Your browser does not support javascript:   Search for gard hereSearch for news-and-events here.

Diseases

Genetic and Rare Diseases Information Center (GARD)

Print friendly version

Hypophosphatemic rickets


Other Names for this Disease

  • HYP
  • Hypophosphatemia, X-linked
  • Hypophosphatemia, vitamin D-resistant rickets
  • Vitamin D-resistant rickets, X-linked
  • XLH
See Disclaimer regarding information on this site. Some links on this page may take you to organizations outside of the National Institutes of Health.

Your Question

I was diagnosed with hypophosphatemic rickets 24 years ago. My brother is not affected. Are my future children at risk to have this condition?

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 causes hypophosphatemic rickets?

Hypophosphatemic rickets is nearly always hereditary.[1] The specific gene involved determines the way it is inherited. X-linked hypophosphatemic (XLH) rickets is caused by mutations in the phosphate-regulating endopeptidase gene (PHEX) located on chromosome Xp22.2-p22.1.[2] Autosomal dominant hypophosphatemic rickets (ADHR) is caused by mutations in a gene encoding a member of the fibroblast growth factor family, FGF23, on chromosome 12p13.[3] Autosomal recessive hypophosphatemic rickets (ARHR) is caused by mutations in the DMP1 gene on chromosome 4q21.[4] An X-linked recessive form is caused by mutations in the CLCN5 gene at Xp11.22.[5]

The genetic defect causes a kidney abnormality that allows an inappropriately high amount of phosphate to be excreted into the urine, resulting in low levels of phosphate in the blood. Because bones need phosphate for growth and strength, this deficiency causes defective bones. In rare cases, the disorder develops as a result of certain cancers, such as giant cell tumors of bone, sarcomas, prostate cancer, and breast cancer.[1]

Last updated: 9/17/2009

How is hypophosphatemic rickets inherited?

Hypophosphatemic rickets is most often inherited as an X-linked trait. However, autosomal dominant and recessive forms, as well as X-linked recessive forms have been reported in the medical literature.[2][6]

Last updated: 9/17/2009

Because I have hypophosphatemic rickets, are my children at risk to suffer the same disorder?

Hypophosphatemic rickets is a genetic condition. This puts your offspring at risk to inherit the mutation which causes the disease. To learn more about the specific risks to your future children, we recommend that you consult with a genetics professional.
Last updated: 9/17/2009

How can I find a genetics professional in my area?

Genetics clinics are a source of information for individuals and families regarding genetic conditions, treatment, inheritance, and genetic risks to other family members. More information about genetic consultations is available from Genetics Home Reference. To find a genetics clinic, we recommend that you contact your primary healthcare provider for a referral.

The following online resources can help you find a genetics professional in your community:
Last updated: 6/5/2014

References
Other Names for this Disease
  • HYP
  • Hypophosphatemia, X-linked
  • Hypophosphatemia, vitamin D-resistant rickets
  • Vitamin D-resistant rickets, X-linked
  • XLH
See Disclaimer regarding information on this site. Some links on this page may take you to organizations outside of the National Institutes of Health.