Characterization of β-globin haplotypes using blood spots from a population-based cohort of newborns with homozygous HbS

Abstract

Purpose: A population-based cohort from three state newborn screening programs was used to describe β-globin gene cluster variation. Methods: Blood spots from newborns homozygous for HbS were genotyped for five restriction fragment length polymorphisms (RFLPs) to construct β-globin haplotypes. Haplotype distributions were compared by race/ethnicity and sex. Expected heterozygosities were calculated and compared with observed heterozygosities. Results: Haplotype distributions did not differ between sexes for either blacks or Hispanics. Neither racial/ethnic group deviated from Hardy-Weinberg equilibrium; however, Hispanics had higher heterozygosity at two RFLPs compared with blacks. Conclusion: The differences between populations probably reflect recent migration and admixture rather than selection.