Incidental Identification of Possible Delta-Beta Thalassemia Trait in a Family: A Rare Cause of Elevated Hb F

Delta-Beta thalassaemia is an unusual variant of thalassaemia with elevated level of foetal haemoglobin (HbF). The clinical presentation of delta-beta thalassaemia is mild in both heterozygote and homozygote cases. We hereby describe a rare cause of elevated Hb F in a father and his two daughters. A 52-year-old diabetic male patient, on evaluation of chromatogram of cation exchange HPLC for HbA1c, we incidentally identified elevated Hb F of approximately 20%. Haematological investigation of the patient revealed decreased haemoglobin, normal RBC, leucocyte and platelet count, decreased MCV and MCH. Red cell morphology showed predominantly normocytic normochromic cells with mild anisopoikilocytosis, few microcytes and hypochromic cells seen. His liver function test was normal. Haemoglobin variant analysis revealed decreased Hb A (79.4%), normal Hb A2 (2%) and increased Hb F (19.75%). A possible diagnosis of heterozygous δ β-thalassaemia was considered. Since most laboratories perform HbA1c by cation exchange HPLC method, a careful evaluation of the chromatogram yields useful information. In our case, the elevated Hb F in a father and further careful evaluation of clinical and haematological parameters in the family members made us to possibly think of rare disorders like heterozygous Delta-Beta thalassaemia in the family and provide valuable genetic counseling.