[Calcium phosphate metabolism in thalassemia]

The AA. performed a screening test on 113 patients affected by beta thalassemia major ranging between 2 and 40 years of age, randomized among those who come to the Microcitemic Center of our Institute, and on a control group. In all of them serum levels of calcium, phosphate, parathyroid hormone (PTH), calcitonin and 25-OH vitamin D were measured. Average serum levels of PTH were significantly (P < 0.001) lower in our patients than in control group and 12.4% of the former were clearly under normal range, especially in the group over 16 years of age. Also serum levels of 25-OH vitamin D were lower in thalassemic patients than in controls, because of the presence of 32 patients with average values under normal limit. Our results are in agreement with current literature and underline the increasing incidence of endocrine complications in thalassemic patients who undergo high transfusion regimens, because of to the increase of hemosiderosis due to the low compliance to iron chelation therapy. Controversial is the pathogenesis of the absence of hypocalcemia in many patients with hypoparathyroidism and the cause of the deficit of vitamin D.