Becker muscular dystrophy (BMD) is a genetic disorder that causes progressive muscle weakness and decreased muscle tissue (atrophy). BMD is a milder form of Duchenne muscular dystrophy. It is seen mostly in males with symptoms typically beginning in the teenage years or later. Symptoms of the condition begin with muscle weakness in the lower body, usually in the legs and pelvis area. This weakness progresses, causing difficulty with walking, running, and jumping. Individuals with BMD may lose the ability to walk, but typically much later than individuals with Duchenne muscular dystrophy. Another symptom of BMD is weakness of the heart muscle (cardiomyopathy), which may cause shortness of breath, abnormal heartbeat (arrhythmia), and extreme tiredness (fatigue).
BMD, which is caused by mutations in the DMD gene, is inherited in an X-linked recessive pattern. Males have one copy of the DMD gene while females have two copies. Males who have a mutation in their only copy of the gene have the condition, while females with a mutation in one of their two copies typically do not.
In order to diagnose this condition, your child’s doctor will take a detailed medical history, perform a physical exam, and likely perform one of many possible tests, which can include collecting and examining a small piece of muscle tissue (muscle biopsy), measuring electrical activity in muscles (electromyography), measuring the amount of CK enzyme in blood, as well as monitoring the heart and lungs. DMD gene testing is typically needed to confirm the diagnosis. Treatment of BMD is geared towards managing symptoms in order to maximize quality of life. Medications may be prescribed to help with pain. Physical activity can help maintain strength. Physical therapy and orthopedic devices such as braces and wheelchairs may be helpful for self-care and independent movement. Talk with a doctor about the right treatment for you or your child.