Frequently Asked Questions about Genetic Testing

This section defines genetic testing, explains why people might consider having genetic testing, describes how to start the testing process and work with a healthcare provider to choose a testing plan, explains what test results mean, and includes questions you might want to ask your healthcare provider.

What is genetic testing?

Genetic ( Glossary Link DNA) testing is the process of examining a person's DNA. For DMD/BMD, the dystrophin Glossary Link gene is checked to see if any mutations (changes) that keep the gene from working properly can be found.

Genetic testing can be done on blood, saliva, muscle, or other tissue. Different types of genetic tests look for different types of gene changes. Some people with DMD/BMD need to have more than one test to find a Glossary Link mutation.

Genetic information does not change over time. Testing can be done at any time.

Why consider genetic testing for DMD/BMD?

There are benefits of genetic testing, but also some limitations. It is important to learn about the benefits and limitations before choosing testing for you or your child.

Benefits are that genetic testing can usually diagnose DMD or BMD, finding a mutation makes Glossary Link carrier testing easier, and genetic testing provides more information about risk in the family. Some clinical treatment trials now require a person to have genetic testing before he can be considered for the study.

In rare cases, genetic testing is not able to find a mutation in the dystrophin gene.

Having genetic testing does not guarantee that you will be able to be a part of a research study. Some treatment studies are looking for people with a specific genetic change.

How do I start the genetic testing process?

Children with symptoms of Duchenne or Becker muscular dystrophy can have genetic testing to diagnose the disorder.

Your family doctor will likely first order a screening test called CPK if he or she thinks your child might have a muscle problem. If the results are abnormal, some family doctors who are familiar with genetic testing may order it. Other doctors will refer you to a specialist to help decide about testing.

It is important to talk with your healthcare provider about the genetic testing process before you get started. For example, you should know what type of test your provider is ordering, why the provider chose the test, and what information you may get back.

Genetic testing costs between $400 and $5000 depending on what type of test is ordered. More than one genetic test may be necessary to find the genetic change.

Some insurance companies will cover testing and some will not. It is important to ask your insurance company what they will cover before the test is ordered.

What is the best strategy for diagnostic genetic testing?

There are many different methods used in genetic testing to find different types of mutations (changes) in the dystrophin gene. The best method to use depends on whether there is a known mutation in the family.

If the mutation in the family is known, the healthcare provider should choose a testing method that finds that kind of mutation.

If the mutation in the family is not known, the healthcare provider should start testing by choosing a method that finds deletions and duplications, because deletions and duplications cause most cases of DMD/BMD. If the lab does not find a mutation, the provider should then move on to a method that finds point mutations.

What do genetic test results mean?

Finding a disease-causing mutation means that the person has Duchenne or Becker muscular dystrophy. Finding a mutation in one person makes it easier for other people in the family to be tested to see if they have the disease or are at risk of having a child with the disease.

If a genetic test does not find a mutation, it may be necessary to have another type of genetic test. In rare cases, the lab cannot find a mutation, even after a full set of genetic tests. New genetic tests will be available in the future and might be able to find the mutation.

Sometimes a genetic change is found, but the lab does not know whether it causes disease or whether it is a harmless change. Other times the lab knows the genetic mutation causes disease, but does not know whether it causes Duchenne muscular dystrophy or Becker muscular dystrophy. More information about the mutation may become available in the future.

What should I know before starting genetic testing?

Before testing, you and your family should understand:
  • What test is the provider ordering?
  • What information will you get from the test results?
  • Why did the provider choose this test?
  • How long does it take for results to come back?
  • What does it mean if the test finds a mutation?
  • What are the next steps if the test does not find a mutation?
Genetic testing can involve several steps, and you need to have a knowledgeable healthcare provider who can answer questions through the process. Your healthcare provider will come up with a testing plan, draw a blood sample, send the sample to the specialized lab for testing, and interpret and explain the results to your family. Laws that specify who is allowed to order genetic testing vary from state to state; in general, however, genetic testing can be ordered by primary care doctors, specialist doctors, or genetic counselors.

What is the cost of genetic testing? Will my insurance cover these costs?

The cost of genetic testing varies, but generally ranges from about $400 to $5000 for each test, depending on the type of test ordered. It is important to understand that there are different types of genetic testing for Duchenne and Becker muscular dystrophy. No one test will detect 100% of mutations, and it is sometimes necessary to order more than one test to identify the mutation in the dystrophin gene.
 
Every insurance company and policy is different, so it is important to work with your insurance company and your healthcare provider to understand your level of coverage for genetic testing. In some cases, comparable tests are available at different laboratories, and your insurance company may cover testing at one lab but not another. Some laboratories have programs in place to help you determine the amount of insurance coverage before testing is ordered. Your healthcare provider’s office can also help with this process.
 
Insurance companies will often ask for the test CPT and ICD-9 codes to decide about coverage. CPT codes represent the specific procedures that are needed to do the genetic test. Each type of test has its own set of CPT codes; for example, deletion testing will have a different set of codes than sequencing. The ICD-9 code is the code from the healthcare provider that indicates the reason for testing. Your healthcare provider should be able to give you the codes.