GSTM1 and thalassemia: Notably, the levels of Hb D-Punjab in a case with compound heterozygous α0-thalassemia/α+-thalassemia (−−/−α) were lower than those in Hb D-Punjab carriers with the normal HBA gene (αα/αα) or heterozygous α+-thalassemia (−α/αα), at 23.6% vs. 32.6–39.3%.