Making sense of genetic testing: The importance of a genetic diagnosis in DMD – Hear from our expert
Are you aware of the diagnostic techniques available for making a genetic diagnosis for children with suspected Duchenne muscular dystrophy (DMD)? Do you know about the critical importance of identifying the specific mutation?
Underscoring the importance of mutation types, Dr Aartsma-Rus discusses key steps for the early diagnosis of DMD. Mutations in the DMD gene eliminate or diminish dystrophin function, causing DMD and Becker muscular dystrophy (BMD; a milder inherited progressive muscle-wasting condition).1,2 As such, establishing a genetic diagnosis is critical for confirming diagnosis of DMD.3
Watch now to find out more about the:
- Disease continuum of DMD and the progressive loss of functionality
- Frequency and effect of different types of DMD-causing mutations on the dystrophin transcript
- Distinctions between mutations found in BMD and DMD
- Techniques available for making a genetic diagnosis for children with suspected DMD
- Importance of having a specific genetic diagnosis in the context of disease prognosis and genetic counselling
Prof. Dr. Annemieke Aartsma-Rus, Professor of Translational Genetics at Leiden University Medical Center (LUMC), the Netherlands, discusses the importance and methods of obtaining an early and accurate genetic diagnosis for DMD. She has played an important role in the development of antisense-mediated exon-skipping therapy for DMD during her PhD research at the Department of Human Genetics of the LUMC. In 2007, she became Group Leader of the Duchenne exon-skipping group. Since 2013, she has a visiting professorship at the Institute of Genetic Medicine of Newcastle University (UK).
Genetic testing is the only way to diagnose DMD. If you want to know more, click here.
Carrier screening for Duchenne muscular dystrophy (DMD): why is it important and who is eligible?
Early detection means that women who are carrying the DMD mutation can:
- Be offered genetic counselling, which can inform them about the risks of transmitting the mutated allele in future pregnancies2
- Have the option of prenatal genetic testing2
- Be made aware of alternative reproductive options, such as the use of donor eggs or human assisted reproduction with preimplantation genetic diagnosis (PGD)2
- Undergo regular surveillance for cardiomyopathy from early adulthood5
- Receive early cardiac treatment if heart involvement is detected3,4
Who is eligible for carrier analysis?
Family members of an individual with DMD should receive genetic counselling to establish who is at risk of being a carrier.1
Carrier genetic testing should be performed in female relatives of a boy or man who has been genetically confirmed to have DMD.1
Carrier testing may help reduce the transmission of Duchenne muscular dystrophy and improve outcomes for women at risk.1-4 Click here for the 2018 Duchenne Care Considerations.
The importance of early diagnosis
While there is no cure for Duchenne muscular dystrophy, studies have shown that early diagnosis and care can help slow DMD progression and minimise the risks and complications of the disease.1-5
This means that patients may:1,2,5-8
Remain ambulatory for longer
Preserve their pulmonary and cardiac function longer
Have a better quality of life
Live Longer
It also means:
- Parents of patients can have earlier access to genetic counselling, which can assist with family planning2
- It may be possible to enroll the child in research-based registries and clinical trials of investigational treatments2
Your role in detecting DMD has never been more important
Prompt intervention is critical to help delay disease progression and help preserve muscle function for as long as possible.
Early diagnosis and care can help slow Duchenne muscular dystrophy progression and minimize the risks of complications of the disease.
If you see signs and symptoms of Duchenne muscular dystrophy, order a creatine kinase (CK) test – click here to learn more
Genetic testing for Duchenne muscular dystrophy
Genetic testing is the only method for determining a patient’s specific mutation type.1,2 This is important because a specific genetic diagnosis may help identify medical management options and potential to enrol into clinical trials.2
Additionally, once a mutation is identified, female relatives can find out their carrier status. This is important for two main reasons:2
Female carriers can pass on Duchenne muscular dystrophy to their children
Female carriers need medical assessment and follow-up
A genetic diagnosis involves two types of tests
First-level testing1,3
- The majority of mutations (~70%) are detected by multiplex ligation-dependent probe amplification (MLPA)
- MLPA can detect both large deletions and large duplications in patients and carriers
Second-level testing1
- If no mutation is found, gene sequencing should be performed
- Only gene sequencing can definitely detect smaller mutation types. These mutations include point mutations (nonsense or missense), small deletions, and small duplications or insertions
How to accurately diagnose Duchenne muscular dystrophy1,2
Genetic testing is the only way to determine the specific mutation causing Duchenne muscular dystrophy and could help patients get on the right treatment pathway1,2