1,25-DIHYDROXYCHOLECALCIFEROL IN HYPOPHOSPHATAEMIC OSTEOMALACIA PRESENTING IN ADULTS

Abstract

ABSTRACT The effects of exogenous 1,25-dihydroxycholecalciferol (1,25(OH)2D3) in two adults with late-onset hypophosphataemic osteomalacia were studied. In the presence of elevated 25-hydroxyvitamin D levels 1,25(OH)2D3 improved intestinal 17Ca absorption and increased urinary calcium, phosphate and hydroxyproline excretion. Hypophosphataemia, parathyroid hormone and bone mineralization were not significantly affected. The rise of the 1,25-dihydroxyvitamin D concentrations was dose dependent. The results indicate that the impaired renal phosphate conservation - the primary defect in this disorder - is not corrected by exogenous 1,25-dihydroxycholecalciferol.