GSTM1 and hypochromic anemia: It has been documented that heterozygous β−50(G>A) had microcytic hypochromic RBCs with increased Hb A2 (4.6%) and Hb F (1.2%) levels, and compound heterozygous of β−50(G>A) and β0-thalassemia revealed moderate microcytic hypochromic anemia with high Hb F levels (27.7%), and a β0/β+ thalassemia phenotype.