Summary
Previous studies reported a gender-specific association between plasma fibrinogen
concentrations and incident hypertension. We systematically analysed polymorphisms
and haplotypes across the fibrinogen gene cluster with fibrinogen levels and assessed
their contribution to prevalent hypertension in 2,200 men and 2,159 women from the
population-based MONICA/KORA Augsburg study. Eleven tagging single nucleotide polymorphisms
(SNPs) were systematically selected in the three fibrinogen genes and haplotypes were
reconstructed. The minor alleles of two SNPs, rs2227401 (FGB) and rs2070016 (FGA) and the haplotypes tagged by those variants, were significantly associated with
higher fibrinogen concentrations in both, men and women, explaining 1% of the total
variance of fibrinogen concentrations. In addition, a FGG haplotype, tagged by rs1049636, was associated with lower concentrations of fibrinogen
in women, but not in men. Regarding hypertension, we detected a significant association
with a FGA promoter variant (rs2070008) in women only, whereas fibrinogen haplotypes were not
associated with hyper-tension after correction for multiple comparisons in either
men or women. In conclusion, our results suggest that variants in all three fibrinogen
genes are significantly associated with differences in fibrinogen concentrations with
modest contribution to phenotypic variance. It is likely that other genetic variants
outside the fibrinogen gene loci are involved in the regulation of fibrinogen concentrations.
In addition, one FGA promoter variant was significantly associated with hypertension in women. Confirmation
of these findings by future studies is warranted.
Keywords
Hypertension - fibrinogen - genetics - haplotypes