Prevalence of Hypoparathyroidism in Children and Young Adults with Thalassemia Major.

Endocrinopathies are frequently reported in children with thalassemia major. Affected children at our center are transfused regularly to maintain hemoglobin of at least 8–9 gm/dl. Most subjects are chelated with Desferrioxamine or Deferiprone or a combination of the two drugs, although a majority of children have poor compliance and are poorly chelated. Hypoparathyroidism usually occurs in thalassemia major due to excess iron deposition in the parathyroid glands. All patients suffering from thalassemia major are screened routinely at our clinic for their bone metabolism. The fasting serum calcium, phosphorus, intact parathormone and alkaline phosphatase levels are checked annually to screen for hypoparathyroidism and Vitamin D deficiency. A diagnosis of hypoparathyroidism is made if the serum calcium is low, phosphorus is high, alkaline phosphatase level is normal and serum parathormone level (intact) is low normal. Mean S. ferritin levels of all the subjects were calculated by averaging the ferritin values over the last 5 years. We analyzed the screening results for hypoparathyroidism in 110 subjects with Thalassemia Major between the ages of 10–25 years. Of these 110 subjects 19 (17.3%) were found to be suffering from hypoparathyroidism and 91 patients had a normal screen. Mean S. ferritin level was 5997ng/ml in the affected subjects (ranging from 2900 to 10,904 ng/ml), compared with the mean S. ferritin level of 3793ng/ml in the unaffected subjects, which was clinically significant, showing a direct correlation between the poor chelation and development of hypoparathyroidism. Only 2 subjects from our affected group had an average ferritin of 2000–3000 ng/ml, although they also had other endocrine disorders such as short stature and hypothyroidism. Of the affected subjects, 9 were males and 10 were females (M: F = 1.1:1). The reported male: female ratio for hypoparathyroidism in thalassemics is 3:1. Age of onset of hypoparathyroidism ranged from 10.9 years to 23 years with mean age of onset being 16 years. The youngest subject (10.9 years) had an average ferritin of 2908 ng/ml. All the affected subjects above 15 years of age had hypogonadism, 7 of the 19 affected subjects (36.84%) had diabetes, 4 (21%) of them had an abnormal glucose tolerance test, and 5 (26.3%) had hypothyroidism. The incidence of hypoparathyroidism reported in our group of patients is higher compared to those reported from other continents (3.6–4.5%) probably due to poor chelation., both males and females are equally affected and the age of onset is earlier compared to reports from other countries.. This suggests that high ferritin levels due to poor chelation is a major factor in the development of hypoparathyroidism and most subjects who develop it, have multiple endocrine disorders.