Muscular Dystrophy

Recently Answered

• QWhat is muscular dystrophy (MD)?

  1 Answer

  A

  

  A Riverside Center for Neurosciences answered

  Muscular dystrophy (MD) refers to a group of more than 30 genetic diseases that cause progressive weakness and degeneration of skeletal muscles used during voluntary movement. The word dystrophy is derived from the Greek dys, which means difficult or faulty, and troph, which means nourish. These disorders vary in the age of onset, severity, and the pattern of affected muscles. All forms of MD grow worse as muscles progressively degenerate and weaken. The majority of patients eventually lose the ability to walk.

  Some types of MD also affect the heart, the gastrointestinal system, endocrine glands, the spine, the eyes, the brain, and other organs. Respiratory and cardiac diseases are common, and some patients may develop a swallowing disorder. MD is not contagious and cannot be brought on by injury or activity.

  This answer is based on source information from the National Institute of Neurological Disorders and Stroke.

• QHow many people are affected with muscular dystrophy (MD)?

  1 Answer

  A

  

  A Riverside Center for Neurosciences answered

  Muscular dystrophy (MD) occurs worldwide, affecting all races. Its incidence varies, as some forms are more common than others. Its most common forms in children, Duchenne and Becker MDs, alone affect approximately 1 in every 3,500 to 5,000 boys, or between 400 and 600 live male births each year in the United States. Some types of MD are more prevalent in certain countries and regions of the world. Most MDs are familial, meaning there is some family history of the disease.
  This answer is based on source information from National Institute of Neurological Disorders and Stroke.
• QHow does muscular dystrophy (MD) affect muscles?

  1 Answer

  A

  

  A Riverside Center for Neurosciences answered

  Muscles are made up of thousands of muscle fibers. Each fiber is actually a number of individual cells that have joined together during development and are encased by an outer membrane. Muscle fibers that make up individual muscles are bound together by connective tissue.

  Muscles are activated when an impulse, or signal, is sent from the brain along the peripheral nerves (nerves that connect the central nervous system to sensory organs and muscles) to the neuromuscular junction (the space between the nerve fiber and the muscle it activates). There, a release of the chemical acetylcholine triggers a series of events that cause the muscles to contract.

  The muscle fiber membrane contains a group of proteins-the dystrophin-glycoprotein complex-which prevents damage as muscle fibers contract and relax. When this protective membrane is damaged, muscle fibers begin to leak the protein creatine kinase (needed for the chemical reactions that produce energy for muscle contractions) and take on excess calcium, which causes further harm. Affected muscle fibers eventually die from this damage, leading to progressive muscle degeneration.

  Although muscular dystrophy (MD) can affect several body tissues and organs, it most prominently affects the integrity of muscle fibers. The disease causes muscle degeneration, progressive weakness, fiber death, fiber branching and splitting, phagocytosis (in which muscle fiber material is broken down and destroyed by scavenger cells), and, in some cases, chronic or permanent shortening of tendons and muscles. Also, overall muscle strength and tendon reflexes are usually lessened or lost due to replacement of muscle by connective tissue and fat.

  This answer is based on source information from the National Institute of Neurological Disorders and Stroke.

• QWhat is the prognosis of muscular dystrophy (MD)?

  1 Answer

  A

  

  A Riverside Center for Neurosciences answered

  The prognosis varies according to the type of muscular dystrophy (MD) and the speed of progression. Some types are mild and progress very slowly, allowing normal life expectancy, while others are more severe and result in functional disability and loss of ambulation. Life expectancy may depend on the degree of muscle weakness and any respiratory and/or cardiac complications.

  This answer is based on source information from the National Institute of Neurological Disorders and Stroke.