Duchenne Muscular Dystrophy

Duchenne muscular dystrophy, also referred to as DMD, is a genetic disorder. That means it is passed from parents to children. DMD causes muscle breakdown and weakness over time.

Children with DMD may have cognitive issues along with physical symptoms of the disease. DMD affects mostly boys. It occurs in about 1 in 3,500 to 5,000 babies from all ethnic groups.

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

Cause of Duchenne muscular dystrophy

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

The gene change in DMD affects the production of dystrophin. Dystrophin is a protein made by muscle cells. When the gene is changed or deleted, muscles do not produce enough dystrophin. Without that protein, muscle fibers don’t work 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 gene from the healthy X chromosome. But boys have an X chromosome from their mother and a Y chromosome from their father. If the gene for dystrophin on their X chromosome is affected, they cannot create more dystrophin.

Girls with this gene change may have some 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. The symtoms often start in the hips and thighs. Then they spread to the arms and rest of the body.

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

• Fall frequently
• Walk on the balls of their feet, called a toe walk
• Run slowly
• Use their hands to get up from sitting or lying down. This movement is called a Gower’s sign.
• Have large calves
• Have learning problems

As DMD progresses, your child may have:

• Heart problems or irregular heartbeat
• Tiredness and weakness
• Scoliosis, a curve in the spine
• Easily broken bones
• A need for assistive devices or a wheelchair
• Stiff joints and difficulty moving

Diagnosis of Duchenne muscular dystrophy

Your health care team diagnoses DMD by taking a detailed medical history, discussing symptoms, and doing a physical exam. They may refer you to a neurologist. A neurologist is a doctor who has had special training to treat muscle and nerve diseases.

Your care team may also use one or more of these tests to help with 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 look at the cells under a microscope. This can show 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 health care team will help your child manage the condition and retain as much function as possible. Your child’s health care team may include:

• Neurologist
• Cardiologist for heart conditions
• Pulmonologist for lung conditions
• Physical and occupational therapists to create exercise and stretching programs. They can also develop plans to best perform daily 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 care team may also prescribe medicines to treat heart problems. Scientists are researching new medicines for DMD that target the problems in the gene. Talk to your health care team about new treatments and whether they might be an option for your child.
• Medical devices. To treat heart conditions, your child may benefit from a pacemaker to maintain a regular heartbeat. In the later stages of the disease, muscles that support breathing may weaken. Your child may need a bi-level positive airway pressure (BI-PAP) machine while they sleep. They may also need breathing support during the day.
• Physical and occupational therapy teams can create exercise plans for your child. The exercises can help your child maintain range of motion and muscle function. By maintaining muscles, your child can prevent bone breaks and preserve flexibility. Therapists can also help your child use assistive devices for daily activities.