GSTM1 and anemia (phenotype): Anemia was the primary symptom, including mild anemia (Hb 90–120 g/L) in 8 (13%), moderate (Hb 60–90 g/L) in 38 (59%), severe (Hb 30–60 g/L) in 15 (23%), and very severe (Hb <30 g/L) in 1 cases (2%).