Paraoxonase activity and gene polymorphismin patients with metabolic syndrome

Aim: Metabolic Syndrome is defined as the coexistence of many risk factors. It is one of the most important and most common causes of both cardiovascular diseases and type 2 diabetes. Paraoxonase (PON1) is an important liver enzyme linked to HDL in human serum. The enzymatic activity of PON1 shows individual differences. These changes in PON1 activity are caused by polymorphisms in the gene region encoding this enzyme. The paraoxonase gene family includes three genes. The PON1 gene encoding region undergoes amino acid changes in two polymorphic regions. These are amino acid changes of Leucine → Methionine (55th codon L / M) and Glutamine → Arginine (192nd codon Q / R). In homozygous individuals with glutamine at position 192, paraoxonase activity was found to be low, activity was found to be high in individuals with arginine whereas moderate activity was observed in heterozygous individuals. It is known that serum PON1 activity is low in individuals with metabolic syndrome features. We aimed to investigate the probability of serum PON1 activity among routine laboratory studies in individuals with metabolic syndrome and the relationship with paraoxonase gene polymorphism Materials and Methods: Our study was carried on with 101 patients who applied to Endocrinology Clinic and Polyclinic of Dicle University Medical Faculty Research and Application Hospital and who had at least three of the MS diagnostic criteria and who were diagnosed with MS and with a control group consisting of 59 healthy individuals. Distribution of PON 55 and PON 192 gene polymorphisms in the 101 MS patients included in the study was examined by polymerase chain reaction-restriction fragment length polymorphism (PCR RFLP) method and their serum PON activity levels were measured and compared with 59 healthy individuals in the control group. Findings: Serum PON activity level showed a statistically significant decrease in the patient group(p <0.01). Individuals with the PON1 QQ genotype exhibited low enzyme activity whereas those with PON1 MM genotype had no statistically significant difference in the patient and control groups. Result: We observed that PON activity decreased in MS. We also found that genotype frequencies support these changes, in terms of genetic polymorphism. Key words: Paraoxonase, Metabolic syndrome, Polymorphism, Diabetes, Obesity.