GSTM1 and thalassemia: Since no abnormal Hb band corresponding to the Hb Amsterdam A1 was visible on alkaline electrophoresis, high performance liquid chromatography (HPLC), and capillary electrophoresis, screening for this α-thalassemia variant should be done by PCR–RFLP assay using BtsC1 restriction enzyme as shown in Fig. 4.