In addition, the interaction of thalassemic Hb variants with thalassemia can contribute to moderate to severe thalassemia phenotypes, as seen in Hb H with Hb Constant Spring (CS, HBA2:c.427T>C) disease and Hb E/β-thalassemia disease, which are commonly observed in the southeast Asian population5,6. Here, GSTM1 is linked to thalassemia.