GSTM1 and thalassemia: As shown in Table 2, retrospective analysis of 4,934 fetuses at PND for hemoglobinopathies, we identified that 3,880 (78.6%) fetuses were at risk of having the three targeted severe thalassemia diseases; homozygous α0-thalassemia, β-thalassemia major and Hb E-β0-thalassemia.