Becker Muscular Dystrophy: What You Need to Know

Written by Roma Kunde
Medically Reviewed by Shruthi N, MD on March 26, 2025
6 min read

Becker muscular dystrophy (BMD) is a type of muscular dystrophy, a genetic condition that weakens and damages muscles. It can worsen with age. 

However, its symptoms are less severe than those of Duchenne muscular dystrophy (DMD), which is more common. 

Becker muscular dystrophy is one of the nine types of muscular dystrophy. It was named after the German doctor Peter Emil Becker, who identified it in the 1950s. It is a genetic disorder that causes muscle weakness and damage. It belongs to a group of muscular dystrophies called dystrophinopathies. 

Dystrophinopathies (including BMD and DMD) happen due to certain mutations in the genetic code. One gene, for instance, controls the production of dystrophin, a protein that protects muscle fibers from damage. A change in this gene results in limited or discontinued dystrophin production.

Duchenne vs. Becker muscular dystrophy

If you have Becker muscular dystrophy, your body produces abnormal levels of dystrophin. A lack of dystrophin makes your muscle fibers prone to damage by enzymes or other proteins, leading to muscle degeneration. 

If you have Duchenne muscular dystrophy, your body produces little or no dystrophin. Symptoms are more severe than those of Becker muscular dystrophy.

Becker muscular dystrophy occurs when there’s a change or mutation in the gene that produces the protein dystrophin. The mutation can happen randomly or be passed down from your parents. If you have this mutation, the gene produces less dystrophin than you need. Without dystrophin, your muscle cells remain unprotected and are at risk of damage.

Becker muscular dystrophy is a genetic disorder linked to the X chromosome. The dystrophin gene that causes it is located on the X chromosome.

Becker muscular dystrophy inheritance

Because males have only one X chromosome, they’ll only receive one copy of the dystrophin gene. If they receive the changed or mutated dystrophin gene from a parent, their body will only produce abnormal dystrophin.  

Females carry two X chromosomes, meaning they’ll have two copies of the gene. Even if one X chromosome has the mutated gene, the other one can produce normal dystrophin protein. 

This is why Becker muscular dystrophy affects males more often than females. Also, females tend to have milder symptoms than males. 

However, females can be carriers. Even if they don’t have symptoms, they have a 50% chance of passing it on to their children without knowing it.

Becker muscular dystrophy symptoms can be mild, but the condition is progressive and worsens with age. Symptoms can start at any age from 5 to 60 years, but they vary from person to person.

The main symptoms include muscle weakness and loss of muscle mass. It mainly affects voluntary muscles — those that you can move at will, such as the hip, pelvic, thigh, and shoulder muscles. It doesn’t affect your bladder, bowel muscles, or sexual function. 

If you have Becker muscular dystrophy, other symptoms you may have due to muscle weakness include:

  • Falling often
  • Limited ability to exercise
  • Feeling tired
  • Losing balance
  • Trouble moving your muscles 
  • Being unable to walk fast, climb stairs, or lift heavy things
  • Waddling, walking on your toes, or sticking out your stomach to make up for weak muscles

In some cases of Becker muscular dystrophy, you may not feel any muscle pain, but you can get cramps, which typically go away with medication. 

Other affected muscles and organs

Heart. If you have Becker muscular dystrophy, you may also develop cardiac problems such as cardiomyopathy or heart muscle damage. This side effect is rare but dangerous. Heart problems due to BMD can be life-threatening even in teenagers. If you have the condition, it’s best to avoid strenuous exercise, as it can further damage weak heart muscles.

Lungs. BMD doesn’t initially affect lung muscles, but they can become weaker over time. You may develop conditions such as sleep apnea or respiratory infections.

Brain. A lack of dystrophin can even affect your brain. It can cause neurological and behavioral problems. However, people with Duchenne muscular dystrophy show more severe neurological symptoms. People with BMD may also have learning disabilities.

Becker muscular dystrophy in children

BMD symptoms in children can start between the ages of 5 and 15, but they can also begin at a later age. Children with Becker muscular dystrophy may start walking later than other kids. Trouble with mobility is usually apparent by age 15 or 16, when muscle weakness starts to happen in the hips and pelvis.

Children who show symptoms at a younger age are at a higher risk of heart problems than those who show symptoms later.

If you have symptoms of Becker muscular dystrophy, your doctor will physically examine you. They may order tests and refer you to specialists to complete a more focused exam and additional testing. They’ll also check your medical history and family history.

Doctors use the following tests to diagnose Becker muscular dystrophy:

Creatine phosphokinase blood test. This test checks levels of a muscle protein called creatine phosphokinase (CPK), also called creatine kinase. When you have Becker muscular dystrophy, your muscle cells break down and release CPK into your blood. High levels of CPK indicate that you have the condition.

Electromyography. This uses special needles to check the strength of electrical signals from your brain to your muscles. The needles record the electrical activity, which is displayed on a computer. Abnormal patterns indicate muscle damage.

Muscle biopsy. It involves collecting a sample of muscle tissue, usually from the thigh, to check its dystrophin levels. If there’s no dystrophin, you have Duchenne muscular dystrophy. However, if there are small amounts of dystrophin, you have Becker muscular dystrophy.

Genetic testing. Doctors take your tissue samples to study your genes. They check if your dystrophin gene has a change or mutation.

Western blot test. Doctors use this lab test to measure dystrophin levels in your muscle cells and check the severity of the disease.

There’s no known cure for Becker muscular dystrophy. Doctors use the following treatments to manage the condition:

  • Ankle or foot braces, scooters, wheelchairs, or other physical aids to help in movement
  • Occupational and physical therapy
  • Medication for heart problems
  • Regular checkups of the heart’s condition
  • Surgery or a heart transplant in cases of severe cardiomyopathy

Doctors must be careful with anesthesia, as it can cause complications in people with Becker muscular dystrophy.

Becker muscular dystrophy is a type of muscular dystrophy, a genetic condition that weakens and damages muscles and can worsen with age. The main symptoms include muscle weakness and loss of muscle mass. Symptoms can begin at any age from 5 to 60 years. Trouble is usually apparent by age 15 or 16. While there is no cure for BMD, there are treatment options including occupational and physical therapy, foot and ankle braces, and wheelchairs.

What are the early signs of Becker muscular dystrophy (BMD)?

Children with Becker muscular dystrophy may start walking at a later age than usual. Symptoms usually appear between the ages of 5 and 15, when muscle weakness begins in the hips and pelvis.

Can Becker muscular dystrophy be prevented?

Because BMD is passed down from parents, it can’t be prevented. However, if you have BMD, consider undergoing genetic counseling to confirm the risk of passing on the condition to a child.

How common is Becker muscular dystrophy?

Becker muscular dystrophy is rare. Only about 11,000 people in the U.S. have either BMD or Duchenne muscular dystrophy.