Muscular dystrophies are genetic disorders characterised by progressive muscle wasting and weakness that begin with microscopic changes in the muscle. As muscles degenerate over time, the person’s muscle strength declines.
Duchenne muscular dystrophy (DMD) was first described by the French neurologist Guillaume Benjamin Amand Duchenne in the 1860s. Becker muscular dystrophy (BMD) is named after the German doctor Peter Emil Becker, who first described this variant of DMD in the 1950s. In DMD, boys begin to show signs of muscle weakness as early as age 3.
The disease gradually weakens the skeletal or voluntary muscles, those in the arms, legs and trunk. By the early teens or even earlier, the boy’s heart and respiratory muscles may also be affected. BMD is a much milder version of DMD. Its onset is usually in the teens or early adulthood, and the course is slower and far less predictable than that of DMD.
(Though DMD and BMD affect boys almost exclusively, in rare cases they can affect girls. See “Does It Run in the Family?” What causes Duchenne and Becker Muscular Dystrophies? Until the 1980s, little was known about the cause of any kind of muscular dystrophy. In 1986, 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.
More Information about Duchenne and Becker Muscular Dystrophies (DMD & BMD)
