As we were starting to construct the first-ever comprehensive natural history study of XLH, we realized it was a huge challenge, because, unlike some conditions, XLH affects pretty much every system of the body.
Scientists divide the human body into ten systems: 1) cardiovascular, 2) digestive, 3) endocrine, 4) integumentary/exocrine, 5) lymphatic/immune, 6) musculo-skeletal, 7) nervous, 8) renal/urinary, 9) reproductive, 10) respiratory.
It's immediately obvious that the endocrine, musculo-skeletal and renal (kidney) systems are relevant to XLH. The endocrine system regulates phosphorus and FGF23, muscle function and skeleton structure are adversely affected by elevated FGF23 and low phosphorus, and the kidneys are where the phosphate wasting occurs. Some digestive issues have been reported with phosphorus supplements. Some XLHers have nerve involvement as a secondary effect, when calcification impinges on nerves or when the patient has a Chiari malformation or syringomyelia (both of which may or may not be related to XLH).
What about the other, less obviously affected body systems? Wouldn't it be good to know if there's any correlation between XLH and an increased (or decreased!) risk of heart disease or elevated blood pressure? Between XLH and lung conditions? Between XLH and infertility? Or, more generally, and crossing a variety of systems: is there any correlation between XLH and an increased/decreased incidence in various forms of cancer? And what about pain and its treatment: what's the nature/extent of the pain, what's being prescribed and what, if anything, is most likely to be effective?
No one has those answers, in part because the questions have never been asked in a rigorously scientific manner. But we're hoping to change that soon!
The Network’s Registry and Data are part of the National Organization for Rare Disorders’(NORD) Natural History Program.We are thankful for NORD’s investment in the health and wellbeing of all rare disorder communities, including ours.
Showing posts with label questions. Show all posts
Showing posts with label questions. Show all posts
Wednesday, July 26, 2017
Wednesday, April 29, 2015
Thinking out loud
Today's post is by Gin Jones, wearing her "member at large" hat, and not on behalf of the entire Board. I'm just sharing some thoughts that keep me awake in the middle of the night. I don't have any answers, but all discovery starts with questions.
There's so much about XLH that isn't known, so many questions to ask researchers to look into. Some of that work has begun, like the Gait, Mobility and Range of Motion Study by our Scientific Advisory Board Chair, Carolyn M. Macica PhD, and her student at Quinnipiac University's Frank H. Netter M.D. School of Medicine, Eva Amenta, who's examining bone mineral composition and tooth structure in XLH patients as a biological surrogate for bone mineral.
What else would I like to see investigated? So many things! To keep the list manageable, I'll start with three topics across a range of symptoms.
First there's hearing loss and tinnitus (ringing in the ears). There's been some speculation that since hearing is a function of small bones in the ear, and our bones are affected in a variety of ways, perhaps we're at risk of hearing loss. Is there a higher incidence of hearing loss and tinnitus among XLH patients, and if so, what's the underlying cause and what can be done to minimize the risk?
What about our diets? We know that our bone problems are not caused by a nutritional insufficiency, like the rickets caused by lack of vitamin D intake. But are there foods that could help (or hurt) our limited ability to mineralize our bones? What about interactions between certain foods and the phosphorus and calcitriol we take?
And finally, I'd love to see more crossing of lines between different conditions. I recently ran across an article on achondroplasia (a form of dwarfism in which the cartilage during early development isn't properly converted to bone, especially in the arms and legs, with resulting short stature), which has a different biochemical cause, but some of the same bone-related symptoms as XLH. Apparently spinal stenosis is common, even in children with achondroplasia, and, as in XLH patients (where the stenosis is frequently seen in adulthood), no one knows exactly why the stenosis occurs. Perhaps researchers could compare notes on the two conditions and get to a better understanding of the biochemical processes involved in bone formation and the calcification of cartilage.
That's enough to think about for one day. If you've got questions you'd like to see researchers answer, please share them with me: GinJones at xlhnetwork.org I could use some new material to gnaw on during my sleepless nights.
There's so much about XLH that isn't known, so many questions to ask researchers to look into. Some of that work has begun, like the Gait, Mobility and Range of Motion Study by our Scientific Advisory Board Chair, Carolyn M. Macica PhD, and her student at Quinnipiac University's Frank H. Netter M.D. School of Medicine, Eva Amenta, who's examining bone mineral composition and tooth structure in XLH patients as a biological surrogate for bone mineral.
What else would I like to see investigated? So many things! To keep the list manageable, I'll start with three topics across a range of symptoms.
First there's hearing loss and tinnitus (ringing in the ears). There's been some speculation that since hearing is a function of small bones in the ear, and our bones are affected in a variety of ways, perhaps we're at risk of hearing loss. Is there a higher incidence of hearing loss and tinnitus among XLH patients, and if so, what's the underlying cause and what can be done to minimize the risk?
What about our diets? We know that our bone problems are not caused by a nutritional insufficiency, like the rickets caused by lack of vitamin D intake. But are there foods that could help (or hurt) our limited ability to mineralize our bones? What about interactions between certain foods and the phosphorus and calcitriol we take?
And finally, I'd love to see more crossing of lines between different conditions. I recently ran across an article on achondroplasia (a form of dwarfism in which the cartilage during early development isn't properly converted to bone, especially in the arms and legs, with resulting short stature), which has a different biochemical cause, but some of the same bone-related symptoms as XLH. Apparently spinal stenosis is common, even in children with achondroplasia, and, as in XLH patients (where the stenosis is frequently seen in adulthood), no one knows exactly why the stenosis occurs. Perhaps researchers could compare notes on the two conditions and get to a better understanding of the biochemical processes involved in bone formation and the calcification of cartilage.
That's enough to think about for one day. If you've got questions you'd like to see researchers answer, please share them with me: GinJones at xlhnetwork.org I could use some new material to gnaw on during my sleepless nights.
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