Paraoxonase gene polymorphisms: Understanding the biochemical and genetic basis of coronary artery disease

OBJECTIVES: Serum paraoxonase (PON) is a glycoprotein with antioxidant and anti-atherosclerotic activities. The Q192R and L55M gene polymorphisms of PON have been implicated as risk factors for coronary artery disease (CAD) but have not been extensively explored in South Indians. We aimed to assess the Q192R and L55M genetic polymorphisms of the PON1 gene in participants with CAD, including genotypes and allele frequencies for PON1 gene polymorphism. METHODS: This prospective case-control study involved 20 participants in each group. Patients with angiographically demonstrated CAD were included in the case group. PON1 activity was measured, and PON gene polymorphism was determined. Serum PON was quantitatively analyzed with a RayBio® Human PON1 ELISA kit. Chi square tests were used to assess the association of the genotypes with sex and any comorbidities in cases and controls. A p value ≤ 0.05 was considered significant. RESULTS: Mutant type L55M polymorphism was observed in 50% of patients, whereas wild type Q192R polymorphism was observed in 42.5% of the participants. The mean PON values between groups did not significantly differ, whereas PON U/L was significantly (p = 0.001) lower in the case group. The L55M polymorphism did not significantly differ between the case and the control groups (p = 0.213), whereas the Q192R polymorphism was statistically significant in cases compared with controls (p ≤ 0.001) CONCLUSION: Low plasma PON1 and HDL levels, and higher LDL, total cholesterol and triglyceride levels were observed in patients with CAD. More patients with CAD than healthy individuals had Q192R polymorphism.