Association of R279Q and C1562T polymorphisms of matrix metalloproteinase 9 gene and increased risk for myocardial infarction in patients with premature coronary artery disease.

Background: A number of matrix metalloproteinase (MMP) gene polymorphisms has been identified which may be probably related to premature myocardial infarction (MI).

Objective: We assessed the relationship between the two polymorphisms of the MMP9 gene including R279Q and C1562T and occurrence of premature MI.

Methods: The study has two phases including a case-control study as the first phase and cohort study as the second phase. Initially, 1000 patients with premature coronary artery disease were classified into MI and non-MI groups. Genotyping of the polymorphism was conducted by PCRRFLP and high-resolution melting techniques. Given the two conditions of patients residing in Tehran and faced with their first episode of MI, 640 of 1000 study samples previously followed up with a median follow-up time of 45.74 months were assessed in a retrospective cohort phase regarding long-term major adverse cardiac events (MACE).

Results: The prevalence of wild, heterozygous, and mutant genotypes of R279Q polymorphism in MI group was 14.5%, 57.3%, and 28.2% and in non-MI group was 36.9%, 38.4%, and 24.7%, respectively, with a considerable difference (P<.001). There was a significant difference in the prevalence of wild, heterozygous, and mutant genotypes of C1562T polymorphisms in MI group (12.4%, 41.2%, and 46.4%, respectively) and in non-MI group (46.8%, 38.6%, and 14.7%, respectively; P<.001). No difference was found in total MACE-free survival rate between genotypes of R279Q and C1562T polymorphisms.

Conclusion: C1562T and R279Q polymorphisms are associated with the susceptibility to premature MI, but cannot predict long-term cardiac events in these patients.