Muscular dystrophy
disability; dystrophy; dystrophies; Duchenne; muscular; muscle; weak; scoliosis; gene; inherit; chromosome; X linked; carrier; genetic; Gower; Gower's test. ;
Contents
The Muscular Dystrophies are a group of muscle diseases which are caused by changes in genes. They are progressive (the weakness and disability becomes more of a problem as the child gets older). The pattern of muscle weakness can help work out which type of muscular dystrophy a child or young person has.
This topic focuses on Duchenne Muscular Dystrophy which is the most common type of Muscular Dystrophy, but there is a lot of information about other forms of muscular dystrophy, and much more in depth information about Duchenne Muscular Dystrophy, in the internet resource list below.
How does Duchenne Muscular Dystrophy affect children?
- Muscular Dystrophy causes muscles to become weaker over many years.
- Duchenne Muscular Dystrophy affects only boys. The genetic disorder is on the X chromosome (it is an X-linked recessive disorder). Boys have only one X chromosome (from their mother), while girls have two X chromosomes. Having a normal X chromosome (from an unaffected father) protects girls who also have an affected X chromosome (carriers).
- It is rare, affecting about 3 boys in 10,000.
- Duchenne Muscular Dystrophy is present at birth, but the signs of the problem are usually first noticed when the boys are between 3 and 5 years old.
- The boys usually start walking later than most other boys, and by the age of 3 or so years they have difficulty keeping up with other children of their age, they fall often, and have trouble with running, hopping and climbing.
- Over the following years their muscles become weaker, and by the time that they are around 12 most will need a wheelchair to be mobile, and by their late adolescence they often have major problems with movement, including with breathing and swallowing.
Other effects of Duchenne Muscular Dystrophy
- While it has been stated that some boys with Duchenne Muscular Dystrophy have a mild to moderate developmental delay ( 'a lower intelligence'), the development of most boys will be in the 'normal' range.
- As they grow older they will be fully aware that they have a major health problem, that their muscles will become weaker, and they will have a much shorter life than other boys.
- They and their families (including their siblings) will experience ongoing stress and distress, as well as the disability and handicap of having a major health problem.
How it is diagnosed
- Duchenne Muscular Dystrophy is usually suspected because of the difficulties that the boys have with running, jumping and climbing.
- They often have larger than usual muscles in the calves and other parts of the body, so that they look well developed even though they have weak muscles.
- Checks may be made on the strength of leg muscles of all boys by a screening test called the "Gowers' Test" when boys are 4 to 5 years old. This is not usually done now as almost all boys with Duchenne Muscular Dystrophy are picked up well before this age.
- Blood tests (for Serum Creatine Kinase, SCK), then muscle biopsy (cutting out a small sample of a muscle) will confirm the diagnosis.
Genetic testing
- Genetic testing can be done to find out which gene is affected, so that testing of other family members can be done.
- The boy's mother can usually be tested to find out whether the boy's disease is a new mutation (she is not a carrier), or whether she has a copy of the affected gene (she is a carrier).
- Knowing this may help parents to decide whether they will have another child, and what testing might be useful during a pregnancy.
- If the boy has a sister, she too can be tested to find whether she is a carrier, and she can then make choices about having children herself. Making the choices that genetic testing makes possible is very difficult, and many genetic testing laboratories have people who can provide guidance and support before testing, as well as after testing.
Treatment of Duchenne Muscular Dystrophy
- At present there is no cure for Muscular Dystrophy, and progress cannot be stopped.
- How rapidly the disability develops is variable, but usually the boy will be dependent on a wheelchair in his early teenage years. Most affected people survive into their twenties.
- Joints tend to become restricted in their movements (called 'contractures'), and scoliosis (curved spine) can develop.
- The increasing disability can be helped by supports, such as those that can be provided by a physiotherapist or occupational therapist.
Resources and references
As indicated above, this is a very brief introduction to Duchenne Muscular Dystrophy. There is a great deal of information available on the Internet ranging from the genetic and cellular abnormalities to supports for boys, parents and siblings. The content of these sites has been viewed, but Child and Youth Health cannot take any responsibility for information published on these sites.
- The 'scientific' information used to prepare this topic has come from Harrison's Principles of Internal Medicine (Chapter 383 'Muscular Dystrophies and other muscle diseases'). This is published on the Internet, but has limited access. www.harrisonsonline.com
- The Muscular Dystrophy Association of South Australia has a site at www.mdasa.org.au which has a lot of information about living with Muscular Dystrophy, as well as a large number of related sites. 'The Muscular Dystrophy Association provides a range of individually designed support services for all persons with muscular dystrophy and neuromuscular disorders, their families and their carer/support provider, including therapy, information, equipment loan and counselling.'
- The Australian Muscular Dystrophy Association, which is based in Melbourne has a site www.mda.org.au This site also has extensive information, and the association provides support to people living with muscular dystrophy, including parents and other family members.
- Novita (formerly the Crippled Children's Association of South Australia) - providing therapy, equipment and home support to South Australian children and young people with physical disabilities. http://www.novita.org.au/
The information on this site should not be used as an alternative to professional care. If you have a particular problem, see a doctor, or ring the Parent Helpline on 1300 364 100 (local call cost from anywhere in South Australia).
This topic may use 'he' and 'she' in turn - please change to suit your
child's sex.