GSTM1 and congenital dyserythropoietic anemia: Analyses in the non-transfusion-dependent hereditary anemia group without treatment were obtained in patients diagnosed with congenital sideroblastic anemia (CSA, N = 13), hereditary spherocytosis (N = 3), congenital dyserythropoietic anemia (CDA, N = 5), non-transfusion dependent β–thalassemia (NTDT, N = 2), HbE/β–thalassemia (N = 1), pyruvate kinase deficiency (PKD, N = 1) and Hb Adana (N = 4).