Muscular Dystrophy

By: Hannah Connolley

What is Muscular Dystrophy?

Muscular dystrophy (MD) is a group of inherited diseases in which the muscles that control movement (voluntary muscles) progressively weaken.

What causes Muscular Dystrophy?

  • Muscular dystrophy is caused by defects in certain genes, with type determined by the abnormal gene.
  • Most of the muscular dystrophies are a form of inherited disease called X-linked disorders or genetic diseases that mothers can transmit to their sons even though the mothers themselves are unaffected by the disease.
  • Men carry one X chromosome and one Y chromosome. Females carry two X chromosomes. Thus, in order for a girl to become affected by muscular dystrophy, both of her X chromosomes would have to carry the defective gene


For most types of muscular dystrophy, symptoms start to show up in childhood or in the teen years.

  • Fall down often
  • Have weak muscles
  • Have muscle cramps
  • Have trouble getting up, climbing stairs, running, or jumping
  • Walk on their toes or waddle
  • A curved spine (scoliosis)
  • Droopy eyelids
  • Heart problems
  • Trouble breathing or swallowing
  • Vision problems
  • Weakness in the muscles of the face

Nine major forms of muscular dystrophy:

  1. Myotonic: most common in adults, prolonged spasm or stiffening of muscles after use
  2. Duchenne: most common in children and affects only males, It appears between the ages of 2 and 6. Those with Duchenne MD usually die in their late teens or early 20s.
  3. Becker: similar to Duchenne muscular dystrophy, but the disease is much milder
  4. Limb-girdle: most common in the teens to early adulthood and affects males and females. Causes progressive weakness that begins in the hips and moves to the shoulders, arms, and legs.
  5. Facioscapulohumeral: refers to the muscles that move the face, shoulder blade, and upper arm bone. Most common in the teens to early adulthood and affects males and females.
  6. Congenital: present at birth, progresses slowly and affect males and females. Cause muscle weakness at birth or in the first few months of life, along with severe and early contractures (shortening or shrinking of muscles that causes joint problems).
  7. Oculopharyngeal: refers to eye and throat, This form of muscular dystrophy appears in men and women in their 40s, 50s, and 60s.
  8. Distal: this group of rare diseases affects adult men and women. It causes weakness and wasting of the distal muscles (those farthest from the center) of the forearms, hands, lower legs, and feet.
  9. Emery-Dreifuss: This rare form appears from childhood to the early teens and affects only males. It causes muscle weakness and wasting in the shoulders, upper arms, and lower legs.

New study found:

Researchers at a US university have published exciting results of a potential method to protect the heart muscle from damage caused by muscular dystrophy. Experiments using a dog model of Duchenne muscular dystrophy have shown that repeated injection into the blood stream of a man-made chemical called poloxamer-188 (P188) – over an 8-week period helped to protect heart cells from dying and maintained the heart structure. This is the first time it has been shown that relatively long-term administration of P188 can help prevent heart damage in a large-animal model of Duchenne muscular dystrophy.