[Electrophoresis of 1,149 samples of umbilical cord blood and assessment of the heterogeneity of the relationship between gamma G and gamma A chains of fetal hemoglobin]. / Electroforesis de 1.149 muestras de sangre de cordón umbilical y evaluación de la heterogeneidad de la relación entre cadenas gamma G y gamma A de la hemoglobina fetal.

A total number of 1,149 specimens of cord-blood were subjected to cellulose acetate gel electrophoresis in order to estimate the incidence of haemoglobinopathies in newborn infants (NBI). It was found that 4.37% of black NBI and 0.54% of white NBI were AS carriers. Those samples with HbS or HbC were verified by means of agar-citrate electrophoresis at pH 6.2. Haemoglobin Bart was commonest in black (3.1%) than in white (0.4%) NBI. A slow haemoglobin variant was found with an alpha-chain mutation. The concentration of gamma G was estimated by separation of gamma G and gamma A chains with polyacrylamide gel electrophoresis, and it ranged between 52% and 94%, which could be attributed to the fact that the shift from HbF to HbA is not simultaneous in all the red-cell population.