HBE1 and thalassemia: The carrier frequency in some areas was between 6% and 10%, while the pattern of mutation varied widely within each region.36 The frequency and type of hemoglobinopathy and thalassemia differs depending on geographical area and ethnic group.36 The most frequent mutations to be found are HbE (29%), IVSI-nt5 (19%), and Cd35 (8%).