Becker muscular dystrophy (BMD) is a genetic disorder that causes progressive muscle degeneration and weakness. This can cause a person to have reduced mobility such as problems walking. BMD can make it difficult for a person to carry out everyday tasks.

BMD is a type of muscular dystrophy. Muscular dystrophy is a group of disorders that cause muscle weakness that worsens over time.

This article looks at BMD symptoms and causes. It also discusses diagnosis, treatment options, and more.

A note about sex and gender

Sex and gender exist on spectrums. This article will use the terms “male,” “female,” or both to refer to sex assigned at birth. Click here to learn more.

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BMD usually begins with muscle loss in the:

  • hips
  • pelvis
  • thighs
  • shoulders

Common symptoms of BMD include:

  • problems walking
  • trouble running or jumping
  • frequent falls
  • frequent stumbling
  • trouble climbing stairs
  • problems standing from a lying down or sitting position
  • reduced endurance
  • enlarged calf muscles

Symptoms of BMD tend to progress slowly over decades. Some males with BMD require wheelchair use by age 30 years or later. Others may manage with minor walking aids, such as a walking cane.

As the condition progresses, it may cause a person to develop a number of complications. These include:

  • cardiomyopathy
  • loss of lung and liver function
  • scoliosis
  • loss of the ability to walk
  • cognitive impairment
  • bone fractures

BMD is a genetic condition. Genetic disorders occur due to changes or alterations in a gene.

BMD occurs due to a mutation in a protein called dystrophin. This mutated gene is present in the Xp21.2 chromosome.

In most cases, a person inherits the condition from a parent. It is an X-linked recessive disorder.

There are some cases where a person develops the disorder due to a change in the gene that is not inherited. Medical professionals refer to this as a spontaneous mutation.

Becker muscular dystrophy is one of the two most common types of muscular dystrophy that doctors diagnose in children. The other type is Duchenne muscular dystrophy (DMD).

To assist with reaching an accurate diagnosis, a doctor may:

  • take the child’s medical history and their family medical history
  • carry out a thorough physical examination
  • order laboratory tests to confirm a diagnosis

Physical examination

During a physical examination, the doctor may want to see how the child stands up from a sitting position on the floor. This is because children with muscular dystrophy may stand up in a unique way due to weak leg muscles. Medical professionals often refer to this method of standing as the Gower’s maneuver.

A child typically performs Gower’s maneuver in the following ways.

  1. They start on their hands and feet.
  2. They then plant their feet widely apart and push their bottoms upward.
  3. The child then uses their hands to push themselves up on their knees and thighs until they are upright.

The doctor will also watch the child walking, and they may evaluate the child’s muscles and nervous system.

Laboratory tests

There are a number of laboratory tests that a doctor may use to confirm an MD diagnosis. These include:

  • Blood tests: Blood tests can show that the person has high levels of the enzyme creatine kinase. High levels of creatine kinase can be a sign that muscle damage has occurred.
  • Electromyography: During this test, a doctor will place small electrodes on the skin over the muscles. This can measure the electrical activity within the muscle. Certain changes in the pattern of this electrical activity may show that a person has muscular dystrophy.
  • Muscle biopsy: During this procedure, a doctor will remove a small piece of muscle for analysis in a laboratory. Lab analysis can help a medical professional rule out other muscle conditions.
  • Genetic testing: A medical professional can send a blood sample to a lab for genetic testing. This testing can help identify whether certain genetic mutations are present, helping diagnose BMD.

There is no cure for BMD, but treatment and supportive therapy can help a person slow the progression of the condition and reduce complications of BMD. Treatment can also help improve a person’s quality of life.

Treatment for BMD may include physical therapy, medications, assistive devices, and surgery.

Physical therapy

Physical therapy for BMD may include stretching exercises to help improve walking ability. It may also include therapy designed to help maintain a range of motion in stiff joints.

A physical therapist may also suggest a person wear walking braces to help support weakened muscles and to help keep the body flexible.

Medication

Doctors may prescribe corticosteroids to help treat BMD. Corticosteroids can:

  • improve lung function
  • delay scoliosis
  • delay the onset of cardiomyopathy
  • prolong survival

Assisted devices

Assisted devices can help a person maintain their mobility and independence. Devices that a person with BMD can use include:

  • canes
  • walkers
  • wheelchairs
  • power wheelchairs

Surgery

In some cases, a doctor may recommend surgery to help maintain functional skills and treat scoliosis. A doctor can advise on whether they recommend surgery and what it can involve.

According to a 2023 article, BMD affects anywhere from 0.1–1.8 per 10,000 males. A 2022 study suggests that the global prevalence of BMD is around 3.6 per 100,000 people.

The condition almost exclusively affects boys.

Here are some frequently asked questions about BMD.

What is the life expectancy of a person with Becker muscular dystrophy?

If a person has BMD, their chances of survival tend to decrease with time. This is due to the progression of the condition.

The average life expectancy for a person with BMD is usually around 40–50 years.

The most common cause of death in people with BMD is dilated cardiomyopathy.

Each person’s outlook differs. A person’s doctor can provide them with more accurate information based on their individual circumstances.

How serious is Becker muscular dystrophy?

BMD is generally less severe than DMD. However, it is still a serious medical condition that affects a person’s quality of life.

BMD can cause a person to rely on walking aids or wheelchairs to move. It can also cause complications, such as scoliosis and cardiomyopathy.

It can also shorten someone’s life, with life expectancy being around 40–50 years, though this can differ for each individual.

Becker muscular dystrophy (BMD) causes muscle loss in the hips, pelvis, thighs, and shoulders. This can cause a person to experience symptoms, such as problems walking, frequent falls, problems standing, reduced endurance, and muscle weakness.

Complications of BMD include cardiomyopathy, loss of lung and liver function, scoliosis, loss of the ability to walk, cognitive impairment, and bone fractures.

There is no cure for BMD, but a doctor may recommend physical therapy to help improve a person’s ability to move as well as their quality of life. They may also prescribe corticosteroids to help reduce the progression of the condition and to help delay scoliosis.