Duchenne-Muscular-Dystrophy

DUCHENNE MUSCULAR DYSTROPHY  by Haven and Alyssa

Definition: Muscular Dystrophy (MD): a progressive* genetic condition that causes the muscles to weaken
 * gets worse over time, instead of better

There are over 30 types of MD, but the most common is Duchenne. Duchenne affects mostly boys and is diagnosed from one to three years of age. This type of MD affects 1/3500 boys worldwide.

Mutation/Sequence/Cause/etc: The gene that causes Duchenne produces a protein known as dystrophin. When this mutation occurs, dystrophin is not produced in adequate amounts, making its location (under muscle fibers) very fragile and subject to tearing easily. Dystrophin is an attachment protein that helps hold muscles together and them stronger. In the figure below, you see that Dystrophin (in red) attaches to the actin-binding region and the C terminus, connecting the Sarcolemma to the Actin filaments. In other words, this connects muscle fibers to each other. When the amount of Dystrophin is lessened, the attachment is made weaker, and therefore causes tears to become much more likely. Any slight mutation in the gene that codes for dystrophin can cause Duchenne MD. There are several different levels and variations of the disease, each depending on the mutation that occurs. This disease is caused by a mutation on the X chromosome. It is SEX-LINKED. It is more common in boys than in girls because boys only get one copy of the X chromosome, while females get two. If a female carrier of Duchenne MD has a male child, there is a 50% chance that she will pass the disease on to her child. This disease occurs very rarely in females. Occasionally, but very rarely, there may be a spontaneous mutation that causes Duchenne.



Symptoms: Children who have Duchenne MD may have difficulty walking or standing up or learning or behavioral difficulties. As Duchenne patients grow older, they may develop respiratory and heart problems due to the thinning of muscle tissues.

Treatment: To date, there is no cure for Duchenne MD. Duchenne patients do have several options to help them cope with their MD, however. One important treatment is exercise: it is important, especially for MD patients, that they keep their working muscles strong and flexible. Another possible treatment is physical therapy to maintain muscle fitness. Physical aids, such as braces or wheelchairs may also aid MD patients in their mobility.

http://www.nhs.uk/Conditions/Muscular-dystrophy/Pages/Introduction.aspx http://www.dmd.nl/dmd_all.html
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