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The Causes and Symptoms of Duchenne Muscular Dystrophy (DMD)

What is DMD?

DMD is the most common and most severe form of muscular dystrophy.

People with DMD can’t make a special protein called dystrophin, which acts as a shock absorber or stabilizer for muscles. Without dystrophin, muscle cells are easily damaged.

If the body does not have enough dystrophin, muscles become more sensitive to damage and deteriorate over time.

The injured muscles are gradually replaced with fat and scar tissue.

The lack of dystrophin and resulting loss of muscle lead to the symptoms of DMD.

Over time, the damage to muscles causes problems with movements such as getting up from the floor and walking.


Where does DMD occur?

DMD can occur in all muscles of the body–including muscles in the arms and legs, as well as the heart muscle and those involved in breathing. This can lead to problems with:






Mechanism of disease


Is DMD fatal?

DMD leads to early death. While there is no cure for DMD at the present time, people with DMD are living longer than ever before. With the right care, people with DMD may live into their 30s and beyond.

While the progression and severity of DMD symptoms differ for every individual, most will experience some of the stages shown in the graphic.


Important Terms and Concepts

Basic terms and key definitions

Neuromuscular disorders

Neuromuscular disorders affect the muscles and nerves, and most of the causes are genetic. This means they are either passed down through the family or caused by changes in an individual person’s genes.

Most neuromuscular disorders cause muscle weakness that worsens over time. Signs and symptoms of neuromuscular diseases can vary and may be mild, moderate, or severe.

Most often, when a child has a neuromuscular disease, they don’t grow and develop as fast as other children their age. They are often slow to start lifting their head, sitting, walking, and talking.

Treatment and supportive care may improve the symptoms of a neuromuscular disorder, increasing mobility and even life expectancy.

Muscular dystrophy

Muscular dystrophy is the term for a group of neuromuscular disorders that cause muscle weakness and muscle loss.

Duchenne muscular dystrophy (DMD) is a type of muscular dystrophy that causes muscle weakness that worsens over time. The progression and symptoms can vary from person to person.

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Date of preparation: September 2022