After a median follow-up of 40 months (IQR 25–58), the median hemoglobin reached 11.0 g/dL (IQR 10.0–12.3), and 64% (n = 44) of the patients had persistent anemia (hemoglobin [Hb] < 12 g/dL). This evidence concerns the gene GSTM1 and anemia (phenotype).