Will I Pass XLH to My Children?

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by Emily Malcolm |

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XLH inheritance in children

If you have a rare genetic disease like X-linked hypophosphatemia (XLH), and are considering whether to have a baby, you may wonder if your children will inherit the progressive disorder. You and your partner should discuss this possibility with your doctor, who may recommend genetic testing.

What causes XLH?

Mutations in the PHEX gene cause XLH. This gene is located on the X chromosome, one of two sex-determining chromosomes. Females have two X chromosomes (one inherited from each parent). Males have one X chromosome (inherited from the mother) and one Y chromosome (inherited from the father).

PHEX provides instructions for making an enzyme that is predominantly active in the bones and teeth. This enzyme controls the synthesis of a phosphate-regulating protein called fibroblast growth factor 23 (FGF23). However, the mechanisms of this process are not well-understood.

Mutations in PHEX cause increases in circulating levels of FGF23, which decreases phosphate reabsorption in the kidneys. In turn, this causes low phosphate levels in the body and the symptoms of XLH.

How is XLH inherited?

XLH is inherited in an X-linked dominant pattern, meaning that a single copy of a disease-causing mutation can cause the disease even if the other copy of the gene is normal.

Will our children inherit XLH?

If you are the father and have XLH, but your partner does not have the disease, you will pass the disease to all your daughters, but not to your sons.

If you are the mother and have XLH, but your partner does not, your sons and daughters both will have a 50% chance of inheriting the disease.

In case both partners have the disease, you have a 25% chance of having a boy without the disease.

What are our reproductive options?

You may be able to minimize the risk of your children inheriting XLH using reproductive options such as in vitro fertilization and pre-implantation genetic diagnosis. Your baby also can undergo genetic testing before birth.

If you are planning to expand your family, you should discuss your options with your doctor and genetic counselor. They may help you determine which option is best for your family.


Last updated: Aug. 28, 2020


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.