Supranormal 25-hydroxyvitamin D and subnormal 1,25-dihydroxyvitamin D: their role in X-linked hypophosphatemic rickets.

Abstract

Serum 25-hydroxyvitamin D (25-OH-D) and 1,25-dihydroxyvitamin D (1,25-(OH)2D) and bone mineral content by the photon-absorption technique were determined in eight patients with X-linked hypophosphatemic rickets treated for at least 24 months with oral sodium phosphate and high-dosage ergocalciferol (vitamin D2). Mean 25-OH-D2 level was 129.5 +/- 67.5 ng/mL (mean +/- SD); the level of 25-OH-D3 was 10.5 +/- 5.8 ng/mL. These values were significantly higher than in normal subjects (total 25-OH-D mean of 27 +/- 10 ng/mL). Serum 1,25-(OH)2D was 16.9 +/- 8.5 pg/mL (mean +/- SD) in the eight patients, significantly lower than 47 +/- 16 pg/mL in 27 age-matched controls. Values indicative of significant demineralization were found in seven of the eight phsophate-treated patients, who had no radiologic evidence of rickets. These results suggest that any theory of the pathogenesis of this disorder must account for inappropriate renal vitamin D metabolism and for renal hyperphosphaturia. The failure of high-dosage oral phosphate and ergocalciferol to fully correct demineralization may suggest a role for calcitriol (1,25-(OH)2D3) as a therapeutic agent.

• Authors: R W Chesney, R B Mazess, P Rose, A J Hamstra, H F DeLuca
• Journal: American journal of diseases of children (1960) (Am J Dis Child) Vol. 134 Issue 2 Pg. 140-3 (Feb 1980) ISSN: 0002-922X [Print] United States
• PMID: 6243443 (Publication Type: Journal Article, Research Support, U.S. Gov't, P.H.S.)

Chemical References

• Dihydroxycholecalciferols
• Ergocalciferols
• Hydroxycholecalciferols
• Parathyroid Hormone
• Phosphates
• Alkaline Phosphatase
• Magnesium
• Calcium

Topics

• Absorption
• Adolescent
• Alkaline Phosphatase (blood)
• Bone and Bones (metabolism)
• Calcium (blood)
• Child
• Child, Preschool
• Dihydroxycholecalciferols (blood)
• Ergocalciferols (therapeutic use)
• Female
• Humans
• Hydroxycholecalciferols (blood)
• Hypophosphatemia, Familial (blood, drug therapy)
• Light
• Magnesium (blood)
• Male
• Parathyroid Hormone (blood)
• Phosphates (blood, therapeutic use)