X-Linked Hypophosphatemia

PHEX-related hereditary phosphate-wasting rickets driven by elevated FGF23.

Written by: Saygı Hospital Health Guide Editorial Board

Last updated: June 11, 2026

This content has been compiled by the Saygı Hospital Health Guide Editorial Board and is periodically reviewed by a specialist physician.

References (5)

This content is for informational purposes only and does not constitute medical advice. You can book an appointment at our Endokrinoloji department. Book Appointment →

What is X-Linked Hypophosphatemia?

X-linked hypophosphatemia (XLH) is an X-dominant disorder caused by loss-of-function mutations in the PHEX gene, leading to elevated FGF23, renal phosphate wasting and impaired 1,25-OH vitamin D synthesis.

Phenotype includes rickets in childhood, short stature, lower-limb deformities, dental abscesses and adult osteomalacia. Severity varies even within families.

Diagnosis is based on persistent hypophosphatemia with low/normal 1,25-OH vit D, elevated alkaline phosphatase, increased FGF23 levels and confirmation by PHEX gene analysis.

Symptoms

Bowing of the legs (genu varum/valgum)

Short stature and gait disturbance

Bone pain and limp

Dental abscesses and enamel defects

Frontal bossing in childhood

Stress fractures and pseudofractures in adults

Joint stiffness and enthesopathy

Risk Factors

Affected parent (X-linked dominant)

Family history of rickets or osteomalacia

PHEX gene mutation

Recurrent dental abscesses in childhood

Female carriers may be mildly affected

When to See a Doctor?

If you experience any of the following symptoms, seek medical attention promptly:

Bowing of legs in a toddler
Persistent low serum phosphate with normal calcium
Multiple dental abscesses without caries
Family history of XLH or hereditary rickets
Adult-onset bone pain with prior childhood rickets

Treatment Methods

Burosumab (anti-FGF23 monoclonal antibody) — first-line in eligible patients

Conventional therapy: oral phosphate supplements with active vitamin D (calcitriol/alfacalcidol)

Orthopedic correction of severe limb deformities

Dental and ENT surveillance

Multidisciplinary follow-up (endocrinology, pediatrics, dentistry)

Genetic counseling for the family

Which Department to Visit?

You can visit our Endokrinoloji department for these complaints. Our specialist physicians will create the most suitable treatment plan for you.

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Let us help you

You can make an appointment with our specialists or contact us for your concerns.

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Health Disclaimer: The information on this page is prepared for general informational purposes only. It does not replace medical diagnosis and treatment. Please consult your physician for your complaints. Saygı Hospital does not accept responsibility for actions taken based on the information on this page.