RESUMEN
Thalassemia is the most common inherited hemoglobinopathy worldwide. Variation of clinical symptoms in this hemoglobinopathy entails differences in disease-onset and transfusion requirements. The aim of this study was to investigate the role of α-globin gene deletions in modulating the clinical heterogeneity of ß-thalassemia (ß-thal) syndromes. A total number 270 ß-thal subjects were enrolled. Hematological parameters were recorded. ß-Globin mutations were determined by amplified refractory mutation system-polymerase chain reaction (ARMS-PCR), gap-PCR and Sanger sequencing. α-Globin gene deletions were determined by multiplex PCR. Out of 270 ß-thal subjects, 19 carried ß+/ß+, 74 had ß0/ß0 and 177 had the ß0/ß+ genotype. When we determined the severity of the different ß-thal subjects in coinherited with the α gene deletion, it was revealed that, 84.2% ß+/ß+ subjects carried a non severe phenotype and did not have an α gene deletion. Of the ß0/ß0 individuals, 95.9% presented a severe phenotype, irrespective of α-globin gene deletions. In cases with the ß0/ß+ genotype, 19.2% subjects also carried a deletion on the α gene. Of these, 61.8% presented a non severe phenotype and 38.2% were severely affected. Only in the ß0/ß+ category did α gene deletions make a significant contribution (p < 0.001) toward alleviation of clinical severity. Therefore, it can be stated that α-globin gene deletions play a role in ameliorating the phenotype in patients with a ß+/ß0 genotype.
