GSTM1 and thalassemia: Other forms of high Hb F determinants including Hb E-δβ0-thalassemia, Hb E-HPFH, homozygous δβ0-thalassemia, δβ0-thalassemia/HPFH, and HPFH/β-thalassemia are all associated with mild phenotype of thalassemia or clinically normal [5, 29–32].