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1.
J Hum Genet ; 67(1): 65-67, 2022 Jan.
Article in English | MEDLINE | ID: mdl-34230590

ABSTRACT

Recently, a common genetic variant E756del in the human gene PIEZO1 was associated with protection from severe malaria. Here, we performed a genetic association study of this gain-of-function variant in a large case-control study including 4149 children from the Ashanti Region in Ghana, West Africa. The statistical analysis did not indicate an association with protection from severe malaria and, thus, providing evidence against a strong protective effect of the PIEZO1 E756del variant on severe malaria susceptibility.


Subject(s)
Disease Resistance/genetics , Genetic Association Studies , Genetic Predisposition to Disease , Ion Channels/genetics , Malaria/genetics , Sequence Deletion , Adolescent , Adult , Aged , Aged, 80 and over , Alleles , Case-Control Studies , Child , Female , Genetic Association Studies/methods , Genotype , Ghana , Humans , Malaria/diagnosis , Malaria/parasitology , Male , Middle Aged , Severity of Illness Index , Young Adult
2.
G3 (Bethesda) ; 7(3): 859-864, 2017 03 10.
Article in English | MEDLINE | ID: mdl-28104671

ABSTRACT

In a recent report, the cellular receptor CD55 was identified as a molecule essential for the invasion of human erythrocytes by Plasmodium falciparum, the causal agent of the most severe form of malaria. As this invasion process represents a critical step during infection with the parasite, it was hypothesized that genetic variants in the gene could affect severe malaria (SM) susceptibility. We performed high-resolution variant discovery of rare and common genetic variants in the human CD55 gene. Association testing of these variants in over 1700 SM cases and unaffected control individuals from the malaria-endemic Ashanti Region in Ghana, West Africa, were performed on the basis of single variants, combined rare variant analyses, and reconstructed haplotypes. A total of 26 genetic variants were detected in coding and regulatory regions of CD55 Five variants were previously unknown. None of the single variants, rare variants, or haplotypes showed evidence for association with SM or P. falciparum density. Here, we present the first comprehensive analysis of variation in the CD55 gene in the context of SM and show that genetic variants present in a Ghanaian study group appear not to influence susceptibility to the disease.


Subject(s)
CD55 Antigens/genetics , Genetic Association Studies , Genetic Predisposition to Disease , Malaria, Falciparum/genetics , Polymorphism, Single Nucleotide/genetics , Case-Control Studies , Child , Ghana , Haplotypes/genetics , Humans , Infant , Phenotype
3.
PLoS One ; 11(5): e0156046, 2016.
Article in English | MEDLINE | ID: mdl-27214039

ABSTRACT

Toll like receptors (TLR) are key elements of the innate immune response and involved in the recognition of pathogens. To test common and rare TLR variants involved in susceptibility or resistance to infection with Mycobacterium tuberculosis we screened the exons of the genes encoding TLR 1, 2, 4, and the adaptor molecule TIRAP in more than 4500 tuberculosis (TB) cases and controls from Ghana. The analysis yielded 109 variants with possible functional impact, including 101 non-synonymous variants, three stop-variants, and five indels. Association analyses yielded a significant result for the TLR1 variant rs3923647, conferring strong protection against TB (Odds ratio [OR] 0.21, CI confidence interval [CI] 0.05-0.6, Pnominal 1 x 10-3) when applying a recessive model of inheritance. Replication analyses with an additional 3370 Ghanaian cases and control samples, and with data from a recent TB study of 533 African-Americans confirmed the protective effect and resulted in a combined OR of 0.19, with a nominal P value of 2.2 x 10-5, and a corrected P value of 4.1 x 10-4. The SNP is located near the binding pocket of TLR1 and causes an amino acid exchange from histidine to leucine at position 305. The observed effect may, therefore, be attributable to structural changes in the recognition site of the TLR1 molecule, allowing to bind those mycobacterial ligands which preferentially may induce a protective immune response. This is supported by the analysis of BCG-stimulated peripheral blood mononuclear cells, showing increased induction of the proinflammatory cytokine IFN-γ in carriers of the mutant TLR1 rs3923647 TT genotype, compared to the IFN-γ levels of individuals with the AT and AA genotypes.


Subject(s)
Disease Resistance/genetics , Polymorphism, Single Nucleotide , Toll-Like Receptor 1/genetics , Tuberculosis, Pulmonary/genetics , Amino Acid Substitution , Case-Control Studies , Gene Frequency , Genes, Recessive , Genetic Association Studies , Genetic Predisposition to Disease , Ghana/epidemiology , Histidine/genetics , Humans , Leucine/genetics , Tuberculosis, Pulmonary/epidemiology , Tuberculosis, Pulmonary/immunology
4.
Mediators Inflamm ; 2016: 4245028, 2016.
Article in English | MEDLINE | ID: mdl-26977119

ABSTRACT

The contribution of interleukin- (IL-) 4 receptor-alpha- (Rα-) dependent events in the pathogenesis of tuberculosis (TB) is controversial. We have recently shown IL-13 overexpression in mice to cause recrudescent Mtb replication and centrally necrotizing granulomas strongly resembling pathology of human TB. A deletion of IL-4Rα completely abrogates TB tissue pathology in these mice. To validate our results in human TB patients, we here determined the association of distinct variants of the IL4, IL13, IL4RA, IL13RA1, and IL13RA2 genes with cavity formation in a large Ghanaian cohort of HIV-negative individuals with newly diagnosed pulmonary TB. In fact, the structural variant of the IL4RA I50V, previously shown to result in enhanced signal transduction, was significantly associated with greater cavity size, and a variant of IL13RA2 was associated with disease in females. To evaluate whether the human-like TB pathology in IL-13-overexpressing mice is specifically mediated through the IL-4Rα subunit, we analyzed IL-13 transgenic mice with a genetic ablation of the IL-4Rα. In these mice, the IL-13-mediated increased susceptibility, human-like pathology of collagen deposition around centrally necrotizing granulomas, and alternative macrophage activation were abolished. Together, our genetic association study in human TB patients further supports the assumption that IL-13/IL-4Rα-dependent mechanisms are involved in mediating tissue pathology of human TB.


Subject(s)
Interleukin-4 Receptor alpha Subunit/genetics , Tuberculosis, Pulmonary/genetics , Animals , Female , Ghana , Humans , Interleukin-13/metabolism , Interleukin-13 Receptor alpha2 Subunit/metabolism , Interleukin-4/metabolism , Male , Mice , Mice, Transgenic , Mutation , Signal Transduction/genetics , Signal Transduction/physiology
5.
Eur J Hum Genet ; 24(5): 748-55, 2016 May.
Article in English | MEDLINE | ID: mdl-26242990

ABSTRACT

The concept of interferon-γ (IFN-γ) having a central role in cell-mediated immune defence to Mycobacterium tuberculosis has long been proposed. Observations made through early candidate gene studies of constituents of the IFN-γ pathway have identified moderately associated variants associated with resistance or susceptibility to tuberculosis (TB). By analysing 20 major genes whose proteins contribute to IFN-γ signalling we have assessed a large fraction of the variability in genes that might contribute to susceptibility to TB. Genetic variants were identified by sequencing the promoter regions and all exons of IFNG, IFNGR1, IFNGR2, IRF1, IL12A, IL12B, IL12RB1, IL12RB2, IL23A, IL23R, IL27, EBI3, IL27RA, IL6ST, SOCS1, STAT1, STAT4, JAK2, TYK2 and TBX21 in 69 DNA samples from Ghana. In addition, we screened all exons of IFNGR1 in a Ghanaian study group comprising 1999 TB cases and 2589 controls by high-resolution melting point analysis. The fine-mapping approach allows for a detailed screening of all variants, common and rare. Statistical comparisons of cases and controls, however, did not yield significant results after correction for multiple testing with any of the 246 variants selected for genotyping in this investigation. Gene-wise haplotype tests and analysis of rare variants did not reveal any significant association with susceptibility to TB in our investigation as well. Although this analysis was applied on a plausible set of IFN-γ pathway genes in the largest African TB cohort available so far, the lack of significant results challenges the view that genetic marker of the IFN-γ pathway have an important impact on susceptibility to TB.


Subject(s)
Genetic Loci , Interferon-gamma/genetics , Polymorphism, Single Nucleotide , Receptors, Interferon/genetics , Tuberculosis/genetics , Case-Control Studies , Exons , Ghana , Humans , Interferon-gamma/metabolism , Interleukins/genetics , Interleukins/metabolism , Promoter Regions, Genetic , STAT Transcription Factors/genetics , STAT Transcription Factors/metabolism , Interferon gamma Receptor
6.
Infect Genet Evol ; 36: 517-523, 2015 Dec.
Article in English | MEDLINE | ID: mdl-26319998

ABSTRACT

We conducted a prospective study to establish factors associated with survival in tuberculosis patients in Russia including social, clinical and pathogen-related genetic parameters. Specifically we wished to determine whether different strains/clades of the Beijing lineage exerted a differential effect of survival. HIV-negative culture-confirmed cases were recruited during 2008-2010 across Samara Oblast and censored in December 2011. Molecular characterization was performed by a combination of spoligotyping, multilocus VNTR typing and whole genome sequencing (WGS). We analyzed 2602 strains and detected a high prevalence of Beijing family (n=1933; 74%) represented largely by two highly homogenous dominant clades A (n=794) and B (n=402) and non-A/non-B (n=737). Multivariable analysis of 1366 patients with full clinical and genotyping data showed that multi- and extensive drug resistance (HR=1.86; 95%CI: 1.52, 2.28 and HR=2.19; 95%CI: 1.55, 3.11) had the largest impact on survival. In addition older age, extensive lung damage, shortness of breath, treatment in the past and alcohol abuse reduced survival time. After adjustment for clinical and demographic predictors there was evidence that clades A and B combined were associated with poorer survival than other Beijing strains (HR=0.48; 95%CI 0.34, 0.67). All other pathogen-related factors (polymorphisms in genes plcA, plcB, plcC, lipR, dosT and pks15/1) had no effect on survival. In conclusion, drug resistance exerted the greatest effect on survival of TB patients. Nevertheless we provide evidence for the independent biological effect on survival of different Beijing family strains even within the same defined geographical population. Better understanding of the role of different strain factors in active disease and their influence on outcome is essential.


Subject(s)
Genotype , HIV Seronegativity , Mycobacterium tuberculosis/genetics , Tuberculosis/microbiology , Tuberculosis/mortality , Female , Genetic Linkage , Genome, Bacterial , Humans , Kaplan-Meier Estimate , Male , Mycobacterium tuberculosis/classification , Mycobacterium tuberculosis/drug effects , Proportional Hazards Models , Prospective Studies , Risk Factors , Russia/epidemiology , Tuberculosis/epidemiology
7.
Nat Genet ; 47(5): 523-527, 2015 May.
Article in English | MEDLINE | ID: mdl-25774636

ABSTRACT

Human genetic factors predispose to tuberculosis (TB). We studied 7.6 million genetic variants in 5,530 people with pulmonary TB and in 5,607 healthy controls. In the combined analysis of these subjects and the follow-up cohort (15,087 TB patients and controls altogether), we found an association between TB and variants located in introns of the ASAP1 gene on chromosome 8q24 (P = 2.6 × 10(-11) for rs4733781; P = 1.0 × 10(-10) for rs10956514). Dendritic cells (DCs) showed high ASAP1 expression that was reduced after Mycobacterium tuberculosis infection, and rs10956514 was associated with the level of reduction of ASAP1 expression. The ASAP1 protein is involved in actin and membrane remodeling and has been associated with podosomes. The ASAP1-depleted DCs showed impaired matrix degradation and migration. Therefore, genetically determined excessive reduction of ASAP1 expression in M. tuberculosis-infected DCs may lead to their impaired migration, suggesting a potential mechanism of predisposition to TB.


Subject(s)
Adaptor Proteins, Signal Transducing/genetics , Dendritic Cells/physiology , Tuberculosis, Pulmonary/genetics , Adaptor Proteins, Signal Transducing/metabolism , Adult , Case-Control Studies , Cell Movement , Cells, Cultured , Female , Gene Expression , Genetic Predisposition to Disease , Genome-Wide Association Study , Humans , Introns , Male , Middle Aged , Polymorphism, Single Nucleotide , Protein Transport
8.
Pediatr Cardiol ; 36(2): 295-9, 2015 Feb.
Article in English | MEDLINE | ID: mdl-25135600

ABSTRACT

The genetic basis of congenital heart disease remains unknown in most of the cases. Recently, a novel mouse model shed new light on the role of CCN1/CYR61, a matricellular regulatory factor, in cardiac morphogenesis. In a candidate gene approach, we analyzed a cohort of 143 patients with atrial septal defects (ASD) by sequencing the coding exons of CCN1. In addition to three frequent polymorphisms, we identified an extremely rare novel heterozygous missense mutation (c.139C > T; p.R47W) in one patient with severe ASD. The mutation leads to an exchange of residues with quite different properties in a highly conserved position of the N-terminal insulin-like growth factor binding protein module. Further bioinformatic analysis, exclusion of known ASD disease genes as well as the exclusion of the mutation in a very high number of ethnically matched controls (more than 1,000 individuals) and in public genetic databases, indicates that the p.R47W variant is a probable disease-associated mutation. The report about ASD in mice in heterozygous Ccn 1 +/- animals strongly supports this notion. Our study is the first to suggest a relationship between a probable CCN1 mutation and ASD. Our purpose here was to draw attention to CCN1, a gene that we believe may be important for genetic analysis in patients with congenital heart disease.


Subject(s)
Cysteine-Rich Protein 61/genetics , Heart Septal Defects, Atrial/genetics , Adult , DNA Mutational Analysis , Female , Genetic Association Studies , Genetic Variation , Heart Septal Defects, Atrial/diagnostic imaging , Humans , Male , Mutation , Polymorphism, Single Nucleotide/genetics , Ultrasonography
9.
PLoS One ; 9(12): e115770, 2014.
Article in English | MEDLINE | ID: mdl-25541704

ABSTRACT

BACKGROUND: Two recent reports have identified the Endothelial Protein C Receptor (EPCR) as a key molecule implicated in severe malaria pathology. First, it was shown that EPCR in the human microvasculature mediates sequestration of Plasmodium falciparum-infected erythrocytes. Second, microvascular thrombosis, one of the major processes causing cerebral malaria, was linked to a reduction in EPCR expression in cerebral endothelial layers. It was speculated that genetic variation affecting EPCR functionality could influence susceptibility to severe malaria phenotypes, rendering PROCR, the gene encoding EPCR, a promising candidate for an association study. METHODS: Here, we performed an association study including high-resolution variant discovery of rare and frequent genetic variants in the PROCR gene. The study group, which previously has proven to be a valuable tool for studying the genetics of malaria, comprised 1,905 severe malaria cases aged 1-156 months and 1,866 apparently healthy children aged 2-161 months from the Ashanti Region in Ghana, West Africa, where malaria is highly endemic. Association of genetic variation with severe malaria phenotypes was examined on the basis of single variants, reconstructed haplotypes, and rare variant analyses. RESULTS: A total of 41 genetic variants were detected in regulatory and coding regions of PROCR, 17 of which were previously unknown genetic variants. In association tests, none of the single variants, haplotypes or rare variants showed evidence for an association with severe malaria, cerebral malaria, or severe malaria anemia. CONCLUSION: Here we present the first analysis of genetic variation in the PROCR gene in the context of severe malaria in African subjects and show that genetic variation in the PROCR gene in our study population does not influence susceptibility to major severe malaria phenotypes.


Subject(s)
Antigens, CD/genetics , Malaria, Falciparum/genetics , Polymorphism, Single Nucleotide , Receptors, Cell Surface/genetics , Adolescent , Case-Control Studies , Child , Child, Preschool , Endothelial Protein C Receptor , Gene Frequency , Genetic Predisposition to Disease/genetics , Genotyping Techniques , Ghana , Haplotypes , Humans , Infant , Linkage Disequilibrium , Phenotype , Plasmodium falciparum/physiology
10.
Cell Microbiol ; 16(5): 701-8, 2014 May.
Article in English | MEDLINE | ID: mdl-24444337

ABSTRACT

The adhesion of infected red blood cells (iRBCs) to human endothelium is considered a key event in the pathogenesis of cerebral malaria and other life-threatening complications caused by the most prevalent malaria parasite Plasmodium falciparum. In the past 30 years, 14 endothelial receptors for iRBCs have been identified. Exposing 10 additional surface proteins of endothelial cells to a mixture of P. falciparum isolates from three Ghanaian malaria patients, we identified seven new iRBC receptors, all expressed in brain vessels. This finding strongly suggests that endothelial binding of P. falciparum iRBCs is promiscuous and may use a combination of endothelial surface moieties.


Subject(s)
Cell Adhesion , Endothelial Cells/physiology , Erythrocytes/physiology , Erythrocytes/parasitology , Plasmodium falciparum/growth & development , Ghana , Humans , Plasmodium falciparum/isolation & purification , Plasmodium falciparum/parasitology
11.
Nat Genet ; 46(3): 279-86, 2014 Mar.
Article in English | MEDLINE | ID: mdl-24464101

ABSTRACT

The molecular mechanisms determining the transmissibility and prevalence of drug-resistant tuberculosis in a population were investigated through whole-genome sequencing of 1,000 prospectively obtained patient isolates from Russia. Two-thirds belonged to the Beijing lineage, which was dominated by two homogeneous clades. Multidrug-resistant (MDR) genotypes were found in 48% of isolates overall and in 87% of the major clades. The most common rpoB mutation was associated with fitness-compensatory mutations in rpoA or rpoC, and a new intragenic compensatory substitution was identified. The proportion of MDR cases with extensively drug-resistant (XDR) tuberculosis was 16% overall, with 65% of MDR isolates harboring eis mutations, selected by kanamycin therapy, which may drive the expansion of strains with enhanced virulence. The combination of drug resistance and compensatory mutations displayed by the major clades confers clinical resistance without compromising fitness and transmissibility, showing that, in addition to weaknesses in the tuberculosis control program, biological factors drive the persistence and spread of MDR and XDR tuberculosis in Russia and beyond.


Subject(s)
Mycobacterium tuberculosis/drug effects , Mycobacterium tuberculosis/genetics , Tuberculosis, Multidrug-Resistant/transmission , Bacterial Proteins/genetics , DNA-Directed RNA Polymerases , Drug Resistance, Multiple, Bacterial/genetics , Evolution, Molecular , Extensively Drug-Resistant Tuberculosis/epidemiology , Extensively Drug-Resistant Tuberculosis/microbiology , Extensively Drug-Resistant Tuberculosis/transmission , Genes, Bacterial , Humans , Mutation , Mycobacterium tuberculosis/pathogenicity , Phylogeny , Polymorphism, Single Nucleotide , Prevalence , Prospective Studies , Russia/epidemiology , Tuberculosis, Multidrug-Resistant/epidemiology , Tuberculosis, Multidrug-Resistant/microbiology , Virulence/genetics
12.
Blood Cells Mol Dis ; 50(4): 247-51, 2013 Apr.
Article in English | MEDLINE | ID: mdl-23321370

ABSTRACT

BACKGROUND: ß-Thalassemia is a disorder caused by mutations at the hemoglobin ß-gene (HBB) locus. Its most important manifestation, the major form, is characterized by severe hypochromic and hemolytic anemia and is inherited in an autosomal recessive mode. In Gaza Strip, Palestine 0.02% of the population has been identified as ß-thalassemia major. DESIGN AND METHODS: An assessment of mutations was performed in 49 transfusion dependent patients with ß-thalassemia major and in 176 ß-thalassemia carriers diagnosed with a mean erythrocyte cell volume (MCV) <80fl and a proportion of HbA2>3.5%. In addition 39 individuals suspicious for ß-thalassemia carrier status due to a reduced MCV (<80fl) but a normal HBA2 were screened. RESULTS: By screening with three hybridization assays a proportion of 80% of the thalassemic chromosomes from patients and carriers was identified to carry five different mutations of the hemoglobin (Hb) ß-gene. Subsequent DNA sequencing confirmed these and revealed further 9% of the chromosomes to be affected by other mutations. In addition six chromosomes from suspicious carriers were detected to carry ß-thalassemia mutations. Of the 15 different HBB mutations identified the variant IVS-I-110 G>A was the most frequent mutation identified in 34% of the thalassemic chromosomes, followed by IVS-I-1 G>A, IVS-I-6 T>C, Codon 39 C>T, and Codon 37 G>A. Three novel HBB variants were discovered by direct sequencing of the gene: 5' UTR-50 (-/G), 5' UTR-43 C>T, and IVS-II-26 T>G. CONCLUSIONS: The spectrum of HBB mutations described is of the Mediterranean type whereby the allele frequencies of the most common mutations differ from those, which were previously described for the population of the Gaza Strip and other Palestinian populations. The data presented may promote the introduction of molecular testing to the Palestinian premarital screening program for ß-thalassemia in Gaza Strip, which will improve the screening protocol and genetic counseling in the future.


Subject(s)
Mutation , beta-Globins/genetics , beta-Thalassemia/genetics , Exons , Gene Frequency , Genotype , Humans , Middle East/epidemiology , beta-Thalassemia/epidemiology
13.
Nature ; 489(7416): 443-6, 2012 Sep 20.
Article in English | MEDLINE | ID: mdl-22895189

ABSTRACT

Malaria causes approximately one million fatalities per year, mostly among African children. Although highlighted by the strong protective effect of the sickle-cell trait, the full impact of human genetics on resistance to the disease remains largely unexplored. Genome-wide association (GWA) studies are designed to unravel relevant genetic variants comprehensively; however, in malaria, as in other infectious diseases, these studies have been only partly successful. Here we identify two previously unknown loci associated with severe falciparum malaria in patients and controls from Ghana, West Africa. We applied the GWA approach to the diverse clinical syndromes of severe falciparum malaria, thereby targeting human genetic variants influencing any step in the complex pathogenesis of the disease. One of the loci was identified on chromosome 1q32 within the ATP2B4 gene, which encodes the main calcium pump of erythrocytes, the host cells of the pathogenic stage of malaria parasites. The second was indicated by an intergenic single nucleotide polymorphism on chromosome 16q22.2, possibly linked to a neighbouring gene encoding the tight-junction protein MARVELD3. The protein is expressed on endothelial cells and might therefore have a role in microvascular damage caused by endothelial adherence of parasitized erythrocytes. We also confirmed previous reports on protective effects of the sickle-cell trait and blood group O. Our findings underline the potential of the GWA approach to provide candidates for the development of control measures against infectious diseases in humans.


Subject(s)
Disease Resistance/genetics , Genetic Loci/genetics , Genome-Wide Association Study , Malaria, Falciparum/genetics , ABO Blood-Group System , Anemia, Sickle Cell , Case-Control Studies , Chromosomes, Human, Pair 1/genetics , Chromosomes, Human, Pair 16/genetics , Ghana , Humans , Malaria, Falciparum/parasitology , Malaria, Falciparum/pathology , Membrane Proteins/genetics , Plasma Membrane Calcium-Transporting ATPases/genetics , Polymorphism, Single Nucleotide/genetics
14.
Genome Res ; 22(4): 735-45, 2012 Apr.
Article in English | MEDLINE | ID: mdl-22294518

ABSTRACT

Extensively drug-resistant (XDR) tuberculosis (TB), which is resistant to both first- and second-line antibiotics, is an escalating problem, particularly in the Russian Federation. Molecular fingerprinting of 2348 Mycobacterium tuberculosis isolates collected in Samara Oblast, Russia, revealed that 72% belonged to the Beijing lineage, a genotype associated with enhanced acquisition of drug resistance and increased virulence. Whole-genome sequencing of 34 Samaran isolates, plus 25 isolates representing global M. tuberculosis complex diversity, revealed that Beijing isolates originating in Eastern Europe formed a monophyletic group. Homoplasic polymorphisms within this clade were almost invariably associated with antibiotic resistance, indicating that the evolution of this population is primarily driven by drug therapy. Resistance genotypes showed a strong correlation with drug susceptibility phenotypes. A novel homoplasic mutation in rpoC, found only in isolates carrying a common rpoB rifampicin-resistance mutation, may play a role in fitness compensation. Most multidrug-resistant (MDR) isolates also had mutations in the promoter of a virulence gene, eis, which increase its expression and confer kanamycin resistance. Kanamycin therapy may thus select for mutants with increased virulence, helping preserve bacterial fitness and promoting transmission of drug-resistant TB strains. The East European clade was dominated by two MDR clusters, each disseminated across Samara. Polymorphisms conferring fluoroquinolone resistance were independently acquired multiple times within each cluster, indicating that XDR TB is currently not widely transmitted.


Subject(s)
Evolution, Molecular , Extensively Drug-Resistant Tuberculosis/microbiology , Genome, Bacterial/genetics , Mycobacterium tuberculosis/genetics , Bacterial Proteins/genetics , DNA Fingerprinting , DNA, Bacterial/chemistry , DNA, Bacterial/genetics , Drug Resistance, Multiple/genetics , Genotype , Geography , Humans , Microbial Sensitivity Tests , Models, Genetic , Mutation , Mycobacterium tuberculosis/classification , Mycobacterium tuberculosis/pathogenicity , Phylogeny , Polymorphism, Single Nucleotide , Promoter Regions, Genetic/genetics , Russia , Sequence Analysis, DNA , Species Specificity , Virulence/genetics
15.
Nat Genet ; 44(3): 257-9, 2012 Feb 05.
Article in English | MEDLINE | ID: mdl-22306650

ABSTRACT

After imputation of data from the 1000 Genomes Project into a genome-wide dataset of Ghanaian individuals with tuberculosis and controls, we identified a resistance locus on chromosome 11p13 downstream of the WT1 gene (encoding Wilms tumor 1). The strongest signal was obtained at the rs2057178 SNP (P = 2.63 × 10(-9)). Replication in Gambian, Indonesian and Russian tuberculosis case-control study cohorts increased the significance level for the association with this SNP to P = 2.57 × 10(-11).


Subject(s)
Chromosomes, Human, Pair 11/genetics , Genetic Predisposition to Disease/genetics , Genetic Variation/genetics , Tuberculosis/genetics , Case-Control Studies , Cell Cycle Proteins , Cohort Studies , Genotype , Ghana , Humans , Models, Genetic , Nuclear Proteins/genetics , Polymorphism, Single Nucleotide/genetics , RNA Splicing Factors
16.
PLoS One ; 6(6): e20908, 2011.
Article in English | MEDLINE | ID: mdl-21695215

ABSTRACT

Structural variants of the Mannose Binding Lectin (MBL) cause quantitative and qualitative functional deficiencies, which are associated with various patterns of susceptibility to infectious diseases and other disorders. We determined genetic MBL variants in 2010 Ghanaian patients with pulmonary tuberculosis (TB) and 2346 controls and characterized the mycobacterial isolates of the patients. Assuming a recessive mode of inheritance, we found a protective association between TB and the MBL2 G57E variant (odds ratio 0.60, confidence interval 0.4-0.9, P 0.008) and the corresponding LYQC haplotype (P(corrected) 0.007) which applied, however, only to TB caused by M. africanum but not to TB caused by M. tuberculosis. In vitro, M. africanum isolates bound recombinant human MBL more efficiently than did isolates of M. tuberculosis. We conclude that MBL binding may facilitate the uptake of M. africanum by macrophages, thereby promoting infection and that selection by TB may have favoured the spread of functional MBL deficiencies in regions endemic for M. africanum.


Subject(s)
Mannose-Binding Lectin/genetics , Mannose-Binding Lectin/metabolism , Mycobacterium tuberculosis/pathogenicity , Polymorphism, Single Nucleotide , Tuberculosis, Pulmonary/genetics , Case-Control Studies , Genetic Predisposition to Disease/genetics , Genotype , HIV/pathogenicity , Humans , Mycobacterium tuberculosis/classification , Mycobacterium tuberculosis/genetics , Species Specificity , Tuberculosis, Pulmonary/microbiology , Tuberculosis, Pulmonary/virology
17.
PLoS Genet ; 7(5): e1002066, 2011 May.
Article in English | MEDLINE | ID: mdl-21625619

ABSTRACT

Human genetics and immune responses are considered to critically influence the outcome of malaria infections including life-threatening syndromes caused by Plasmodium falciparum. An important role in immune regulation is assigned to the apoptosis-signaling cell surface receptor CD95 (Fas, APO-1), encoded by the gene FAS. Here, a candidate-gene association study including variant discovery at the FAS gene locus was carried out in a case-control group comprising 1,195 pediatric cases of severe falciparum malaria and 769 unaffected controls from a region highly endemic for malaria in Ghana, West Africa. We found the A allele of c.-436C>A (rs9658676) located in the promoter region of FAS to be significantly associated with protection from severe childhood malaria (odds ratio 0.71, 95% confidence interval 0.58-0.88, p(empirical) = 0.02) and confirmed this finding in a replication group of 1,412 additional severe malaria cases and 2,659 community controls from the same geographic area. The combined analysis resulted in an odds ratio of 0.71 (95% confidence interval 0.62-0.80, p = 1.8×10⁻7, n = 6035). The association applied to c.-436AA homozygotes (odds ratio 0.47, 95% confidence interval 0.36-0.60) and to a lesser extent to c.-436AC heterozygotes (odds ratio 0.73, 95% confidence interval 0.63-0.84), and also to all phenotypic subgroups studied, including severe malaria anemia, cerebral malaria, and other malaria complications. Quantitative FACS analyses assessing CD95 surface expression of peripheral blood mononuclear cells of naïve donors showed a significantly higher proportion of CD69+CD95+ cells among persons homozygous for the protective A allele compared to AC heterozygotes and CC homozygotes, indicating a functional role of the associated CD95 variant, possibly in supporting lymphocyte apoptosis.


Subject(s)
Malaria, Falciparum/genetics , Plasmodium falciparum/physiology , Polymorphism, Single Nucleotide , Promoter Regions, Genetic , fas Receptor/genetics , Adolescent , Adult , Aged , Case-Control Studies , Child , Child, Preschool , Genetic Linkage , Haplotypes , Humans , Infant , Malaria, Falciparum/pathology , Middle Aged , Young Adult
18.
BMC Genet ; 12: 34, 2011 Apr 19.
Article in English | MEDLINE | ID: mdl-21504590

ABSTRACT

BACKGROUND: The monocyte chemoattractant protein 1 (MCP-1) is involved in the recruitment of lymphocytes and monocytes and their migration to sites of injury and cellular immune reactions. In a Ghanaian tuberculosis (TB) case-control study group, associations of the MCP1 -362C and the MCP1 -2581G alleles with resistance to TB were recently described. The latter association was in contrast to genetic effects previously described in study groups originating from Mexico, Korea, Peru and Zambia. This inconsistency prompted us to further investigate the MCP1 gene in order to determine causal variants or haplotypes genetically and functionally. RESULTS: A 14 base-pair deletion in the first MCP1 intron, int1del554-567, was strongly associated with protection against pulmonary TB (OR=0.84, CI 0.77-0.92, Pcorrected=0.00098). Compared to the wildtype combination, a haplotype comprising the -2581G and -362C promoter variants and the intronic deletion conferred an even stronger protection than did the -362C variant alone (OR=0.78, CI 0.69-0.87, Pnominal=0.00002; adjusted Pglobal=0.0028). In a luciferase reporter gene assay, a significant reduction of luciferase gene expression was observed in the two constructs carrying the MCP1 mutations -2581 A or G plus the combination -362C and int1del554-567 compared to the wildtype haplotype (P=0.02 and P=0.006). The associated variants, in particular the haplotypes composed of these latter variants, result in decreased MCP-1 expression and a decreased risk of pulmonary TB. CONCLUSIONS: In addition to the results of the previous study of the Ghanaian TB case-control sample, we have now identified the haplotype combination -2581G/-362C/int1del554-567 that mediates considerably stronger protection than does the MCP1 -362C allele alone (OR=0.78, CI 0.69-0.87 vs OR=0.83, CI 0.76-0.91). Our findings in both the genetic analysis and the reporter gene study further indicate a largely negligible role of the variant at position -2581 in the Ghanaian population studied.


Subject(s)
Chemokine CCL2/genetics , Genetic Variation , Immunity, Innate/genetics , Sequence Deletion , Tuberculosis, Pulmonary/genetics , Tuberculosis, Pulmonary/immunology , Case-Control Studies , Chemokine CCL2/physiology , Genome-Wide Association Study , Ghana , Haplotypes , Humans , Linkage Disequilibrium
19.
Hum Mol Genet ; 20(6): 1173-81, 2011 Mar 15.
Article in English | MEDLINE | ID: mdl-21224257

ABSTRACT

Using segregation analyses, control of malaria parasites has previously been linked to a major gene within the chromosomal region 5q31-33, but also to complex genetic factors in which effects are under substantial age-dependent influence. However, the responsible gene variants have not yet been identified for this chromosomal region. In order to perform association analyses of 5q31-33 locus candidate single nucleotide polymorphisms (SNPs), 1015 children were recruited at the age of 3 months and followed monthly until the age of 2 years in an area holoendemic for Plasmodium falciparum malaria in Ghana. Quantitative (incidence rates of malaria episodes) and qualitative phenotypes (i.e. 'more than one malaria episode' or 'not more than one malaria episode') were used in population- and family-based analyses. The strongest signal was observed for the interleukin 3 gene (IL3) SNP rs40401 (P = 3.4 × 10(-7), P(c)= 1.4 × 10(-4)). The IL3 genotypes rs40401(CT) and rs40401(TT) were found to exert a protective effect of 25% [incidence rate ratio (IRR) 0.75, P = 4.1 × 10(-5)] and 33% (IRR 0.67, P = 3.2 × 10(-8)), respectively, against malaria attacks. The association was confirmed in transmission disequilibrium tests (TDT, qTDT). The results could argue for a role of IL3 in the pathophysiology of falciparum malaria.


Subject(s)
Chromosomes, Human, Pair 5/genetics , Genetic Variation , Interleukin-3/genetics , Malaria, Falciparum/genetics , Child, Preschool , Female , Ghana/epidemiology , Humans , Immunity, Innate , Infant , Interleukin-3/immunology , Malaria, Falciparum/epidemiology , Malaria, Falciparum/immunology , Malaria, Falciparum/prevention & control , Male , Plasmodium falciparum/physiology , Polymorphism, Single Nucleotide , Recurrence
20.
Int J Legal Med ; 125(1): 149-54, 2011 Jan.
Article in English | MEDLINE | ID: mdl-20827485

ABSTRACT

Paternity and maternity investigations in immigration procedures are frequently done in Germany. Since mostly only one parent and one or more children are investigated, the occurrence of possible mutational events has to be interpreted with great care and the analysis of as many STRs as possible is recommended. The new Powerplex® ESX17 and Powerplex® ESI17 kits from Promega comprising both eleven established STRs and additionally the loci D1S1656, D2S441, D10S1248, D12S391, and D22S1045 (in different order) are potential tools in such paternity or maternity analyses, but only few allele frequency data for the five new loci exist. Here, we provide allele frequencies for the five additional STRs from three different populations from Africa. In addition, we present two maternity cases and one paternity case in which a clear inclusion or exclusion of the alleged parent could only be achieved by the additional application of the new Powerplex® ESX17 kit.


Subject(s)
Gene Frequency , Genetics, Population , Paternity , Adolescent , Adult , Aged , DNA Fingerprinting , Female , Genotype , Ghana , Humans , Madagascar , Male , Middle Aged , Morocco , Polymerase Chain Reaction , Tandem Repeat Sequences , Young Adult
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