What Is Duchenne Muscular Dystrophy?

There are nine types of muscular dystrophy. Duchenne muscular dystrophy (DMD) is a genetic condition characterized by progressive weakening of voluntary muscles. DMD worsens more rapidly than other types of muscular dystrophy. It’s also the most common form of muscular dystrophy. The Centers for Disease Control and Prevention estimated that one out of every 5,600 to 7,700 males between 5 and 24 years of age has DMD.

The symptoms of DMD begin in early childhood, and those with DMD usually die in early adulthood.

The symptoms of DMD generally start to appear between ages 2 and 6. Many children with DMD develop normally during infancy and early childhood. DMD symptoms may include:

  • difficulty walking
  • a loss of ability to walk
  • enlarged calves
  • learning disabilities, which occurs in about one-third of affected individuals
  • a lack of motor skills development
  • fatigue
  • rapidly worsening weakness in the legs, pelvis, arms, and neck

DMD is a genetic disease. Those who inherit it have a defective gene related to a muscular protein called dystrophin. This protein keeps muscle cells intact. Its absence causes rapid muscular deterioration as a child with DMD grows.

A family history of DMD is a risk factor, but the condition may pass down without a known family history. A person can be a silent carrier of the condition. This means that a family member can carry a copy of the defective gene, but it doesn’t cause DMD in that person. Sometimes, the gene can pass down for generations before affecting a child.

Males are more likely to have DMD than females. Males and females who are born to a mother who carries the defective gene each have a chance of inheriting the defect. However, girls who inherit the gene will be asymptomatic carriers, and boys will present with symptoms.

Routine wellness exams may uncover signs of muscular dystrophy. You and your child’s pediatrician may notice that your child’s muscles are weakening and that your child has a lack of coordination. Blood tests and muscle biopsies can confirm a diagnosis of DMD.

The blood test used to reach this diagnosis is called a creatine phosphokinase test. When muscles deteriorate, they release a large amount of creatine phosphokinase enzyme into the blood. If the test detects high levels of creatine phosphokinase, muscle biopsies or genetic tests will determine the type of muscular dystrophy.

There’s no cure for DMD. Treatment can only make symptoms less severe and extend life expectancy.

Children with DMD often lose the ability to walk and require a wheelchair by about age 12. Leg bracing may extend the amount of time a child can walk independently. Regular physical therapy keeps the muscles in the best possible condition. Steroid treatments may also prolong muscle function.

Weakening muscles can cause conditions such as scoliosis, pneumonia, and abnormal heart rate. A doctor should treat and monitor conditions as they occur.

Lung function begins to deteriorate in the late stages of the disease. A ventilator may be necessary to prolong life.

DMD is a fatal condition. Most individuals with DMD pass away during their 20s. However, with diligent care, some people with DMD survive into their 30s. In the later stages of the disease, most people with DMD will need full-time care to maintain quality of life.

The condition is degenerative, which means that the need for medical care increases as the condition worsens. As symptoms begin to appear between ages 2 and 6, the child will usually need regular monitoring by a medical team. As the final stages of the disease emerge during the teen and young adult years, the person may need to enter the hospital or receive hospice care.

If you have DMD or are a parent whose child has DMD, seek support from friends and family. You can also locate support groups where you can talk and listen to others going through the same experience.

You can’t prevent DMD before conception because it passes down from the mother. Geneticists are researching technology that may be able to prevent the defect from being passed on, but they haven’t discovered a successful cure.

Genetic testing before conception can determine whether a couple has an increased risk of having children with DMD.