Phosphate plays a critical part in the regulation of cell metabolism,and phosphate homeostasis is closely regulated in normal humans.Chronic hypophosphatemia can cause abnormal mineralization of bone,increased alkaline phosphatase and,in the longer term,metabolic bone disease.Osteomalacia is the main metabolic bone disorder caused by chronic hypophosphatemia,which is characterized by inadequate or delayed mineralization of osteoid in mature cortical or spongy bone.