Association of PON-1 Genes (Q192R and L55M) Polymorphism with Cardiovascular Disease in Type 2 Diabetes Mellitus in Indian Population

Background: Paraoxonase 1 (PON1) is known to modulate the antioxidant and anti-inflammatory role of HDL and may protect against cardiovascular complications in Type 2 Diabetes Mellitus (T2DM). This study evaluates association with PON-1 L55M and Q195R polymorphisms with serum PON1 levels and lipid profile in T2DM patients from the Indian population. Methods: This case-control study included 75 T2DM patients divided into 3 subgroups (i) Newly diagnosed T2DM patients (ii) T2DM on oral hypoglycemic drugs for at least 6 months period (iii) T2DM with complications (CAD) group. Additionally, 25 healthy controls were taken. Lipid profile and blood glucose levels were measured. DNA was extracted manually, PON1 polymorphisms were analysed using PCR-RFLP. Serum PON1 levels were estimated using standard protocol. Statistical analysis included t-test, Chi-Square and ANOVA tests. Results: Total cholesterol and LDL-C were significantly higher in newly diagnosed T2DM (p < 0.001), while HDL-C was significantly lower in T2DM with CAD group (p = 0.004). The homozygous GG genotype of PON1 Q192R was associated with a 10.5-fold increased risk of T2DM with CAD (OR = 10.50, p = 0.04). The G allele was more frequent in the T2DM-CAD group (OR = 3.26, p = 0.03). Serum PON1 levels were significantly lower in T2DM with CAD (p < 0.0001) and among GG genotype carriers (p = 0.0001). No significant association was found with PON1 L55M. Conclusion: PON1 Q192R polymorphism and lower PON1 levels may contribute to CAD risk in T2DM. Larger studies are needed to validate these findings.