Several studies on different populations have suggested that the non-deletion types of Hb H disease(--/αTα) are usually more severe than the deletion types (--/-α), with greater anaemia, jaundice, splenomegaly and early anaemic symptoms, and a higher proportion of patients who require blood transfusion and splenectomy28, 33. This evidence concerns the gene GSTM1 and Splenomegaly.