An inherited l disorder characterized by progressive muscle weakness. The disorder is caused by a genetic anomaly and results in insufficient quantities of or ineffective dystrophin which is needed for normal muscle functioning. The disorder is expressed in males but females can be carriers.
Abnormal gait Duck-like waddle Toe walking Difficulty walking Frequent falls Gower's sign Muscle weakness Scoliosis Lordosis Pseudohypertrophy of calf muscles Contractures of Achilles tendon Weak shoulder muscles Weak intercostal muscles Weak pelvic muscles Weak back muscles Weak neck muscles Contractures of iliopsoas Contractures of hamstrings Contractures of forearm flexors Contractures of fingers flexors Atrophy of arm muscle Atrophy of thigh muscles Atrophy of pectoral muscles Weakness of mouth muscles Weakness of facial muscles Dyslexia Dysphagia Dysarthria Speech difficulty
Until the 1980s, little was known about the cause of any kind of muscular dystrophy. In 1986, MDA-supported researchers identified the gene that, when flawed — a problem known as a mutation — causes DMD. In 1987, the protein associated with this gene was identified and named dystrophin. Genes contain codes, or recipes, for proteins, which are very important biological components in all forms of life. DMD occurs when a particular gene on the X chromosome fails to make the protein dystrophin. BMD results from different mutations in the same gene. People with BMD have some dystrophin, but it’s not enough or it’s poor in quality. Having some dystrophin protects the muscles of those with Becker from degenerating as badly or as quickly as those of people with Duchenne. By the way, eating or not eating food with protein can’t replace lost dystrophin
Doctors suspect muscular dystrophy when a young boy becomes weak and grows weaker. An enzyme (creatine kinase) leaks out of muscle cells, causing levels of creatine kinase in the blood to be abnormally high. However, high blood levels of creatine kinase do not necessarily mean that a person has muscular dystrophy because other muscle diseases may also cause elevated levels of this enzyme. Duchenne muscular dystrophy is diagnosed when blood tests show the gene for the protein dystrophin to be absent or abnormal and when a muscle biopsy (removal of a piece of muscle tissue for examination under a microscope) shows extremely low levels of dystrophin in the muscle. Under the microscope, the muscle generally shows dead tissue and abnormally large muscle fibers. In the late stages of Duchenne muscular dystrophy, fat and other tissues replace the dead muscle tissue. Similarly, Becker muscular dystrophy is diagnosed when blood tests show the gene for the protein dystrophin to be abnormal and a muscle biopsy shows low levels of dystrophin in the muscle, but not as low as in Duchenne muscular dystrophy. Other tests to support the diagnosis include electrical studies of muscle function (electromyography) and nerve conduction studies (see Diagnosis of Brain, Spinal Cord, and Nerve Disorders: Electromyography and Nerve Conduction Studies).
Neither Duchenne nor Becker muscular dystrophy can be cured. Physical therapy, exercise, and sometimes wearing braces help prevent the muscles from contracting permanently around joints. Sometimes surgery is needed to release tight, painful muscles. Boys need fewer calories because they are less active. They should avoid overeating.