Osteomalacia in adults

Learn more about this key feature of XLH.

Osteomalacia is characterized by progressive weakening of the bones that can occur in children and adults, possibly due to a decreased amount of phosphate in the body. Osteomalacia is a hallmark of XLH and can lead to worsening symptoms if left untreated.


Symptoms of osteomalacia can present as bone pain, muscle weakness, fractures, difficulty walking, and muscle spasms. Bones in the feet, legs, and hips are the most vulnerable to worsening symptoms due to bearing the most weight. Osteomalacia is characterized by the bowing in or out of the legs, which leads to short stature and a wobbly walk.


Diagnosis of osteomalacia is mostly dependent on physical presentation, low phosphate levels, high alkaline phosphatase (ALP), and X-ray evaluation. Phosphate and ALP are tested through blood work that can be taken with other routine lab tests at a doctor’s office. An X-ray is a quick, painless test that produces an image of the bones to help diagnosis diseases such as osteomalacia.


Recognizing XLH and establishing care at a young age can help slow disease progression and manage ongoing symptoms.

Learn more about symptoms of XLH in adults

See the signs and symptoms