is a progressive disease characterized by chronic hypophosphataemia due to increased fibroblast growth factor (FGF23) activity, resulting in skeletal defects, muscular dysfunction, and dental abnormalities.1,2

—Dr. Thomas Carpenter, XLH expert

XLH is inherited within families but about 20% to 30% of cases may arise spontaneously.3 With XLH, increased FGF23 activity leads to chronic hypophosphataemia manifesting as rickets and osteomalacia in children and osteomalacia in adults, the sources of progressive and compounding symptoms of XLH. 1,2,4

XLH Diagnostic Overview

Learn how to recognize and assess XLH in your patients


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The Impact of XLH

XLH can create a significant burden in the daily lives of children.5


Unresolved symptoms in adults can result in disability.6,7

—Sean and James Cooney, XLH Patients


1. 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. 2. Ruppe MD. X-Linked Hypophosphatemia. In: Adam MP, Ardinger HH, Pagon RA, et al, eds. GeneReviews® [Internet]. Seattle (WA): University of Washington, Seattle; 1993-2017. 3. Gaucher C, Walrant-Debray O, Nguyen TM, Esterle L, Garabedian M, Jehan F. PHEX analysis in 118 pedigrees reveals new genetic clues in hypophosphatemic rickets. Hum Genet. 2009;125(4):401-411. 4. Linglart A, Biosse-Duplan M, Briot K, et al. Therapeutic management of hypophosphatemic rickets from infancy to adulthood. Endocr Connect. 2014;3(1):R13-30. 5. Klepper S. Measures of pediatric function: Child Health Assessment Questionnaire (C-HAQ), Juvenile Arthritis Functional Assessment Scale (JAFAS), Pediatric Outcomes Data Collection Instrument (PODCI), and Activities Scale for Kids (ASK). Arthritis Care Res. 2011;63:S371-S382. doi:10.1002/acr.20635. 6. Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). American College of Rheumatology Website. https://www.rheumatology.org/I-Am-A/Rheumatologist/Research/Clinician-Researchers/Western-Ontario-McMaster-Universities-Osteoarthritis-Index-WOMAC. Accessed March 1, 2018. 7. Skrinar A, Dvorak-Ewell M, Evins A, et al. The lifelong impact of X-linked hypophosphatemia: results from a burden of disease survey. J Endocr Soc. 2019;3(7):1321-1334.