A novel single nucleotide polymorphism within the NOD2 gene is associated with pulmonary tuberculosis in the Chinese Han, Uygur and Kazak populations

Liliang Wei,Tingting Jiang,Mengyuan Zhao,Xing Zhang,Ji-Cheng Li,Xiling Deng,Yuxiang Zhang,Xiaojun Sun,Fang Wu,Wanjiang Zhang,Le Zhang,Dapeng Fan,Yun Xue,Fujian Li,Feng Jiang,Jiyan Liu

doi:10.1186/1471-2334-12-91

Abstract

BackgroundThe present study aimed to investigate the genetic polymorphisms in exon 4 of the NOD2 gene in tuberculosis patients and healthy controls, in order to clarify whether polymorphisms in the NOD2 gene is associated with tuberculosis.MethodsA case-control study was performed on the Chinese Han, Uygur and Kazak populations. Exon 4 of the NOD2 gene was sequenced in 425 TB patients and 380 healthy controls to identify SNPs.ResultsThe frequency of T/G genotypes for the Arg587Arg (CGT → CGG) single nucleotide polymorphism (SNP) in NOD2 was found to be significantly higher in the Uygur (34.9%) and Kazak (37.1%) populations than the Han population (18.6%). Also, the frequency of G/G genotypes for the Arg587Arg SNP was significantly higher in the Uyghur (8.3%) and Kazak (5.4%) populations than the Han population (0.9%). Meanwhile, no significant difference was found in the Arg587Arg polymorphism between the tuberculosis patients and healthy controls in the Uyghur and Kazak populations (P > 0.05) whereas, a significant difference was observed in the Arg587Arg polymorphism between the tuberculosis patients and healthy controls in the Han population (P < 0.01). The odd ratio of 2.16 (95% CI = 1.31-3.58; P < 0.01) indicated that the Arg587Arg SNP in NOD2 may be associated with susceptibility to tuberculosis in the Chinese Han population.ConclusionsOur study is the first to demonstrate that the Arg587Arg SNP in NOD2 is a new possible risk factor for tuberculosis in the Chinese Han population, but not in the Uyghur and Kazak populations. Our results may reflect racial differences in genetic susceptibility to tuberculosis.

Highlights

The present study aimed to investigate the genetic polymorphisms in exon 4 of the Nucleotide-binding oligomerization domain containing2 (NOD2) gene in tuberculosis patients and healthy controls, in order to clarify whether polymorphisms in the NOD2 gene is associated with tuberculosis
We investigated the Arg587Arg polymorphism within the exon 4 of NOD2 in the Chinese Han, Uygur and Kazak populations associated with TB, which was located in the winged helix and superhelical domain of NOD2 [16]
The exon 4 of the NOD2 gene was sequenced in 425 TB patients and 380 healthy controls to identify single nucleotide polymorphism (SNP), in the Chinese Han, Uygur and Kazak populations (Figure 1)

Summary

Introduction

The present study aimed to investigate the genetic polymorphisms in exon 4 of the NOD2 gene in tuberculosis patients and healthy controls, in order to clarify whether polymorphisms in the NOD2 gene is associated with tuberculosis. It is estimated that 1/3 of the world’s population has been infected with mycobacterium TB. China has the world’s second largest TB epidemic. The TB epidemic in the Western China is higher than the national average. The prevalence rate of active, sputum smear and culture positive TB in the Uygur, Kazak and Mongolian populations of the Xinjiang Uygur Autonomous Region (Northwest China) was found to be 12.4%, 16.9% and 18.4% higher than the Chinese Han population, respectively [4]. The differences in susceptibility to TB may be related to a genetic predisposition. Several genes such as the natural resistanceassociated macrophage protein 1 [5], vitamin D receptor [6], toll-like receptor [7] and interleukin [8,9] have been associated with susceptibility to TB

Methods

Results

Discussion

Conclusion