Prevalence of Delta Beta Thalassemia Minor in Southern Iran

Hb A2 is elevated in subjects with beta thalassemia minor but small percent of carriers have normal Hb A2 with elevated levels of HbF (2-10%). This type of thalassemia is called delta beta thalassemia, and can be missed in pre-marriage hematologic consults or screening which leads to increased risk of child birth with beta thalassemia major. In this prospective descriptive study, 17768 subjects participated from January 2007 to January 2008. Complete blood count was checked for subjects. If MCV was below 80 fl or MCH was below 27pg, HbA2 was checked with column chromatography. If HbA2 was higher than 3.4 %, subject was labelled as beta thalassemia minor. If HbA2 was normal, 45 days of iron therapy were started for patients whom serum iron, serum ferritin and total iron-binding capacity were in favour of iron deficiency anemia. CBC was rechecked after iron therapy and if MCV or MCH still was below normal range, HbF was checked using alkaline denaturation method as well as Hb electrophoresis. Patients with HbF in the range of 2-10% were diagnosed as delta beta thalassemia minor. 17768 subjects were recruited in this study and 1326 subjects (7.4%) were diagnosed as beta thalassemia minor. 1133 of 1326 thalassemia minor subjects (85.4%) had MCV below 70 fl and 193 subjects (14.6%) had MCV between 70 fl and 80 fl. Three subjects from 17768 (0.01%) had normal HbA2 with HbF between 2% and 10% (delta beta thalassemia). It is very important to use Hb electrophoresis and check HbF by alkaline denaturation method for all people coming for pre-marriage hematologic consultation to detect delta beta thalassemia or other hemoglobinopathies.