C-reactive protein (CRP) gene polymorphisms: implication in CRP plasma levels and susceptibility to acute myocardial infarction.

C-reactive protein (CRP) is one of the many molecular factors involved in pathogenesis of coronary artery disease which its plasma levels are associated with increased risk of cardiovascular events. The present study designed to determine whether polymorphisms in the CRP gene are associated with plasma CRP levels and susceptibility to acute myocardial infarction (AMI). Plasma CRP levels were measured in patients with AMI and control subjects and genomic DNA and peripheral blood mononuclear cells (PBMCs) were extracted. The -717A/G and 1059G/C CRP polymorphisms were detected. The mRNA expression of CRP gene and plasma levels of CRP and interleukin-6 (IL-6) were also analyzed. The -717A/G variation was significantly associated with higher CRP levels, but 1059G/C variation was associated with lower CRP levels. The AA genotype frequency of -717A/G variation was significantly more frequent in the patients than control subjects. By contrast, the genotype and allele distribution in 1059G/C of patient were not statistically different between patients and controls. There were significant differences in circulating levels of CRP and IL-6 in the patients than in controls. The mRNA expression levels of CRP were significantly higher in the patient plasma compared with controls. Our results indicate relationship between many polymorphisms in CRP gene and risk of AMI which suggest that genetic variations in CRP might be helpful for determining susceptibility to AMI in Iranian patients. In addition, CRP gene polymorphisms are associated with plasma CRP levels and susceptibility to AMI might be related to CRP gene expression which affects its plasma levels.