Relationship between H1 and H2 haplotypes of the 17q21 inversion and pregnancy loss in Bosnian population: A case - control study

Background: The 17q21.31 band is one of the most structurally complex and evolutionarily dynamic region of the genome. Frequencies of two SNPs: rs9468 and rs1800547 determine worldwide distribution of H1 and H2 haplotypes. Recent studies have demonstrated that H2 haplotype is ancestral in hominoids and under positive selection in European populations. The role of non-inverted orientation (H1 haplotype) and inverted orientation (H2) remains unclear, i.a. it is suggested that mothers who are H1H2 heterozygotes, tend to have more children than H2H2 homozygotes on average. Materials and methods: We investigated the prevalence of haplotypes of the 17q21 inversion in 154 women with pregnancy loss and 154 mothers with at last one live-born child, mean age: 33.0 (±5.4) y/o and 31.4 (±6.7) y/o, respectively. Following DNA extraction from buccal swabs, the genotyping was performed. All tests were performed using the R CRAN statistical software. Haplotypes were compared between groups. Results: In women with and without pregnancy loss we identified: 74.7% and 79.2% H1H1, 24.0% and 17.5% H1H2 and 1.3% and 3.3% H2H2 of haplotypes, respectively. There were no significant differences between the distributions of haplotypes in women with and without pregnancy loss. Statistically significant difference between the average number of children in women with H1H2 haplotype (navg. = 1.54) compared to women with H2H2 haplotype (navg. = 1.29), was not found. Conclusion: Haplotype H2 of the 17q21.31 inversion was not linked to pregnancy loss and number of children in Bosnian women.