Becker muscular dystrophy
Becker muscular dystrophy is an inherited disorder that involves slowly worsening muscle weakness of the legs and pelvis.
Benign pseudohypertrophic muscular dystrophy; Becker's dystrophy
Causes, incidence, and risk factors
Becker muscular dystrophy is very similar to Duchenne muscular dystrophy, except that it gets worse at a much slower rate.
The disorder is passed down through families (inherited). Having a family history of the condition raises your risk.
Becker muscular dystrophy occurs in approximately 3 - 6 out of every 100,000 males. It is less common than Duchenne muscular dystrophy.
Females rarely develop symptoms. Males will develop symptoms if they inherit the defective gene. Symptoms usually appear in boys at about age 12, 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 25-30 the person is usually unable to walk
- Frequent falls
- Difficulty with running, hopping, and jumping
- Loss of muscle mass
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
Signs and tests
The health care provider will do a nervous system (neurological) and muscle examination. A careful medical history is also important, because the pattern of symptom development resembles that of Duchenne's 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)
- Abnormality of heart muscle function (cardiomyopathy)
- Congestive heart failure or irregular heartbeat (arrhythmias) - 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 on 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. The goal of treatment is to control symptoms to maximize the person's quality of life. Some doctors 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 mobility and self-care.
Genetic counseling may be recommended. Daughters of a man with Becker muscular dystrophy may carry the defective gene and could pass it onto their sons.
You can ease the stress of illness by joining a support group where members share common experiences and problems.
Becker muscular dystrophy leads to slowly worsening disability, although the degree of disability varies. Some men may need a wheelchair, while others may only need to use walking aids such as canes or braces.
Calling your health care provider
Call your health care provider if:
Genetic counseling may be advised if there is a family history of Becker muscular dystrophy.
Kliegman RM, Behrman RE, Jenson HB, Stanton BF. Muscular dystrophies. In: Kliegman RM, Behrman RE, Jenson HB, Stanton BF, eds. Nelson Textbook of Pediatrics. 18th ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 608.
Reviewed By: Neil K. Kaneshiro, MD, MHA, Clinical Assistant Professor of Pediatrics, University of Washington School of Medicine; and Daniel B. Hoch, PhD, MD, Assistant Professor of Neurology, Harvard Medical School, Department of Neurology, Massachusetts General Hospital. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.