GSTM1 and anemia: In contrast, individuals with ß-thal major, with the genotype of β+/β0 or β0/β0 and severe anemia (Hb persistently <70 g/L), require regular blood transfusions and standardized iron-free therapy to survive (Writing Group For Practice Guidelines For Diagnosis And Treatment Of Genetic Diseases Medical Genetics Branch Of Chinese Medical Association et al., 2020).