Objective: Investigations of the possible role of polymorphic genes in pregnancy outcome may be influenced by ethnic variations in genotype or allele frequencies. Differences in allelic carriage of immune system-related genes among white, black, and Hispanic pregnant women living in New York City and Boston were evaluated.
Methods: DNA was extracted from buccal or vaginal epithelial cells collected from 198 white, 75 black, and 114 Hispanic pregnant women who delivered at term and who had no history of a preterm birth. Genetic polymorphisms in the immunoregulatory genes encoding interleukin (IL)-1beta, tumor necrosis factor-alpha, IL-4, IL-10, IL-1 receptor antagonist (IL-1ra), mannose-binding lectin, toll-like receptor-4, and the 70-kDa heat shock protein were determined.
Results: Allele 2 of the IL-1ra gene (IL1RN*2) and IL-4 -590C homozygosity were 4-fold less common in blacks than in whites or Hispanics (P <.001). The IL-4 -590T allele was almost 2-fold more common in Hispanics than in whites (P <.001). The frequency of the 70-kDa heat shock protein 1267G allele was at least 1.4 times greater in blacks compared with whites (P <.001) or Hispanics (P =.002), whereas the homozygous mannose-binding lectin codon 54G allele was observed at least 4.5 times more often in Hispanics compared with whites (P =.007) or blacks (P =.02).
Conclusion: Investigations of the role of genetic factors affecting pregnancy outcome must be cognizant of ethnic variations when enrolling case and control subjects for studies on allele and genotype frequencies.