GSTM1 and thalassemia: Therefore, since the percentage of HbF, HbA, and Hb Barts were significantly different among α-thalassemia, β-thalassemia, their different genotype subgroups, and normal fetuses in our study, and they also correlated with the number of affected genes, HbF, HbA, and Hb Barts is valuable in diagnosing and differentiating thalassemia.