XLH is X-linked hypophosphatemia.
XLH | X-Linked Hypophosphatemic Rickets | Familial Hypophosphatemic Rickets | Hereditary Hypophosphatemic Rickets | Vitamin D-Resistant Rickets Vitamin D-Resistant Osteomalacia | X-Linked Vitamin D-Resistant Rickets | Hypophosphatemic Rickets | Hypophosphatemic Vitamin D-Resistant Rickets (HPDR) X linked rickets | Genetic Rickets | Familial Hypophosphatemia
Mechanism of disease
What does XLH look like in action?
Role of FGF23
FGF23 is a protein hormone that regulates serum phosphate levels by suppressing both phosphate reabsorption in the kidney intestinal absorption of dietary phosphate. 6,7
In patients with XLH, excess FGF23 leads to chronic hypophosphatemia caused by renal phosphate wasting and decreased intestinal absorption of phosphate 1,12,13
- Low serum phosphate concentrations and reduced tubular reabsorption of phosphate corrected for glomerular filtration rate (TmP/GFR) are the characteristic laboratory findings in XLH patients 1
1. Ruppe, MD. X-linked hypophosphatemia. In: Pagon RA, Adam MP, Ardinger HH, et al, eds. Gene Reviews. https://www.ncbi.nlm.nih.gov/books/NBK83985/. Accessed October 20, 2017. 2. Hereditary hypophosphatemic rickets. NIH Genetics Home Reference Web site. https://ghr.nlm.nih.gov/condition/hereditary-hypophosphatemic-rickets. Accessed October 11, 2017. 3. Jackson WPU, Dowdle E, Linder GC. Vitamin-D-resistant osteomalacia. Brit Med J. 1958:1269-1274. 4. Rickets and osteomalacia. NHS Choices Web site. https://www.nhs.uk/Conditions/Rickets/Pages/Treatment. Accessed October 11, 2017. 5. Familial Hypophosphatemia. National Organization for Rare Disorders Web site. https://rarediseases.org/rare-diseases/familial-hypophosphatemia/. Accessed October 11, 2017. 6. Martin A, Quarles LD. Evidence for FGF23 involvement in a bone-kidney axis regulating bone mineralization and systemic phosphate and vitamin D homeostasis. Adv Exp Med Biol. 2012;728:65-83. 7. Schiavi SC. Fibroblast growth factor 23: the making of a hormone. Kidney Int. 2006;69(3):425-427. 8. Riminucci M, Collins MT, Fedarko NS, et al. FGF-23 in fibrous dysplasia of bone and its relationship to renal phosphate wasting. J Clin Invest. 2003;112(5):683-692. 9. Ferrari SL, Bonjour J-P, Rizzoli R. Fibroblast growth factor-23 relationship to dietary phosphate and renal phosphate handling in healthy young men. J Clin Endocrinol Metab. 2005;90(3):1519-1524. 10. Che H, Roux C, Etcheto A, et al. Impaired quality of life in adults with X-linked hypophosphatemia and skeletal symptoms. Eur J Endocrinol. 2016;174(3):325-333. 11. Gattineni J, Bates C, Twombley K, et al. FGF23 decreases renal NaPi-2a and NaPi-2c expression and induces hypophosphatemia in vivo predominantly via FGF receptor 1. Am J Physiol Renal Physiol. 2009;297(2):F282-F291. 12. Carpenter TO, Imel EA, Holm IA, Jan de Beur SM, Insogna KL. A clinician's guide to X-linked hypophosphatemia. J Bone Miner Res. 2011;26(7):1381-1388. 13. Penido MG, Alon US. Phosphate homeostasis and its role in bone health. Pediatr Nephrol. 2012;27(11):2039-2048.