Frequency Distribution of Mannose Binding Lectin-2 and Vitamin D Receptor Gene Variants: Putative Markers for Tuberculosis.

Anuroopa Gupta,Harish Padh

doi:10.1155/2015/264120

Abstract

Genetic polymorphism in Mannose Binding Lectin-2 (MBL-2) and Vitamin D Receptor (VDR) is known to influence the susceptibility to tuberculosis. The objective of the present study was to evaluate the frequency distribution of the MBL-2 promoter and structural polymorphism (−550 H/L, −221 Y/X, and +4 P/Q; R52C, G54D, and G57F) and VDR polymorphism (FokI, BsmI, TaqI, and ApaI) in healthy individuals of Indian population and comparative analysis with the global population. In Indian population, the frequency of VDR mutant alleles “f” for FokI, “b” for BsmI, “t” for TaqI, and “a” for ApaI was 25%, 54%, 30%, and 61%, respectively. The allelic frequency of MBL-2 promoter polymorphism −550 H/L was H versus L: 32% versus 68%, −221 Y/X was Y versus X: 68% versus 32%, and +4 P/Q was P versus Q: 78% versus 22%. Mutant allelic frequencies of the MBL-2 exon 1 D, B, and C allele were 6%, 11%, and 3%, respectively. Comparative analysis with global populations showed a noteworthy difference for MBL-2 and VDR polymorphism frequency distribution, indicating the ethnic variability of Indians. The study signifies the differential distribution of susceptibility genes in Indian population, which can influence the understanding of the pathophysiology of tuberculosis in Indian population.

Highlights

Mycobacterium tuberculosis is one of the most ancient and life-threatening pathogens for mankind
All polymorphism with the exception of R52C were in Hardy-Weinberg equilibrium
The observed genotype and allele frequencies in Indian population were compared with the previously reported different populations worldwide by using chi-square tests to elucidate the differences in the distribution of Mannose Binding Lectin-2 (MBL-2) structural variant alleles (D, B, and C) and promoter variants (Figure 1)

Summary

Introduction

Mycobacterium tuberculosis is one of the most ancient and life-threatening pathogens for mankind. More than onethird of the world’s population harbours the tubercle bacilli asymptomatically. Only 5–10% of the infected individuals develop the disease [1]. In 2012, one-third of the global deaths occurring due to tuberculosis were reported in India and South Africa [2]. The interindividual variation in disease susceptibility and progression is a consequence of the varied extent of host response to M. tuberculosis. Genetic polymorphism in Mannose Binding Lectin-2 (MBL-2), a central player in the innate immune response and Vitamin D Receptor (VDR), an immunomodulator has been found to influence the susceptibility to tuberculosis [3, 4]

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