XLH and Vitamin D

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by Emily Malcolm |

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X-linked hypophosphatemia (XLH) is a genetic disease caused by mutations in a gene called PHEX. These mutations lead to excessive amounts of a protein called FGF23. High FGF23 levels cause the body to lose phosphate in urine, instead of retaining it.

This drop in the amount of phosphate available in your system affects and weakens your bones, and bone deformities are among the hallmark symptoms of XLH.

What is vitamin D?

Vitamins are compounds that your body needs to grow and develop normally. Vitamin D helps your body absorb calcium from your diet; calcium, along with phosphate, is essential for healthy bones and teeth.

Vitamin D deficiency, especially in childhood, can cause many complications. These include a condition known as rickets, characterized by the softening of bones, bowing of legs, and delayed growth and abnormal stature — and treated with vitamin D and calcium supplements.

The form of rickets associated with XHL, however, differs.

Why doesn’t vitamin D alone treat XLH?

Vitamin D affects the uptake of calcium from the diet. XLH is caused by a lack of phosphate and is not linked to deficiencies in vitamin D or calcium. For this reason, vitamin D alone cannot slow or reverse the progression of this disease.

What treatments can help?

Supplements containing phosphate in combination with vitamin D and calcium (often in form of high-dose calcitriol) can help to slow disease progression in children with XLH and to ease pain in adults. Such supplements are usually given to children through their growth years.

Early diagnosis is key, as a prolonged loss of phosphate can cause irreparable damage to bones and teeth, as well as stunted growth.


Last updated: Dec. 8, 2019


XLH News Today is strictly a news and information website about the disease. It does not provide medical advice, diagnosis, or treatment. This content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health providers with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on this website.