Abstract:Aim To investigate the polymorphisms and haplotypes in α-fibrinogen and β-fibrinogen gene and their relationship to coronary heart disease(CHD). Methods Plasma fibrinogen level was measured by turbidmetric assay. The TaqI polymorphism in α-fibrinogen gene and the single nucleotide polymorphisms-455G/A,-249C/T,-148C/T,+1689T/G,BsmAIG/C,448G/A,BclIG/A and HinfIA/C in β-fibrinogen gene were characterized by PCR-RFLP in one hundred and twenty one cases of CHD and one hundred and thirty healthy individuals from Hainan Han population.Haplotypes were estimated by the EH+program.The statistical differences of allelic,genotype and haplotype frequencies between the case group and the control were estimated by Chi square test. Results The allelic frequencies of the polymorphisms-455A,-148T,448A were 0.343,0.351 and 0.326 in CHD group,whereas the allelic frequencies of the polymorphisms-455A,-148T,448A were 0.254,0.254 and 0.242 in the control.The allelic frequencies of-455A,-148T,448A were higher in the CHD group than in the control(p<0.05).The allelic frequencies of the other six polymorphisms were not significantly different between the CHD group and the control(p>0.05).The odds ratios(OR) with the rare alleles of A-455 、T-148 and A448 were 1.53,1.59 and 1.51 respectively.Haplotypes constructed from the nine polymorphisms showed that the frequency haplotype H16 with β-455G,β-249C,β-148C,β+1689T,βBsmAI G,β448G,βBclI G,βHinfI A and αTaqI T2 were lower in the CHD group than in the control.Among the haplotypes constructed from polymorphisms including-455G/A,-249C/T,-148C/T in the promoter region of β-fibrinogen gene,haplotype h1 with-455G,-249C and-148 C alleles appeared more frequently in control group(p<0.01),whereas haplotype h5 with-455A,-249C and-148C and haplotype h6 with-455A,-249C and-148T occurred more frequently in the CHD group(p<0.01). Conclusions The results of multi-allele and haplotype analysis indicated that the polymorphisms-455G/A,-148 C/T and 448G/A in beta fibrinogen gene were associated with CHD in Hainan Han population.The allele with-455A,-148 T and 448 A may represents a genetic risk factor for CHD.