ABSTRACT
Cardiovascular diseases as being one of the major causes of morbidity and mortality drags attention for the study of their pathogenesis which seems multifactorial including habitual/ environmental and genetic causes. The major cause for atherosclerosis is deposition of oxidized lipoproteins in the blood vessel. Paraoxonase [PON1], an enzyme tightly linked to HDL plays an important role in decreasing the susceptibility of LDL-cholesterol for oxidation, thus minimizing atherosclerotic changes in the blood vessels. Paraoxonase activity in the serum alone is not a determining factor for this role. This function is also controlled and affected by many polymorphisms occurring in the PON1 gene, The aim of this study was to evaluate the effect of one of this genetic polymorphism [at position 192] on cardiovascular diseases in Saudi population. This study included 169 subjects [100 cases and 69 controls]. For all participants in the study paraoxonase activity, lipid profile, Apo A-l and genetic polymorphism was done. The percentage distribution of this genetic polymorphism differs in Saudi population than those observed in previous studies as in Mexican population and is more similar to those in Japanese population. There was no significant difference in the genetic distribution between control and CVD groups. The activity of paraoxonase was lower in the CVD group compared to the control; also there was no significant correlation between this genetic polymorphism and the lipid composition of the blood. PON1 activities toward paraoxon are lower in subjects with CVD than in control subjects regardless of the PON1 genotype although the PON1 activity is much lower in RR genotype than QQ genotype