Hemoglobin Bart's in a Brazilian black population.

Hemoglobin Bart's was measured spectrophotometrically after electrophoresis on cellulose acetate strips in cord blood from 320 full-term randomly selected black newborns from the University Hospital of Campinas, State of São Paulo, in the southeast of Brazil. Hb Bart's was detected in 38 of the 320 newborns (11.9%), with the levels presenting the following bimodal distribution: 10.3% of the infants in the 1-3.5% range and 1.6% in the 5-10% range. The data suggest that the frequency of alpha-thalassemia gene in the Brazilian black population is 0.125 since individuals with Bart's Hb in the 5-10% range are usually alpha(+)-thalassemia homozygotes.