AA: Control group with normal Hb, AS: Sickle cell trait, SS: Sickle cell anemia/diseases, HCT: hematocrit, MCV: mean corpuscular volume, MCH: mean corpuscular hemoglobin, MCHC: mean corpuscular hemoglobin concentration, RBC: red blood cell, TLC: Total leucocyte count, PC: Platelet count, RC: Reticulocyte count. This evidence concerns the gene GSTM1 and sickle cell disease.