Phosphaturia in Thalassemia

Thirteen phosphorus balances were performed in four thalassemic children aged 6 to 10 years. No correlation was found between phosphorus intake and serum level or between phosphorus intake and net absorption. There was a positive correlation among daily phosphorus intake, net absorption, and 24-hour urinary excretion. The 24-hour urinary excretion level was higher than net absorption, indicating that these children have normal phosphorus absorption but abnormally high renal phosphaturia, which leads to a deficiency of phosphorus. A strongly positive correlation was found between values for hemoglobin and serum alkaline phosphatase. In the thalassemic patients with hemoglobin levels ≥7.5 gm/100 ml, the serum alkaline phosphatase values were ≥15 King-Armstrong units, suggesting normal osteoblast function.