Duchenne Muscular Dystrophy (DMD)


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Source: https://www.cdc.gov/ncbddd/musculardystrophy/facts.html

OpenStax Anatomy and Physiology

Duchenne muscular dystrophy (DMD) is a disorder of the muscular system which involves the progressive weakening of the skeletal muscles. The deficiency of the dystrophin protein causes DMD. Dystrophin helps bind the thin filaments of myofibril to the sarcolemma, but with the lack of dystrophin, sarcolemma may tear during muscle contractions which results in the influx of calcium ions causing muscle cell damage and degradation of muscle fibers. After a period of time, the accumulation of muscle damage results in the lost of muscular mass and the development of functional impairments.

– What causes the disease Duchenne muscular dystrophy?

DMD can be inherited because it originates from an abnormal X chromosome. Males have higher risk and usually discovered in early childhood. The first sign of DMD is usually difficulty with balance and motion. Later, the person is unable to walk. It affects the lower part of the body first and moves upward towards the superior part of the body. When DMD affects the diaphragm, the organ responsible for breathing, respiratory failure occurs and ultimately causes death. DMD patients do not usually live over 20 years old.

– What is the first sign of Duchenne muscular dystrophy?

Mutation in the gene that codes for dystrophin causes DMD. Researchers have thought that introducing normal myoblast (embryonic precursor of muscle cell) into DMD patient might be the cure. Myoblast should carry normal genes that produce the dystrophin required for muscle contraction. Unfortunately, the idea has been unsuccessful. Another approach involved trying to increase the production of utrophin which is similar to dystrophin. Utrophin may be able to take the role of dystrophin and help prevent the muscle cells from damaging.

– What is the embryonic precursor of muscle cell?

Betts, J. G., Young, K. A., Wise, J. A., Johnson, E., Poe, B., Kruse, D. H., … DeSaix, P. (n.d.). Anatomy and Physiology. Houston, Texas: OpenStax. Access for free at: https://openstax.org/details/books/anatomy-and-physiology