Endocrine involvement in children with beta-thalassaemia major. Transverse and longitudinal studies. I....

Area of Science:

• Pediatric Endocrinology
• Hematology
• Thyroidology

Background:

• Beta-thalassaemia major is a genetic blood disorder requiring lifelong transfusions.
• Iron overload is a common complication of transfusions, potentially affecting endocrine function.
• Thyroid dysfunction is a recognized, yet not fully understood, complication in beta-thalassaemia major.

Purpose of the Study:

• To investigate thyroid function in prepubertal children with beta-thalassaemia major using a Thyrotropin-Releasing Hormone (TRH) test.
• To correlate thyroid hormone levels and TRH test responses with age and serum ferritin levels.
• To explore the relationship between pituitary-thyroidal axis function and iron overload (siderosis) in this population.

Main Methods:

• A TRH stimulation test was performed on 24 prepubertal children (ages 3-15) with beta-thalassaemia major.
• Basal levels of T4, T3, TBG, and TSH were measured.
• TSH levels were assessed during the TRH test; some participants underwent repeat testing over time (longitudinal study).

Main Results:

• Children with beta-thalassaemia major showed lower basal T4, T3, and TBG levels, and higher basal and TRH-stimulated TSH levels compared to controls.
• A cross-sectional (transversal) study found no significant correlation between hormonal parameters, age, or ferritin levels.
• A longitudinal study revealed significant positive correlations between variations in TSH levels and serum ferritin levels, suggesting a link between siderosis and thyroid function.

Conclusions:

• Children with beta-thalassaemia major present with compensated sub-clinical primary hypothyroidism.
• Thyroid impairment in these patients is dependent on iron overload, with individual gland sensitivity influencing cross-sectional observations.
• Longitudinal data are crucial for demonstrating the ferritin dependence of thyroid dysfunction in beta-thalassaemia major.