Signs and symptoms of XLH in adults

X-linked hypophosphatemia (XLH) may have been diagnosed during childhood, but the effects of an ongoing condition do not go away with time.


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Osteomalacia, the softening and weakening of bones, continues into adulthood. As a result, new symptoms may continue to appear or existing symptoms may worsen over time, which can limit the body’s movements. Understanding the progression of XLH and how the symptoms may affect daily life can help you or your loved one prepare for the challenges ahead.



Phosphate plays an important role in the development and growth of the bones. Low phosphate levels in the blood result in poor bone mineralization, which can impact bone health and function. Over time, new or worsening symptoms can appear if left unresolved from childhood.

Short stature: XLH symptom in adults

Short stature

Osteomalacia: XLH symptom in adults

Osteomalacia, which is the softening of bones due to poor mineralization

Bone and joint pain: XLH symptoms in adults

Bone and joint pain

Bowed legs & knock-knees: XLH symptoms in adults

Lower limb abnormalities such as bowed legs and knock-knees

Irregular head shape: XLH symptom in adults

Irregularities in the shape of the head, called craniosynostosis

Headaches: XLH symptom in adults

Headaches, often due to a condition called Chiari malformation where brain tissue may occupy space in part of the spinal canal

Enthesopathy: XLH symptom in adults

Enthesopathy or mineralization of tendons and ligaments surrounding the Achilles, knees, hips, and spine

Osteoarthritis: XLH symptom in adults

Early onset of osteoarthritis or inflammation in the bones and joints

Fractures & pseudofractures: XLH symptoms in adults

Fractures and pseudofractures (a kind of fracture where the bone thickens at the site of an injury but is not completely broken)

Hearing loss: XLH symptom in adults

Hearing loss caused by poor mineralization of the small bones in the ears



Healthy bones support the normal development of muscles in the body. Weakened leg muscles can lead to a wobbly walk (waddling gait) and impaired physical ability.
Muscle weakness: XLH symptom in adults

Muscle weakness

Muscle stiffness: XLH symptom in adults

Muscle stiffness

Muscle pain: XLH symptom in adults

Muscle pain



The health of teeth depends on the amount of phosphate in the body. Low phosphate levels can result in dental defects such as tooth pain, tooth infections, and eventual tooth loss.
Tooth abscesses: XLH symptom in adults

Tooth abscesses

Periodontitis: XLH symptom in adults

Periodontitis, a severe gum infection that can lead to tooth loss


Learn how XLH symptoms can be managed

Manage XLH