• The levels of vitamin D metabolites were measured in three children with a decreased dietary intake of calcium and vitamin D and sun exposure. All three children had hypocalcemia, hypophosphatemia, and elevated alkaline phosphatase activities. Two children had rickets, aminoaciduria, and elevated immunoreactive parathyroid hormone (iPTH) concentrations. The concentrations of vitamins D2 and D3, 25-hydroxyvitamins D2 and D3 (25-OH-D2 and 25-OH-D3), and 24,25-dihydroxyvitamin D (24,25-[OH]2D) were reduced. Nonetheless, the levels of calcitriol (1,25-[OH]2D) were normal. The combination of hypocalcemia, hypophosphatemia, and increased iPTH concentrations should result in supranormal calcitriol concentrations. Moreover, the ratio of PTH to calcitriol is significantly higher than in normal subjects. Accordingly, in patients with vitamin D deficiency and "normal" calcitriol values, the synthesis of this compound may be reduced. The evaluation of vitamin D deficiency should include the measurement of all metabolites.
(Am J Dis Child 1981;135:1025-1028)
Chesney RW, Zimmerman J, Hamstra A, DeLuca HF, Mazess RB. Vitamin D Metabolite Concentrations in Vitamin D Deficiency: Are Calcitriol Levels Normal? Am J Dis Child. 1981;135(11):1025–1028. doi:10.1001/archpedi.1981.02130350029010
Coronavirus Resource Center
Customize your JAMA Network experience by selecting one or more topics from the list below.
Create a personal account or sign in to: