We made a minireview on the association of many candidate genes with TB based on recent research studies systematically, such as the human leukocyte antigen (HLA) gene, the solute carrier family 11 member 1 (SLC11A1) gene system, the vitamin D receptor (VDR) gene, the mannan-binding lectin (MBL) gene, the nitric oxide synthase 2A (NOS2A) gene, the speckled 110 (SP110) gene, and the P2X7 receptor (P2X7) gene.
Studies have reported genetic markers to predict TB development in human leukocyte antigen (HLA) and non-HLA genes like killer immunoglobulin-like receptor (KIR), toll-like receptors (TLRs), cytokine/chemokines and their receptors, vitamin D receptor (VDR) and SLC11A1 etc.
The (GT)n promoter alleles 2 and 3 (rs534448891), which alter SLC11A1 expression, were significantly associated with tuberculosis (OR=1.47 (1.30-1.66), OR=0.76 (0.65-0.89), respectively) and infectious disease (OR=1.25 (1.10-1.42), OR=0.83 (0.74-0.93), respectively).
Many genes involved in tuberculosis susceptibility (e.g., NRAMP1 (SLC11A1), IFNG, NOS2A, VDR, ISG15, TACO, TLR1, TLR, IL18R1, chemokines, PADI, DUSP14, MBL, and MASP-2) have been subjected to epigenetic modification.
Multiple host iron status biomarkers, Haptoglobin and solute carrier family 11, member 1 (SLC11A1) genotypes were modeled to characterize how indicators of host iron metabolism were associated with TB susceptibility.
Susceptibility to TB-IRD associated with carriage of TNFA-1031*T (rs1799964; P=0.05) and SLC11A1 D543N*G (rs17235409; P=0.04) in Cambodian patients and carriage of IL18-607*G (rs1946518; P=0.02) and VDR FokI (F/f)*T (rs10735810; P=0.05) in Indian patients.
The association between SLC11A1 polymorphisms and tuberculosis susceptibility observed in our analyses supports the hypothesis that NRAMP1 might play an important role in the host defense to the development of tuberculosis.
Several important candidate genes like human leucocyte antigen/alleles and non-human leucocyte antigen genes, such as cytokines and their receptors, chemokines and their receptors, pattern recognition receptors (including toll-like receptors, mannose binding lectin and the dendritic cell-specific intercellular adhesion molecule-3 grabbing nonintegrin), solute carrier family 11A member 1 (formerly known as natural resistance-associated macrophage protein 1) and purinergic P2X7 receptor gene polymorphisms, have been associated with differential susceptibility to TB in various ethnic populations.
The natural resistance-associated macrophage protein (NRAMP1), Vitamin-D receptor (VDR) and Tumor necrosis factor (TNF-alpha) have been associated in susceptibility to tuberculosis, but the results have been inconsistent.
The M. tuberculosis Beijing genotype, which comprised 29.8% of all isolates, was strongly associated with 2 polymorphisms in SLC11A1: the D543N G allele (odds ratio [OR], 2.15; P=.005) and the 3' untranslated region (3'UTR) insertion/insertion genotype (OR, 2.5; P=.001).