In Nepal and Canada, the samples were from 30 (21.7%) unaffected (HbAA), 23 (16.7%) β-thalassemia trait (HbA/β-thalassemia), 45 (32.6%) sickle cell trait (HbAS), and 40 (29.0%) sickle cell disease (11 HbS/β-thalassemia and 29 HbSS) participants, all of whose diagnoses were confirmed with Hb HPLC. Here, GSTM1 is linked to sickle cell disease.