Detection of haemoglobinopathies at birth in Togo

The incidence and nature of haemoglobinopathies were investigated at birth in Togo, using isoelectric focussing on 385 samples of umbilical cord blood. Abnormalities were found in 37.6% of blood samples: Hb A/S, 18.7% (0.5% with Hb Bart's); Hb A/C, 8.9% (0.3% with Hb Bart's); Hb S/C, 1.3% (0.3% with Hb Bart's); Hb S/S, 1%; Hb C/C, 0.3%; isolated Hb Bart's, 5.7%; gamma chain variants 0.8%; acetyl Hb F greater than Hb A, 1%. To date now, no systematic screening of Hb abnormalities has been performed in Togo. Our results showed that Hb S is the principal abnormal Hb found in the population which we studied, with a sickle cell gene frequency of qs = 0.110 and an Hb C gene frequency of qc = 0.053. Our work also confirmed the presence of alpha and beta + thalassaemias (acetyl Hb F greater than Hb A) in Togo. One of the advantages of investigating umbilical cord blood by isoelectric focusing is that detection of Hb S/S and Hb S/C (which had an incidence of 2.3% in our study) can be carried out at birth, allowing the children to be taken care of as soon as possible. About 150,000 children are born each year in Togo, and the infant mortality is estimated at 5 per 100 live births in Lomé and at 10 per 100 live births outside the capital.