Unresolved childhood symptoms of XLH may continue to manifest in adulthood

The lifelong presence of elevated FGF23 activity causes unresolved childhood symptoms to continue to progress into adulthood, paired with new, potentially irreversible symptoms that can appear due to ongoing active disease.1,2

Chronic hypophosphatemia is persistent among adults with XLH and may manifest as symptoms such as:

Persistent childhood symptoms

XLH symptom in adults: osteomalacia
XLH symptoms in adults: leg bowing and knock-knees
Lower extremity abnormalities (leg bowing, knock-knees, windswept deformities)4
XLH symptom in adults: short stature
Short stature2,4
XLH symptom in adults: skeletal pain
Skeletal pain2,3,5
XLH symptom in adults: craniosynostosis
XLH symptom in adults: Chiari malformation
Chiari malformations2,4

New symptoms in adulthood

XLH symptom in adults: enthesopathy
Enthesopathy (feet, knees, Achilles, hips, neck, spine)2-5
XLH symptom in adults: spinal stenosis
Spinal stenosis5
XLH symptom in adults: osteoarthritis
XLH symptoms in adults: fractures and pseudofractures
Fractures and pseudofractures2,3
XLH symptom in adults: hearing loss
Hearing loss2,4

In addition to poor bone health, chronic hypophosphatemia continues to affect the muscles in the body.5 Adults may present with:

XLH symptoms in adults: muscle pain, stiffness, and weakness
Stiffness, pain, and weakness5
XLH symptom in adults: waddling gait
Waddling gait5

Chronic hypophosphatemia can also lead to dental defects by causing enlargement of the pulp chambers and erosion of the enamel.4 Symptoms manifest as:

XLH symptom in adults: dental abscesses

Dental abscesses3,4

XLH symptom in adults: periodontitis



Video: diagnosing children with XLH

DR. THOMAS CARPENTER — XLH Treatment in adults with Dr. Carpenter

Watch Dr. Carpenter discuss the chronic symptoms in adults with XLH.

Video: diagnosing children with XLH

DR. ERIK IMEL — Treating adults with XLH: Dr. Imel Shares His Experience

Watch Dr. Imel discuss his experiences managing chronic symptoms of XLH.


1. Carpenter TO, Imel EA, Holm IA, et al. A clinician’s guide to X-linked hypophosphatemia. J Bone Miner Res. 2011;26(7):1381-1388. 2. 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. 3. Ruppe MD, Zhang X, Imel EA, et al. Effect of four monthly doses of a human monoclonal anti-FGF23 antibody (KRN23) on quality of life in X-linked hypophosphatemia. Bone Rep. 2016;5:158-162. 4. Ruppe MD. X-linked hypophosphatemia. In: Adam MP, Ardinger HH, Pagon RA, et al, eds. GeneReviews®. University of Washington, Seattle; 1993-2022. Published February 9, 2012. Updated April 13, 2017. https://www.ncbi.nlm.nih.gov/books/NBK83985/ 5. 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.