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Duchenne muscular dystrophy

Marathon is working to gain approval for a new treatment option in the U.S. for people with Duchenne Muscular Dystrophy.

There is currently no medicine available in the U.S. to treat Duchenne Muscular Dystrophy, a fatal, progressive disease.1 Marathon Pharmaceuticals is working to develop a new treatment option for children with Duchenne Muscular Dystrophy.

What It Is

Duchenne muscular dystrophy (Duchenne) is the progressive deterioration of muscle fibers. It is the most common and severe form of muscular dystrophy among children.2 Although it can — on rare occasions — appear in girls, Duchenne largely occurs in boys.1 More than 300,000 boys live with Duchenne Muscular Dystrophy worldwide, with nearly 15,000 of those affected in the United States.3

Duchenne is caused by mutations in the dystrophin protein gene.4 Dystrophin is critical to the health, resilience, and connection of muscle fibers that allow the body to move, breathe and circulate blood. People with Duchenne do not produce the dystrophin protein in their muscles, resulting in a progressive deterioration of muscle fibers. As the disease progresses, patients with Duchene suffer cardiac, respiratory and movement issues and may have learning and developmental difficulties.1

Boys with Duchenne usually inherit it from their mothers through a dystrophin mutation on the X chromosome.5 A son born to a mother with this mutation has a 50% chance of inheriting the gene and having DMD. A daughter has a 50% chance of inheriting the mutation and becoming a carrier.

Symptoms and Progression1

Symptoms begin between the ages of three and five. Muscle weakness first affects the hips, pelvic area, thighs and shoulders. Toddlers with Duchenne walk later than their peers and typically have enlarged calf muscles. Once they begin to walk, they’ll typically struggle to run, climb stairs and get up off of the floor. Children with Duchenne often walk with a waddling pattern, moving from the balls of their feet or their toes. If left untreated, progressive muscle degeneration occurs which can lead to the loss of ambulation by age 13.

A weakening of the diaphragm and other lung muscles leads to frail respiratory function. Dystrophin abnormalities in the brain may also result in learning disabilities, causing problems with verbal learning, memory and emotional interaction.

Muscle weakness later advances to the skeletal muscles in the arms, legs, trunk. The heart and respiratory muscles weaken in the early teens. Despite advances, people with Duchene Muscular Dystrophy often die of heart trouble, respiratory complications or infection.

Resources on Duchenne Muscular Dystrophy


  1. Bushby K, Finkel R, Birnkrant D et al. Diagnosis and management of Duchenne muscular dystrophy, Part 1: Diagnosis, and pharmacological and psychosocial management. Lancet, published online November 30, 2009.
  2. Yiu, E; Kornberg, A. “Duchenne muscular dystrophy”. Neurology India. 2008;56(3):236-47.
  3. “What is Duchenne?” Cure Duchenne Website. Accessed December 15, 2014.
  4. Hoffman EP, Brown RH Jr, Kunkel LM. Dystrophin: The protein product of the Duchenne muscular dystrophylocus. Cell. 1987;51:919-28.
  5. “Causes/Inheritance.” Muscular Dystrophy Association Website. Accessed December 15, 2014.
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