Summary about Disease
Becker muscular dystrophy (BMD) is a genetic condition primarily affecting males, characterized by progressive muscle weakness and wasting. It is a milder and more slowly progressive form of muscular dystrophy compared to Duchenne muscular dystrophy (DMD). Both conditions stem from mutations in the dystrophin gene, but in BMD, some dystrophin is still produced, leading to a less severe phenotype. The onset and rate of progression vary significantly among affected individuals.
Symptoms
Muscle weakness (typically starting in the hips and thighs)
Muscle cramps and fatigue with exercise
Difficulty running, jumping, and climbing stairs
Walking on toes (toe walking)
Enlarged calf muscles (pseudohypertrophy)
Late onset of walking
Curvature of the spine (scoliosis) may develop
Heart problems (cardiomyopathy) may develop
Causes
BMD is caused by mutations in the DMD gene located on the X chromosome. This gene provides instructions for making dystrophin, a protein essential for muscle cell structure and function. In BMD, the mutations allow for some production of a partially functional dystrophin protein. Because it is X-linked, males are primarily affected. Females carrying one copy of the mutated gene are usually carriers and may experience mild symptoms.
Medicine Used
Corticosteroids (e.g., prednisone, deflazacort): May help to slow muscle degeneration and improve muscle strength and function for a period of time.
Heart medications (e.g., ACE inhibitors, beta-blockers): Used to manage cardiomyopathy and prevent heart failure.
Creatine: Some studies suggest creatine supplementation may improve muscle strength in some individuals.
Physical therapy: To maintain muscle strength and range of motion.
Occupational therapy: To assist with activities of daily living.
Pain relievers: Over-the-counter or prescription medications may be used to manage muscle pain and cramps.
Investigational therapies: Gene therapy and other targeted treatments are under development.
Is Communicable
No, Becker muscular dystrophy is not communicable. It is a genetic disorder and cannot be spread from person to person.
Precautions
Regular monitoring: Cardiac function should be monitored regularly due to the risk of cardiomyopathy.
Avoidance of strenuous activity: While activity is important, excessive strain on weakened muscles should be avoided.
Fall prevention: Measures should be taken to prevent falls, such as using assistive devices (e.g., canes, walkers) and modifying the home environment.
Vaccinations: Routine vaccinations are important to protect against respiratory infections, which can be particularly dangerous for individuals with respiratory muscle weakness.
Genetic counseling: Important for families with a history of BMD.
How long does an outbreak last?
BMD is not an infectious disease and does not have outbreaks. It is a chronic, progressive condition that lasts throughout the affected individual's lifetime.
How is it diagnosed?
Physical examination: Assessment of muscle strength, reflexes, and gait.
Blood tests: Elevated creatine kinase (CK) levels are a sign of muscle damage.
Genetic testing: Confirms the diagnosis by identifying mutations in the DMD gene.
Muscle biopsy: A small sample of muscle tissue is examined under a microscope to assess dystrophin levels and muscle fiber structure.
Electromyography (EMG): Measures the electrical activity of muscles.
Echocardiogram and EKG: to assess heart function.
Timeline of Symptoms
The timeline of symptom onset and progression varies widely among individuals with BMD. However, a general timeline includes:
Childhood/Adolescence: Subtle motor delays, muscle cramps, and fatigue may be present.
Adolescence/Early Adulthood: Muscle weakness typically becomes more noticeable, affecting activities such as running, climbing stairs, and carrying heavy objects.
Adulthood: Progressive muscle weakness continues, potentially leading to the need for assistive devices for mobility. Cardiomyopathy may develop.
Later Life: Respiratory muscle weakness can occur, potentially requiring ventilatory support.
Important Considerations
Variability: The severity and progression of BMD can vary significantly between individuals, even within the same family.
Cardiac Involvement: Regular monitoring for cardiomyopathy is crucial, as heart problems can be a significant complication of BMD.
Respiratory Function: Monitor for respiratory muscle weakness, and consider vaccinations against influenza and pneumonia.
Psychosocial Support: Living with a chronic, progressive condition can be challenging, and psychosocial support is important for individuals and their families.
Multidisciplinary Care: Management of BMD requires a multidisciplinary team, including neurologists, cardiologists, pulmonologists, physical therapists, occupational therapists, and other healthcare professionals.
Research Advances: Ongoing research is focused on developing new therapies for BMD, including gene therapy and other targeted treatments.