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Genetic and Rare Diseases Information Center (GARD)

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Hypophosphatemic rickets

Other Names for this Disease
  • HYP
  • Hypophosphatemia, X-linked
  • Hypophosphatemia, vitamin D-resistant rickets
  • Vitamin D-resistant rickets, X-linked
  • XLH
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Your Question

My son has hypophosphatemic rickets and frequently develops abscesses in his mouth. Our doctor believes this is due to the weakened bones caused by this condition. Can you give me more information on this?

Our Answer

We have identified the following information that we hope you find helpful. If you still have questions, please contact us.

What is hypophosphatemic rickets?

Hypophosphatemic rickets (previously called vitamin D-resistant rickets) is a disorder in which the bones become painfully soft and bend easily because the blood contains low levels of phosphate and has inadequate amounts of the active form of vitamin D.[1] The condition can be caused by mutations in the phosphate-regulating endopeptidase gene, also known as the PHEX gene and is nearly always inherited.[2] The aim of treatment is to raise phosphate levels in the blood, which will promote normal bone formation. Phosphate can be taken by mouth and should be combined with calcitriol, the activated form of vitamin D.[1]
Last updated: 9/17/2009

What symptoms are associated with hypophosphatemic rickets?

The symptoms of hypophosphatemic rickets usually begin in the first year of life and can vary greatly from child to child.  The condition can be so mild that it produces no noticeable symptoms at all, to so severe that it produces bowing of the legs and other bone deformities, bone pain, and short stature. Other symptoms may include limited joint movement in children with bony outgrowth in areas where muscles attach to bones. Also the skull bones in babies with hypophosphatemic rickets may close too soon, leading to seizures.[1]
Last updated: 9/13/2009

Can hypophosphatemic rickets lead to frequent dental abscesses?

Spontaneous dental abscesses are frequently encountered in hypophosphatemic rickets.[3][4][5] Both primary and permanent teeth may be affected.[5] These abscesses occur in the absence of a history of trauma or dental decay and result from hypomineralization of the dentine and enlargement of the pulp.[3][4][6] 
Last updated: 9/13/2009

How might the dental features of hypophosphatemic rickets be managed?

The challenge for the dentist is to prevent and treat these lesions.[4][6] Treatment of children with hypophosphatemic rickets with 1-(OH) vitamin D and oral phosphate helps to insure good dentin development and mineralization, and may prevent clinical anomalies such as the dental necrosis classically associated with the disease. Starting treatment during early childhood and good adherence to the therapy are necessary to observe these beneficial effects.[7] If dental features are already present, the application of fluid resin composites with a self-etching primer bonding system to all primary teeth has been shown to prevent abscess formation in some individuals for more than 1 year. This may lead to the avoidance of endodontic treatment or extraction down the line.[4]

Last updated: 9/13/2009

Where can I learn more about the dental issues faced by individuals with hypophosphatemic rickets?

You can find relevant journal articles on dental abcesses in patients with hypophosphatemic rickets through a service called PubMed, a searchable database of medical literature. Information on finding an article and its title, authors, and publishing details is listed here.  Some articles are available as a complete document, while information on other studies is available as a summary abstract.  To obtain the full article, contact a medical/university library (or your local library for interlibrary loan), or order it online using the following link. Using "hypophosphatemic rickets AND abscesses" as your search term should locate articles. To narrow your search, click on the “Limits” tab under the search box and specify your criteria for locating more relevant articles.  Click here to view a search.

The National Library of Medicine (NLM) Web site has a page for locating libraries in your area that can provide direct access to these journals (print or online). The Web page also describes how you can get these articles through interlibrary loan and Loansome Doc (an NLM document-ordering service). You can access this page at the following link You can also contact the NLM toll-free at 888-346-3656 to locate libraries in your area.

Last updated: 9/13/2009