Benign pseudohypertrophic muscular dystrophy; Becker's dystrophy
Becker muscular dystrophy is an inherited disorder that involves slowly worsening muscle weakness of the legs and pelvis.
Becker muscular dystrophy is very similar to Duchenne muscular dystrophy. The main difference is that it gets worse at a much slower rate and it is less common.
The disorder is passed down through families (inherited). Having a family history of the condition raises your risk.
Becker muscular dystrophy occurs in about 3 to 6 out of every 100,000 births. The disease is found mostly in boys.
Females rarely develop symptoms. Males will develop symptoms if they inherit the defective gene. Symptoms most often appear in boys between ages 5 and 15, but may begin later.
Muscle weakness of the lower body, including the legs and pelvis area, slowly gets worse, causing:
- Difficulty walking that gets worse over time; by age 25 to 30, the person is usually unable to walk
- Frequent falls
- Difficulty getting up from the floor and climbing stairs
- Difficulty with running, hopping, and jumping
- Loss of muscle mass
- Toe walking
- Muscle weakness in the arms, neck, and other areas is not as severe as in the lower body
Other symptoms may include:
- Breathing problems
- Cognitive problems (these do not get worse over time)
- Loss of balance and coordination
Exams and Tests
The health care provider will do a nervous system (neurological) and muscle exam. A careful medical history is also important, because symptoms are similar to those of Duchenne muscular dystrophy. However, Becker muscular dystrophy gets worse much more slowly.
An exam may find:
- Abnormally developed bones, leading to deformities of the chest and back (scoliosis)
- Abnormal heart muscle function (cardiomyopathy)
- Congestive heart failure or irregular heartbeat (arrhythmia) - rare
- Muscle deformities, including contractures of heels and legs, abnormal fat and connective tissue in calf muscles
- Muscle loss that begins in the legs and pelvis, then moves to the muscles of the shoulders, neck, arms, and respiratory system
Tests that may be done include:
There is no known cure for Becker muscular dystrophy. However there are many new drugs currently undergoing clinical testing that show significant promise in treating the disease.The current goal of treatment is to control symptoms to maximize the person's quality of life. Some providers prescribe steroids to help keep a patient walking for as long as possible.
Activity is encouraged. Inactivity (such as bed rest) can make the muscle disease worse. Physical therapy may be helpful to maintain muscle strength. Orthopedic appliances such as braces and wheelchairs may improve movement and self-care.
Genetic counseling may be recommended. Daughters of a man with Becker muscular dystrophy will very likely carry the defective gene and could pass it on to their sons.
Becker muscular dystrophy leads to slowly worsening disability. However, the amount of disability varies. Some people may need a wheelchair. Others may only need to use walking aids such as canes or braces.
Lifespan is most often shortened if there are heart and breathing problems.
Complications may include:
- Heart-related problems such as cardiomyopathy
- Lung failure
- Pneumonia or other respiratory infections
- Increasing and permanent disability that leads to decreased ability to care for self, decreased mobility
When to Contact a Medical Professional
Genetic counseling may be advised if there is a family history of Becker muscular dystrophy.
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Sarnat HB. Muscular dystrophies. In: Kliegman RM, Stanton BF, St. Geme JW, Schor NF, eds. Nelson Textbook of Pediatrics. 20th ed. Philadelphia, PA: Elsevier; 2016:chap 609.
Selcen D. Muscle diseases. In: Goldman L, Schafer AI, eds. Goldman-Cecil Medicine. 25th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 421.