ABSTRACT
Despite high rates of exposure, only 5-10% of people infected with Mycobacterium tuberculosis will develop active tuberculosis (TB) disease, suggesting a significant role for genetic variation in the human immune response to this infection. Here, we studied TB association and expression of 18 genes involved in the Toll-like receptor (TLR) pathways. Initially, we genotyped 149 sequence polymorphisms in 375 pulmonary TB patients and 387 controls from Indonesia. We found that four polymorphisms in the TLR8 gene on chromosome X showed evidence of association with TB susceptibility in males, including a non-synonymous polymorphism rs3764880 (Met1Val; P = 0.007, odds ratio (OR) = 1.8, 95% c.i. = 1.2-2.7). We genotyped these four TLR8 polymorphisms in an independent collection of 1,837 pulmonary TB patients and 1,779 controls from Russia and again found evidence of association in males (for rs3764880 P = 0.03, OR = 1.2, 95% c.i. = 1.02-1.48). Combined evidence for association is P = 1.2x10(-3)-6x10(-4). In addition, a quantitative PCR analysis indicated that TLR8 transcript levels are significantly up-regulated in patients during the acute phase of disease (P = 9.36x10(-5)), relative to baseline levels following successful chemotherapy. A marked increase in TLR8 protein expression was also observed directly in differentiated macrophages upon infection with M. bovis bacille Calmette-Guérin (BCG). Taken together, our results provide evidence, for the first time, of a role for the TLR8 gene in susceptibility to pulmonary TB across different populations.
Subject(s)
Toll-Like Receptor 8/genetics , Tuberculosis, Pulmonary/genetics , Tuberculosis, Pulmonary/immunology , Adolescent , Adult , Aged , Aged, 80 and over , Case-Control Studies , Cell Line , Chromosomes, Human, X/genetics , Female , Gene Expression , Gene Frequency , Genetic Predisposition to Disease , Haplotypes , Humans , Indonesia , Linkage Disequilibrium , Male , Middle Aged , Polymorphism, Single Nucleotide , RNA, Messenger/genetics , RNA, Messenger/metabolism , Sex Characteristics , Toll-Like Receptor 8/metabolismSubject(s)
Genetic Linkage , Membrane Glycoproteins/genetics , Polymorphism, Single Nucleotide , Receptors, Interleukin-1/genetics , Tuberculosis, Pulmonary/genetics , Case-Control Studies , DNA Mutational Analysis , Gene Frequency , Ghana , Humans , Indonesia , Leucine/genetics , Russia , Serine/geneticsABSTRACT
The Wellcome Trust Case Control Consortium (WTCCC) primary genome-wide association (GWA) scan on seven diseases, including the multifactorial autoimmune disease type 1 diabetes (T1D), shows associations at P < 5 x 10(-7) between T1D and six chromosome regions: 12q24, 12q13, 16p13, 18p11, 12p13 and 4q27. Here, we attempted to validate these and six other top findings in 4,000 individuals with T1D, 5,000 controls and 2,997 family trios independent of the WTCCC study. We confirmed unequivocally the associations of 12q24, 12q13, 16p13 and 18p11 (P(follow-up) Subject(s)
Chromosome Mapping
, Diabetes Mellitus, Type 1/genetics
, Genetic Predisposition to Disease
, Genome, Human
, Adolescent
, Case-Control Studies
, Humans
, Polymorphism, Single Nucleotide
ABSTRACT
Recently, the Intracellular pathogen resistance 1 (Ipr1) gene was shown to control susceptibility to Mycobacterium tuberculosis in mice. We examined whether common sequence variants of its human orthologue, the SP110 gene, are associated with susceptibility to tuberculosis in a human population. We resequenced SP110 exons in 96 individuals and identified new polymorphisms. Then, we combined our sequence and HapMap data for 83 distinct polymorphisms and selected tags that capture information for all common variants in the 100 kb region around SP110. We genotyped 29 single nucleotide polymorphisms including seven amino-acid changing variants in 1,912 HIV-negative culture-confirmed adult pulmonary tuberculosis patients and 2,104 adult healthy controls from Russia and found no evidence of association. Our results indicate that common polymorphisms of the SP110 gene have no major effect on susceptibility to tuberculosis in this population.
Subject(s)
Nuclear Proteins/genetics , Nuclear Proteins/physiology , Polymorphism, Genetic , Sequence Analysis, DNA/methods , Tuberculosis, Pulmonary/genetics , Alleles , Exons , Genetic Predisposition to Disease , Genotype , Humans , Introns , Minor Histocompatibility Antigens , Mutation , Mycobacterium tuberculosis/metabolism , Odds Ratio , Russia , Tuberculosis, Pulmonary/microbiologyABSTRACT
Recently, the interleukin-18 cytokine gene (IL18) was reported to be associated with type 1 diabetes. In the present report, we calculated that the reported genotypes of the two 5' region/promoter single nucleotide polymorphisms (SNPs), -607 (C-->A) (rs1946518) and -137 (G-->C) (rs187238), were not in Hardy-Weinberg equilibrium (HWE). We therefore investigated the association of the -607 and -137 SNPs in a U.K. type 1 diabetic Caucasian case-control collection (1,560 case and 1,715 control subjects tested at -607 and 4,323 case and 4,610 control subjects tested at -137) as well as a type 1 diabetic Caucasian collection comprised of families of European ancestry (1,347 families tested at -137 and 1,356 families tested at -607). No evidence for association with type 1 diabetes was found, including for the -607 A/A and C/A genotypes. To evaluate whether common variation elsewhere in the gene was associated with disease susceptibility, we analyzed eight IL18 tag SNPs in a type 1 diabetic case-control collection (1,561 case and 1,721 control subjects). No evidence for association was obtained (P = 0.11). We conclude that common allelic variation in IL18 is unlikely to contribute substantially to type 1 diabetes susceptibility in the populations tested and recommend routine application of tests for HWE in population-based studies for genetic association.
