Coinheritance of B-Thalassemia and Sickle Cell Anaemia in Southwestern Nigeria

BACKGROUND Genes for haemoglobin S are found in high frequencies in Nigeria. However, there is little information on beta thalassemia in sickle cell anaemia in this population. The clinical presentation of HbS- β thalassemia is enormously variable, ranging from an asymptomatic state to a severe disorder similar to homozygous sickle cell disease. MATERIALS AND METHODS Haemoglobin A2 and HbF were determined in sickle cell anaemia patients attending LAUTECH Teaching Hospital, Osogbo, by elution after electrophoresis and alkaline denaturation methods respectively. Haematological parameters were estimated using Sysmex KX-21N and percentage target cells using Leishman's staining technique. RESULTS Exactly 6% f the SCA patients were found to have elevated HbA2 (>3.3%) and HbF (>1.3%). These patients also had normal erythrocyte indices, increased platelet count, a significantly higher HCT and an increased % target cell. CONCLUSION These findings confirm that the frequency of beta thalassaemia in sickle cell patients in Nigeria is higher than previously thought. It is therefore important to consider the possibility of this variant in patients with sickle cell anaemia since their course may differ from that of patients with homozygous sickle cell anaemia.