GSTM1 and thalassemia: When αWSα was co-inherited with other α+-thalassemia genes, the Hb and MCH levels of the genotypes (αWSα/–α3.7, αWSα/–α4.2, αWSα/αWSα, and αWSα/αQSα) were higher than those of other common α-thalassemia minor genotypes (αα/–SEA, –α3.7/–α3.7, –α4.2/–α4.2, –α3.7/–α4.2, αQSα/–α3.7, αQSα/–α4.2).