Hypoparathyroidism in transfusion-dependent patients with β-thalassemia

Purpose: To determine the prevalence of hypoparathyroidism in transfusion-dependent patients with beta-thalassemia. Patients and Methods: A total of 28 transfusion-dependent patients with beta-thalassemia were interviewed, and their serum calcium, phosphate, magnesium, and intact parathyroid hormone levels were checked. Serum ferritin levels were measured to monitor the effect of chelation therapy. Blood urea nitrogen, creatinine, total protein, and albumin were measured in patients with undetectable or low intact parathyroid hormone levels. Results: The prevalence of hypoparathyroidism was 10.7% (3/28). Mean age at diagnosis was 18 years. The serum ferritin levels of patients with hypoparathyroidism were 1,032, 2,102, and 7,680 mug/L. Only one patient had clinical symptoms of hypocalcemia. All three of the patients with hypoparathyroidism had hypogonadism, and 66.7% (2/3) of the patients had insulin-dependent diabetes mellitus. Conclusions: Hypoparathyroidism in transfusion-dependent patients with beta-thalassemia seems to be accompanied by other endocrinopathies. Serum ferritin may not have been a reliable indicator of iron overload in the three patients with hypoparathyroidism. Severe iron overload would easily explain these multiple endocrinopathies. This pattern is commonly seen in iron-overloaded patients with thalassemia elsewhere.