ABSTRACT
<p><b>OBJECTIVE</b>To investigate the distribution characters and linkage disequilibrium of single nucleotide polymorphisms (SNPs) -148C/T, -455G/A and -854G/A in the promoter region of fibrinogen B(FGB) beta gene.</p><p><b>METHODS</b>Genotype and allele frequencies of FGB beta gene were examined by polymerase chain reaction-restriction fragment length polymorphism and nucleotide sequencing methods in 377 Chinese southern Han individuals. Three FGB beta SNPs Hardy-Weinberg equilibrium and linkage disequilibrium were analyzed with population genetics methods.</p><p><b>RESULTS</b>The allele frequencies of 3 SNPs are in good agreement with Hardy-Weinberg equilibrium. A total of 9 genotypes among the 377 individuals were identified in 3 SNPs. The genotype frequencies of -148CC, CT and TT were 0.597, 0.358 and 0.045, respectively; the -455G/A genotype frequencies were the same as that of -148C/T SNP; the genotype frequencies of -854GG,GA, AA were 0.820,0.178,0.002, respectively. The frequencies of rare allele -148T, -455A and -854A were 0.224,0.224 and 0.092, respectively, while the common allele frequencies were 0.776 for -148C, 0.776 for -455G, and 0.908 for -854G. There were no statistically significant differences in genotype and allele frequencies between the male and female groups (P>0.05). The relationship between -455G and -148C was completely concordant, but there was a random distribution between -854 and -148 (-445) SNPs.</p><p><b>CONCLUSION</b>The results show there is a complete linkage disequilibrium between -148C/T and -455G/A and a negative linkage disequilibrium between -854G/A and -148C/T, as well as between -854G/A and -455G/A. This study has provided population genetics data on FGB beta gene promoter in Chinese southern Han population.</p>