Biology 223- Anatomy & Physiology
23 February 2009
Duchenne Muscular Dystrophy
Guillaume Benjamin Amand Duchenne is the first doctor to have studied Duchenne Muscular Dystrophy in the late 1860’s. That is where the name Duchenne comes from. According to an article posted in the UK, Duchenne Muscular Dystrophy “is a genetic condition which affects the muscles, causing muscle weakness.” The condition is a very serious condition that is found mainly in boys. One in thirty-five hundred and the numbers are unknown in females due to how rare to be found in girls. Most children show signs of this disease by the age of two. Most children show signs of falling frequently and sometimes have trouble sitting. According to another articles by the mayo clinic the definition is “a group of inherited muscle diseases in which muscle fibers are unusually susceptible to damage.” It is also the most common type of this disease that there is no cure for but there is medicine that can sometimes help control different functions. The disease affects levels of dystrophin in the muscle tissue. Dystophin is a protein in the muscle. Another sign of this disease is the under development of the calve muscles which is known as “pseudohypertrophy”. Pseudohypertrophy is a condition in which the muscle tissue in the legs becomes fat and connective tissue. With this is happening the “muscle fibers shorten and fibrosis occurs in the connective tissue.”
There are many causes of this disease and multiple ways that it can be inherited. The biggest cause of muscular dystrophy is that it causes a change in the genetic makeup of the muscle tissue. “Every person has a large number of genes in their cells. One set of genes is from the father and the other is from the mother. The genes have been copied from the parent’s cells into the child’s cells.” Duchenne muscular dystrophy is inherited by the x-linked recessive gene. Because boys only have one x-chromosome it is more likely that they get the disease rather than females, consider that females have and extra x-chromosome to help with the defective one. If the mother is carrying the disease, it is possible for her sons to have a fifty percent chance of having the disease and her daughters have a fifty percent chance of being a carrier of the disease. Women that carry this and only have one x-chromosome can also have heart problems called “cardiomyopathy” and some muscle weakness. “The disease can skip a generation until another son inherits the defective gene on the x-chromosome. In some cases of Duchenne’s the disease arises from a new mutation in a gene rather than from an inherited defective gene.”
Children start showing some signs of symptoms around the age of one to three. But most parents at first don’t realize the disease. The symptoms start first by affecting the walking, running and jumping of a child’s movement, all the muscles in the legs. Children’s first signs with walking include the “waddling” effect. Most children by the age of ten will be confined to a wheelchair or some kind of walking brace. The second symptom is that when parents pick up there children they feel that they “slip through your hands” because of the loose muscle tissue in the upper body. The third symptom would be that boys calve muscles are bigger even though they are not fully developed. This is called “Hypertrophy of the calve muscles.” The fourth symptom is when the child gets older he will use his hands to get up which is called “Gower’s sign.” This is referred to as “Climbing up his legs.” The fifth symptom is that the disease will also cause some learning disabilities and will not progress pass a certain level. There are many ways to tell if your child has this disease but there is a blood test called “creatine kinase blood test” that will tell if your child has this disease or is a carrier of the gene for muscular dystrophy. The test shows...