10 people with BMD develop heart problems, such as cardiomyopathy, which is heart muscle weakness.

BMD is also more common in children assigned male at birth. Many with this condition won’t need an assistive device until their mid-30s, and some people may never require one. Most people with BMD live until middle age or later.

In the United States, BMD occurs in about 0.26 per 10,000 males. Combined, DMD and BMD affect up to 18 in 100,000 males globally.

3. Congenital muscular dystrophy (CMD)

Congenital muscular dystrophy (CMD) is often apparent between birth and 2 years old. This is when parents begin noticing that their child’s motor functions and muscle control aren’t developing as they should.

Symptoms vary and may include:

  • muscle weakness
  • poor motor control
  • inability to sit or stand without support
  • scoliosis
  • foot deformities
  • trouble swallowing
  • respiratory issues
  • vision problems
  • speech problems
  • learning differences

Symptoms range from mild to severe, and the life expectancy for people with CMD also varies, depending on their symptoms. Some people with CMD pass away in infancy, while others live until adulthood.

Up to 2.5 in 100,000 people of all ages are living with CMD.

4. Myotonic dystrophy (DM)

Myotonic dystrophy (MD), also known as Steinert’s disease, is a form of muscular dystrophy that causes myotonia, which is an inability to relax muscles after they contract.

There are two types of MD. They’re each characterized by an autosomal dominant mutation in two different genes, but their symptoms are often similar:

  • DM1 (DMPK gene): Symptoms most commonly affect distal muscles, which are those further away from the body’s center. These may include the hands, neck, face, and lower legs.
  • DM2 (CNBP gene): Symptoms typically affect the proximal muscles, which are those closer to the center of your body. These may include the shoulders, elbows, hips, and neck.

DM1 and DM2 are the two most common types of muscular dystrophy that begin in adulthood.

People with other types of muscular dystrophy don’t experience myotonia, but it’s a symptom of other muscle diseases. MD can affect your muscles, as well as your:

Symptoms most often appear between ages 20 and 30 years. Along with muscle loss and weakness, you may experience:

  • drooping muscles in the face, producing a thin, drawn look
  • difficulty lifting the neck due to weak neck muscles
  • difficulty swallowing
  • droopy eyelids (ptosis)
  • early baldness in the front area of the scalp
  • vision problems, including cataracts
  • weight loss
  • increased sweating

DM1 is more likely to cause impotence, testicular atrophy, irregular periods, and infertility.

DM1 is typically more severe than DM2, but symptoms may be similar. The severity of symptoms can vary greatly. Some people experience mild symptoms, while others have potentially life threatening symptoms involving the heart and lungs.

Some researchers estimate that DM may affect up to 36 in 100,000 people globally. Many people with the condition live a long life.

5. Facioscapulohumeral muscular dystrophy (FSHD)

Facioscapulohumeral muscular dystrophy (FSHD) affects the muscles in the face, shoulders, and upper arms. This type of muscular dystrophy is also known as Landouzy-Dejerine disease.

FSHD is classified into two subtypes, but both types typically have the same outlook. Type 1 affects 95% of people with FSHD.

FSHD may cause:

A smaller number of people with FSHD may develop hearing and respiratory problems.

FSHD tends to progress slowly. Symptoms usually appear during teenage years, but they sometimes don’t appear until a person is in their 40s. Most people with this condition live a full life span.

About 4 in 100,000 people in the United States live with FSHD.

6. Limb-girdle muscular dystrophy (LGMD)

Limb-girdle muscular dystrophy (LGMD) refers to a group of more than 20 inherited conditions that cause muscle weakening and loss. Symptoms usually begin in the shoulders and hips but may also occur in the legs and neck.

You may find it hard to get up out of a chair, use stairs, and carry heavy items if you have LGMD. You may also stumble and fall more easily.

Overall, about 2 in 100,000 people in the United States live with LGMD. As there are many subtypes of LGMD, your outlook and life expectancy may vary widely.

7. Oculopharyngeal muscular dystrophy (OPMD)

Oculopharyngeal muscular dystrophy (OPMD) causes weakness in your facial, neck, and shoulder muscles. Other symptoms may include:

  • drooping eyelids
  • vision problems
  • trouble swallowing
  • voice changes
  • heart problems
  • difficulty walking

OPMD is one of the rarer types of muscular dystrophy, affecting fewer than 1 in 100,000 people in the United States. Individuals usually begin to experience symptoms in their 40s or 50s.

8. Distal muscular dystrophy

Distal muscular dystrophy, also called distal myopathy, is a group of conditions that affect the muscles furthest from the shoulders and hips, specifically the:

  • forearms
  • hands
  • calves
  • feet

The condition may also affect your respiratory system and heart muscles. The symptoms tend to progress slowly and include a loss of fine motor skills and difficulty walking.

Most people develop symptoms of distal muscular dystrophy between ages 40 and 60 years.

This condition is also particularly rare, affecting fewer than 1 in 100,000 people in the United States.

9. Emery-Dreifuss muscular dystrophy (EDMD)

Emery-Dreifuss muscular dystrophy (EDMD) usually begins in childhood and tends to affect more children assigned male at birth than children assigned female at birth. The symptoms include:

  • weakness in the upper arm and lower leg muscles
  • breathing problems
  • heart problems
  • shortening of the muscles in the spine, neck, ankles, knees, and elbows

Fewer than 1 in 100,000 people in the United States have EDMD.

By 30 years old, nearly all people with EDMD have a heart condition that requires intervention, such as a pacemaker. The most common causes of limited life expectancy are progressive heart or lung issues.

Muscular dystrophy is caused by genetic irregularities. So far, researchers have identified 40 genes that may contribute to muscular dystrophy.

Thousands of genes are responsible for the proteins that determine muscle integrity. People carry genes on 23 pairs of chromosomes, with one-half of each pair inherited from a biological parent.

One of these pairs of chromosomes is sex-linked, which means the traits or conditions you inherit as a result of those genes may depend on your sex or that of your parent. The other 22 pairs are autosomal chromosomes.

People develop muscular dystrophy in one of four ways. The gene differences that cause muscular dystrophy are normally inherited, but they can also come from a spontaneous mutation.

Autosomal dominant inherited disorder

A person inherits a gene difference from just one parent, on one of the 22 autosomal chromosomes.

Each child has a 50% chance of inheriting muscular dystrophy, and people of all sexes are equally at risk. Because this is a dominant gene, only one parent needs to be a carrier for their child to develop muscular dystrophy.

Autosomal recessive inherited disorder

A person inherits a gene difference from both parents, on one of the 22 autosomal chromosomes. The parents are carriers of the gene but don’t develop muscular dystrophy themselves.

Children have a 50% chance of inheriting one copy of the gene and becoming carriers of the condition. They have a 25% chance of inheriting both copies of the gene. All sexes carry the risk equally.

Sex-linked (X-linked) disorder

This inheritance is associated with the genes located on the X chromosome.

Parents may carry two X chromosomes or an X and a Y chromosome. A child may receive an X chromosome from one parent and either an X or a Y chromosome from the other.

If a child receives a gene difference on the X chromosome from the parent with two X chromosomes, they’ll become carriers of the gene or develop muscular dystrophy.

A child with a faulty X chromosome develops muscular dystrophy if they also inherit a Y chromosome (as is typically the case with children assigned male at birth).

They’re only carriers if they inherit an unaffected X chromosome from the other parent (as with children assigned female at birth). This other unaffected X chromosome offsets the effect of the X chromosome with the gene difference, as it can produce dystrophin.

Spontaneous mutation

In this case, muscular dystrophy develops due to a spontaneous genetic mutation. It occurs in people whose biological parents were not carriers of the gene difference.

Once the change occurs, the carrier can pass it on to their children.

Muscular dystrophy progresses differently for each person. Complications may vary depending on the type of muscular dystrophy. Some complications of muscle dystrophy may include:

  • Mobility changes: Progressive muscle weakness can eventually limit mobility. Many people with muscular dystrophy will eventually use assistive technology and devices, such as a wheelchair.
  • Bone demineralization: Muscle dystrophy may increase the risk of osteoporosis, scoliosis, osteopenia, and bone fractures.
  • Heart problems: People with muscular dystrophy often have cardiomyopathy or heart muscle disease.
  • Respiratory issues: Muscular dystrophy can cause breathing problems, as muscle weakness makes breathing harder. Trouble swallowing can lead to aspiration, or having substances in the airway or lungs.

People with muscular dystrophy who become pregnant are also at a greater risk for complications during gestation and labor.

Generalized muscle weakness could lead to pregnancy loss. Pregnancy can also lead to people with myotonic dystrophy experiencing a faster onset of their condition and a worsening of their symptoms.

A number of tests can help a doctor diagnose muscular dystrophy, including:

  • Blood testing: High levels of serum creatine kinase, serum aldolase, and myoglobin may all signal the need for further testing to confirm or rule out muscular dystrophy.
  • Genetic testing: High levels of creatine kinase and signs of insufficient dystrophin may indicate a need for genetic testing. This type of testing looks for a large mutation of the dystrophin (DMD) gene. If there’s no large mutation, the next set of genetic tests will look for small mutations.
  • Electromyography (EMG): EMG measures the electrical activity of a muscle using an electrode needle that is inserted into the muscle. It can help doctors distinguish muscular dystrophy from a nerve disorder.
  • Neurological physical exam: This exam helps rule out nervous system disorders and assesses muscle strength and reflexes.
  • Cardiac testing: Cardiac testing identifies heart problems that sometimes occur with muscular dystrophy. Tests include an echocardiogram to examine the heart’s structure.
  • Imaging tests: MRI and ultrasound help doctors assess the amount of muscle inside the body.
  • Exercise assessments: These evaluate muscle strength, breathing, and the impact of exercise on the body.

There’s currently no cure for muscular dystrophy, but treatments can help manage your symptoms and slow disease progression.

Treatments depend on your symptoms and the kind of muscular dystrophy you have, as many different genetic mutations can cause muscular dystrophy.

Medications

The Food and Drug Administration (FDA) has approved several new treatments for some people with DMD, including:

These treatments utilize a new process called “exon skipping,” where the faulty segment (exon) of the dystrophin gene is patched over, allowing the body to produce the protein. The medications are all administered via infusion.

Other treatments approved by the FDA for DMD include:

Muscle therapy

Muscle therapy may also help various forms of muscle dystrophy. These techniques involve working with a professional to improve physical function. Types of therapy include:

  • Physical therapy: Targeted exercises, stretches, and general physical activity can keep muscles strong and flexible.
  • Respiratory therapy: This may help prevent or delay breathing problems.
  • Speech therapy: Using specific techniques, such as slower speech, pausing between breaths, and using special equipment, may help conserve muscle strength.

Occupational therapy, a process that focuses on daily activities, can help those with muscular dystrophy:

  • become more independent
  • gain access to community services
  • improve coping skills
  • improve social skills

Other treatments

Other treatment options include:

  • corticosteroid drugs to help strengthen muscles and slow muscle deterioration
  • assisted ventilation if the respiratory muscles are affected
  • medication or surgery for cardiac problems
  • surgery to help correct the shortening of muscles
  • surgery to repair cataracts
  • surgery to treat scoliosis

The life expectancy of a person living with muscular dystrophy depends on the type. For example, people with BMD tend to live for about 40 to 50 years, while most individuals with EDMD may live through middle age.

There’s currently no known cure for any of the muscular dystrophies, but treatments and therapies can help manage symptoms.

Congenital muscular dystrophy typically develops from birth. But it could be diagnosed anytime between birth and adulthood, depending on the type and severity of the specific muscular dystrophy.

A person’s type of muscular dystrophy largely determines their symptoms, age of onset, and outlook.

Breakthrough research and medications have the potential to slow the progression of DMD symptoms and offer more advanced medical options for many people with muscular dystrophy and their families.