Becker muscular dystrophy (BMD) is a rare genetic disorder which occurs primarily in boys and men, although women can be carriers and some women develop symptoms, most commonly in the form of heart problems such as cardiomyopathy. This condition is part of a larger family of conditions known as muscular dystrophies, and it is among the most common of these conditions.
In patients with Becker muscular dystrophy, the body is not able to produce enough dystrophin, an enzyme which prevents muscle tissue from breaking down. As a result, the patient develops progressive muscle weakness. In Becker muscular dystrophy, the weakness starts in the lower body, creating problems with walking or balancing. Over time, the weakness can become severe, and it may be accompanied with heart problems as this condition often involves the heart muscle.
This form of muscular dystrophy is very similar to Duchenne muscular dystrophy, except that Duchenne muscular dystrophy is much more severe, with the body not producing any dystrophin at all. The age of onset of symptoms for Becker muscular dystrophy is generally around age 12, in contrast with early childhood for patients with Duchenne muscular dystrophy. Becker muscular dystrophy also progresses more slowly, with patients living until middle to late adulthood with the condition.
This condition is an x-linked recessive trait, which means that it is carried on the x chromosome. In order for a man to get it, he just needs to inherit one copy of the defective gene. Women, on the other hand, need two copies, which means that their mothers need to be carriers and their fathers need to have Becker muscular dystrophy. This is relatively rare, which is why women generally do not get this condition.
If a couple has a boy with Becker muscular dystrophy, it usually means that the mother is a carrier, although the gene may have mutated spontaneously. Daughters of the couple may become carriers if they inherit the bad gene from their mothers, and future sons have a 50% chance of developing Becker muscular dystrophy, depending on whether or not they get the gene.
There is no cure for Becker muscular dystrophy. If intervention is provided soon after symptoms are observed, however, the quality of life for the patient can be greatly improved. Physical activity tends to keep patients functional longer, as does physical therapy. Patients can also wear braces to prevent contractures and other problems which make it difficult to walk. Eventually, a patient may need a walker, cane, or wheel chair for mobility. Patients with Becker muscular dystrophy generally do not experience cognitive impairments, and many live very rich, active lives despite their condition.