During the past several decades, researchers have discovered more than 100 genetic mutations that cause CMT. In the same time frame, scientists have developed tests that can look at parts of someone’s genetic makeup and identify changes that could cause certain conditions like CMT.

Genetic testing for CMT can confirm your diagnosis and tell you what type of CMT you have. Knowing your type of CMT can help you understand more about your condition and how it might change over time. It can also tell you how likely you are to pass it on to your children.

Genetic testing is always optional. If you decide to do it, you will go to a hospital and have a sample of your blood drawn. The sample will be sent to a lab, where it will be checked for mutations. Some genetic testing is done with saliva samples.

The processing time varies depending on the type of test, but you will typically have your results in a few weeks. You will then meet with a physician or genetic counselor to discuss the results and what they mean for you.

A negative test result doesn’t mean you don’t have CMT. Genetic tests can confirm certain mutations but cannot test every single gene for every possible mutation.

Types of Genetic Testing for CMT

The different CMT genetic tests have their pros and cons, and your doctor can recommend which one is best for you. The available tests include:

• Single gene sequencing, where the DNA and any mutations are identified for one gene. This test has to be done one gene at a time. While it can be cost-effective if you have an idea of what type of CMT you have, it gets expensive and time-consuming if you must test one gene at a time and have multiple tests.
• Next-generation sequencing, a newer test that can identify the DNA and any mutations in multiple genes at once. This test can be time consuming and results can sometimes be unclear.
• Microarray testing, which uses a microchip to compare the DNA from your sample to a normal DNA sample. This test is good for detecting known mutations but might not pick up on new ones.

Should I Do Genetic Testing for CMT?
Genetic testing is not for everyone. If CMT runs in your family and you already know the type your family members have, you won’t need a genetic test because it’s very unlikely you have a different type.

Some people choose not to do genetic testing because the tests can be expensive and are not always covered by insurance, and some people fear that having a positive test result could prevent them from qualifying for some other types of insurance.

You should always talk to your doctor and genetic counselor about your options, but the decision to do genetic testing is up to you.

Genetic testing can be a helpful tool to better understand your condition and how it impacts your life. But because CMT treatment is currently limited to symptom management, your results won’t change the course of your treatment now. CMT researchers and the CMT Research Foundation are working today to develop drugs that will target specific genes to slow or reverse the progression of CMT, and in the future, genetic testing might help your doctor decide if a certain drug could be a good treatment option for you.

Right now, in order to qualify for clinical trials for CMT, a genetic diagnosis is required.