THYROID-FUNCTION IN CHILDREN WITH BETA-THALASSEMIA MAJOR IN NORTH JORDAN

Basal thyroid function was assessed by serum thyroxine, tri-iodothyron ine and thyroid-stimulating hormone levels in 90 patients 2-10 years o ld with beta-thalassaemia major. Based on measured serum ferritin leve ls, patients were classified into two groups: group (I) which included 63 patients with ferritin concentrations ranging from 300 to 7000 ng/ ml (mild iron overload) and group (II) which included 27 patients with ferritin concentrations higher than 7000 ng/ml (severe iron overload) . The results of thyroid function in both groups were compared with th ose of 50 control subjects. In group (I), the mean concentrations of a ll measured hormones were not significantly different from those of th e controls. In group (II), the mean concentrations of thyroxine and tr i-iodothyronine decreased by 29 and 35 per cent (P < 0.05), respective ly, and the mean concentration of thyroid-stimulating hormone showed a 2.6-fold increase (P < 0.01) in comparison with those of the controls . The data clearly demonstrate the occurrence of impaired thyroid func tion and its possible association with iron overload in a considerable proportion of transfusion-dependent beta-thalassaemic patients.