The haematological parameters in HbE disease were similar with β-thalassemia major with the exception that β-thalassemic patients had a very high level of Hb F and absence of Hb E. Hb E-trait patients had milder anaemia comparable to β-thallasemia minor with significantly higher levels of Hb E (P = 0.001). Here, GSTM1 is linked to anemia (phenotype).