Understanding the Similarities and Differences Between Duchenne and Becker Muscular Dystrophy

Mutations in the same gene produce identical illnesses, Duchenne and Becker muscular dystrophy. On the other hand, Duchenne muscular dystrophy manifests symptoms earlier in life, is more severe, and advances more quickly.

A class of hereditary illnesses known as muscular dystrophies cause progressive weakening and degeneration of the muscles. The consequences of muscular dystrophy progressively make daily tasks and mobility more difficult.

There are more than thirty different kinds of muscular dystrophy, according to the National Institute of Neurological Disorders and Stroke. Duchenne muscular dystrophy (DMD) and Becker muscular dystrophy (BMD) are two of these.

While DMD and BMD have certain similarities, they also differ significantly. To learn more about these two varieties of muscular dystrophy, continue reading.

What are Duchenne and Becker muscular dystrophy?

A pair of closely similar forms of muscular dystrophy are DMD and BMD. They are brought on by hereditary mutations in the same gene and share comparable symptoms.

How are Duchenne and Becker muscular dystrophy different?

The distinctions between DMD and BMD are numerous. Now let’s dissect them.

Age of onset

DMD symptoms usually start in early childhood, usually between the ages of three and six. DMD can present with difficulties moving the head and delays in sitting or standing up without help.

Later on, at approximately age 11, BMD symptoms start to show up. These symptoms can include difficulty walking and climbing stairs. Even as adults, people can have BMD symptoms.

Rate of progression

The symptoms of BMD usually worsen much more slowly than those of DMD, which tends to advance more swiftly.

Severity

BMD is not as severe as DMD. Compared to people with BMD, those with DMD have a lower life expectancy.

What are the symptoms of Duchenne and Becker muscular dystrophy?

The primary signs of muscular dystrophy are wasting (thinning) and weakness of the muscles, which get worse over time. Similar body parts are affected by both DMD and BMD.

The muscles in your upper legs and pelvis begin to weaken early in both situations. This may involve having trouble with:

walking
running
getting up from a seated position
jumping
climbing stairs

Your neck, shoulders, and upper arms eventually become affected by muscle weakening and damage to your lower legs. These symptoms can eventually spread to other parts of your body, including your heart, throat, and lungs.

Throughout the ailment, further DMD and BMD signs and symptoms that may occur are as follows:

changes in gait or posture
frequent falls
enlarged calf muscles
scoliosis
cardiomyopathy
difficulty swallowing
Contractures: a visible physical alteration caused by the shortening of muscles, tendons, and other soft tissues
trouble breathing

What are the causes of Duchenne and Becker muscular dystrophy?

Mutations in the DMD gene are the cause of both BMD and DMD. The dystrophin protein, which is mostly present in skeletal and cardiac muscle and aids in stabilising muscle fibres, is made by this gene.

When the DMD gene is mutated, your body is unable to produce dystrophin efficiently. As a result, the muscle fibres lose their structural integrity and sustain injury during contraction and relaxation. Damaged fibres eventually start to die.

What are the risk factors for Duchenne and Becker muscular dystrophy?

If either ailment runs in your family and you are a man, your chances of having DMD or BMD are increased. Since the DMD gene is located on the X chromosome, X-linked inheritance is the mechanism by which DMD and BMD are caused by mutations.

One of the two sex chromosomes is the X chromosome. There is only one X chromosome in males. Thus, BMD or DMD in males is caused by inheriting a single copy of a mutant DMD gene.

There are two X chromosomes in females. Consequently, only if they inherit two copies of a defective DMD gene (one from each parent) will they acquire DMD or BMD. This is far less typical.

Carriers of the gene are females with one copy of a mutant DMD gene. Carriers can experience modest symptoms like weakening or cramping in their muscles as a result of a decrease in dystrophin production. DMD mutations may also be inherited by their offspring. Their male offspring would have the illness, but their female offspring might be carriers.

How are Duchenne and Becker muscular dystrophy diagnosed?

A comprehensive personal and family medical history will be taken by a doctor before beginning the diagnostic procedure. They will also perform neurological and physical examinations.

The following tests can be used by a doctor to rule out other illnesses and confirm the diagnosis if they suspect you have BMD or DMD:

a test for creatinine kinase in the blood, which is produced when muscles are injured
genetic testing to search for DMD gene mutations
examination of a muscle biopsy to detect alterations in the muscle fibres
research on nerve conduction, which evaluates the speed at which messages go via nerves
The examination of muscle activity in response to nerve stimulation is known as electromyography.
an ECG and echocardiography to evaluate the condition of the heart
further imaging examinations like CT, MRI, or X-rays

What’s the treatment for Duchenne and Becker muscular dystrophy?

Neither BMD nor DMD currently have a treatment. Rather, the goals of treatment are to enhance quality of life, encourage independence, and control symptoms.

The following are some possible DMD and BMD treatments:

occupational therapy
speech therapy
corticosteroids or other drugs to assist in preventing or delay the weakening of muscles
physical treatment, which entails low-impact exercise and frequent stretching
wheelchairs, standing assistance, and braces are examples of mobility aids
drugs like beta-blockers or ACE inhibitors to treat and prevent cardiomyopathy
supplements of calcium and vitamin D may help lower the risk of osteoporosis from using corticosteroids
surgery for scoliosis or contractures
aided breathing when the respiratory muscles are affected

To investigate novel or improved DMD and BMD treatments, clinical trials are now being conducted. For a list of trials that are now accepting participants, go to ClinicalTrials.gov. Additionally, your healthcare team might be able to suggest clinical studies for which you might qualify.

What is the outlook for patients with Becker and Duchenne muscular dystrophy?

Both BMD and DMD are progressive disorders. This implies that as time goes on, the symptoms will get worse.

Compared to BMD, DMD is more severe and tends to advance more quickly. Indeed, by the time they are 12 years old, many DMD patients will require a wheelchair. Individuals with DMD also have a lower life expectancy than those with BMD.

The most common causes of death related to DMD or BMD problems are cardiomyopathy or respiratory issues.

However, it's crucial to keep in mind that every person with muscular dystrophy is unique. You can get more information about your specific prognosis, available treatments, and what to anticipate from your care team.

Takeaway

The two forms of muscular dystrophy, known as BMD and DMD, share comparable symptoms and are brought on by mutations in the same gene. However, they also differ in a few ways.

DMD advances more fast and has an earlier age of onset than BMD. Additionally, the life expectancy of DMD patients is lower than that of BMD patients.

DMD and BMD currently have no known cure, however, clinical trials are being conducted to create new or more effective treatments. The goals of treatment for both BMD and DMD are to enhance quality of life, increase independence, and control symptoms.