Serum 1,25-Dihydroxyvitamin D in Bone Disease

To the Editor: In a recent paper¹ Scriver et al. stated that in patients with hypophosphatemic bone disease, active rickets is not observed, while serum phosphate is low and the level of 1α,25-dihydroxyvitamin D is normal. On the other hand, in patients with X-linked hypophosphatemia rachitic bone disease is present with similarly low levels of serum phosphate and decreased concentrations of 1α,25-dihydroxyvitamin D. This finding encouraged the authors to believe that a normal level of 1α,25-dihydroxyvitamin D prevents severe bone demineralization or, perhaps better, severe impairment of mineralization. It is possible to agree with this line of thought if the.