Tumour-induced osteomalacia: a curable condition

Osteomalacia is a condition characterised by failure of bone mineralisation. While abnormalities of vitamin D supply, metabolism or action are the most common and well-known causes, chronic phosphate deficiency, due to either insufficient input (intake or absorption) or renal losses are also important causes of rickets or osteomalacia. Hypophosphataemia also commonly co-exists with vitamin D deficiency, pursuant to secondary hyperparathyroidism. Other causes include chronic calcium deficiency, hypophosphatasia, fluoride and aluminium excess. In respect of chronic hypophosphataemia-associated rickets/osteomalacia, the commonest aetiology is X-linked dominant hypophosphataemia, XLH, (1:20000 births). Others include Fanconi syndrome, autosomal dominant hypophosphataemic rickets (ADHR) and tumour-induced osteomalacia (TIO).