National Center for Advancing and Translational Sciences Genetic and Rare Diseases Information Center, a program of the National Center for Advancing and Translational Sciences

Hypophosphatemic rickets

Back to List of Questions
If vitamin D is increased will calcium levels raise higher than they usually are? Because I have x-linked vitamin D resistant rickets, can any of my boys who inherited this disease, pass it on to their children? I was told "no" by one doctor and "yes" by another. Thank you for checking on this for us.

The following information may help to address your question:


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.[1] This is done carefully because over treatment with calcitrol can lead to too much calcium which can harm the kidneys and other body tissues.[2]
Last updated: 3/2/2016

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.[3]

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.[3]

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.[3]

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).[3]
Last updated: 3/2/2016

We hope this information is helpful. We strongly recommend you discuss this information with your doctor. If you still have questions, please contact us.

Warm regards,
GARD Information Specialist

Please see our Disclaimer.

  1. James CM Chan, Karl S Roth. Hypophosphatemic Rickets: Treatment & Medication. eMedicine. December 2, 2015; http://emedicine.medscape.com/article/922305-treatment.
  2. Ruppe MD. X-linked Hypophosphatemia. GeneReviews. October 16, 2014; http://www.ncbi.nlm.nih.gov/books/NBK83985/#rickets-xlh.Management_1. Accessed 11/11/2015.
  3. Hereditary hypophosphatemic rickets. Genetics Home Reference. September 2010; http://ghr.nlm.nih.gov/condition/hereditary-hypophosphatemic-rickets. Accessed 12/13/2016.