GSTM1 and anemia (phenotype): In children younger than five years, anaemia is categorized as mild when the Hb is between 10.0 and 10.9 g/dl, moderate, if the Hb is between 7.0 and 9.9 g/dl, severe, for Hb < 7.0 g/dl, and normal if Hb ≥ 11.0 g/dl [[12], [13], [14]].