GSTM1 and cholelithiasis: Moreover, among nontransfusion-dependent thalassemia (NTDT) patients, major complications are cholelithiasis (35.0%), abnormal liver function (29.0%), and extramedullary hematopoiesis (EMH) (25.0%) [38], and a prospective study reported that nontransfusion-dependent Hb E/β-thalassemia and α-thalassemia (Hb H disease) result in the development of several severe diseases, particularly gallstones and serious infections [39].