Duchenne and Becker muscular dystrophy are similar conditions caused by mutations in the same gene. However, Duchenne muscular dystrophy begins to cause symptoms at an earlier age, is more severe, and progresses more rapidly.
Muscular dystrophies are a group of inherited diseases that lead to progressive muscle weakness and deterioration. The effects of muscular dystrophy gradually lead to greater difficulty with daily activities and mobility.
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DMD and BMD have some similarities and some important differences. Keep reading to find out more about these two types of muscular dystrophy.
DMD and BMD are two closely related types of muscular dystrophy. They have similar symptoms and are caused by inherited mutations in the same gene.
There are several differences between DMD and BMD. Let’s break them down now.
Age of onset
The symptoms of DMD typically begin during early childhood, often between 3 and 6 years of age. The first symptoms of DMD may include difficulty with head movement and delays in sitting or standing without assistance.
BMD symptoms appear later on,
Rate of progression
DMD tends to progress quickly, while the symptoms of BMD typically worsen much more slowly.
Severity
DMD is more severe than BMD. People with DMD have a shorter life expectancy than those with BMD.
The main symptoms of muscular dystrophy are muscle weakness and wasting (thinning), which worsen as time passes. DMD and BMD affect similar parts of your body.
In both conditions, the muscles of your pelvis and upper legs start to show signs of weakness first. This can include difficulty with:
- walking
- running
- jumping
- climbing stairs
- getting up from a seated position
Muscle damage and weakness eventually affect your lower legs as well as your shoulders, upper arms, and neck. As the condition progresses, these symptoms can also affect other areas of your body, such as your lungs, heart, and throat.
Additional signs and symptoms of DMD and BMD that can happen over the course of the condition include:
- changes in gait or posture
- frequent falls
- enlarged calf muscles
- contractures (shortening of muscles, tendons, and other soft tissues that can cause noticeable physical changes)
- scoliosis
- cardiomyopathy
- difficulty swallowing
- trouble breathing
Both DMD and BMD are caused by mutations in the DMD gene. This gene provides instructions for making the protein dystrophin, which is found mainly in skeletal and cardiac muscle and helps stabilize muscle fibers.
Mutations in the DMD gene mean that your body cannot effectively make dystrophin. This results in a loss of integrity of the muscle fibers, causing them to become damaged as they contract and relax. Over time, damaged fibers begin to die.
You have a higher risk of developing DMD or BMD if either condition runs in your family and if you are male. The DMD gene is on the X chromosome, which means the mutations that cause DMD and BMD are inherited in an X-linked manner.
The X chromosome is one of two sex chromosomes. Males have only one X chromosome. As a result, inheriting just one copy of a mutated DMD gene leads to BMD or DMD in males.
Females have two X chromosomes. Therefore, they will develop DMD or BMD only if they receive two copies of a mutated DMD gene (one from each parent). This is much less common.
Females who have one copy of a mutated DMD gene are called carriers of the gene. Sometimes, carriers can have mild symptoms, such as muscle cramping or weakness, due to some decreased production of dystrophin. Their children can also inherit mutations in DMD. Their female children can be carriers, while their male children would have the disease.
A doctor will start the diagnostic process by taking a thorough personal and family medical history. They will also do physical and neurological exams.
If a doctor suspects that you have DMD or BMD, they can use the following tests to help rule out other conditions and confirm the diagnosis:
- a blood test for creatinine kinase, which is released when muscles are damaged
- genetic testing to look for mutations in the DMD gene
- analysis of a muscle biopsy to check for changes in muscle fibers
- nerve conduction studies, which measure how fast signals travel along nerves
- electromyography, which looks at muscle activity in response to nerve stimulation
- an electrocardiogram and echocardiogram to assess heart health
- other imaging tests such as X-rays, CT scans, or MRI scans
There’s currently no cure for DMD or BMD. Instead, treatment aims to manage symptoms, promote independence, and improve quality of life.
Potential treatments that can be used for DMD and BMD include:
- corticosteroids or other medications to help slow muscle weakening
- physical therapy, which includes regular stretching and low impact exercise
- occupational therapy
- speech therapy
- mobility aids such as braces, standing devices, and wheelchairs
- medications such as ACE inhibitors or beta-blockers to manage and help prevent cardiomyopathy
- calcium and vitamin D supplements to help reduce the risk of osteoporosis due to corticosteroid use
- surgery to treat contractures or scoliosis
- assisted ventilation when the condition affects respiratory muscles
Clinical trials are underway to explore new or updated treatments for DMD and BMD. You can visit ClinicalTrials.gov to find trials that are actively recruiting. Your care team may also be able to recommend clinical trials that you may be eligible for.
DMD and BMD are progressive conditions. This means the symptoms will continue to worsen as time passes.
DMD is more severe and tends to progress more quickly than BMD. In fact, many people with DMD will need to use a wheelchair
Death typically results from complications associated with DMD or BMD — most commonly cardiomyopathy or respiratory complications.
But it’s important to remember that each person with muscular dystrophy is different. Your care team can give you a better idea of your individual outlook, your treatment options, and what to expect.
How common are Duchenne and Becker muscular dystrophy?
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What’s the life expectancy for Duchenne and Becker muscular dystrophy?
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Can Duchenne or Becker muscular dystrophy be prevented?
There’s no way to prevent DMD or BMD. But if either condition runs in your family, you might consider consulting a genetic counselor before trying to have children. They can help you find out how likely it is that your future children will have DMD or BMD.
DMD and BMD are two types of muscular dystrophy that are caused by mutations in the same gene and have similar symptoms. But they also have several differences.
Compared with BMD, DMD has an earlier age of onset and progresses more quickly. People with DMD also have a shorter life expectancy than those with BMD.
There’s currently no cure for DMD or BMD, although clinical trials are in progress to develop new or improved treatments. Treatment for DMD and BMD focuses on managing symptoms, boosting independence, and improving quality of life.