GSTM1 and anemia (phenotype): Comparing with a study from India [22], our results showed that Hb levels in transfused patients were less than 7.0 g/dL in 86.2% vs. 75.7%, respectively, and 39.3% of our children have a higher rate of severe anemia (Hb ˂ 5.0 g/dL) compared to 23.3% in their sample.