Causes
With current standards of care, many patients with DMD can now expect to live into their fourth decade of life. Duchenne muscular dystrophy (DMD) is an X-linked recessive and severely debilitating neuromuscular disease with an estimated incidence of about 1 in 3800–6300 live male births [ 1, 2 ].
Symptoms
What is the prognosis of muscular dystrophy (MD)? The prognosis varies according to the type of muscular dystrophy (MD) and the speed of progression. Some types are mild and progress very slowly, allowing normal life expectancy, while others are more severe and result in functional disability and loss of ambulation.
Prevention
There are nine different types of MD:
- Myotonic: Most common MD in both men and women.
- Duchene: Most common in children from 2-6 years of age (life expectancy of 20 years).
- Becker: Symptoms tend to appear more slowly between 2-16 years old, but it can appear at age 20 (males may live to adulthood).
- Limb-girdle: Occurs in men and women from teenagers to adults. ...
Complications
People with muscular dystrophy will often live shorter-than-average life spans. However, this can vary depending on the type and involvement of their muscular dystrophy. Duchenne muscular dystrophy is the most common type of muscular dystrophy. Life expectancy with this type is around the ages of 16 to the early 20s.
What is the life expectancy of muscular dystrophy?
What is the prognosis of muscular dystrophy?
What are some facts about muscular dystrophy?
What is life like with muscular dystrophy?
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What does muscular dystrophy cause?
Muscular dystrophy is a group of diseases that cause progressive weakness and loss of muscle mass. In muscular dystrophy, abnormal genes (mutations) interfere with the production of proteins needed to form healthy muscle.
How do you get Duchenne muscular dystrophy?
Duchenne muscular dystrophy is inherited in an X-linked recessive pattern. Males have only one copy of the X chromosome from their mother and one copy of the Y chromosome from their father. If their X chromosome has a DMD gene mutation, they will have Duchenne muscular dystrophy.
Who is most likely to get Duchenne muscular dystrophy?
Due to the localization of the dystrophin gene on the X chromosome, DMD predominantly affects male children, while females are likely to be asymptomatic “healthy carriers” [2].
What happens in Duchenne muscular dystrophy?
Duchenne MD happens because of a lack of dystrophin (dis-TRO-fin), a protein made by the muscle cells. In DMD, a variation or missing part of the dystrophin gene causes a loss of the dystrophin protein. This protein loss prevents the muscle fibers from working properly, leading to weakness.
Does muscular dystrophy come from the mother or father?
In most cases, muscular dystrophy (MD) runs in families. It usually develops after inheriting a faulty gene from one or both parents. MD is caused by mutations (alterations) in the genes responsible for healthy muscle structure and function.
Is Duchenne muscular dystrophy painful?
The muscle problems can cause cramps at times, but in general, DMD isn't painful. Your child will still have control of their bladder and bowels. Although some children with the disorder have learning and behavior problems, DMD doesn't affect your child's intelligence.
How long do DMD patients live?
The breathing or heart problems usually become more serious for older teenagers or people in their 20s. In the past, most people with DMD did not live beyond their early 20s. Improvements in treatment have meant that life expectancy has increased. At present, average life expectancy for people with DMD is 27 years.
When do the first symptoms of Duchenne muscular dystrophy appear?
It usually starts when a child is between ages 2 and 5. Symptoms of Duchenne muscular dystrophy include: Muscle weakness that begins in the hips, pelvis, and legs. Difficulty standing.
How does a child get muscular dystrophy?
What Causes Muscular Dystrophy? Muscular dystrophy is a genetic condition. Genetic conditions are passed from a parent (or parents) to their child. In muscular dystrophy, a gene change prevents the body from making the proteins needed to build and maintain healthy muscles.
Can Duchenne muscular dystrophy be prevented?
Because DMD is a genetic disorder, you can't do much to prevent it. But if DMD runs in your family, you may consider talking with a genetic counselor and getting testing before having children.
Can you develop muscular dystrophy at any age?
It can affect anyone from teenagers to adults in their 40s. Distal muscular dystrophy affects the muscles of the arms, legs, hands, and feet. It usually comes on later in life, between ages 40 and 60. Oculopharyngeal muscular dystrophy starts in a person's 40s or 50s.
Can Duchenne muscular dystrophy be prevented?
Because DMD is a genetic disorder, you can't do much to prevent it. But if DMD runs in your family, you may consider talking with a genetic counselor and getting testing before having children.
When does Duchenne muscular dystrophy occur?
DMD symptom onset is in early childhood, usually between ages 2 and 3. The disease primarily affects boys, but in rare cases it can affect girls.
When do the first symptoms of Duchenne muscular dystrophy appear?
It usually starts when a child is between ages 2 and 5. Symptoms of Duchenne muscular dystrophy include: Muscle weakness that begins in the hips, pelvis, and legs. Difficulty standing.
What is the gene that causes Duchenne?
Many of the genetic mutations that cause Duchenne occur in the region of the gene responsible for dystrophin (called the DMD gene) that controls the middle of the protein, with the repeating spectrin units. But instead of just affecting the middle of the dystrophin molecule, these mutations usually stop the protein from being built any further, resulting in a much shorter, dysfunctional protein.
Why does Duchenne have a dysfunctional protein?
But no matter the type of mutation, in Duchenne, it results in a dysfunctional protein — usually because it causes a premature stop codon, cutting the molecule short. “The end result is always the same,” says Nelson. “No dystrophin.”.
What are the two types of mutations that cause Duchenne?
Deletions and duplications are two kinds of mutations that can cause Duchenne, with long stretches of DNA called exons — which contain tens of thousands to millions of nucleotides — either left out or repeated when a cell divides. About 60 to 70 percent of mutations that cause Duchenne are deletions, according to Nelson.
What is the function of dystrophin in muscle cells?
In normal muscle cells, dystrophin transfers the force of muscle contractions from the inside toward the outside of the cell. “Dystrophin is the shock absorber that helps mitigate any damage in the muscle when muscle cells contract,” explains Barry Byrne, MD, PhD, the director of the Powell Gene Therapy Center at the University of Florida in Gainesville and the chief medical adviser of the Muscular Dystrophy Association. “Without it, muscles are damaged, there’s inflammation, and those muscles ultimately deteriorate.”
What is the role of dystrophin in muscle contractions?
Dystrophin acts as a shock absorber within the muscle cells, reducing any damage caused by muscle contractions. Shutterstock. Duchenne muscular dystrophy, a genetic disease characterized by progressive muscle weakness, is present at birth in people who have the condition. In people with Duchenne, the muscles lack a protein called dystrophin, ...
What is the middle of a dystrophin molecule?
The middle of the dystrophin molecule consists of a long series of repeated units , known as spectrin units. Research suggests that it’s not critically important for the entire length of spectrin units to be present for the dystrophin protein to be somewhat functional — instead, the molecule simply needs to be not a great deal shorter, and it needs to look normal at both ends.
Which protein allows it to reach the center of muscle cells?
Each end of the dystrophin molecule is tailored to interact with either the center or the edge of muscle cells, and it’s a long protein, which allows it to reach from the center to the edge of muscle cells.
What is the most common form of muscular dystrophy?
Duchenne muscular dystrophy ( DMD) is a genetic condition characterized by progressive weakening of voluntary muscles. DMD worsens more rapidly than other types of muscular dystrophy. It’s also the most common form of muscular dystrophy. The Centers for Disease Control and Prevention. Trusted Source. estimated that one out of every 5,600 ...
What tests can be done to check for muscular dystrophy?
You and your child’s pediatrician may notice that your child’s muscles are weakening and that your child has a lack of coordination. Blood tests and muscle biopsies can confirm a diagnosis of DMD.
How do you know if you have DMD?
The symptoms of DMD generally start to appear between ages 2 and 6. Many children with DMD develop normally during infancy and early childhood. DMD symptoms may include: 1 difficulty walking 2 a loss of ability to walk 3 enlarged calves 4 learning disabilities, which occurs in about one-third of affected individuals 5 a lack of motor skills development 6 fatigue 7 rapidly worsening weakness in the legs, pelvis, arms, and neck
Why can't you prevent DMD before conception?
You can’t prevent DMD before conception because it passes down from the mother. Geneticists are researching technology that may be able to prevent the defect from being passed on, but they haven’t discovered a successful cure.
How long can a person with DMD live?
However, with diligent care, some people with DMD survive into their 30s. In the later stages of the disease, most people with DMD will need full-time care to maintain quality of life. The condition is degenerative, which means that the need for medical care increases as the condition worsens.
What is a DMD?
DMD is a genetic disease. Those who inherit it have a defective gene related to a muscular protein called dystrophin. This protein keeps muscle cells intact. Its absence causes rapid muscular deterioration as a child with DMD grows.
What are the symptoms of DMD?
DMD symptoms may include: difficulty walking. a loss of ability to walk. enlarged calves. learning disabilities, which occurs in about one-third of affected individuals. a lack of motor skills development. fatigue. rapidly worsening weakness in the legs, pelvis, arms, and neck.
How is Duchenne muscular dystrophy diagnosed?
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.
What are the symptoms of Duchenne muscular dystrophy?
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.
What is the DMD gene?
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 3500 male births worldwide.
How to detect dystrophin in muscle?
A muscle biopsy (taking a sample of muscle) for dystrophin studies can be done to look for abnormal levels of dystrophin in the muscle. The dystrophin protein can be visualized by staining the muscle sample with a special dye that allows you to see the dystrophin protein. A muscle which has average amounts of dystrophin will appear with the staining technique as though there is caulking around the individual muscles cells and it is holding them together like window panes. A boy with Duchenne, on the other hand, will have an absence of dystrophin and appear to have an absence of the caulking around the muscle cells. Some individuals can be found to have an intermediate amount of the dystrophin protein. Often these boys are classified as having Becker muscular dystrophy.
What is the name of the mutation that causes muscular dystrophy?
About Duchenne Muscular Dystrophy. Duchenne muscular dystrophy (DMD) is a rapidly progressive form of muscular dystrophy caused by a mutation in the DMD gene.
What is the cause of DMD?
It is caused by an alteration (mutation) in a gene, called the DMD gene that can be inherited in families in an X-linked recessive fashion, but it often occurs in people from families without a known family history of the condition.
When do Duchenne muscular dystrophy symptoms appear?
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.
What is Duchenne muscular dystrophy?
Duchenne muscular dystrophy ( DMD) affects the muscles, leading to muscle wasting that gets worse over time. DMD occurs primarily in males, though in rare cases may affect females. The symptoms of DMD include progressive weakness and loss (atrophy) of both skeletal and heart muscle. Early signs may include delayed ability to sit, stand, ...
How is Duchenne muscular dystrophy diagnosed?
Duchenne muscular dystrophy (DMD) is diagnosed in young boys based on clinical examination, signs and symptoms, family history, and may be confirmed by the results of genetic testing. A muscle biopsy may be done to remove a small piece of muscle for examination under a microscope. Blood tests looking for increased levels of certain special proteins called muscle enzymes are used to check for muscle damage. [1] [7]
What causes muscle weakness in children?
Heart and breathing problems also begin in the teen years and lead to serious, life threatening complications. DMD is caused by genetic changes ( DNA variants) in the DMD gene.
Why do boys with DMD have breathing problems?
By the early teens, most boys with DMD are using a wheelchair. Breathing problems occur due to weakness of the diaphragm and the other muscles around the lungs. Scoliosis and tight joints ( contractures) may develop as muscle loss gets worse.
What is delayed motor development?
Delayed motor development (taking longer to learn to sit, stand, or walk)
Is DMD inherited?
DMD is inherited in an X-linked recessive pattern and may occur in people who do not have a family history of DMD. Diagnosis of DMD is based on the symptoms, clinical exam, and the result of a biopsy to remove a small piece of muscle for examination under a microscope.
Is Duchenne muscular dystrophy a recessive disorder?
Duchenne muscular dystrophy (DMD) is inherited in an X-linked recessive pattern. [1] . X-linked means that the gene for the condition is located on the X- chromosome, one of the sex chromosomes. In males (who have only one X chromosome ), one altered copy of the gene is enough to cause the condition.
How many babies are affected by Duchenne muscular dystrophy?
Duchenne muscular dystrophy mostly affects boys and occurs in one in 3,500 to 5,000 newborns. There is no higher risk for any ethnic group. Children affected by DMD may have some degree of cognitive problems, yet some have average or even higher-than-average intelligence.
What is the most severe muscular dystrophy?
Duchenne muscular dystrophy, or DMD, is associated with the most severe clinical symptoms of all the muscular dystrophies. It is caused by a genetic mutation on one of the mother’s X chromosomes, and researchers have identified some of the affected genes.
What causes muscles to weaken and atrophy?
Muscular dystrophy is a genetic problem that causes muscles to weaken and atrophy (become smaller and waste away).
What is multidisciplinary approach to DMD?
A multidisciplinary approach with a team of specialists with experience in treating DMD can offer your child the chance for longer survival and better quality of life.
What is the cause of DMD?
DMD is a genetic disease caused by a gene on the X chromosome that mothers can pass on to their sons. The gene affects a protein called dystrophin that muscles require to function normally.
How old is too old to have DMD?
DMD most commonly appears in children between 3 and 6 years old. Children may have difficulty walking or getting up from a seated position or from lying down. Parents or caretakers may notice weakness of the shoulder and pelvis, abnormal clumsiness and frequent falling. Other symptoms and signs include:
Can a muscle biopsy confirm DMD?
Muscle biopsy: For those children who have clinical evidence of DMD but who do not show one of the common mutations, a small sample of muscle tissue examined under a microscope can confirm the diagnosis.
What is the genetic disorder of muscle degeneration?
Duchenne muscular dystrophy (DMD) is a genetic disorder characterized by progressive muscle degeneration and weakness due to the alterations of a protein called dystrophin that helps keep muscle cells intact. DMD is one of four conditions known as dystrophinopathies.
When does Becker muscular dystrophy start?
Becker muscular dystrophy (BMD) is a similar to DMD, but with onset usually in the teens or early adulthood. The disease course for BMD is slower and less predictable compared to DMD.
What are the symptoms of DMD?
Muscle weakness is the principal symptom of DMD. It can begin as early as age 2 or 3, first affecting the proximal muscles (those close to the core of the body) and later affecting the distal limb muscles (those close to the extremities). Usually, the lower external muscles are affected before the upper external muscles. The affected child might have difficulty jumping, running, and walking. Other symptoms include enlargement of the calves, a waddling gait, and lumbar lordosis (an inward curve of the spine). Later on, the heart and respiratory muscles are affected as well. Progressive weakness and scoliosis result in impaired pulmonary function, which can eventually cause acute respiratory failure. For more about DMD symptoms, see Signs and Symptoms.
What are DMD “carriers”?
DMD carriers are females who have a normal dystrophin gene on one X chromosome and an abnormal dystrophin gene on the other X chromosome. Most carriers of DMD do not themselves have signs and symptoms of the disease, but a minority do. Symptoms can range from mild skeletal muscle weakness or cardiac involvement to severe weakness or cardiac effects and can begin in childhood or adulthood. For more, read Females and DMD in Causes/Inheritance.
What is the status of DMD research?
MDA-supported researchers are actively pursuing several exciting strategies in DMD, such as gene therapy , exon skipping , stop codon read-through and gene repair. Human clinical trials are underway for some of these strategies. For an overview of DMD research strategies and the latest research news, see Research.
What is the DMD of the arms?
What is Duchenne muscular dystrophy? In the early stages, DMD affects the shoulder and upper arm muscles and the muscles of the hips and thighs. These weaknesses lead to difficulty in rising from the floor, climbing stairs, maintaining balance and raising the arms. Duchenne muscular dystrophy ...
When was DMD first discovered?
DMD was first described by the French neurologist Guillaume Benjamin Amand Duchenne in the 1860s, but until the 1980s, little was known about the cause of any kind of muscular dystrophy. In 1986, MDA-supported researchers identified a particular gene on the X chromosome that, when flawed (mutated), leads to DMD.
What are the symptoms of Duchenne muscular dystrophy?
Although girls can be carriers and mildly affected, it's much more common in boys. Signs and symptoms, which typically appear in early childhood, might include: Frequent falls. Difficulty rising from a lying or sitting position.
Why is muscular dystrophy caused?
Muscular dystrophy occurs when one of these genes is defective. Each form of muscular dystrophy is caused by a genetic mutation particular to that type of the disease. Most of these mutations are inherited.
What causes the efficiency of the heart muscle to decrease?
Heart problems. Muscular dystrophy can reduce the efficiency of the heart muscle.
What muscles are affected first with muscular dystrophy?
Limb-girdle. Hip and shoulder muscles are usually affected first. People with this type of muscular dystrophy might have difficulty lifting the front part of the foot and so might trip frequently. Onset usually begins in childhood or the teenage years.
What are some examples of muscular dystrophy?
Some types of muscular dystrophy are defined by a specific feature or by where in the body symptoms begin. Examples include: Myotonic. This is characterized by an inability to relax muscles following contractions. Facial and neck muscles are usually the first to be affected.
When does Becker muscular dystrophy start?
Becker muscular dystrophy. Signs and symptoms are similar to those of Duchenne muscular dystrophy, but tend to be milder and progress more slowly. Symptoms generally begin in the teens but might not occur until the mid-20s or later.
Is muscular dystrophy a risk factor?
Muscular dystrophy occurs in both sexes and in all ages and races. However, the most common variety, Duchenne, usually occurs in young boys. People with a family history of muscular dystrophy are at higher risk of developing the disease or passing it on to their children.
