GSTM1 and thalassemia: On the other hand, iron deficiency parameters and common α-thalassemia defects were not detected in all subjects (Table 1), demonstrating that the red cell alterations may affect Hb E. It is noteworthy that hematological parameters noted in these subjects were not likely to be more severe when compared with heterozygous Hb E, despite coinheritance of this variant [26].