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PubMed This is a summary of 19 peer-reviewed journal articles Updated
Neurosurgery

XLH Symptoms and Warning Signs Across the Lifespan

At a Glance

XLH symptoms change with age: children may develop soft bones, bowed legs, waddling, and slowed growth, while adults may have bone pain, small bone cracks, stiffness, or hearing problems. Severe headaches, vision changes, new numbness or weakness, or sharp new pain need urgent care.

While the underlying cause of X-Linked Hypophosphatemia (XLH) remains the same throughout life, the way it shows up in your body changes as you grow. Because phosphate is so critical for bone hardening, the symptoms often follow the natural timeline of bone development [1][2].

Childhood: The Rickets Phase

In infants and young children, XLH primarily affects the growth plates—the areas of active bone growth near the ends of long bones. When these plates don’t mineralize (harden) properly, it results in rickets [3][4]. Active osteomalacia (softening of the bone matrix) can also occur.

  • Bowing and Alignment: As a child begins to walk and bear weight, the softened bones may curve. This most commonly appears as “bowed legs” (genu varum) or “knock-knees” (genu valgum) [5][4].
  • Waddling Gait: Due to limb bowing and muscle weakness, children often develop a distinctive “waddling” walk [6][7].
  • Growth Changes: You may notice a slowing of height growth, often leading to disproportionate short stature, where the legs appear shorter relative to the torso [5][3].
  • Physical Signs: Other signs include enlarged wrists or ankles, a prominent forehead (frontal bossing), and bone or joint pain that may make a child less active than their peers [5][7].

Adulthood: The Osteomalacia Phase

Once the growth plates close, the disease burden often shifts toward chronic pain and structural complications driven by osteomalacia—a generalized softening of the entire skeleton [8][4].

  • Pseudofractures: These are small, “incomplete” fractures (also called Looser zones) that appear as thin lines on X-rays. They occur most often in the weight-bearing bones of the legs or hips and can be very painful [8][9].
  • Enthesopathy: This is a hallmark of adult XLH where the ligaments and tendons that attach to bone begin to mineralize or “turn to bone” [4][10]. This can cause significant stiffness and reduced range of motion, particularly in the spine, hips, and ankles.
  • Joint Issues: Early-onset osteoarthritis and joint stiffness are common in many adults with XLH, though the severity of symptoms differs substantially between individuals [11][4].
  • Hearing Loss: Over time, some adults develop hearing loss or tinnitus (ringing in the ears), likely due to changes in the tiny bones or the mineralized environment of the inner ear. Because reported rates vary by study, patients should follow a defined baseline audiology plan [12].

Recognizing “Red Flags”

While chronic aches and stiffness are expected with XLH, certain symptoms indicate a complication that needs urgent medical attention.

🚨 EMERGENCY: Craniosynostosis (In Children)

Craniosynostosis occurs when the plates of a child’s skull fuse together too early. If the skull cannot expand, it may cause increased intracranial pressure (pressure inside the head) [13][14].

GO TO THE EMERGENCY DEPARTMENT NOW IF YOU NOTICE:
Persistent or worsening headaches, unexplained vomiting, or changes in vision [13][15]. An unusually long/narrow head shape (scaphocephaly) without these severe signs warrants a prompt appointment with your clinician.

🚨 EMERGENCY: Spinal Stenosis (In Adults)

Spinal stenosis is a narrowing of the spaces within your spine, which can put pressure on the nerves. This is often caused by the thickening and mineralization of spinal ligaments [16][17].

GO TO THE EMERGENCY DEPARTMENT NOW IF YOU NOTICE:
New numbness in the “saddle area” (groin/buttocks), new loss of bladder or bowel control, or rapidly progressive weakness in your legs [16][17][18].

Acute vs. Chronic Pain

Distinguishing between “normal” XLH pain and a new issue is a key skill for patients.

  • Expected XLH Pain: Typically a dull, familiar ache or stiffness that affects multiple joints or areas and stays relatively stable day-to-day [8][11].
  • Urgent Pain: A sharp, new pain in a specific spot—especially if it gets significantly worse when you try to walk or put weight on it—should be evaluated promptly by a clinician. This could indicate a new pseudofracture or a complete fracture that requires a change in your management plan [8][19]. Do not try to exercise through it.

Common questions in this guide

How do XLH symptoms differ between children and adults?
Children with XLH can develop rickets because the growth plates do not harden normally, leading to bowed legs or knock-knees, a waddling gait, and slowed or disproportionate growth. After the growth plates close, adults may develop osteomalacia with bone pain, pseudofractures, enthesopathy, stiffness, and joint problems.
What does a pseudofracture feel like in XLH?
A pseudofracture is a small, incomplete crack in a bone, often in a weight-bearing bone of the leg or hip. It may cause sharp, new, localized pain that worsens with walking or putting weight on the area and should be evaluated promptly.
Which symptoms of craniosynostosis in a child require emergency care?
Persistent or worsening headaches, unexplained vomiting, or changes in vision can signal increased pressure inside the skull and require emergency evaluation. An unusually long or narrow head shape without these severe symptoms still warrants a prompt appointment with the child's clinician.
What are the emergency warning signs of spinal stenosis in adult XLH?
New numbness in the saddle area, meaning the groin or buttocks, new loss of bladder or bowel control, or rapidly progressive weakness in the legs can mean that spinal nerves are being compressed. Go to an emergency department immediately if any of these symptoms occur.
Can XLH cause hearing loss or ringing in the ears?
Some adults with XLH develop hearing loss or tinnitus, which is ringing in the ears. Because reported rates vary, ask your care team to set a baseline hearing test and decide how often screening is needed.
How can I tell routine XLH pain from pain that needs urgent evaluation?
Routine XLH pain is often a familiar, dull ache or stiffness in several joints or areas that stays fairly stable. New sharp pain in one spot, especially pain that worsens with walking or weight-bearing, should be checked promptly because it may indicate a pseudofracture or complete fracture.

Questions to Ask Your Doctor

Curated prompts to bring to your next appointment.

  1. 1.In my (or my child's) case, how do we differentiate between routine XLH bone pain and the pain of a new pseudofracture?
  2. 2.What specific changes in head shape or neurologic symptoms should trigger an immediate call to your office or a neurosurgical referral?
  3. 3.Given the risk of spinal stenosis in adults, what baseline neurologic tests or imaging do you recommend I have now?
  4. 4.Are there specific physical activities I should avoid to prevent pseudofractures or to protect my joints?
  5. 5.How often should my (or my child's) hearing be screened as part of routine XLH monitoring?

Questions For You

Tap a prompt to share your answer — we'll use it plus this page's context to start a tailored conversation.

References

References (19)
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    Mineralized tissues in hypophosphatemic rickets.

    Robinson ME, AlQuorain H, Murshed M, Rauch F

    Pediatric nephrology (Berlin, Germany) 2020; (35(10)):1843-1854 doi:10.1007/s00467-019-04290-y.

    PMID: 31392510
  2. 2

    The Diagnosis and Therapy of XLH.

    Böckmann I, Haffner D

    Calcified tissue international 2025; (116(1)):66 doi:10.1007/s00223-025-01374-w.

    PMID: 40295317
  3. 3

    Diagnosis and management of X-linked hypophosphatemia in children and adolescent in the Gulf Cooperation Council countries.

    Al Juraibah F, Al Amiri E, Al Dubayee M, et al.

    Archives of osteoporosis 2021; (16(1)):52 doi:10.1007/s11657-021-00879-9.

    PMID: 33660084
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    The Lifelong Impact of X-Linked Hypophosphatemia: Results From a Burden of Disease Survey.

    Skrinar A, Dvorak-Ewell M, Evins A, et al.

    Journal of the Endocrine Society 2019; (3(7)):1321-1334 doi:10.1210/js.2018-00365.

    PMID: 31259293
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    Fibroblast growth factor 23 levels in cord and peripheral blood during early neonatal period as possible predictors of affected offspring of X-linked hypophosphatemic rickets: report of three female cases from two pedigrees.

    Nabeshima Y, Sato T, Zukeran H, et al.

    Journal of pediatric endocrinology & metabolism : JPEM 2023; (36(8)):786-790 doi:10.1515/jpem-2023-0120.

    PMID: 37342899
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    The first Korean case report with scaphocephaly as the initial sign of X-linked hypophosphatemic rickets.

    Lee KS, Lee BL

    Child's nervous system : ChNS : official journal of the International Society for Pediatric Neurosurgery 2019; (35(6)):1045-1049 doi:10.1007/s00381-018-04042-7.

    PMID: 30613854
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    X-linked Hypophosphatemic Rickets Revealed by Exome Sequencing: A Pediatric Case Report of a PHEX Pathogenic Variant.

    Larbi Ouassou K, Amale H, Abilkassem R

    Cureus 2026; (18(5)):e109583 doi:10.7759/cureus.109583.

    PMID: 42359178
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    Burosumab Improved Histomorphometric Measures of Osteomalacia in Adults with X-Linked Hypophosphatemia: A Phase 3, Single-Arm, International Trial.

    Insogna KL, Rauch F, Kamenický P, et al.

    Journal of bone and mineral research : the official journal of the American Society for Bone and Mineral Research 2019; (34(12)):2183-2191 doi:10.1002/jbmr.3843.

    PMID: 31369697
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    X-linked hypophosphatemia: Management and treatment prospects.

    Lambert AS, Zhukouskaya V, Rothenbuhler A, Linglart A

    Joint bone spine 2019; (86(6)):731-738 doi:10.1016/j.jbspin.2019.01.012.

    PMID: 30711691
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    Prevalence of enthesopathies in X-linked hypophosphatemia: an explorative ultrasound study.

    Bachfischer L, Behanova M, Rath E, et al.

    JBMR plus 2025; (9(9)):ziaf113 doi:10.1093/jbmrpl/ziaf113.

    PMID: 40800666
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    Musculoskeletal Features in Adults With X-linked Hypophosphatemia: An Analysis of Clinical Trial and Survey Data.

    Javaid MK, Ward L, Pinedo-Villanueva R, et al.

    The Journal of clinical endocrinology and metabolism 2022; (107(3)):e1249-e1262 doi:10.1210/clinem/dgab739.

    PMID: 34636401
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    The Metabolic Bone Disease X-linked Hypophosphatemia: Case Presentation, Pathophysiology and Pharmacology.

    Vincze J, Skinner BW, Tucker KA, et al.

    Life (Basel, Switzerland) 2021; (11(6)) doi:10.3390/life11060563.

    PMID: 34203792
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    X-linked hypophosphatemic rickets and sagittal craniosynostosis: three patients requiring operative cranial expansion: case series and literature review.

    Jaszczuk P, Rogers GF, Guzman R, Proctor MR

    Child's nervous system : ChNS : official journal of the International Society for Pediatric Neurosurgery 2016; (32(5)):887-91 doi:10.1007/s00381-015-2934-9.

    PMID: 26510652
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    Orthopedic and neurosurgical care of X-linked hypophosphatemia.

    Rocco FD, Rothenbuhler A, Adamsbaum C, et al.

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    Hypophosphatemic rickets and craniosynostosis: a multicenter case series.

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    X-linked hypophosphatemia and spinal cord compression: a systematic review and illustrative case.

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    Minimally Invasive Surgical Management of Thoracic Ossification of the Ligamentum Flavum Associated with X-linked Hypophosphatemia.

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    Incidence of Complications in 25 Adult Patients With X-linked Hypophosphatemia.

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  19. 19

    Case Report: Increased FGF23 and new insufficiency fractures at burosumab discontinuation in X-linked hypophosphatemia.

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This page is for informational purposes only and does not constitute medical advice. Ask your XLH care team to interpret symptoms, and seek emergency care for severe headaches, vomiting, vision changes, saddle-area numbness, loss of bladder or bowel control, or rapidly worsening leg weakness.

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