Autosomal dominant hypophosphatemic rickets
Encyclopedia
Autosomal dominant hypophosphatemic rickets (ADHR) is a rare hereditary disease
in which excessive loss of phosphate
in the urine
leads to poorly formed bones (rickets
), bone pain
, and tooth abscess
es. ADHR is caused by a mutation in the fibroblast growth factor 23
(FGF23). ADHR affects men and women equally; symptoms may become apparent at any point from childhood through early adulthood. Blood tests reveal low levels of phosphate (hypophosphatemia
) and inappropriately normal levels of vitamin D
. Treatment consists of increasing phosphate intake and high doses of vitamin D. Occasionally, hypophosphatemia may improve over time as urine losses of phosphate partially correct.
Genetic disorder
A genetic disorder is an illness caused by abnormalities in genes or chromosomes, especially a condition that is present from before birth. Most genetic disorders are quite rare and affect one person in every several thousands or millions....
in which excessive loss of phosphate
Phosphate
A phosphate, an inorganic chemical, is a salt of phosphoric acid. In organic chemistry, a phosphate, or organophosphate, is an ester of phosphoric acid. Organic phosphates are important in biochemistry and biogeochemistry or ecology. Inorganic phosphates are mined to obtain phosphorus for use in...
in the urine
Urine
Urine is a typically sterile liquid by-product of the body that is secreted by the kidneys through a process called urination and excreted through the urethra. Cellular metabolism generates numerous by-products, many rich in nitrogen, that require elimination from the bloodstream...
leads to poorly formed bones (rickets
Rickets
Rickets is a softening of bones in children due to deficiency or impaired metabolism of vitamin D, magnesium , phosphorus or calcium, potentially leading to fractures and deformity. Rickets is among the most frequent childhood diseases in many developing countries...
), bone pain
Bone pain
Bone pain is a debilitating form of pain emanating from the bone tissue. It occurs as a result of a wide range of diseases and/or physical conditions and may severely impair the quality of life for patients who suffer from it...
, and tooth abscess
Abscess
An abscess is a collection of pus that has accumulated in a cavity formed by the tissue in which the pus resides due to an infectious process or other foreign materials...
es. ADHR is caused by a mutation in the fibroblast growth factor 23
Fibroblast growth factor 23
Fibroblast growth factor 23 or FGF23 is a protein that in humans is encoded by the FGF23 gene. FGF23 is a member of the fibroblast growth factor family which is responsible for phosphate metabolism.- Function :...
(FGF23). ADHR affects men and women equally; symptoms may become apparent at any point from childhood through early adulthood. Blood tests reveal low levels of phosphate (hypophosphatemia
Hypophosphatemia
Hypophosphatemia is an electrolyte disturbance in which there is an abnormally low level of phosphate in the blood. The condition has many causes, but is most commonly seen when malnourished patients are given large amounts of carbohydrates, which creates a high phosphorus demand by cells,...
) and inappropriately normal levels of vitamin D
Vitamin D
Vitamin D is a group of fat-soluble secosteroids. In humans, vitamin D is unique both because it functions as a prohormone and because the body can synthesize it when sun exposure is adequate ....
. Treatment consists of increasing phosphate intake and high doses of vitamin D. Occasionally, hypophosphatemia may improve over time as urine losses of phosphate partially correct.