The holy Grail of hypermobile Ehlers Danlos Syndrome? Diagnosis by genetic testing
Since the publication of the 2017 revised Ehlers Danlos Syndrome (EDS) diagnostic criteria, we have had 12 subtypes of EDS with a defined genetic basis. These are primarily genes involved in the synthesis, folding, transport or other modification of elements of the extracellular matrix which is the component of tissues that support cells. But then there’s hEDS or hypermobile EDS - the most common of the 13 subtypes of EDS for which no genetic basis has been identified……. or has it?
On July 14 this year, MUSC (Medical University of South Carolina) announced that a team in the Norris lab on the MUSC campus have identified a gene mutation associated with hEDS and are currently running tests on a model before publishing their findings. Their work started with genetic sequencing on two distant relatives with hEDS and moved on to studying the wider family of these individuals followed by large group of hEDS patients who signed up to a patient registry established by the team.
So just what would it mean to have an identified genetic basis of hEDS? A common discussion point amongst patients and clinicians currently managing hEDS is the value of diagnosis. As it stands, management is generally directed at the presenting difficulties experienced by an individual with hEDS and other connective tissue disorders. While we are increasingly understanding the types of issues that commonly present in hEDS and how best to manage these, it is also known that there is great variability between individuals and predicting how any individual will be affected is currently an imprecise science. Many people conclude that a diagnosis won’t change the way we manage the issues they face at this time and therefore the often arduous process of obtaining a firm diagnosis is of no value. On the flipside however, a firm diagnosis can help to validate a patient’s experience and allow them to concisely communicate regarding their healthcare needs with the broad range of medical professionals they are likely to come in contact with, as well as other important people in their life. A definitive diagnosis is also often essential to accessing supports, such as through insurance schemes. A simplified diagnostic process that could become possible with a defined genetic basis of hEDS could save patients with this condition from the necessity of investing large amounts of time, energy and resources into obtaining a diagnosis to explain their healthcare challenges and to access the support they need to manage their health and prevent unnecessary complications. It could also expedite the diagnostic process, helping to identify sufferers earlier so that strategies to prevent secondary complications can be put in place.
Additionally, identification of the genetic basis of hEDS can inform further research into the biological mechanisms responsible for many of the common symptoms. This has the potential to significantly improve our understanding of the causes and likely progression of the symptoms of hEDS which can affect multiple body systems, sometimes leading to significant impacts on function and quality of life. This may help to identify or refine treatment options for the broad range of issues associated with hEDS. Coupled with the ability to more easily diagnose hEDS, targeted interventions could begin sooner to prevent or reduce deterioration of an individual’s health.
The EDS community will undoubtedly be excitedly awaiting publication of the Norris lab’s results hoping to be Dazzled * by new understandings of hEDS.
* NB: A Dazzle is the collective term for a group of zebras. EDS patients often refer to themselves as zebras in reference to the saying commonly shared with medical students for decades: “when you hear hoofbeats, look for horses not zebras" meaning to look for the common, simple explanation of the patient's symptoms rather than the rare or surprising. The zebra became the symbol of the EDS Society because those with Ehlers-Danlos syndrome and hypermobility spectrum disorder are the unexpected. “Sometimes when you hear hoofbeats, it really is a zebra.”
MUSC researchers announce gene mutation discovery associated with EDS. https://web.musc.edu/about/news-center/2021/07/14/musc-researchers-announce-gene-mutation-discovery-associated-with-eds-ehlers-danlos?fbclid=IwAR2edX-mnR11R7CsIN4fDLkp-VfhglDlvYlq2jnkFhHxn--KG0sIDgrW7dc. Accessed 16/07/2021.
Gensemer, C., Burks, R., Kautz, S., Judge, D. P., Lavallee, M., & Norris, R. A. (2021). Hypermobile Ehlers‐Danlos syndromes: Complex phenotypes, challenging diagnoses, and poorly understood causes. Developmental Dynamics, 250(3), 318-344.
Malfait, F., Francomano, C., Byers, P., Belmont, J., Berglund, B., Black, J., ... & Tinkle, B. (2017, March). The 2017 international classification of the Ehlers–Danlos syndromes. In American Journal of Medical Genetics Part C: Seminars in Medical Genetics (Vol. 175, No. 1, pp. 8-26).
Why the Zebra? https://www.ehlers-danlos.com/why-the-zebra/ . Accessed 17/07/2021