Essay Example on Coronary artery disease CAD is a Complex Trait

The most studied PON1 gene polymorphism result from amino acid substitutions at positions 192 Glutamine Q Arginine R in the coding region of the gene Alleles at the 192 Q and R allele loci of the PON1 codon have been associated with enzyme activity and concentration respectively The QQ genotype exhibits a low PON activity low activity phenotype while RR genotype exhibits a high PON activity high activity phenotype However there is also marked variation in enzyme activity between individuals of the same genotype 10 PON1 position 192 R isoform binds with HDL with a 3 fold lower affinity than the Q isoenzyme and consequently exhibits reduced stability lapolactonase arylesterase activity It has been suggested that the Q allele which is more abundant than the R allele is responsible for the protective effect against atherosclerosis whereas the R allele has been related to CAD because of less protection against LDL These differences in the properties of PON1 192 Q R isoenzyme provide the basis for the contribution of 192 Q R polymorphism to the susceptibility to atherosclerosis 11 So many authors revealed that PON1 Q192R polymorphism are an important risk for MI and CAD populations 12 13 Contrastingly some studies reported that no such association between Q192R polymorphism and an elevated atherosclerosis risk 14 Moreover several studies have indicating that it is an important to determine the phenotype not just the genotype when studying the atherosclerosis 15 16 Thus in this case control study we assess the lipid profile lipid peroxidation product MDA the distribution and frequency of PON1 Q192R polymorphism and the concerned phenotype arylesterase activity was analyzed with the risk of CAD and healthy controls in the population of the central province of Saudi Arabia