For a long time, researchers have been focused on differences among health issues, rather than commonalities. There are historical and sometimes practical reasons for this approach, but it’s not necessarily beneficial for patients.
Consider the separation of “health” care and “dental” care. XLHers, of all people, can attest to dental care being a critical part of health care. Is there a logical reason for separating either the training of the respective specialists or the providing of these services? No. It’s just an accident of history that continues more out of habit (and entrenched special interests) than logic or considerations of the patients’ best interest. The proposed Ensuring Lasting Smiles Act is a good first step toward improving access to dental care for patients who have dental issues directly related to underlying medical issues, but it’s only a first step. Regardless of the cause of, say, a dental infection, getting it treated is key to a patient’s health and should not be viewed as somehow being outside “health care.”
Even closer to home, consider the history of nomenclature for XLH, and how it places the focus on how XLH is different from other hypophosphatemias, rather than how it’s similar. The original name, “Vitamin D Resistant Rickets” got it completely wrong, lumping the disorder in with rickets, rather than hypophosphatemia, and we’re still experiencing the consequences of too many clinicians and decision-makers (like insurers and the governmental agencies determining access to new treatments in countries with national health services) who still believe XLH is a purely pediatric bone disorder.
More recently (which isn’t that recent, now that I do the math: it’s been close to fifty years now!), researchers and clinicians have established that XLH is not primarily a form of rickets (and definitely not due to vitamin D deficiencies), but instead is a form of hypophosphatemia a/k/a phosphate-wasting. But that initial historical fluke persists in the way that XLH remains isolated from other forms of hypophosphatemia, as if it were sui generis (one of a kind), and has to be studied in isolation, rather than as part of a group of related disorders.
There are undoubtedly times when it’s necessary to focus on XLH specifically, as when researchers are creating a database of the mutations on the X chromosome (or elsewhere) that cause hypophosphatemia. And if one is researching whether specific mutations cause specific subcategories of symptoms of hypophosphatemia, then it would be important to know if the mutation is on the X chromosome or somewhere else for autosomal cases. It would also be important to know the exact cause of the hypophosphatemia (e.g., secondary to chronic kidney disease vs genetic hypophosphatemias vs tumor-induced osteomalacia) when comparing the symptoms/progression/treatment across these different groups.
But this focus on specific subgroups first means there’s no big picture of what it means to have hypophosphatemia, no understanding of the commonalities shared across the groups. I also get the impression that clinicians view these common symptom differently, depending on the underlying cause. It’s an emergency if it occurs in an acute case, but it’s shrugged off as not a big deal in the chronic hypophosphatemia patient (XLH, autosomal, or TIO).
A recent journal article finally took the better approach of starting with the key to all these disorders, which is the hypophosphatemia, and only then moving on to the differences where they matter. It’s “An Expert Perspective on Phosphate Dysregulation With a Focus on Chronic Hypophosphatemia.” You can read the full article here: https://asbmr.onlinelibrary.wiley.com/doi/full/10.1002/jbmr.4486?campaign=wolearlyview
The authors focus on the “chronic hypophosphatemias” (not the acute ones that are less likely to have long-term symptoms), which encompasses both genetic (XLH and the autosomals like ENPP1) and acquired (TIO) conditions, and then point out the challenges for access to medical care that are shared by the entire group (the lack of routine phosphorus testing, exacerbated by the conditions’ rarity).
This is their description of what we have in common: “Chronic hypophosphatemia impacts multiple body systems, including the skeletal, muscular, joint, and dental systems, and if unresolved will have lifelong deleterious and cumulative effects, resulting in impaired mobility and physical function, as well as reduced health-related quality of life.”
They go on to recommend a definition of chronic hypophosphatemia for initial diagnosis, and then acknowledge that the specific cause will be important to treatment regimens, since there are options for things like TIO (surgery) that aren’t available for XLH. But having started with the commonality, all chronic hypophosphatemia patients ought to be viewed as having the same need for treatment as any other patient in the larger group.
It’s a logical approach, a fresh start that isn’t limited by historical flukes for how to approach a group of disorders that have more in common than in differences. Starting with the commonalities is likely to 1) produce better, more consistent access to good treatment, and 2) give rise to insights on things like enthesopathy (calcificaction) that we have in common and that are poorly understood. Or, in more scientific terms: “A universally well-accepted definition of chronic hypophosphatemia will help raise awareness of these diseases, aid in the identification and management of affected individuals, and facilitate further clinical studies.”
So, what can patients do to understand the commonalities that underlie our differences? Pay attention, not just to news and research about your specific subgroup, but also the others in our phosphate-wasting community. If you have XLH (the most common subgroup), you should be aware that there’s exciting research happening now for ENPP1 (an autosomal hypophosphatemia with severe calcification) and TIO. And vice versa, of course; research into XLH enthesopathy is likely to shed light on ENPP1 calcifications. And pay attention to gene editing in general and the efforts in the gene-editing community to combine disorders that share a cause (like FGF23 excess), since everything related to that shared underlying cause might be able to be grouped together for a cure, which, with a larger patient population, increases the odds of getting the research funded and recruiting sufficient volunteers for clinical trials.
The bottom line, as patient advocates often say, is that we’re stronger together. And that applies across related disorders, not just within our subgroups.
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Please note that the author is a well-read patient, not a doctor, and is not offering medical or legal advice.
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