Plasma vitamin D metabolites in a patient with sporadic hypophosphataemic osteomalacia (adult-onset type).
Sporadic hypophosphataemic osteomalacia (adult-onset type) was demonstrated in a 40-year-old man on the basis of severe osteomalacia, hypophosphataemia, hyperphosphaturia and glycinuria. Plasma immunoreactive parathyroid hormone (iPTH) concentration was 9.3 ng prot./ml (normal range: 4-8 ng prot./ml). Plasma 25-hydroxy-vitamin D and 24,25-dihydroxy-vitamin D concentrations were 11 and 2.4 ng/ml respectively. Basal 1 alpha,25-dihydroxy-vitamin D concentrations were slightly elevated (116 and 96 pg/ml) and increased to 240 pg/ml after 3 days on a low-phosphorus diet. The patient was put on oral treatment with 25-hydroxycholecalciferol (100 microgram per day) and phosphorus (1500 mg per day). On the 4th month on treatment, a clinical improvement was apparent. Plasma 25(OH)D was 44 ng/ml, plasma 1,25(OH)2D was 256 pg/ml. However, plasma phosphorus remained low (0.77 mmol/l). On the 9th month of treatment a radiological improvement was evident despite a persistent hypophosphataemia (0.68 mmol/l). These facts suggest in our patient the existence of a vitamin D-independent renal phosphorus leak.
D000328:Adult; D002112:Calcifediol; D004032:Diet; D006801:Humans; D006887:Hydroxycholecalciferols / Q000627:therapeutic use; D008297:Male; D010018:Osteomalacia / Q000097:blood* / Q000188:drug therapy; D010710:Phosphates / Q000097:blood; D010758:Phosphorus / Q000627:therapeutic use; D014807:Vitamin D / Q000097:blood*
D006887:Hydroxycholecalciferols; D010710:Phosphates; D014807:Vitamin D; D010758:Phosphorus; D002112:Calcifediol