In cases where muscular dystrophy (MD) develops as the result of a spontaneous gene mutation, there is nothing that can be done to prevent the condition occurring.
For prospective parents who have a family history of MD, and are worried about passing the condition on, genetic testing may help. You should speak to your GP who will be able to refer you for genetic screening and counselling.
Genetic testing
Genetic testing can be used to:
- identify carriers of the condition, and
- confirm a prenatal diagnosis (where a baby is diagnosed before birth).
Identifying carriers
Some types of MD are recessive inherited disorders. This means that it is possible for someone to carry a copy of the faulty gene that causes MD, but not have the condition themselves. Genetic testing can be used to determine who is carrying the disorder.
For example, a woman with a family history of Duchenne MD, but no symptoms herself, may be carrying the gene that causes it. DNA can be taken from cells in the blood, saliva or tissue. The DNA in the relevant gene can then be tested to find out if she is carrying the faulty gene.
If you or your partner are a carrier of MD, and are at risk of passing the condition on to your child, your genetic counsellor will discuss your options with you.
Prenatal diagnosis
Genetic testing can be used for prenatal diagnosis. This is when a baby is diagnosed with MD before it is born, using amniocentesis (a test that is carried out during pregnancy). If you are pregnant and there is a possibility that your unborn baby could have MD, you may be offered this test.
During amniocentesis, a needle is inserted into your abdomen to take a small sample of amniotic fluid (the fluid that surrounds the foetus in the womb). This fluid contains cells that have been shed by the foetus.
The cells from the foetus can be tested to determine whether they have the genetic mutation that is responsible for MD. If they do, it is possible that the baby will have MD once it is born.
You should be aware that this kind of diagnosis is limited. A negative test result is not always reliable, and a positive result only indicates the presence of the genetic mutation that can cause MD. It will not tell you whether your child will actually experience any symptoms, or how severe they might be.
Whether you decide to have amniocentesis, and what to do when you get your results, should be discussed with your genetic counsellor or midwife.
