This is a plea to all who write or talk about XLH (and the other genetic hypophosphatemias), including patients, clinicians, researchers, editors, and academics (and anyone else I’ve forgotten): update your terminology to reflect current understanding of the disorder.
First, stop calling the various chronic hypophosphatemic disorders “a form of rickets” or “hypophosphatemic rickets.” These terms are both inaccurate and harmful to patients. We know the disorders are far more than rickets, a pediatric bone symptom; it affects virtually every system of the body, from bones and teeth to muscles, soft tissue (enthesopathy), hearing, nerves, and energy levels, and it does this damage throughout a patient’s life, not just in childhood. Keep the focus on the hypophosphatemia, not on a single childhood symptom. Otherwise, the nomenclature leads to poor or incomplete treatment of patients, with less-experienced clinicians focused on treating just one symptom or just one, small age range.
Second, stop calling the old phosphorus/calcitriol treatment “conventional,” which is also inaccurate and potentially harmful. We know now that the old treatment is only marginally effective (with serious potential side-effects), and calling it “conventional” gives it more weight than it deserves. We didn’t call the 1950s-era mega-dose vitamin D treatment “conventional” once we knew it didn’t work and had a treatment that at least had the potential to help. By continuing to call the old treatment conventional and burosumab as novel, it inadvertently gives the impression that the old treatment is preferred and better, while burosumab is experimental. We may not know everything about the long-term effects of burosumab treatment, but we already know it’s vastly superior for kids, and the old treatment was seldom used long-term on adults, so the choice for us isn’t between the old treatment and the new, but between no treatment and the new treatment.
These terminology changes are both easy changes to make. They improve the accuracy of the writing, and they prevent harm to patients by not perpetuating old myths that are detrimental to patients. The switch from “conventional” to some other term may take a while longer, but I’ve noticed recently that the other change (not calling the disorder a form of rickets) has been adopted by a number of the very top experts, and you can see the change in their journal articles.
If you’d like to see a good example, the introductory paragraph in the abstract of “X-linked hypophosphatemia and burosumab: practical clinical points from the French experience” in Joint Bone Spine (June 2021) is particularly well done, focusing on the phosphate-wasting first, and then mentioning rickets as just one of the many symptoms of XLH, not the definition of the disorder.
Come on, researchers and clinicians and editors. It’s beyond time for you to up your game when it comes to describing the chronic hypophosphatemias and their treatment options. Do what’s best for patients in both word and deed.
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The author is a well-read patient, not a doctor, and is not offering medical or legal advice.
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