Duchenne Muscular Dystrophy – St. Jude Children’s Research Hospital


Duchenne muscular dystrophy, also called DMD, is a genetic disease. This means that it is transmitted from parents to children. DMD causes muscle breakdown and weakness over time.

Children with DMD may have cognitive problems as well as physical symptoms of the disease. DMD mainly affects boys. It occurs in about 1 in 3,500 to 5,000 babies of all ethnic groups.

There is no cure for DMD. However, your child’s healthcare team works together to manage symptoms and maintain function.

Cause of Duchenne Muscular Dystrophy

Duchenne muscular dystrophy is caused by a genetic change. This gene is located on the X chromosome. A chromosome is the part of a cell that contains genetic information.

The genetic change in DMD affects the production of dystrophin. Dystrophin is a protein made by muscle cells. When the gene is changed or deleted, the muscles do not produce enough dystrophin. Without this protein, muscle fibers do not function as they should. This leads to muscle damage and weakness.

Girls have 2 X chromosomes, one from their mother and one from their father. Because they have 2, they can usually make enough dystrophin with the healthy X chromosome gene. But boys have an X chromosome from their mother and a Y chromosome from their father. If the dystrophin gene on their X chromosome is affected, they cannot create more dystrophin.

Girls with this genetic change may exhibit certain symptoms, such as weakness, heart problems and muscle cramps. These girls are also carriers of the disease. They can pass it on to their children.

Symptoms of Duchenne Muscular Dystrophy

Symptoms often begin in children between 3 and 6 years old. Symptoms often begin in the hips and thighs. Then they spread to the arms and the rest of the body.

You may notice that your child has trouble walking or getting up after lying down or sitting down. They can be clumsy for walking, climbing stairs, and doing other activities. Children with DMD may:

  • fall frequently
  • Walking on the soles of the feet, called toe walking
  • Run slowly
  • Use their hands to get up from a sitting or lying position. This movement is called Gower’s sign.
  • Have big calves
  • Have learning problems

As DMD progresses, your child may have:

  • Heart problems or irregular heartbeat
  • Fatigue and weakness
  • Scoliosis, a curvature of the spine
  • Easily broken bones
  • Need assistive devices or a wheelchair
  • Stiff joints and difficulty moving

Diagnosis of Duchenne muscular dystrophy

Your healthcare team diagnoses DMD by taking a detailed medical history, discussing symptoms, and performing a physical exam. They can refer you to a neurologist. A neurologist is a doctor who has undergone special training to treat muscle and nerve diseases.

Your healthcare team may also use one or more of these tests to help with the diagnosis:

  • Genetic test can show if the dystrophin gene is affected.
  • Muscle biopsy is a small piece of muscle tissue that is usually taken from the thigh. A doctor called a pathologist examines cells under a microscope. This can tell if your child has DMD or another type of muscular dystrophy.
  • Blood tests measure levels of enzymes and proteins in the blood.

Treatment of Duchenne muscular dystrophy

There is no cure for DMD, but your healthcare team will help your child manage the condition and retain as much function as possible. Your child’s healthcare team may include:

  • Neurologist
  • Cardiologist for heart disease
  • Pulmonologist for lung conditions
  • Physiotherapists and occupational therapists to create exercise and stretching programs. They can also make plans to best accomplish day-to-day tasks.
  • Orthopedic surgeon to help treat broken bones and spinal curve

These treatments may be part of your child’s health care plan:

  • Medications such as steroids can improve function and slow muscle loss. Your healthcare team may also prescribe medicine to treat heart problems. Scientists are looking for new drugs for DMD that target the problems in the gene. Talk to your healthcare team about new treatments and ask if they might be an option for your child.
  • Medical equipement. To treat heart disease, your child may benefit from a pacemaker to maintain a regular heartbeat. In the later stages of the disease, the muscles that support breathing may weaken. Your child may need a bi-level positive airway pressure (BI-PAP) device while sleeping. They may also need respiratory support during the day.
  • Physiotherapy and Occupational Therapy teams can create exercise plans for your child. Exercises can help your child maintain range of motion and muscle function. By maintaining their muscles, your child can prevent bone fractures and maintain flexibility. Therapists can also help your child use assistive devices for daily activities.

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