| Abnormal vitamin D metabolism | | (causing secondary hyperparathyroidism and hypophosphatemia) | | Deficient intake or absorption | | Dietary | | Inadequate sunlight exposure | | Malabsorption | | Gastrectomy or gastrointestinal bypass | | Small bowel disease | | Pancreatic insufficiency | | Defective 25-hydroxylation | | Biliary cirrhosis | | Alcoholic cirrhosis | | Some antiseizure medications | | Loss of vitamin D-binding protein | | Nephrotic syndrome | | Defective 1-alpha-hydroxylation | | Hypoparathyroidism | | Chronic kidney disease | | Vitamin D-dependent rickets, type 1 | | Defective target organ response to calcitriol | | Vitamin D-dependent rickets, type 2 (hereditary vitamin D-resistant rickets [HVDRR]) | | | Mineralization defects | | Abnormal matrix | | Chronic kidney disease | | Osteogenesis imperfecta | | Fibrogenesis imperfecta | | Axial osteomalacia | | Enzyme deficiency | | Hypophosphatasia | | Inhibitors of mineralization | | Fluoride | | Aluminium | | Some bisphosphonates (eg, etidronate) | | Phosphate deficiency | | Decreased intake | | Antacids | | Impaired renal reabsorption | | Primary defects | | X-linked hypophosphatemic rickets (vitamin D-resistant rickets [VDRR]) | | Hereditary hypophosphatemic rickets with hypercalciuria | | Sporadic acquired hypophosphatemic rickets | | Fanconi syndrome, Wilson disease, cystinosis, multiple myeloma | | Secondary defects | | Secondary hyperparathyroidism (renal tubular acidosis, type 1 and disorders of vitamin D metabolism) | | Tumor-induced osteomalacia | |
