Haematological values were determined in 246 sickle cell anaemia (SCA)
patients in three centres in Benin City, Nigeria, as well as 84 control
subjects with haemoglobin A (HbAA) confirmed by haemoglobin
electrophoresis at pH 8.6. Automated Coulter counter was used to
determine the complete blood counts while the foetal haemoglobin was
estimated by the modified Betke method, and haemoglobin A2 by the
HbS-free microcolumn chromatography. Six patients (2.4%), comprising of
two males and four females, out of the 246 SCA patients were found to
have elevated haemoglobin A2 (>3.5%). All the six patients also had
elevated haemoglobin F (≥1.5%). The family members of three of
these six patients were successfully screened. These three patients
(1.2%) were found to have positive co-inheritance of thalassaemia trait
and sickle cell anaemia. The erythrocyte indices were all reduced in
these selected families except for one family whose mean cell
haemoglobin concentration was within normal range. Peripheral blood
film revealed the presence of target cells and occasional microcytes
apart from the sickled cells. The possibility of co-inheritance of the
beta thalassaemia gene with the sickle cell gene occurs in about 1.2%
of Nigerians with sickle cell anaemia