Alec Titan
Duchenne Muscular Dystrophy (DMD) is a rare muscle disorder characterised by progressive muscle degeneration and weakness. It is one of the most severe forms of inherited muscular dystrophies and is the most common hereditary neuromuscular disease. DMD is caused by a mutation of the dystrophin gene, which is located on the X chromosome and inherited from the mother. This gene is responsible for creating a protein called dystrophin, which is essential for maintaining muscle fibre integrity. Without this protein, muscle cells die and are replaced by connective and adipose tissue, causing muscle weakness and atrophy. DMD is a progressive disease, with symptoms usually appearing in early childhood, and predominantly affects boys. While there is currently no cure, advances in cardiac and respiratory care have increased life expectancy, with survival into the early 30s becoming more common.
| Characteristics | Values |
|---|---|
| Type | Muscular dystrophy |
| Severity | One of the most severe forms of inherited muscular dystrophies |
| Common name | Duchenne muscular dystrophy (DMD) |
| Cause | Mutations in the dystrophin gene |
| Gene location | X chromosome |
| Gene locus | Xp21 |
| Protein affected | Dystrophin |
| Function of protein | Provides structural integrity to muscle cells |
| Prevalence | 1 in 3,500-3,600 male births worldwide |
| Median life expectancy | 27-31 years |
| Survival into early 30s | Becoming more common |
| Treatment | Palliative care, glucocorticoids, corticosteroids, physiotherapy |
| Progression | Voluntary muscles affected first, especially hips, pelvic area, thighs, calves, then shoulders, neck, arms, respiratory muscles |
| Symptoms | Muscle weakness, fatigue, difficulty in walking, running, climbing stairs, frequent falls, waddling gait, toe walking, cognitive impairment, learning disorders, scoliosis, short stature, irregular heartbeat, enlarged heart muscle tissue, enlarged calves, lumbar hyperlordosis, spinal curvature, breathing difficulties, shortness of breath |
| Onset | Early childhood, usually between ages 2-6 |
| Sex | Predominantly affects boys, but can rarely affect girls |
Explore related products
What You'll Learn
Symptoms
Duchenne muscular dystrophy (DMD) is a severe and progressive muscle-wasting condition that causes skeletal and heart muscle weakness that quickly worsens over time. It is the most common type of muscular dystrophy and is the most common hereditary neuromuscular disease. DMD is a genetic disease caused by a mutation of the dystrophin gene, located on the short arm of the X chromosome, which codes for dystrophin protein. Dystrophin is a protein that muscles require to function normally, and its absence leads to muscle cell death. The disease is characterised by weakness and atrophy of the muscles, initially in the pelvic area, thighs, pelvis, and calves, and then extending to the arms, shoulders, neck, and eventually the heart and gut muscles.
Other symptoms of DMD include scoliosis, or curvature of the spine, which can cause further breathing difficulties, and lumbar hyperlordosis, an inward curve of the spine thought to be a compensatory mechanism for muscle weakness. Some individuals may also experience cognitive and learning difficulties, such as delayed speech and language development, as well as behavioural disorders such as ADHD.
DMD is a fatal disease, with most people dying in their twenties or thirties due to respiratory muscle weakness or cardiomyopathy. However, with advances in cardiac and respiratory care, survival into the thirties and beyond is becoming more common. While there is currently no cure or treatment to halt the progression of the disease, palliative care and comprehensive management can improve quality of life and prolong survival.
Palpating Neck Muscles: A Step-by-Step Guide for Beginners
You may want to see also
Explore related products
Causes
Duchenne muscular dystrophy (DMD) is a genetic disorder characterised by progressive muscle degeneration and weakness. It is one of the most severe forms of inherited muscular dystrophies and is the most common hereditary neuromuscular disease. It does not exhibit a predilection for any race or ethnic group.
DMD is caused by a mutation in a gene on the X chromosome that makes a protein called dystrophin. This protein helps keep muscle cells intact and is required for normal muscle function. The mutated gene fails to produce functional dystrophin, which leads to progressive muscle fibre degeneration and weakness. This weakness may initially present with difficulty in walking, but it progressively advances to the extent that affected patients are unable to carry out daily activities and must use wheelchairs.
The majority of mutations in the dystrophin gene are deletions of one or more parts of it. DMD occurs more commonly in males, as they only have one copy of the gene on the X chromosome, so they will be affected if one of those genes is mutated. Females have two copies of the X chromosome, so they are less likely to develop an X-linked condition because the healthy copy of the chromosome can usually compensate for the mutated version. However, in rare instances, a girl may lack a second X chromosome or have sustained serious damage to it, resulting in little or no dystrophin production and the development of a dystrophinopathy.
Symptoms of DMD include enlargement of the calves, a waddling gait, lumbar lordosis (an inward curve of the spine), and progressive weakness and scoliosis, which result in impaired pulmonary function and can eventually cause acute respiratory failure. Cardiac and orthopedic complications are also common, and death usually occurs in the twenties due to respiratory muscle weakness or cardiomyopathy. The disease course is typically slower and less predictable in females, with a later onset in the teens or early adulthood.
Loosening Your Booty Muscles: Tips and Tricks for Flexibility
You may want to see also
Explore related products
Diagnosis
Duchenne muscular dystrophy (DMD) is a rare muscle disorder characterised by progressive muscle degeneration and weakness. It is one of the most severe and frequent genetic conditions, affecting approximately 1 in 3,500 to 5,000 male births worldwide.
DMD is caused by a genetic problem in producing dystrophin, a protein that protects muscle fibres from breaking down. The disease is progressive, and most individuals require a wheelchair by their teenage years.
DMD is usually recognised between three and six years of age. Symptoms include muscle weakness and wasting (atrophy) of the muscles of the pelvic area, followed by the involvement of the shoulder muscles. As the disease progresses, muscle weakness and atrophy spread to the trunk and forearms and gradually progress to involve additional muscles of the body. Other symptoms include enlargement of the calves, a waddling gait, and lumbar lordosis (an inward curve of the spine).
DMD can be diagnosed through the following tests:
- Blood tests: Genetic blood tests can reveal the gene mutation causing the absence of dystrophin in about two-thirds of boys with DMD.
- Muscle biopsy: For children who have clinical evidence of DMD but do not show one of the common mutations, a small sample of muscle tissue examined under a microscope can confirm the diagnosis.
- Electromyogram (EMG): This test checks if the muscle weakness is due to the destruction of muscle tissue rather than nerve damage.
- Electrocardiogram (ECG or EKG): This test records the electrical activity of the heart and can detect abnormal rhythms and heart muscle damage.
In addition, prenatal testing may be able to diagnose DMD in early pregnancy. However, it is important to consult with a healthcare professional for medical advice and treatment.
Understanding Muscle Fatigue: Causes and Mechanisms
You may want to see also
Explore related products
Treatment
Duchenne muscular dystrophy (DMD) is a genetic disorder characterised by progressive muscle degeneration and weakness due to the lack of a protein called dystrophin. This protein helps keep muscle cells intact. DMD is the most common and one of the most severe types of muscular dystrophy. It usually affects boys and those assigned male at birth. Currently, there is no cure or treatment to halt the progression of the disease. Treatment options are palliative and focus on improving the patient's quality of life.
Medication
Glucocorticoids can be used to treat DMD. In 2017, the FDA approved deflazacort (Emflaza) to treat DMD. Other FDA-approved drugs include Vyondys 53 and Viltepso, which are "exon skipping" drugs that target a section of DNA called exon 53. These drugs may help up to 8% of individuals with DMD. Additionally, medication can be prescribed to strengthen weak bones, which is a common issue in children with DMD who use wheelchairs.
Surgery
Surgery may be used to correct scoliosis, a condition that can be caused by DMD.
Heart Function
Many people with DMD develop dilated cardiomyopathy, which affects the heart muscles. Regular electrocardiograms (ECGs) and echocardiograms are used to monitor heart function. Cardiologists may prescribe medication or insert an ICD (implantable cardioverter defibrillator) to help with heart function.
Breathing Support
DMD can cause breathing problems, and patients may require breathing support machines at night and sometimes during the day. Serial monitoring of breathing capacity should start at the age of 5 or 6.
Physiotherapy
Physiotherapy can help prevent orthopedic complications. Additionally, exercises and techniques can be prescribed to help with learning problems, which are common in children with DMD.
Interprofessional Team
The management of patients with DMD is best done with an interprofessional team that includes specialty-trained nurses, therapists, primary care providers, physiatrists, neurologists, orthopedists, thoracic surgeons, and pharmacists.
Muscle Memory: Fact or Fiction?
You may want to see also
Explore related products
Life expectancy
Duchenne muscular dystrophy (DMD) is a rare, progressive disease that affects all voluntary muscles and involves the heart and breathing muscles in later stages. It is caused by a genetic change that affects the muscles, specifically a mutation in the dystrophin gene, which leads to progressive muscle fibre degeneration and weakness. This condition mainly affects boys, causing skeletal and heart muscle weakness that worsens over time.
In the past, most people with DMD did not survive beyond their teens or early twenties. However, advancements in cardiac and respiratory care have led to a significant increase in life expectancy. The current average life expectancy for people with DMD is approximately 25 to 30 years, with individual variations depending on the severity of the condition. With excellent medical care, some affected individuals can live into their thirties, and in rare cases, even into their forties or early fifties with proper positioning in wheelchairs, ventilator support, and heart medications.
The most common direct cause of death for people with DMD is respiratory failure, with respiratory complications such as severe chest infections being the usual cause of death. Cardiac-related conditions, such as heart failure due to dilated cardiomyopathy, are also a leading cause of death. Other serious complications that can impact life expectancy include acute respiratory failure, scoliosis, and progressive weakness.
There is currently no cure for DMD, and treatment options are palliative, focusing on managing symptoms and improving quality of life. Medications such as glucocorticoids, calcium channel blockers, and anticonvulsants are used to slow skeletal and cardiac muscle degeneration and control seizures. Physical therapy is also recommended to maintain muscle strength, flexibility, and function.
Research efforts are ongoing to find medications that can address the root cause of DMD by returning the ability to produce dystrophin or utrophin and blocking the entry of calcium ions into muscle cells. Gene therapy and exon skipping techniques show promise, and several drugs are currently available or undergoing clinical trials.
Treating Muscle Hypertrophy: Effective Strategies for Optimal Results
You may want to see also
