What causes Becker's muscular dystrophy?
Genetic counseling is indicated for individuals or families who may carry this condition. Becker muscular dystrophy is a type of dystrophinopathy which include a spectrum of muscle disease caused by mutations in the DMD gene, which encodes the protein dystrophin. Becker's muscular dystrophy a milder form of Duchenne's muscular dystrophy. Both Duchenne and
Becker's muscular dystrophy are X-linked recessive diseases. Becker's is named after the German doctor Peter Emil Becker.
The disorder is inherited with an X-linked recessive inheritance pattern -- the gene is located on the X chromosome. Since women have two X chromosomes, if one X chromosome has the defective gene, the second X chromosome will have a working copy of the gene to compensate. In these cases, some women have much milder symptoms because of this ability to compensate. Men have an X and a Y and because they don't have another X to compensate for the defective gene, they will develop symptoms if they inherit the defective gene.
Becker's muscular dystrophy is very similar to Duchenne's muscular dystrophy, except that it progresses at a much slower rate. People with this disorder experience progressive muscle weakness of the legs and pelvis, which is associated with a loss of muscle mass (wasting). Muscle weakness also occurs in the arms, neck, and other areas, but not as severely as in the lower half of the body. Calf muscles initially enlarge (an attempt by the body to compensate for loss of muscle strength), but the enlarged muscle tissue is eventually replaced by fat and connective tissue (pseudohypertrophy). Muscle contractures occur in the legs and heels, causing inability to use the muscles because of shortening of muscle fibers and fibrosis of connective tissue. Bones develop abnormally, causing skeletal deformities of the chest and other areas.
Cardiomyopathy (damage to the heart) does not occur as commonly with this disorder as it does with Duchenne's muscular dystrophy. Cognitive problems may accompany the disorder, but they are not inevitable and do not worsen as the disorder progresses. Becker's muscular dystrophy occurs in approximately 3-6 in 100,000 male births. Symptoms usually appear in men at about age 12, but may sometimes begin later. The average age of becoming unable to walk is 25-30. Women rarely develop symptoms. Because this is an inherited disorder, risks include having a family history of Becker's muscular dystrophy.
More information on muscular dystrophy
What is muscular dystrophy? - Muscular dystrophy is a group of inherited diseases that are characterized by weakness and wasting away of muscle tissue.
What types of muscular dystrophy are there? - There are nine types of muscular dystrophy including Duchenne muscular dystrophy, Becker muscular dystrophy, facioscapulohumeral muscular dystrophy.
What causes Duchenne muscular dystrophy (DMD)? - Duchenne muscular dystrophy is a rapidly progressive form of muscular dystrophy. It is caused by a defective gene.
What're the symptoms of Duchenne muscular dystrophy? - Symptoms of Duchenne muscular dystrophy include progressive muscle weakness of the legs and pelvis, mental impairment or heart problems.
What causes Becker's muscular dystrophy? - Becker muscular dystrophy is a type of dystrophinopathy which include a spectrum of muscle disease caused by mutations in the DMD gene.
What're the symptoms of Becker's muscular dystrophy? - Symptoms of Becker-type muscular dystrophy are similar to those of Duchenne dystrophy, but they are milder and begin later.
What causes limb-girdle muscular dystrophy? - Limb-girdle muscular dystrophy is an inherited disorder, it may be inherited as a dominant, recessive, or X-linked genetic defect.
What're the symptoms of limb-girdle muscular dystrophy? - Symptoms of limb-girdle muscular dystrophy include progressive muscle weakness in the shoulders and hips, together with breathing problems.
What causes facioscapulohumeral muscular dystrophy? - Facioscapulohumeral muscular dystrophy involves progressive muscle weakness and loss of muscle tissue.
What're the symptoms of facioscapulohumeral muscular dystrophy? - Symptoms of facioscapulohumeral muscular dystrophy may begin during infancy, late childhood, or early adulthood.
What causes myotonic dystrophy? - Myotonic dystrophy is caused by an inherited gene defect. Myotonic dystrophy is the most common form of adult muscular dystrophy.
What're the symptoms of myotonic dystrophy? - Symptoms of myotonic dystrophy include muscle weakness and wasting, cataracts, heart problems, constipation and other digestive problems.
How is muscular dystrophy diagnosed? - Diagnosis of muscular dystrophy involves a medical history and physical exam to determine the distribution of symptoms and to rule out other causes.
What's the treatment for muscular dystrophy? - Treatments for muscular include decreased mobility and dexterity, contractures, scoliosis, heart defects, and respiratory weaknesses.