Duchenne Muscular Dystrophy. It’s a muscle wasting disease, often known as a boy’s disease. It is an “equal opportunity disease”, playing no favorites to a specific race, culture, or economic status. And it frequently appears unannounced.
About ⅓ of the families affected by Duchenne have no family history and it is often assumed that the spontaneous mutation occurred in the boy himself. However, germline mosaicism and spontaneous mutation in the mother can tell a very different story for the whole family.
For the other ⅔ of the families, Duchenne is inherited from the boy’s mother, since it is an X linked mutation. This genetic connection also puts other children in the family at risk for having, or carrying, the same mutation.
According to Parent Project Muscular Dystrophy Carrier Information (page 13) “Studies suggest that 10–20% of women who have a DMD pathogenic variant [i.e. carrier] will have skeletal muscle symptoms. In the past, these girls and women were called manifesting carriers. Now some experts suggest that a better term is female with dystrophinopathy. The symptoms can be variable, ranging from very mild symptoms to symptoms as severe as a male with muscular dystrophy.”
While we are still lacking definitive data regarding all the symptoms a carrier could exhibit, it stands to reason that her health could be affected in the same ways that males are – and not just physical health. Additional health risks to consider include cognitive health and social-emotional health.
Manifesting carriers are not as rare as once thought. In fact, more than 10% of carriers are manifesting. Due to X-inactivation, women and girls can exhibit health complications as severe as males and it is vital to know the carrier status of mothers to protect their health and get them the care and support that they need.
From an information ethics standpoint, there are many reasons why mothers should be able to determine their carrier status sooner rather than later.
- You have a right to know if you are a carrier so you can get adequate preventative care for your heart. As explained in Rare Disease Advisor, “If they’re a carrier, they really need to be screened to comprehensively assess their cardiovascular status. We have drugs and medications that can delay or prevent development of cardiomyopathy if started early in their lives.”
- Knowing carrier status is especially important to determine the appropriate exercise and activity levels, so as to not further break down muscles.
- Biofeedback data tells us that carriers are prone to experiencing heightened anxiety, just like males with Duchenne. Unfortunately, heightened anxiety can affect reasoning and learning.
- Learning differences, such as dysgraphia, dyscalculia and dyslexia, are common in males with Duchenne. There is currently a lack of scientific research on this topic for females, but due to X-inactivation, it stands to reason that learning differences could present itself as a symptom of carriers, as well.
- Lastly, within the male Duchenne cohort, there exists a higher rate of mental health diagnoses than in the general population: anxiety, depression, OCD, autism, selective mutism and many more. Again, while there is no conclusive evidence of an increased occurrence of mental health diagnoses for carriers of Duchenne, due to X-inactivation and the lack of medical knowledge, mental health should definitely be on the radar for our carriers.
While the physical and potential cognitive effects of carrier status are noteworthy, there are other effects to note as well. The impact of carrier status is far reaching for the nuclear family, extended family and community at large.
- Knowing her carrier status can allow a mother to build self-confidence in her own intuition, advocate for herself and not have her concerns minimized by medical professionals.
- Knowing carrier status may help a mother understand why she may be different from her peers. It can also help her get emotional support from her immediate family and from carrier support groups.
- Finally, the more carriers we can identify, the better we can help our community raise awareness about the effects of Duchenne in women. The more data we can collect from known carriers, the more lives we can improve. We can fight for both our sons and our daughters, too.
Advocating for Carrier Testing
Provide your doctor with the information in this article and ask your doctor or geneticist to submit orders for the testing. If they deny the request, then it is likely time to find a new provider.
If the issue preventing the testing is insurance, remember that you can always appeal any coverage decision.
Thank you to co-author Jacob Gapko. Jacob is 44 years old with DMD and is a professionally trained research librarian.
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