Southeast Asian deletion (--SEA), right deletion (-α3.7) and left deletion (-α4.2) are the top three deletions found responsible for α-thalassaemia, whereas Hb ConstantSpring (HBA2:C.427T>C), Hb QuongSze (HBA2:c.377T>C) and Hb Westmead (HBA2:c.369C>G) are the predominant non-deletion types discovered to date. This evidence concerns the gene GSTM1 and thalassemia.