Long-term nocturnal calcium infusions can cure rickets and promote normal mineralization in hereditary resistance to 1,25-dihydroxyvitamin D.
We report the beneficial effects of calcium infusions in a child with hereditary resistance to 1,25(OH)2D and alopecia. This patient after transient responsiveness to vitamin D derivatives became unresponsive to all therapy despite serum 1,25(OH)2D concentrations maintained at levels approximately 100-fold normal. A 7-mo trial with calcium infusions led to correction of biochemical abnormalities and healing of rickets. Bone biopsies (n = 3) showed a normal mineralization and the disappearance of the osteomalacia. Cultures of bone-derived cells demonstrated a lack of activation of 25-hydroxyvitamin D 24-hydroxylase and osteocalcin synthesis by 1,25(OH)2D3 (10(-9) and 10(-6) M). These results demonstrate that even in the absence of a normal 1,25(OH)2D3 receptor-effector system in bone cells, normal mineralization can be achieved in humans if adequate serum calcium and phosphorus concentrations are maintained; and calcium infusions may be an efficient alternative for the management of patients with this condition who are unresponsive to large doses of vitamin D derivatives.
D001842:Bone and Bones / Q000000981:diagnostic imaging / Q000473:pathology; D002112:Calcifediol / Q000097:blood / Q000627:therapeutic use; D002117:Calcitriol / Q000097:blood / Q000627:therapeutic use*; D002118:Calcium / Q000097:blood / Q000627:therapeutic use*; D002135:Calcium-Binding Proteins / Q000096:biosynthesis; D002478:Cells, Cultured; D002648:Child; D003577:Cytochrome P-450 Enzyme System; D005260:Female; D006801:Humans; D007015:Hypophosphatemia, Familial / Q000097:blood / Q000188:drug therapy*; D007785:Lactose / Q000627:therapeutic use; D015675:Osteocalcin; D010012:Osteogenesis / Q000187:drug effects*; D010758:Phosphorus / Q000097:blood; D011859:Radiography; D013250:Steroid Hydroxylases / Q000032:analysis; D065668:Vitamin D3 24-Hydroxylase
D002135:Calcium-Binding Proteins; D015675:Osteocalcin; D010758:Phosphorus; D003577:Cytochrome P-450 Enzyme System; D013250:Steroid Hydroxylases; D065668:Vitamin D3 24-Hydroxylase; D002117:Calcitriol; D007785:Lactose; D002112:Calcifediol; D002118:Calcium