Frequency of Human Paraoxonase-1 Q192R Polymorphism and Measurement of Oxidative Stress Parameters in Infants with G6PD Deficiency

Abstract

Background and Aims: This study aimed to investigate the frequency of Q192R polymorphism and oxidative stress markers in infants with glucose-6phosphate dehydrogenase (G6PD) deficiency.

Materials and Methods: This is a case-control study in which 60 male infants (2-4 months old) with G6PD deficiency along with 60 age- and sexmatched healthy neonates were included. The diagnosis of G6PD deficiency was made by Beutler test by which the G6PD enzyme activity is measured by the fluorescent spot test. The blood samples were taken from all infants, and the sera were isolated for the evaluation of Paraoxonase-1 (PON1) and malondialdehyde (MDA) using the spectrophotometric method. Restriction fragment length polymorphism was applied for determination of Q192R polymorphism (rs 662).

Results: The frequencies of QQ, QR, and RR genotypes were 55%, 39%, and 6%, respectively in infants with G6PD deficiency while the above genotype frequencies were 45%, 49%, and 6%, respectively in healthy neonates. The frequency of R and T alleles failed to show any significant difference when G6PD deficient infants and healthy neonates were compared. The results indicated PON1 activity and MDA levels being significantly (p<0.05) higher in neonates with G6PD deficiency compared with their healthy counterparts.

Conclusion: Contrary to previous studies, it was indicated that the presence of RQ and RR genotypes at Q192R position is associated with decreased activity of PON1 and increased oxidative stress. In this study, no significant differences were found in the genotype and allele frequency of PON1 Q192R polymorphism between the case and control groups. Also, this frequency was not consistent with the results obtained from oxidative stress conditions.