GSTM1 and thalassemia: For common β-thalassemia minor genotypes, there was no significant difference in Hb and MCH levels among βCD17(A>T)/β, βCD41/42 (–TTCT)/β, βCD71/72(+A)/β, and βIVS–II–654(C>T)/β, but all were obviously lower than that of PW without thalassemia.