GSTM1 and anemia (phenotype): When the variant co-existed with Hb S, the corresponding cases usually presented with mild to moderate anemia, jaundice, and splenomegaly, as well as clinical characteristics similar to those with sickle cell disease (SCD), such as acute chest syndrome, recurrent vaso-occlusive painful events, dactylitis, hemolytic and so on (Nagel et al., 1999; Rachmilewitz et al., 1985; Zimmerman et al., 1999).