The DMD gene is the second largest gene to date, which encodes the muscle protein, dystrophin. Boys with Duchenne muscular dystrophy do not make the dystrophin protein in their muscles. Duchenne muscular dystrophy affects approximately 1 in male births worldwide. Because this is an inherited disorder, risks include a family history of Duchenne muscular dystrophy.
The symptoms usually appear before age 6 and may appear as early as infancy. Typically, the first noticeable symptom is delay of motor milestones, including sitting and standing independently. The mean age for walking in boys with Duchenne muscular dystrophy is 18 months. There is progressive muscle weakness of the legs and pelvic muscles, which is associated with a loss of muscle mass wasting. This muscle weakness causes a waddling gait and difficulty climbing stairs.
Muscle weakness also occurs in the arms, neck, and other areas, but not as severely or as early as in the lower half of the body. Calf muscles initially enlarge and the enlarged muscle tissue is eventually replaced with fat and connective tissue pseudohypertrophy.
Muscle contractures occur in the legs, making the muscles unusable because the muscle fibers shorten and fibrosis occurs in connective tissue. Occasionally, there can be pain in the calves. Symptoms usually appear in boys aged 1 to 6.
There is a steady decline in muscle strength between the ages of 6 and 11 years. By age 10, braces may be required for walking, and by age 12, most boys are confined to a wheelchair. Bones develop abnormally, causing skeletal deformities of the spine and other areas. Muscular weakness and skeletal deformities frequently contribute to breathing disorders. Cardiomyopathy enlarged heart occurs in almost all cases, beginning in the early teens in some, and in all after the age of 18 years.
Intellectual impairment may occur, but it is not inevitable and does not worsen as the disorder progresses. Few individuals with DMD live beyond their 30s. Breathing complications and cardiomyopathy are common causes of death. Duchenne muscular dystrophy is diagnosed in several ways. A clinical diagnosis may be made when a boy has progressive symmetrical muscle weakness. The symptoms present before age 5 years, and they often have extremely elevated creatine kinase blood levels which are described below.
If untreated, the affected boys become wheelchair dependent before age 13 years. A muscle biopsy taking a sample of muscle for dystrophin studies can be done to look for abnormal levels of dystrophin in the muscle. Over time, children with Duchenne will develop problems walking and breathing, and eventually the muscles that help them breathe and the heart will stop working. Duchenne is an irreversible, progressive disease. There is currently no cure for Duchenne. The first signs and symptoms of Duchenne are often noticed around the age of 2 or 3.
Children with Duchenne may be slower to sit, stand or walk. Most are unable to run and jump properly due to weakness in the core muscles of the body. Children with Duchenne are more likely to have conditions affecting the brain, such as mental health, learning, or seizure disorders. The key protein for muscle function that is missing in Duchenne, dystrophin, is also believed to have a role in brain development.
To learn more about important considerations for parents, visit Parent Project Muscular Dystrophy's Care for Duchenne resource.
BMD is another type of muscular dystrophy with symptoms like Duchenne, but it is a milder form. BMD is also caused by a change to the gene for dystrophin, but people with BMD make an abnormal but working version of dystrophin. This still results in muscle weakness and damage, but it is less severe and worsens more slowly than in Duchenne.
Our goal is to make Duchenne. By completing a 10 minute survey, you can help us learn what topics interest you most. Treatment advances let kids with Duchenne MD live longer, more active lives than would have been possible 10 or 20 years ago. Reviewed by: Mena T. Scavina, DO. Neurology at Nemours Children's Health. Larger text size Large text size Regular text size. What Is Duchenne Muscular Dystrophy?
Children with Duchenne MD may: run slowly have trouble going up steps fall often toe walk walking on the toes or balls of the feet. Children with Duchenne MD also may have learning difficulties. What Causes Duchenne Muscular Dystrophy? Who Gets Duchenne Muscular Dystrophy? These tests confirm the diagnosis and determine the type of muscular dystrophy: Creatine kinase CK level: This blood test checks the level of creatine kinase, a protein that normally stays inside muscle cells.
Muscle biopsy: Doctors take a biopsy by removing a small piece of muscle, usually from the thigh. This test can show whether the muscular dystrophy is the Duchenne type or the milder Becker type. Genetic testing : This identifies the mistake in the dystrophin gene. This helps the medical team decide how to treat the problem and know what to expect in the future. If the genetic testing, CK level, and physical exam point to a diagnosis of DMD, a muscle biopsy may not be done.
There's no cure yet for Duchenne MD.
0コメント