What are the other Names for this Condition? (Also known as/Synonyms)

• DMD (Duchenne Muscular Dystrophy)

What is Duchenne Muscular Dystrophy? (Definition/Background Information)

• Duchenne Muscular Dystrophy (DMD) is the most common form of muscular dystrophy. It is an inherited disorder that leads to progressive muscle weakness and muscle tissue loss
• The disorder is caused by a defect in the gene responsible for the production of dystrophin, a protein important to the structure of muscles. Individuals with Duchenne Muscular Dystrophy either lack dystrophin or have insufficient levels of the protein, which results in the loss of muscle tissue and function
• Duchenne Muscular Dystrophy is an X-linked recessive disorder, meaning that the gene causing the condition is located on the X-chromosome. The condition is found predominantly in young boys, who inherit only one X-chromosome. Females can have a defective dystrophin gene, but they rarely suffer from symptoms of Duchenne Muscular Dystrophy
• In human genetics, males receive one X-chromosome and one Y-chromosome.  Females receive two X-chromosomes. Because Duchenne Muscular Dystrophy is an X-linked recessive disorder, and males receive their only X-chromosome from their mothers, sons born with a defective gene on their X-chromosome will acquire Duchenne Muscular Dystrophy
• Girls, however, have a second X-chromosome that can compensate for an X-chromosome with the mutated gene. Females, thus, can be “carriers” of DMD, but usually do not experience symptoms of the condition
• Duchenne Muscular Dystrophy signs and symptoms usually arise before the age of 6, and for some, the ability to walk is lost by age 12.  Most DMD individuals die between ages 20 and 30
• There is no cure for the condition, though symptomatic treatment is provided, which may include the use of corticosteroids, physiotherapy, and surgical procedures if necessary. Most individuals would require assistive devices to maintain their mobility

Who gets Duchenne Muscular Dystrophy? (Age and Sex Distribution)

• Duchenne Muscular Dystrophy is primarily found in male children, who usually experience symptoms before the age of 6 years
• Worldwide, DMD affects approximately 1 out of every 3600 male babies
• All races and ethnic groups can be affected

What are the Risk Factors for Duchenne Muscular Dystrophy? (Predisposing Factors)

• Duchenne Muscular Dystrophy is an inherited disorder, and hence, having a history of the condition in the family is the most important risk factor

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases ones chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Duchenne Muscular Dystrophy? (Etiology)

• Duchenne Muscular Dystrophy is caused due to a mutation in a gene responsible for production of a protein in the muscle called dystrophin. Dystrophin has been shown to play a role in supporting the cell membrane of muscle cells. It also helps in lowering the damage that can arise from the stress of moving muscles
• In individuals with Duchenne Muscular Dystrophy, dystrophin is not produced or is found at very low levels
• Boys inherit the condition from their mothers (who are carriers). However, often times, Duchenne Muscular Dystrophy is known to occur in individuals with no family history of the disorder
• About two-thirds of Duchenne Muscular Dystrophy patients inherit the condition from their carrier mothers. However, there are cases (the remaining one-third of cases) that involve individuals with no known family history of the muscular dystrophy. This is due to a novel genetic mutation in the dystrophin gene

What are the Signs and Symptoms of Duchenne Muscular Dystrophy?

Symptoms of Duchenne Muscular Dystrophy typically appear before the age of 6 years, but can arise as early as infancy. DMD first affects the pelvic area, upper legs, and arms. By the time the children reach age 10, they may require the use of braces for mobility; by age 12, most individuals are confined to a wheelchair. By their 20s or early 30s, most DMD patients die due to complications.

The signs and symptoms of Duchenne Muscular Dystrophy include:

• Muscle weakness in legs and pelvic area, as well as in arms, neck, and other body areas
• Delayed walking and frequent falls
• Pseudohypertrophy, which is characterized by enlarged calf muscles that fill with fat and connective tissue
• Difficulty with motor skills, such as jumping and hopping
• Progressive difficulty with walking
• Muscle mass loss, also called wasting
• Mental retardation, mild in some cases

How is Duchenne Muscular Dystrophy Diagnosed?

The following tools are used in the diagnosis of Duchenne Muscular Dystrophy:

• When diagnosing Duchenne Muscular Dystrophy, a physician first takes into account the child’s family history and a physical examination. The family history and physical exam alone can indicate the condition. However, there are other diagnostic tests that are typically performed as Duchenne Muscular Dystrophy shares some symptoms with other disorders
• One special blood test performed in diagnosing Duchenne Muscular Dystrophy is called the creatine kinase test, which measures the level of creatine kinase in blood. Creatine kinase is an enzyme released into the blood by muscles that have been damaged in some way.  High creatine kinase levels in blood suggest muscle is being destroyed and helps healthcare providers narrow the condition down to some type of muscle condition
• If a child is found to have high creatine kinase levels, genetic testing is typically used next to diagnose Duchenne Muscular Dystrophy. Blood samples of a child can be taken to determine if there are mutations, or abnormalities, in the dystrophin gene. One type of genetic test can identify whether regions of the dystrophin gene has been deleted or duplicated. If this is the case, the individual is diagnosed with Duchenne Muscular Dystrophy. Approximately two-thirds of those with DMD are diagnosed by detecting deletions or duplications in their dystrophin gene
• When genetic testing leads to a negative result, a muscle biopsy is generally used to determine the presence or absence of Duchenne Muscular Dystrophy in a child. A muscle biopsy allows healthcare professionals to study the level of dystrophin protein in the muscle. Surgically removing a muscle sample from an individual and staining it with a specific dye will allow the dystrophin protein to be visualized. Individuals with Duchenne Muscular Dystrophy will have low levels of dystrophin upon completion of a muscle biopsy

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Duchenne Muscular Dystrophy?

Common complications of Duchenne Muscular Dystrophy include:

• Cardiomyopathy - weakening and enlargement of the heart muscle
• Scoliosis - curvature in the spine due to weak back muscles, which can lead to complications with breathing, sitting, and sleeping
• Muscle contractures - occur when joints become fixated due to the shortening of the muscle fibers, leading to reduced flexibility
• Pneumonia or respiratory infections
• Respiratory weakness and cardiomyopathy are usually the most common reasons for premature death in DMD patients

How is Duchenne Muscular Dystrophy Treated?

There is no cure for Duchenne Muscular Dystrophy currently. However, there are treatment options that focus on controlling symptoms to help prolong the life of the affected individuals.

• The inflammatory corticosteroid, prednisone, has been shown to enhance muscle strength and slow Duchenne Muscular Dystrophy progression. There are side effects associated with prednisone, however, including:
  • Weight gain
  • High blood pressure
  • Delayed growth
  • Loss of bone density
• It is also suggested for individuals with Duchenne Muscular Dystrophy to stay active. Physical therapy is a treatment method, which aids DMD patients in maintaining flexibility by exercising muscles and joints. This can help delay the development of contractures. Also with the help of a physical therapist, individuals with scoliosis can learn appropriate sitting and sleeping positions, as well as ways to keep their backs as straight as possible
• For individuals experiencing severe scoliosis, surgery is another treatment option. A type of surgery called spinal fusion can help in reducing the pain associated with scoliosis and the severity of the curvature in the spine. Surgery can likewise help with sitting and making sure the spinal curvature does not impact the child’s breathing
• Braces are often used to keep muscles flexible and stretched, which can help in delaying the development of contractures. Other assistive devices, including wheelchairs and walkers, maintain mobility as well as provide an ability to care for oneself

How can Duchenne Muscular Dystrophy be Prevented?

• Currently, there are no specific methods or guidelines to prevent Duchenne Muscular Dystrophy, since it is a genetic condition
• Genetic testing of the expecting parents (and related family members) and prenatal diagnosis (molecular testing of the fetus during pregnancy) may help in understanding the risks better during pregnancy
• If there is a family history of the condition, then genetic counseling will help assess risks, before planning for a child
• Active research is currently being performed to explore the possibilities for treatment and prevention of inherited and acquired genetic disorders, such as Duchenne Muscular Dystrophy

What is the Prognosis of Duchenne Muscular Dystrophy? (Outcomes/Resolutions)

• DMD leads to progressively weakened muscles and the inability to walk by the age of 12, which leaves many Duchenne Muscular Dystrophy children wheelchair-bound
• The majority of individuals with Duchenne Muscular Dystrophy die in their 20s or 30s, usually due to complications, such as breathing or cardiac abnormalities
• Although currently there is no cure for Duchenne Muscular Dystrophy, physicians are working towards slowing muscle deterioration while maintaining muscle function in order to give DMD patients as many active years as possible

Additional and Relevant Useful Information for Duchenne Muscular Dystrophy:

• Becker’s muscular dystrophy (BMD) is a form of muscular dystrophy - a group of inherited disorders that ultimately lead to progressively weakened muscles and loss of function

The following article link will help you understand Becker’s muscular dystrophy:

http://www.dovemed.com/diseases-conditions/beckers-muscular-dystrophy/