What is Muscular Dystrophy?
Muscular dystrophy and other related muscle diseases are rare conditions referred to as “neuromuscular disorders”. Neuromuscular disorders are diseases that weaken the body’s muscles. The causes, symptoms, age of onset, severity and progression vary depending on the exact diagnosis and the individual.
What is Duchenne Muscular Dystrophy (DMD)?
Duchenne Muscular Dystrophy, or DMD, is a type of muscular dystrophy that causes muscles to weaken as a result of the absence of dystrophin, the protein that keeps muscles healthy and functioning properly. The weakening of the muscles gets worse over time and leads to difficulty in physical function, such as standing up, walking, and in later stages, breathing. Eventually, it can also bring about heart failure.
As these functions become more difficult, it becomes harder for the patient to perform daily activities, and that can lead to a loss of independence. Duchenne muscular dystropy mainly affects boys. However, girls can be affected also, but when they are they usually do not experience the full effects of the disease in the same way boys do.
Signs of the disease start at a young age and may be noticed when a child has difficulty standing up, climbing, or running. Duchenne affects about 1 of every 3,600 to 6,000 male births worldwide each year.
What are the sings and symptoms of DMD?
Although children with Duchenne appear healthy when they are born, reaching developmental milestones, such as sitting, walking, and talking, is delayed compared with children who do not have Duchenne. Typically between the ages of 2 and 5, children with Duchenne start to show more obvious signs and symptoms of the disease.
Signs and symptoms of Duchenne can include:
- Frequent falling
- Calf enlargement
- In some cases, learning and behavior problems, including poor attention and memory skills
- Delayed speech development
- Delayed motor development
- Unusual waddling gait
- That can include swaying while walking, walking with the feet far apart, and walking on the toes
- Difficulty keeping up with friends during play and physical activities
- Weakened reflexes
- Breathing difficulties
- Use of Gowers maneuver to get up from the floor or from a chair
- Because their hip and thigh muscles are weak, children with Duchenne may use a technique called Gowers maneuver when getting up from the floor. This maneuver allows them to stand up by using their hands and arms to “walk” up their lower limbs (shins, knees, and thighs) until they reach a standing position.
How does DMD change over time?
Duchenne causes muscle weakness, which worsens over time, resulting in increasing difficulty in performing everyday tasks and functions, such as walking, standing, and breathing–all of which can lead to an eventual loss of independence.
Although the progression and severity of symptoms of Duchenne differ for every child, there are several distinct phases of the disease. Those phases may be referred to by different names by doctors, publications, and websites.
As the symptoms progress over time, so do the care needs of someone living with Duchenne. Although there is no cure for Duchenne, disease management strategies exist that can help maintain muscle function and slow the progression of the disease. Those interventions may help improve a patient’s quality of life.
It is important to report any symptoms to your child’s doctor as soon as possible to help minimize delays in diagnosis and ensure that your child is receiving the necessary testing.
How DMD diagnosed?
Diagnosing Duchenne requires 3 steps
Step 1—Observing signs and symptoms
Those observations can be made by:
- A parent or other family member
- A child’s pediatrician or family doctor
- A school nurse or teacher
- A physical therapist or other specialist who provides care to children with the specific challenges associated with Duchenne muscular dystrophy
Observations may include:
- Difficulty running, jumping, climbing stairs compared with other children of similar age
- Gowers maneuver
- Speech delay, abnormal gait (way of walking), frequent falling, walking on tip-toes, enlarged calf muscles
Step 2—Blood tests to determine enzyme levels
If signs and symptoms of Duchenne are observed, a doctor may recommend blood tests. Blood tests show whether certain blood levels fall within a normal range. A doctor may check levels of the liver enzymes aspartate aminotransferase (AST) and alanine aminotransferase (ALT), high levels of which can result from muscular dystrophies. If liver enzyme levels are above the normal range of 10-40 units per liter (U/L) for AST and 7-56 U/L for ALT, the doctor may then test for high creatine kinase (CK) levels.
CK is an enzyme that is found in the heart, brain, skeletal muscle, and other tissues in the body. High levels of CK indicate muscle damage.
Range of CK levels
22-198 U/L : Normal range
3,000-3,500+ U/L : Duchenne muscular dystrophy
If a child has a high CK level, he or she should be taken, as soon as possible, to a neuromuscular specialist to confirm or rule out a diagnosis of Duchenne with the use of genetic testing.
Step 3—Genetic testing
Genetic testing is used to confirm the majority of Duchenne diagnoses and can be done with a simple blood test. Full gene sequencing can help identify the specific type of mutation that is causing a child’s Duchenne muscular dystrophy, and that can affect how the condition is managed.
Other tests that have been used to diagnose Duchenne include muscle biopsies and electromyography (EMG). An EMG is a test that checks the health of the muscles or nerves that control them. Muscle biopsy and EMG are becoming less common as a means to diagnose Duchenne. A muscle biopsy cannot determine the exact mutation that is causing Duchenne.
Talk to your doctor about genetic testing.
You can also turn to Decode Duchenne. It offers free testing and counselling for people with DMD or Becker muscular dystrophy.
Why is it important to receive a diagnosis of Duchenne as soon as possible?
Getting a confirmed diagnosis as soon as possible is important because:
- The earlier treatment and management strategies are started, the better the chance of preserving muscle strength and function for a longer period of time
- It encourages the urgency for genetic testing, the results of which
- can help determine the specific mutation that caused Duchenne, providing the opportunity to manage the disease with a more targeted approach
- can allow parents to make informed family-planning decisions
- Disease management strategies that are dependent on a child’s specific mutation type are in development.
- You can also turn to Decode Duchenne. It offers free testing and counselling for people with DMD or Becker muscular dystrophy.
What disease management strategies are available for Duchenne?
Corticosteroids (steroid medications)
Corticosteroids are the most commonly used treatment for Duchenne. While they do not address the underlying cause of the disease, they can help manage the symptoms of the disease by preserving muscle strength and movement, and by minimizing later complications, such as scoliosis (a curvature of the spine) and trouble breathing.
It is important to monitor children who take steroids over a long period of time because the drugs can cause serious side effects. Speak with your doctor for more information about these side effects.
Other ways to treat or ease the symptoms of Duchenne
- Leg braces and wheelchairs
- Surgeries that may help with tightness in the joints and scoliosis
- Devices that help with breathing
- Medicines for the heart
- Physical therapy
- Regular, moderate exercise
- Supplements, including vitamin D and calcium to help keep bones strong
- A diet high in fluid and fibre may help ease constipation that can be caused by weak muscles
- Get involved in the Duchenne community: Share your story
Important note: Please remember that the content of this site cannot replace the advice of a competent health professional. By all means, see a doctor.
We wish to acknowledge the good work that went into developing this extremely helpful information, and thank the people and organizations who made it available to the general public.