GSTM1 and thalassemia: All 1182 microcytosis samples were analyzed by a RDB gene chip for the three known α-thalassemia deletions (–SEA, −α3.7, −α4.2), two α-thalassemia mutations (Hb Constant Spring and Hb Quong Sze) and 16 known common Chinese β-thalassemia mutations.