jueves, 31 de mayo de 2012

CDC - Facts, Muscular Dystrophy - NCBDDD

CDC - Facts, Muscular Dystrophy - NCBDDD

Facts about Muscular Dystrophy

Boy with his motherMuscular dystrophies (MDs) are a group of disorders that result in muscle weakness and a decrease in muscle mass over time. The disorders within this group differ in the muscles they affect, the age when signs are first seen, and the genes that cause the disorders.
The major types of muscular dystrophy are:
  • Becker
  • Congenital
  • Distal
  • Duchenne
  • Emery-Dreifuss
  • Facioscapulohumeral
  • Limb–girdle
  • Myotonic
  • Oculopharyngeal
For definitions of these MDs, see the Genetics Home ReferenceExternal Web Site Icon from the National Institutes of Health’s U.S. National Library of Medicine.
We at the Centers for Disease Control and Prevention (CDC) are committed to helping people affected by MD live full lives. CDC’s initial work has focused on Duchenne and Becker muscular dystrophy (DBMD); however, new projects will include other forms of muscular dystrophy as well.

Duchene Muscular Dystrophy Fact Sheet

Duchenne and Becker Muscular Dystrophy

Duchenne Muscular Dystrophy
Duchenne muscular dystrophy (DMD) is the most common form of muscular dystrophy among children.1 DMD occurs among approximately 1 in 3,500 to 6,000 male births.2, 3 This broad range reflects studies of different groups of individuals around the world. Usually, a person with DMD loses the ability to walk sometime during the period when he or she is 7 through 13 years of age, and dies in his or her teens or 20s.4

Becker Muscular Dystrophy
Becker muscular dystrophy (BMD) is a milder form of muscular dystrophy. BMD affects about 1 in 18,500 male births.2 Signs of BMD are similar to those for DMD. Typically, people with BMD lose the ability to walk after they are 16 years of age.
Together, DMD and BMD are called Duchenne/Becker muscular dystrophy (DBMD). Over time, the muscles of people with DBMD get much weaker. While there currently is no cure for DBMD, there are many treatments that can help people with the condition.


Early signs of DBMD can include:
  • Experiencing a delay in walking
  • Having large calf muscles
  • Falling more often than children of the same age
  • Walking on tip toes
  • Having problems getting up from a sitting or lying position (Gower’s maneuver). See a video of Gower’s maneuver.External Web Site Icon
  • Experiencing a delay in using language5
Babies and children should reach milestones in how they play, learn, speak, and act. A delay in any of these milestones could be a sign of DBMD or other developmental problem. Visit our “Learn the Signs. Act Early” webpage to see milestones that children should reach when they are 3 months to 5 years of age.

Causes of DBMD

DBMD is present at birth and mainly affects males. DBMD is caused by a change (mutation) in the gene that makes dystrophin. Dystrophin is a protein found in muscle. Dystrophin is important because it helps muscles stay healthy and strong. Among boys with DMD, there is very little or no dystrophin, causing muscles to weaken and atrophy (or can use decrease in mass or waste away) over time. Among boys with Becker muscular dystrophy (BMD), there might be small amounts of dystrophin, but the dystrophin might not be enough to keep the muscles strong. DBMD can run in a family, or it can be caused by a new change in the gene that makes dystrophin.


Doctors use lab tests to diagnose a person with DMD. Typically, boys with DMD are diagnosed sometime during the period when they are 3 to 6 years of age, even though there might be earlier symptoms.5
  • Doctors can test the level of creatine kinase (CK), a protein in the blood. CK levels are higher among people with DMD.
  • Doctors can test the gene that makes dystrophin.
  • Doctors can do a muscle biopsy. This is a minor surgery in which a doctor removes a small piece of muscle and tests it for dystrophin. Among people with DMD, there is very little or no dystrophin. Among people with BMD, there might be small amounts of dystrophin.

Complications and Treatments

Complications occur over time as DBMD progresses. The main complications of DBMD are problems with muscle health, bone health, heart health, breathing, digestion and nutrition, and emotional and mental health.
While currently there is no cure for DBMD, there are many treatments that address the complex needs of people with DBMD. Treatments for DBMD need to include different specialists working together to improve quality of life. Every person who has DBMD is different and treatment will vary depending on a person’s age and needs. A health care professional can recommend different treatments for each of these complications.

Family sitting on the couchEarly Intervention Services

Early intervention services help children learn important skills. These services can improve a child’s development. Even if the child has not been diagnosed with DBMD, he or she might be eligible for services. These services are provided through an early intervention system in each state. Through this system, you can ask for an evaluation. In addition, treatment such as physical therapy often does not need to wait for a formal diagnosis.

Finding Support

Having support and community resources can help increase confidence in managing DBMD, enhance quality of life, and help meet the needs of all family members. It might be helpful for parents of children with DBMD to talk with one another. One parent might have learned how to address some of the same concerns another parent has. Often, parents of children with special needs can give advice about good resources for these children.
The choices of one family might not be best for another family, so it’s important that parents understand all options and discuss them with their child’s health care providers.
If you have a child with muscular dystrophy, you might:


  1. Emery AE. Duchenne muscular dystrophy. 2nd ed. New York: Oxford University Press; 1987.
  2. Emery AE. Population frequencies of inherited neuromuscular diseases---a world survey. Neuromuscul Disord 1991;1:19--29.
  3. Bradley D, Parsons E. Newborn screening for Duchenne muscular dystrophy. Semin Neonatol 1998;3:27--34.
  4. Wong BL, Christopher C. Corticosteroids in Duchenne muscular dystrophy: a reappraisal. J Child Neurol 2002;17:183--90.
  5. Ciafaloni E, Fox DJ, Pandya S, Westfield CP, Puzhankara S, Romitti PA, et al. Delayed diagnosis in Duchenne muscular dystrophy: data from the Muscular Dystrophy Surveillance, Tracking, and Research Network (MD STARnet). J Pediatr 2009 Sept;155(3):380-5.  

No hay comentarios:

Publicar un comentario