GSTM1 and thalassemia: Further reduction of Hb Bart’s to 11.2 ± 2.6% was noted in homozygous Hb CS and compound Hb CS/Hb Pakse’ disease (n = 14, Table 1), indicating a more excess γ-globin chain as compared to the α0-thalassemia trait (4.8 ± 1.2%) and homozygous α+-thalassemia (4.1 ± 1.5%).