Renal tubular dysfunction in β-thalassemia minor

Background: Persons with beta-thalassemia minor usually are symptomless. However, we previously reported renal tubular dysfunction in a patient with beta-thalassemia minor. The aim of this study is to investigate renal function in patients with beta-thalassemia minor. Methods: Forty-one subjects with beta-thalassemia minor and 20 sex- and age-matched healthy subjects were enrolled in the study. For analysis, patients were divided into 2 groups: group A, all patients with anemia (n = 19), and group B, patients without anemia (n = 22). Blood and 24-hour urine samples were obtained for hematologic and biochemical analysis. Results: Anemic patients had increased urinary zinc excretion (U-zinc) and fractional excretion of sodium (FENa) and uric acid (FEUA) compared with both controls and patients without anemia. Hemoglobin levels correlated significantly in a negative manner with U-zinc, FENa, and FEUA in patients with beta-thalassemia minor. However, serum lactate dehydrogenase levels correlated significantly in a positive manner with the same parameters. In addition, 6 of 41 patients (14.6%) with beta-thalassemia minor showed significant signs of renal tubulopathy, such as hypercalciuria, decreased tubular reabsorption of phosphorus with hypophosphatemia, hypomagnesemia with renal magnesium wasting, hypouricemia with renal uric acid wasting, and tubular proteinuria. Conclusion: Proximal renal tubular dysfunction is not rare in patients with beta-thalassemia minor.