The bone mineral status of 17 girls with Turner's syndrome was evaluated by single photon absorptiometry. Bone mineral content (BMC) was 25.4% below that predicted by normalization for age, sex, height, weight, and bone width. Only 25% of this demineralization could be attributed to delayed skeletal maturation. Bones of girls who received estrogen replacement therapy were less demineralized than those of the others. The bone mineral deficit became less pronounced with advancing age. It could not be determined if the apparent effect of estrogens was related to age or if the apparent improvement with age was really due to an effect of estrogen treatment. For 8 subjects followed longitudinally there was no significant change in the BMC deficit.

No abstract

The bone mineral status of fifty-one children with diabetes mellitus was studied by single photon absorptiometry. The mean bone mineral content was 13% below values predicted by age, sex, height, and weight. Those children whose diabetes was one year or less in duration were as osteopenic as those whose diabetes was of longer duration. The demineralized children received a higher daily insulin dose than others. No association was noted between the degree of skeletal demineralization and sex, statural growth, renal function, and serum calcium and phosphorus. No significant changes in bone mineral content were noted longitudinally.

Vitamin D metabolites were measured in children, untreated with glucocorticoids, who had renal disease. Two groups were defined in relation to endogenous creatinine clearance values: those with impaired clearance , 0 to 48 ml/min per 1.73 m2; and those with unimpaired clearance, 75 to 150 ml/min per 1.73 m2. Serum 1.25(OH)2D was 16 +/- (SD) 12 pg/ml in impaired patients (N=24) and 48 +/- 16 pg/ml in unimpaired patients (N=18). The latter level is not different from healthy childhood controls (43 +/- 12 pg/ml; N=194). Serum samples of 25(OH)D2 and D3 were comparable in each group and not different from control values of 33.2 +/- 10.3 ng/ml. Serum 24,25(OH)2D was 0.6 +/- (SD) 0.14 ng/ml in patients with a clearance of less than 13 ml/min per 1.73 m2, 1.39 +/- 0.54 ng/ml in those with a clearance of 18 to 48 ml/min per 1.73 m2, and 152 +/- 0.91 ng/ml in patients without an impairment of clearance. Only patients with the lowest clearance had values different from control values of 1.70 +/- 0.57 ng/ml. In our study we suggest that a significant reduction in 24,25(OH)2D and 1,25(OH)2D are found at low clearance values in children with tubulointerstitial disease. Our study further suggests that a reduction in renal tubular mass is important in accounting for these changes in vitamin D metabolite values.

\s=b\Serum 25-hydroxyvitamin D (25-OH\x=req-\ D) and 1,25-dihydroxyvitamin D (1, 25\ x=req-\ (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 \m=+-\67.5 ng/mL (mean \m=+-\ SD); the level of 25-OH-D3 was 10.5 \m=+-\5.8 ng/mL. These values were significantly higher than in normal subjects (total 25-OH-D mean of 27 \m=+-\10 ng/mL). Serum 1, 25\ x=req-\ (OH)2D was 16.9 \ m=+-\8.5 pg/ml (mean \m=+-\SD) in the eight patients, significantly lower than 47 \m=+-\16 pg/mL in 27 age-matched controls. Values indicative of significant demineralization were found in seven of the eight phosphate-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.(Am J Dis Child 134: [140][141][142][143] 1980) X-linked hypophosphatemic rickets is characterized by hyperphosphaturia despite severe hypophosphatemia, by normocalcemia, and by rick¬ ets unresponsive to therapy with doses of vitamin D that cure simple vitamin D deficiency. This condition, therefore, has sometimes been called vitamin D-resistant rickets.1 The net tubular reabsorption of phosphate is decreased in all patients with this disorder.2 Two completely opposing theories of the pathogenesis of this disorder have emerged since the first clinical description in 1937 by Albright et al/ Albright and co-workers as¬ cribed the disorder to an abnormality of vitamin D metabolism that would result in intestinal calcium malabsorp¬ tion, secondary hyperparathyroidism with hyperphosphaturia, and hypophosphatemia. However, the finding of normal or only slightly elevated plasma immunoreactive parathyroid