The Role of TLR4 Gene Polymorphism and Haplotypes in the Susceptibility to Toxoplasmosis in Iraqi Aborted Women

Abstract

The activity of TLRs as non-specific immunity in defense against T. gondii infections was observed particularly for TLR4 molecules. Several single-nucleotide polymorphisms (SNPs) residing in tow genes encoding these receptors were reported as significant genetic modifications of TLRs and associated with different pregnancy disorders. This study aimed to investigate the association between two single nucleotide polymorphisms (SNPs) in the toll-like receptor 4 gene (Asp299Gly and Thr399Ile) and susceptibility for toxoplasmosis. A total of 50 aborted women with IgM seropositive for Toxoplasma gondii and 50 aborted women with IgM seronegative for Toxoplasma gondii as controls were included in this study. DNA was extracted from the blood samples taken from these participants. TLR4 gene was amplified with polymerase chain reaction (PCR) using specific primers. Genotyping of the SNPs of interest were subjected for direct sequencing by (Macrogen /Korea), and the resultant sequences were compared with reference sequences in NCBI by using Bio edit software. The frequency of the heterozygous genotype (AG) was higher in patients than controls (20% versus 6%) with a significant difference (OR=3.92, 95%CI=1.01-15.22, p=0.037). Among the haplotype blocks, only ACC was significantly less frequent among patients than controls (85% versus 94%, p=0.038), while frequencies of other haplotypes were very close between patients and controls. The mutant allele (G) of the SNP Asp299Gly may be considered as a risk factor for toxoplasmosis and stimulate abortion in pregnant women.

Keywords

• toxoplasmosis
• single nucleotide polymorphism
• toll-like receptor 4