Introduction: Glucose-6-phosphate dehydrogenase deficiency is the most common enzyme disorder. This enzyme involved in maintaining the balance of active oxygen species and its defect causes oxidative damage. PON1 is an HDL-based glycosylated protein that prevents lipid peroxidation. In this study, the prevalence of PON L55M polymorphism in paraoxonase enzyme in neonates with a deficiency in G6PD activity was evaluated, and the level of oxidative stress was measured.
Methods:  In the present case-control study, 60 infants 2 to 6 months with G6PD enzyme activity deficiency and 60 healthy infants identical in age was selected. Polymorphism examination was done using PCR-RFLP technique, and oxidative stress parameters were measured by spectrophotometry. Chi square and t test statistical analysis of data was performed using SPSS V16 software.
Results: The frequency of genotype LL, LM and MM for PON1 L55M was 43.33%, 43.3% and 13.3% and, 35%, 21.6% and 43.3% in control and case group, respectively. Genotypic frequency of LM and MM was significant between control and control groups (P <0.05). The allele frequency between L and M was also significant (P <0.05). Superoxide dismutase enzyme activity and mean carbonyl level comparison did not show a significant difference (P >0.05), but the activity of catalase enzyme and mean level of thiol was showed a significant difference (P <0.05).
Conclusion: In the present study, the frequency of LM genotype in neonates with G6PD deficiency was significantly different in comparison to the control group. This frequency is consistent with the results obtained from oxidative stress conditions (significant reduction in the level of thiol and catalase activity).
 

Keywords: G6PD, Polymorphism, Oxidative stress, PON1, Neonatal.

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