Association between preterm birth risk and polymorphism and expression of the DNA repair genes OGG1 and APE1 in Saudi women

Genomic instability and mutations caused by increases in oxidative stress during pregnancy can damage the fetoplacental unit and can upshot preterm birth. Oxidative damage to DNA may possibly be involved in etiology of preterm birth (PTB) which can be repaired by DNA repair gene. In the present study, we assessed the association of base excision repair gene family by analyzing the association of single nucleotide polymorphisms and genes expression in 8-oxoguanine glycosylase-1 (OGG1) and apurinic-apyrimidinic endonuclease 1 (APE1) genes with risk of preterm birth in Saudi women. We analyzed genotypes of four single nucleotide polymorphisms (SNPs) (rs1052133, rs293795, rs2072668 and rs2075747) in OGG1 gene and three SNPs (rs1130409, rs3136814, and rs3136817) in APE1 gene using TaqMan Genotyping assay kits in 50 pairs of preterm cases and individually matched controls. Also, gene expression level was explored by RT-PCR in 10 pairs of preterm placental tissues and individually matched normal placental tissues. Two OGG1 SNP, rs1052133 (OR=0.497; c2=1.11; p=0.292) and rs2072668 (OR=0.408; c2=1.90; p=0.167) and one APE1 SNP rs3136817 (OR=0.458; c2=0.40; p=0.527) showed nonsignificant protective effect against PTB development. The expression of both genes under study was found lower in the PTB patients. Genotype and allele frequencies of both gene SNPs did not show any association with the risk of preterm delivery in Saudi women (P˃0.05). However, synthesis and release of OGG1 and APE1 proteins decreased in preterm placental tissues compared to term delivery reflects the probability of being one of the mechanisms leading to preterm birth.