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Duchenne Muscular Dystrophy

What You Need to Know about Duchenne Muscular Dystrophy (DMD)

  • 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.

  • Duchenne muscular dystrophy is caused by a genetic problem in producing dystrophin, a protein that protects muscle fibers from breaking down when exposed to enzymes.

  • 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.

Muscular dystrophy is a genetic problem that causes muscles to weaken and atrophy (become smaller and waste away).

Muscle weakness may affect the skeletal muscle or the heart muscle. It is caused by the inability of muscles to respond to nerve impulses from the brain

Duchenne Muscular Dystrophy Symptoms

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:

  • Difficulty going up stairs

  • Inability to jump

  • Walking on tip-toe

  • Leg pain

  • Facial weakness, including inability to whistle or close eyes

Heart problems may include irregular heartbeat and enlargement of the heart muscle tissue. If the spine becomes curved (scoliosis), breathing and lung function may become difficult.

Risk Factors for Duchenne Muscular Dystrophy

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.

Diagnosing Duchenne Muscular Dystrophy

After conducting a physical and taking a detailed history of signs and symptoms, noting any occurrence of muscular dystrophy in family members, the doctor examines your child and runs tests, including:

Blood tests : These include genetic blood tests, which can reveal the gene mutation causing absence of dystrophin in about two thirds of boys with 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.

Electromyogram (EMG) : This test checks to see if your child’s muscle weakness is a result of destruction of muscle tissue rather than nerve damage.

Electrocardiogram (ECG or EKG) : A test that records the electrical activity of the heart, an ECG shows abnormal rhythms (arrhythmias or dysrhythmias) and detects heart muscle damage.

A genetics counselor reviews the history of disease with each family, discusses the principles of inheritance and helps weigh risks and benefits of genetic testing of various family members, including the affected child and potentially carrier testing for the mother. 

Duchenne Muscular Dystrophy Treatment

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.

The first line of treatment is corticosteroids, which have been shown in clinical trials to decrease the rate of declining strength in people with DMD. A neurologist will manage this treatment and help minimize medications’ side effects.

The neurologist directs your child’s care and coordinates services among the team, which is likely to include additional experts:

  • Physical and occupational rehabilitation professionals design exercise programs for your child and teach stretching activities to minimize limiting contractures.

  • Orthopaedic surgeons with expertise in DMD can treat severe contractures and scoliosis.

  • Pediatric cardiologists track your child’s heart function with EKGs and echocardiograms.

  • A designated Muscular Dystrophy Association liaison is critically important, offering support to families and schools on a number of levels including social, financial and educational.

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