Hypophosphatemic rickets

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

Hypophosphatemic rickets is a genetic condition. This puts your children at risk to inherit the gene mutation that causes the disease. The chance that your child would inherit the condition depends on the inheritance pattern in your family. Hypophosphatemic rickets is most commonly inherited in an X-linked dominant pattern, but some families have been found to have an X-linked recessive, autosomal dominant and autosomal recessive inheritance patterns. To learn about which inheritance pattern is in your family and the specific risks to your future children, we recommend that you consult with a genetics professional.

Last updated on 05-01-20

What causes hypophosphatemic rickets?

Hypophosphatemic rickets is almost always hereditary and may be caused by mutations in any of several genes. The specific gene involved determines the way it is inherited.

Most commonly, it is caused by a mutation in the PHEX gene. Other genes that can be responsible for the condition include the CLCN5, DMP1, ENPP1, __FGF23, _ and SLC34A3_ genes.

The genes associated with hereditary hypophosphatemic rickets are involved in keeping a proper balance of phosphate in the body. Many of these genes directly or indirectly regulate a protein that normally inhibits the kidneys' ability to reabsorb phosphate into the blood. Mutations affecting the function of these genes increase the production (or reduce the breakdown) of the protein, causing the protein to be overactive. The overactivity of the protein reduces phosphate reabsorption by the kidneys, leading to the features of the condition.

Rarer, sporadic, acquired cases are sometimes associated with benign (non- cancerous) mesenchymal tumors that decrease resorption of phosphate.

Last updated on 05-01-20

How is hypophosphatemic rickets inherited?

Hypophosphatemic rickets is most often inherited in an X-linked dominant manner. This means that the gene responsible for the condition is located on the X chromosome, and having only one mutated copy of the gene is enough to cause the condition.

Because males have only one X chromosome (and one Y chromosome) and females have two X chromosomes, X-linked dominant conditions affect males and females differently. Both males and females can have an X-linked dominant condition. However, because males don't have a second, working copy of the gene (as females do), they usually have more severe disease than females.

If a father has the mutated X-linked gene:

  • all of his daughters will inherit the mutated gene (they will all receive his X chromosome)
  • none of his sons will inherit the mutated gene (they only inherit his Y chromosome)

If a mother has the mutated X-linked gene, each of her children (both male and female) has a 50% chance to inherit the mutated gene.

Less commonly, hypophosphatemic rickets is inherited in an X-linked recessive, autosomal dominant, or autosomal recessive manner.

Last updated on 05-01-20

Can males with X-linked hypophosphatemic rickets pass the condition to their children?

Yes. Males with X-linked hypophosphatemic rickets will always pass the condition to their daughters, but never pass the condition to their sons.

X-linked hypophasphatemic rickets (XLH) is most often inherited in an X-linked dominant fashion. XLH occurs when a person inherits one copy of a PHEX gene mutation. PHEX is located on the X chromosome. X chromosomes are one of the two sex chromosomes. Females have two X chromosomes. Males have a X and a Y chromosome.

Females with a PHEX mutation on one copy of their X chromosomes have XLH. Women with XLH have a 1 in 2 or 50% chance with each pregnancy of passing XLH to their offspring, regardless of the child's gender.

Males who inherit a PHEX mutation on their X chromosome also have XLH. A male will always pass his Y chromosome to his male offspring (who will be unaffected), and his X chromosome with the PHEX mutation to his daughters (who will be affected).

Last updated on 05-01-20

Can hypophosphatemic rickets lead to frequent dental abscesses?

The presence of severe dental complications among people with Hypophosphatemic Rickets is now well recognized and is an important part of symptom management . Spontaneous dental abscesses are frequently encountered in hypophosphatemic rickets. Both primary and permanent teeth may be affected. 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.

Last updated on 05-01-20

How might the dental features of hypophosphatemic rickets be managed?

The challenge for the dentist is to prevent and treat these lesions. The use of calcitriol and phosphate helps to insure good dentin development and mineralization, and may prevent clinical anomalies such as the dental necrosis classically associated with the disease. Topical application of fluoride to the teeth and the use of fissure sealants may also be useful in preventing dental disease. Starting treatment during early childhood and good adherence to the therapy are necessary to observe beneficial effects.

If dental features are already present, the use of non-surgical root canal and partial or full crowns may be utilized.

Last updated on 05-01-20

How are adults with hypophosphatemic rickets treated?

The goal of treatment of adults with hypophosphatemic rickets is to manage bone pain and in some cases aid in the healing of bone fracture. Adults with hypoposphatemic rickets that are not experiencing symptoms may not benefit from therapy, but could experience therapy related complication (e.g., nephrocalcinosis and hyperparathyroidism). Treatment for symptomatic adults involves daily divided doses of Calcitriol and phosphate. Adults with hypophospatemic rickets undergoing treatment should carefully follow their prescribed dosing schedule. All adults with hypophosphatemic rickts should be regularly monitored for serum phosphorus, calcium, creatinine, and PTH.

Last updated on 05-01-20

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, due to low levels of phosphate in the blood. Symptoms usually begin in early childhood and can range in severity. Severe forms may cause bowing of the legs and other bone deformities; bone pain; joint pain; poor bone growth; and short stature. In some affected babies, the space between the skull bones closes too soon (craniosynostosis). This sometimes results in developmental abnormalities.

Hypophosphatemic rickets is almost always inherited and may be caused by changes (mutations) in any of several genes. There are several forms which are distinguished by their genetic cause and pattern of inheritance. Most commonly hypophosphatemic rickets is due to changes in the PHEX gene and inherited in an X-linked dominant manner (X-linked hypophosphatemia). Less commonly it is inherited in an X-linked recessive manner (often called Dent disease); autosomal dominant manner; or autosomal recessive manner. Treatment involves taking phosphate and calcitriol in order to raise phosphate levels in the blood and promote normal bone formation.

Last updated on 05-01-20

If a person with X-linked hypophosphatemic rickets increases their vitamin D intake, will their calcium levels rise?

Yes. Taking the activated form of vitamin D, called calcitriol, is a standard part of XLH treatment in children and is considered for adults with XLH in certain situations (e.g., those with skeletal pain, recurring bone fractures, upcoming orthopedic surgery, or osteomalacia with high alkaline phosphatase). Calcitriol increases calcium levels by promoting calcium absorption in the intestines, and calcium retention in kidneys. This is done carefully because over treatment with calcitrol can lead to too much calcium which can harm the kidneys and other body tissues.

Last updated on 05-01-20

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.
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed

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 http://nnlm.gov/members/. You can also contact the NLM toll-free at 888-346-3656 to locate libraries in your area.

Last updated on 05-01-20

What is the long-term outlook for people with hypophosphatemic rickets?

The long-term outlook (prognosis) for people with hypophosphatemic rickets is good. With appropriate management, normal health and normal lifespan are expected.

If the condition is not treated (especially while children are growing), skeletal deformities may be permanent.

Last updated on 05-01-20

How are high calcium levels in adults with hypophosphatemic rickets treated?

High levels of calcium in adults with hypophosphatemic rickets may be due to an excessive calcitriol dose or inadequate dosing of phosphate. Treatment of high calcium levels in adults may involve adjusting calcitrol or phosphate dosing levels/schedule. We strongly encourage you to talk with your healthcare provider regarding your high calcium levels and treatment options.

Last updated on 05-01-20

Name: XLH Network 911 Central Ave., #161
Albany, NY, 12206, United States
Phone: 518-350-4954 Fax : 855-318-7132 Email: info@xlhnetwork.org Url: http://www.xlhnetwork.org/
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Email: info@gaciglobal.org Url: https://gaciglobal.org Contact form: https://gaciglobal.org/about-us/contact-us/

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