Genetic analysis of IL4 (rs2070874), IL17A (rs2275913), and IL33 (rs7044343) polymorphisms in Iraqi multiple sclerosis patients by using T-plex real-time PCR method

Abstract

Multiple sclerosis (MS) is a neurodegenerative autoimmune disease that leads to axon demyelination and white matter plaque formation. The aim of the present study is to inspect the association between single nucleotide polymorphisms (SNPs) of IL4 (rs2070874), IL17A (rs2275913), and IL33 (rs7044343) and MS predisposition. The genotyping of the three genetic variants was conducted through tetra-plex-based real-time polymerase chain reaction (T-plex RT-PCR) method combined with the SYBR green fluorescent dye. Sixty-eight Iraqi MS patients and fifty healthy individuals (controls) were enrolled, and their DNA was extracted from whole blood. The optimum annealing/extension temperature was set at 58 °C. For each SNP, allele-specific fragments were identified by their melting points generated through real-time PCR. Agarose gel electrophoresis was performed to confirm the results. The distribution of the IL4 SNP genotypes in patients and controls was in good agreement with Hardy-Weinberg equilibrium, while there was a skewness from Hardy-Weinberg equilibrium in patients' group for both IL17A and IL33 SNPs. Multinomial logistic regression analysis was performed to investigate the association between the studied variants under four genetic models (dominant, recessive, over-dominant, and co-dominant) and MS risk. However, there were no significant differences in genotype/allele frequencies of three SNPs between patients and controls. Taken together, our study indicated that genotype/allele of IL4 (rs2070874), IL17A (rs2275913), and IL33 (rs7044343) SNPs may not play a considerable role in the predisposition to MS in this sample of the Iraqi population. However, SYBR green-dependent T-plex RT-PCR can be a cost-effective, reproducible and simple method for genotyping SNPs of interest.