Duchenne Muscular Dystrophy

Duchenne Muscular Dystrophy
Duchenne muscular dystrophy is a fatal genetic disorder that causes progressive muscle weakness throughout your body. This disorder is caused my mutations in the dystrophin gene. The dystrophin gene is responsible for the production of a muscle protein. So the muscles suffer a loss of protein and contractile fibers. Then the muscles replaced with fat and connective tissue. DMD mostly affects young males exclusively due to an x-linked recessive inheritance pattern. The site Muscular Dystrophy (http://mda.org/) provides useful information on DMD.
DMD leads to many physical symptoms and complication. As early as the age of 3 the child will show general weakness. First the child will have problems keeping up with children their own age. Tasks such as climbing stairs, running or even walking may be very tiring to the child. In addition the child may seem clumsy and falls down often. The calf muscles become permanently damaged and cause the muscles to enlarge from the deposit of muscle fat. This is known as pseudohypertophy. The child will tend to walk on their forefeet (awkward gait) due to the enlarged calves. Between the ages 11 and 13 the young man will often develop skeletal deformities. The back muscles become weak, and the spine starts to curve. The spine is a column of small bones called vertebrae. There are five sections of the vertebral column. The body’s weight falls on the lumbar vertebrae. This excessive curvature bends toward the front causing the body to lean forward. This condition is known as Lordosis. In addition, lateral curvature of the spine called scoliosis. Depending on the severity scoliosis can be disfiguring and limit the function of the lungs and upper limbs. However, there is a major surgery to help straighten the spine.
As DMD progresses the muscle weakness spreads and joint and tendon restriction called contracture is another symptom of DMD. The Achilles tendon is contracted and pulls the feet into an abnormal position. This causes more problems walking. The young man will then wear ankle-straightening splints at night to keep their feet straight. As the muscle function of the feet and legs decrease blood flow slows causing discoloration and cold feet. The cardiovascular system will send the blood to the organs that need it most for example, the kidneys and brain. As DMD continues the skeletal muscles become useless. By the early teens the person is in a wheelchair. On the other hand mental impairments also affect patients with DMD. About one third of patients have some degree of mental impairments, but only a few have severe retardation. Considering all the physical symptoms and complications of DMD the disease isn’t usually painful. OTC pain relievers treat pain from muscle cramps.
Due to the deficiency of dystrophin the cardiac muscle tissue deteriorates. This muscle layer called myocardium. The Myocardium makes a large portion of the heart. As the myocardium deteriorates the person with DMD is at risk for fatal heart failure. In addition the respiratory muscle function starts to decline. Breathing and coughing will become difficult. Respiratory functions should be monitored by a physiotherapist. Also, the physiotherapist can help with breathing exercises and techniques to clear any secretions. The sight Duchenne’s muscular dystrophy (http://www.answers.com) contains facts about the symptoms and complications of DMD.
To diagnose DMD a doctor starts with physical examination and family history evaluation. If the doctor suspects DMD he will then order a creatine phoshokinase (CPK) test. The CPK test is a blood test that measures an enzyme found in the heart, brain, and skeletal muscles. If the enzymes are high it confirms muscle damage. The defective dystrophin gene is responsible for the disorder. DNA testing and analysis confirms the diagnosis in most cases. Unfortunately DNA can fail to find the mutation. If the DNA fails to find the mutation a muscle biopsy may be performed. Examination of the muscle tells a lot about what’s really happening inside the muscles. Since this disorder is hereditary there are also prenatal tests (amniocentesis, Chorion villus sampling) to find out if there is a risk for the unborn child could have the disorder.
There are medications to help control the symptoms and to maximize the quality of life. According to MDA, “Corticosteroids have been effective in slowing the progression of DMD.” Prednisone is a corticosteroid which, increases energy and strength and defer the severity of some symptoms. According to the American Academy of Neurology, benefits of this medication are, increased muscle strength, pulmonary function, and significantly slows down the progress of weakness. Unfortunately, there are side effects depending on the dosage. The most common is weight gain and puffy face. Other side effects include mood swings, asymptomatic cataracts, and decreased growth.
Inactivity can worsen the muscle disease. There are a variety of exercises that stretch the joints thru physiotherapy and occupational therapy. Physiotherapy is to help minimize contractures and deformities. Some experts recommend moderate swimming and water exercises to help build the skeletal muscles, and to help keep the cardiovascular system healthy. Occupational therapy can help with daily living tasks such as getting dressed. “When contractures have advanced, surgery may be performed to relieve them.” However, after the surgery the patient will have to wear leg braces. To maximize the quality of life braces and wheelchair can help improve mobility and help the person take care of themselves. In addition, respiratory support will be important as DMD progresses.
Genetic counseling is advised if there is a family history of DMD. The genetic counselor provides information and support to families with or at risk for many genetic disorders. In addition, physicians recommend all women of child bearing years should be pre-screened for health and risk potential before becoming pregnant. Many pregnancies aren’t planned so, prenatal testing like amniocentesis can be performed to identify gene mutation.
Currently there is no cure for DMD. Research is being performed to find a cure or a therapy to make it less severe. Future research is very complicated. Doctors know what gene it is that has mutated but it’s not that simple to replace it. Research has been done to use a disabled virus (the vector) to carry substitute gen to the muscles. Unfortunately, the body attacks it as if it were a virus. In addition, to use a substitute protein called utrophin for the dystrophin. Future research is aimed at prevention, stopping the progression, and repairing the damage of it. Other research is pharmacological, exon skipping, and stem cell research.
References

Answers.com, Duchenne’s muscular dystrophy page 1-6, Retrieved October 21, 2008 from The World Wide Web http://www.answers.com/topic/duchenne-muscular-dystrophy?print=true
MDA, Facts about Duchenne and Becker Muscular Dystrophies pages 1-9, Retrieved October 23, 2008 from The World Wide Web http://www.mda.org/publications/fa-dmdbmd-what.html

References: Answers.com, Duchenne’s muscular dystrophy page 1-6, Retrieved October 21, 2008 from The World Wide Web http://www.answers.com/topic/duchenne-muscular-dystrophy?print=true MDA, Facts about Duchenne and Becker Muscular Dystrophies pages 1-9, Retrieved October 23, 2008 from The World Wide Web http://www.mda.org/publications/fa-dmdbmd-what.html