Comparative Study of the Frequency of Paraoxonase1 Gln/Arg192 Polymorphism in Patients with Coronary Artery Stenosis and Control Subjects

Serum paraoxonase (PON1) is an HDL (high density lipoprotein) associated esterase that prevents the oxidation of LDL (low density lipoprotein). A common polymorphism in coding region of the paraoxonase gene involving a Gln (Q) to Arg (R) interchange at position 192 has been demonstrated to affect PON1 activity. It has been shown that R alloenzyme is less efficient at preventing LDL from oxidation and this finding may explain why in some studies the paraoxonase RR genotype has been found at an increased frequency in coronary artery disease (CAD) therefore, to investigate the significance of this polymorphism in pathogenesis of CAD, we performed a comparative study of the frequency of this polymorphism in patients with stenosis and control subjects. Patients and In the present case-control study, PON1 genotypes were determined in 174 subjects who underwent coronary angiography. CAD (>50% stenosis) was detected in 99 subjects (patients) and 75 subjects with <10% stenosis served as controls. PON1 genotypes were determined by PCR and AlwI restriction enzyme digestion. Students’ t-test was used to compare age, BMI, and lipid profile in control and patient groups. Genotype frequencies were compared by Chi-square test. The relationship between PON1 genotypes and the severity of disease in patient group was evaluated by Chi-square test. The frequencies of the QQ, QR and RR genotypes were found as 28.3%,50.5% and 21.2% in patient group and 45.3%, 42,7% and 12% in control subjects respectively (c 2=6.12 p=0.046). The association of this polymorphism with the severity of stenosis was also evaluated,but according to the results of the distribution of PON1 genotypes and compared with the severity of stenosis,it was not statistically significant (c 2=2.67 p=0.27). These results suggest that Gln/Arg 192 genotype is a risk factor for stenosis but does not have any effects on the severity of this disease.