- There is no dystrophin, protein that helps muscles to stay intact, present.
- The gene fails to make dystrophin that works properly.
- Since the disease is a genetic disorder, an X chromosome is mutated which leads to the disease.
- Boys are affected by the disease. Girls may carry the gene, but do not show symptoms.
- Around the age of five, boys are diagnosed, and by their teen years, they are put into wheelchairs. Boys are only really affected because girls have two X chromosomes, and the dystrophin gene that is not affected on the second chromosome compensates for the damaged one. Males have both an X and a Y chromosome, so they do not have a second X chromosome to compensate.
- muscle weakness in early age.
- affects hip, pelvic area, thighs, shoulders, arms, legs, and stomach muscles.
- enlarged calves, pseudohypertrophy or false enlargement
- heart and respiratory muscles are affected
- clumsiness, trouble climbing stairs, running, and walking
- difficulty walking on toes and raising arms
- muscle cramps
- curvature of spine
DMD was discovered by French Neurologist, Guillaume Benjamin Amand Duchenne in the 1860s. At this time, there was not much information on the disease until the 1980s. In 1986, researchers found that a gene on the X chromosome leads to DMD when mutated. The X-linked chromosome has a recessive inheritance pattern and is passed on by the mother. The genetic mutation happens in the mother's egg. It is possible that there is no earlier family history for DMD because it is a recessive gene and is often hidden by a dominant gene, so it does not show up as much.
Since the heart and respiratory muscles are affected by the lack of dystrophin, boys with the disease do not live very long. Boys used to not live much longer than their teen years, but because of advances in cardiac and respiratory care, their life expectancy increased. Today, many boys attend college, have careers, get married, and have kids. They live into their early 30's, but there are some cases where people live into their 40's and 50's.
- DMD can be diagnosed clinically for a boy that has progressive muscle weakness. A muscle biopsy, taking a sample of muscle, can happen to look for unusual levels of dystrophin present in the muscles. The muscle can be stained so doctors can see the amount of dystrophin protein in the muscle.
- There are ways to help those with DMD. There is no cure, but physical therapy and medications can help control symptoms and improve their quality of life. Their bronchial system must be kept clear of secretions. There are devices such as cough assist devices that can help them. Sleep masks can be worn for ventilation and receiving air while sleeping. They can wear back braces to help curved spines, and do exercises to keep their backs straight.
There are researchers doing more research and finding strategies to help genes be repaired and to get a better understanding on what causes DMD, so they can provide better treatment. Researchers are trying to find ways that can replace dystrophin, so it can protect muscles from injury and build up muscle repair and growth. Also, gene therapy and transfer is a topic of research today because with this, it can deliver genes and dystrophin as therapeutic agents for the patient.
DMD is the most common and severe form of muscular dystropathy. In the United States 1 out of every 3,500 boys have the disease. 20,000 people worldwide are diagnosed with the disease.
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- “Duchenne Muscular Dystrophy (DMD).” MDA, www.mda.org/disease/duchenne-muscular-dystrophy/research. Accessed 4 Feb. 2017.
- “Duchenne Muscular Dystrophy: The Basics.” Duchenne.com, www.duchenne.com/about-duchenne. Accessed 4 Feb. 2017.
- IANS. “Decoded: What ‘Silences’ the X Chromosome in Girls.” 12 Jan. 2016, indianexpress.com/article/lifestyle/health/decoded-what-silences-the-x-chromosome-in-girls/. Accessed 4 Feb. 2017.
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- Madsen, Amy. “Participants Sought for Clinical Trial to Test Vamorolone in DMD.” MDA, 8 Nov. 2016, strongly.mda.org/participants-sought-clinical-trial-test-vamorolone-dmd/. Accessed 4 Feb. 2017.