25-Hydroxycholecalciferol. A comparative study in deficiency rickets and different types of resistant rickets.
The effects of 25-hydroxycholecalciferol were studied in 4 children with deficiency rickets and 22 children with D-resistant rickets, including patients with hereditary hypophosphatemic D-resistant rickets, "pseudo-deficiency" rickets, and rickets secondary to cystinosis or to tyrosinosis. Three protocols were used. (a) 8 days after a single oral dose of 16,000 IU of 25-hydroxycholecalciferol, normalization of all biological parameters was observed in all cases of deficiency rickets. A complete lack of response was observed in the different types of resistant rickets. (b) Under prolonged administration of 2,640 IU/day for 2 months, clinical-biological symptoms and X-ray lesions disappeared, and a catch-up growth pattern was observed in deficiency rickets; no relapse of rickets occurred up to 5 months after therapy was stopped. The same dose had no significant effect in 10 patients with hereditary hypophosphatemic D-resistant rickets. A bone biopsy performed in one case showed the persistence of characteristic lesions. (c) With increasing doses of 25-hydroxycholecalciferol varying from 6,000 to 30,000 IU/day and a follow-up of 6 months up to 2 yr duration, clinical-biological-radiologic recovery and catch-up growht was obtained in all cases of "pseudo-deficiency" rickets. In hypophosphatemic hereditary D-resistant rickets, 5 out of 13 patients' serum concentration of phosphorus reached at least 30 mg/liter, but a catch-up growth pattern was not observed. These results indicate that (a) 25-hydroxycholecalciferol is highly active in deficiency rickets; (b) a defect in the conversion of vitamin D(3) to its active 25-hydroxy metabolite is probably not the metabolic defect in any of the different types of vitamin D-resistant rickets studied.
D000284:Administration, Oral; D000469:Alkaline Phosphatase / Q000097:blood; D000592:Amino Acid Metabolism, Inborn Errors / Q000150:complications; D001842:Bone and Bones / Q000000981:diagnostic imaging; D002118:Calcium / Q000097:blood; D002675:Child, Preschool; D002762:Cholecalciferol / Q000627:therapeutic use*; D002951:Citrates / Q000097:blood; D002986:Clinical Trials as Topic; D003554:Cystinosis / Q000150:complications; D004351:Drug Resistance; D005069:Evaluation Studies as Topic; D006801:Humans; D006887:Hydroxycholecalciferols / Q000008:administration & dosage / Q000627:therapeutic use; D007015:Hypophosphatemia, Familial / Q000188:drug therapy* / Q000235:genetics; D007223:Infant; D008274:Magnesium / Q000097:blood; D008852:Microradiography; D010758:Phosphorus / Q000097:blood; D012279:Rickets / Q000188:drug therapy*; D014443:Tyrosine / Q000378:metabolism
D002951:Citrates; D006887:Hydroxycholecalciferols; D002762:Cholecalciferol; D010758:Phosphorus; D014443:Tyrosine; D000469:Alkaline Phosphatase; D008274:Magnesium; D002118:Calcium