GSTM1 and thalassemia: A large study on the prevalence of thalassemia among 1,796 Thai women in northeastern Thailand reported that the highest prevalence of thalassemia in the country was 30.2%, with the highest prevalence of homozygous Hb E being 5.4%, the highest prevalence of the β-thalassemia trait being 0.6%, and the highest prevalence of the α-thalassemia 1 trait being 3.0% [21].