Becker muscular dystrophy (BMD) is a disease that causes the muscles to deteriorate. It is one of several muscular dystrophies, which are genetic (or inherited) diseases of the voluntary muscles or the muscles used to move parts of the body. Although BMD may affect all of the voluntary muscles, patients tend to maintain the function of the smooth, or involuntary muscles, such as those of the bladder and bowel.
BMD is caused by a mutation, or defect, in the DMD gene. This gene provides instructions for making the protein known as dystrophin. This protein helps to keep muscle cells intact, and proper levels of dystrophin are critical for muscle function. People with BMD are deficient in dystrophin; the dystrophin may be produced in low quantities or produced in a form that does not function properly.
BMD may affect all races and ethnicities. However, it primarily affects males and occurs in about one in 30,000 male births. BMD is similar to a more common disease called Duchenne muscular dystrophy (DMD), which affects about one in 3,500 male births. Both conditions are caused by mutations in the DMD gene and both tend to affect more males than females. However, the mutations in the DMD gene are slightly different in each disease. Furthermore, the symptoms of BMD tend to be milder, more variable, typically occur later in life, and they progress more slowly than DMD.
Onset of BMD is generally in adolescence or adulthood. Symptoms usually appear around 10 years of age, but can occur between the ages of two and 21. The disease progresses slowly and may vary from patient to patient but all voluntary muscles may be affected, especially those of the hips, pelvis, thighs, and shoulders. Muscle shrinking tends to be more severe in the lower body.
By the age of 30, the muscle degeneration in BMD becomes so severe that most patients cannot walk. As the muscles of the heart are affected by the disease, heart problems occur between age 20 and 40. Patients with BMD usually die of heart failure. In BMD, the average age of death is 42 years.
Although there is no known cure for BMD, many treatments are available to improve symptoms and maximize quality of life. With proper treatment, many individuals with BMD survive well into mid or late adulthood and have normal life expectancies.
Atrophy, benign pseudohypertrophic muscular dystrophy, BMD, cardiomyopathy, CPK, creatine kinase, creatine phosphokinase, DBMD, DMD, DMD gene, Duchenne muscular dystrophy, Duchenne/Becker muscular dystrophy, dystrophin, dystrophinopathy, Gower sign, voluntary muscle, X-linked recessive disorders.
types of the disease
Becker muscular dystrophy (BMD) is one of several muscular dystrophies, which are genetic (or inherited) diseases of the voluntary muscles, or the muscles used to move parts of the body. While much variation among individuals with Becker muscular dystrophy has been observed, there are no specified different types of the disease.