This information is provided by the National Institutes of Health (NIH) Genetic and Rare Diseases Information Center (GARD).
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.
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