by Kimberly Allen, RN
While there are over 30 different types of muscular dystrophy Duchenne muscular dystrophy is the most common as well as one of the most severe forms. Although Duchenne muscular dystrophy or DMD affects people of all races and cultures it is almost always diagnosed in boys. Every year approximately 1 in every 3,500 boys are born with DMD, that’s approximately 20,000 children that are diagnosed with DMD worldwide every year. Most boy’s with DMD are diagnosed when they are around 3 years old.
DMD is caused by a defective gene in the X chromosome. It is an autosomal recessive disorder, for this reason boys that are born to a mother that is a carrier of the mutated gene have a 50% chance of inheriting DMD. While on the other hand girls born to a mother that is a carrier has a 50% chance of becoming a carrier. Although most cases of DMD are inherited there are some cases where there is no family history of DMD, there is a spontaneous mutation of the gene responsible for DMD. The mutation that causes DMD occurs on the dystrophin gene also known as the DMD gene. The dystrophin gene is the largest gene on the X chromosome. It is responsible for producing a cytoskeletal protein called dystrophin found in muscle fibers.
Typically the symptoms of DMD manifest between infancy and 6 years of age. Usually the first symptom you may notice is that your child’s motor skills are delayed in their development. your child may not be able to sit or stand independently when others their age can. The average age that boys with DMD begin walking is 18 months. The weakening in their legs and pelvis is progressive causing a “waddling” gait as well as difficulty climbing stairs. While the muscle weakness in your child’s lower body is more severe and noticeable the muscles of the upper body including the arms and neck also weaken, just not as early or severely as those in the lower body. Because of the muscle weakness the rest of the body must work harder to make it move there is increased fatigue as well as frequent falls. As DMD progresses your child will demonstrate increasing difficulty with walking. Some children with DMD also develop skeletal deformities like scoliosis. Children with DMD also have a higher risk of learning disabilities like dyslexia as well as neurobehavioral problems like ADHD. Many children with DMD also experience non-progressive weakness in certain cognitive skills, especially short term memory due to the either lack of or malfunction of dystrophin in your child’s brain.
The standard treatment for DMD is focused on managing the symptoms and improving your child’s quality of life. Anti-congestive medications are used to aggressively treat cardiomyopathy while cortico steroids like prednisone are given to improve your child’s strength and function. In addition to these medications your child’s Dr will recommend physical therapy and stretching exercises to assist in maintaining muscle function and preventing contractures. While these treatments may prolong your child’s mobility most children with DMD are in a wheelchair by the time they are 10 years old.
While there is no cure for DMD it has been extensively studied for years. There have been studies that show “restoring the production of dystrophin will be highly functional and alleviate disease symptoms”. There have been new treatments involving adding normal genes to offset the mutated ones. However, there is a new approach being studied at Duke University. The researchers at Duke University have created a way to change the mutated gene causing DMD into a normally functioning gene. It is a process where instead of adding new genes in the traditional way the scientists add new genetic material that will “override” the mutated gene. According to the researchers at Duke university this approach actually repairs the mutated gene. This new approach is believed to be safer and more stable that the gene therapy methods currently being used. You can find this study online in Molecular Therapy and it was also published in the Journal of the American Society for Gene and Cell Therapy.
In the past children born with DMD were not expected to live past their teens. However, with research and advances in medical science and technology better treatments are showing great promise for significantly improving their prognosis.
Kimberly Allen is a registered nurse with an AND in nursing. She has worked in ACF, LCF and psychiatric facilities, although she spent most of her career as a home health expert. She is now a regular contributor to HealthAndFitnessTalk.com, dispensing advice and knowledge about medical issues and questions. You can reach her with any comments or questions at firstname.lastname@example.org.