β-Thalassemia major and its effect on amino acid metabolism and growth in patients in the United Arab Emirates

Background: There may be a marked reduction in essential amino acids in the serum of children with thalassemia major and this is related to decreased growth in affected children. Methods: One hundred patients with beta-thalassemia and 50 control children selected from among those who had presented with minor disorders unrelated to hematological disease were recruited. Urine and heparinized blood were collected from fasting thalassemic patients. After deproteinization and dilution, amino acid concentrations were measured using ion-exchange chromatography. Results: Isoleucine (p<0.0001), phenylalanine (p<0.05), tyrosine (p<0.0001), taurine (p<0.0001) and glutamine (p<0.01) were significantly decreased in the plasma of thalassemic patients compared to the control group. Whereas glutamate (p<0.0001), serine (p<0.05) and proline (p<0.05) were significantly higher in thalassemic patients, threonine, glycine, alanine, valine, methionine, leucine, ornithine, lysine, histidine and arginine values were not different. The essential amino acids taurine (p<0.0001), methionine (p<0.01), valine (p<0.01), phenylalanine (p<0.01) and leucine (p<0.05) were significantly decreased in urine of thalassemic patients vs. controls, but threonine and ornithine were not different. The mean urinary excretion rate of beta-aminoisobutyric acid was not different (69 +/- 96 in thallassemics vs. 41 +/- 52 in controls). However, most plasma and urinary essential amino acids were found to be lower in thallassemics. Thalassemic patients were also found to be significantly growth impaired for age, both in height and weight compared to controls. Conclusion: Lower plasma values of essential amino acids and a decrease in urinary amino acids occur in thalassemic patients. Growth impairment both in height and weight also occurs in thalassemic patients compared to a control population. (C) 2004 Elsevier B.V. All rights reserved.