Relationship between common polymorphisms of NRAMP1 gene and pulmonary tuberculosis in Lorestan LUR population

Abstract

Introduction: Tuberculosis (TB) is caused by Mycobacterium tuberculosis. In humans, a number of genes have been identified as susceptible to pulmonary tuberculosis. The relationship between NRAMP1 polymorphisms and pulmonary tuberculosis has been studied in different populations and has reported contradictory results. The aim of this study was to investigate the relationship between the common polymorphisms of NRAMP1 gene and the susceptibility to pulmonary tuberculosis in the LUR Population of Lorestan province of Iran. Materials and Methods: In this case control study, three common polymorphisms of NRAMP1 gene (3'UTR, INT4 and D543N) were genotyped using PCR-RFLP technique in the LUR population of Lorestan province. In this study, 100 patients with pulmonary tuberculosis (PTB) were studied as case group and 100 healthy controls that matched for age and sex with the patient group, studied as control group. Statistical analysis was performed using SPSS 18 software. Results: In the present study we observed that the GG genotype of D543N polymorphism was statistically significantly associated with increased susceptibility to TB (84% in the case group vs. 72% in the control group, %95CI=1.024-4.071, OR=2.042, P=0.0405). Also, G allele of D543N polymorphism was statistically significantly associated with increased susceptibility to pulmonary tuberculosis (90% in the case group vs. 81.5% in the control group, %95CI=1.140-3.663, OR=2.043, P=0.015). On the other hand, the frequency of allele A of D543N polymorphism was significantly lower in patients than in the control group (10% in the case group vs. 18.5% in the control group, %95CI=0.273-0.878, OR=0.489, P=0.015). Although genotypic and allelic frequency of 3'UTR and INT4 polymorphisms between patients and controls showed no significant differences in the study population. Discussion and conclusion: Our observations showed that GG genotype and G allele of D543N polymorphism have a significant role in increasing the susceptibility to pulmonary tuberculosis in the LUR Population of Lorestan province. Also, allele A of D543N polymorphism has a significant effect on resistance to pulmonary tuberculosis in this population. Although there was no significant correlation between genotypes and alleles of 3'UTR and INT4 polymorphisms with susceptibility to or resistance to pulmonary TB in this population. It is suggested that a larger sample size be used in future studies. It is also recommended to conduct this type of study on other ethnicities. Keywords: NRAMP1, Pulmonary tuberculosis, LUR Population, Lorestan province, Iran.