1
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Band G, Leffler EM, Jallow M, Sisay-Joof F, Ndila CM, Macharia AW, Hubbart C, Jeffreys AE, Rowlands K, Nguyen T, Gonçalves S, Ariani CV, Stalker J, Pearson RD, Amato R, Drury E, Sirugo G, d'Alessandro U, Bojang KA, Marsh K, Peshu N, Saelens JW, Diakité M, Taylor SM, Conway DJ, Williams TN, Rockett KA, Kwiatkowski DP. Malaria protection due to sickle haemoglobin depends on parasite genotype. Nature 2021; 602:106-111. [PMID: 34883497 PMCID: PMC8810385 DOI: 10.1038/s41586-021-04288-3] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Accepted: 11/29/2021] [Indexed: 11/30/2022]
Abstract
Host genetic factors can confer resistance against malaria1, raising the question of whether this has led to evolutionary adaptation of parasite populations. Here we searched for association between candidate host and parasite genetic variants in 3,346 Gambian and Kenyan children with severe malaria caused by Plasmodium falciparum. We identified a strong association between sickle haemoglobin (HbS) in the host and three regions of the parasite genome, which is not explained by population structure or other covariates, and which is replicated in additional samples. The HbS-associated alleles include nonsynonymous variants in the gene for the acyl-CoA synthetase family member2–4PfACS8 on chromosome 2, in a second region of chromosome 2, and in a region containing structural variation on chromosome 11. The alleles are in strong linkage disequilibrium and have frequencies that covary with the frequency of HbS across populations, in particular being much more common in Africa than other parts of the world. The estimated protective effect of HbS against severe malaria, as determined by comparison of cases with population controls, varies greatly according to the parasite genotype at these three loci. These findings open up a new avenue of enquiry into the biological and epidemiological significance of the HbS-associated polymorphisms in the parasite genome and the evolutionary forces that have led to their high frequency and strong linkage disequilibrium in African P. falciparum populations. A strong association has been found between three regions of the Plasmodium falciparum genome and sickle haemoglobin in children with severe malaria, suggesting parasites have adapted to overcome natural host immunity.
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Affiliation(s)
- Gavin Band
- Wellcome Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford, UK. .,Wellcome Sanger Institute, Hinxton, Cambridge, UK. .,Big Data Institute, Li Ka Shing Centre for Health and Information Discovery, Old Road Campus, Oxford, USA.
| | - Ellen M Leffler
- Wellcome Sanger Institute, Hinxton, Cambridge, UK.,Department of Human Genetics, University of Utah School of Medicine, Salt Lake City, UT, USA
| | - Muminatou Jallow
- Medical Research Council Unit The Gambia at the London School of Hygiene and Tropical Medicine, Atlantic Boulevard, Fajara, The Gambia.,Edward Francis Small Teaching Hospital (formerly Royal Victoria Teaching Hospital), Independence Drive, Banjul, The Gambia
| | - Fatoumatta Sisay-Joof
- Medical Research Council Unit The Gambia at the London School of Hygiene and Tropical Medicine, Atlantic Boulevard, Fajara, The Gambia
| | - Carolyne M Ndila
- KEMRI-Wellcome Trust Research Programme, PO Box 230, Kilifi, Kenya
| | | | - Christina Hubbart
- Wellcome Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford, UK
| | - Anna E Jeffreys
- Wellcome Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford, UK
| | - Kate Rowlands
- Wellcome Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford, UK
| | - Thuy Nguyen
- Wellcome Sanger Institute, Hinxton, Cambridge, UK
| | | | | | - Jim Stalker
- Wellcome Sanger Institute, Hinxton, Cambridge, UK
| | - Richard D Pearson
- Wellcome Sanger Institute, Hinxton, Cambridge, UK.,Big Data Institute, Li Ka Shing Centre for Health and Information Discovery, Old Road Campus, Oxford, USA
| | | | | | - Giorgio Sirugo
- Medical Research Council Unit The Gambia at the London School of Hygiene and Tropical Medicine, Atlantic Boulevard, Fajara, The Gambia.,Division of Translational Medicine and Human Genetics, University of Pennsylvania School of Medicine, Philadelphia, PA, USA
| | - Umberto d'Alessandro
- Medical Research Council Unit The Gambia at the London School of Hygiene and Tropical Medicine, Atlantic Boulevard, Fajara, The Gambia
| | - Kalifa A Bojang
- Medical Research Council Unit The Gambia at the London School of Hygiene and Tropical Medicine, Atlantic Boulevard, Fajara, The Gambia
| | - Kevin Marsh
- KEMRI-Wellcome Trust Research Programme, PO Box 230, Kilifi, Kenya.,Nuffield Department of Medicine, NDM Research Building, Roosevelt Drive, Headington, Oxford, UK
| | - Norbert Peshu
- KEMRI-Wellcome Trust Research Programme, PO Box 230, Kilifi, Kenya
| | - Joseph W Saelens
- Division of Infectious Diseases, Duke University School of Medicine, Durham, NC, USA
| | - Mahamadou Diakité
- Malaria Research and Training Center, University of Sciences, Techniques, and Technologies of Bamako, Bamako, Mali
| | - Steve M Taylor
- Division of Infectious Diseases, Duke University School of Medicine, Durham, NC, USA.,Duke Global Health Institute, Duke University, Durham, NC, USA
| | - David J Conway
- Medical Research Council Unit The Gambia at the London School of Hygiene and Tropical Medicine, Atlantic Boulevard, Fajara, The Gambia.,Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London, UK
| | - Thomas N Williams
- KEMRI-Wellcome Trust Research Programme, PO Box 230, Kilifi, Kenya.,Institute for Global Health Innovation, Department of Surgery and Cancer, Imperial College, London, London, UK
| | - Kirk A Rockett
- Wellcome Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford, UK. .,Wellcome Sanger Institute, Hinxton, Cambridge, UK.
| | - Dominic P Kwiatkowski
- Wellcome Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford, UK. .,Wellcome Sanger Institute, Hinxton, Cambridge, UK. .,Big Data Institute, Li Ka Shing Centre for Health and Information Discovery, Old Road Campus, Oxford, USA.
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2
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Ackerman H, Ayestaran A, Olola CHO, Jallow M, Agbenyega T, Bojang K, Roberts DJ, Krishna S, Kremsner PG, Newton CR, Taylor T, Valim C, Casals-Pascual C. The effect of blood transfusion on outcomes among African children admitted to hospital with Plasmodium falciparum malaria: a prospective, multicentre observational study. Lancet Haematol 2020; 7:e789-e797. [PMID: 33091354 PMCID: PMC7611367 DOI: 10.1016/s2352-3026(20)30288-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 08/31/2020] [Accepted: 09/02/2020] [Indexed: 01/13/2023]
Abstract
BACKGROUND Infection with Plasmodium falciparum leads to severe malaria and death in approximately 400 000 children each year in sub-Saharan Africa. Blood transfusion might benefit some patients with malaria but could potentially harm others. The aim of this study was to estimate the association between transfusion and death among children admitted to hospital with P falciparum malaria. METHODS In this prospective, multicentre observational study, we analysed admissions to six tertiary care hospitals in The Gambia, Malawi, Gabon, Kenya, and Ghana that participated in the Severe Malaria in African Children network. Patients were enrolled if they were younger than 180 months and had a Giemsa-stained thick blood smear that was positive for P falciparum. Blood transfusion (whole blood at a target volume of 20 mL per kg) was administered at the discretion of the responsible physicians who were aware of local and international transfusion guidelines. The primary endpoint was death associated with transfusion, which was estimated using models adjusted for site and disease severity. We also aimed to identify factors associated with the decision to transfuse. The exploratory objective was to estimate optimal haemoglobin transfusion thresholds using generalised additive models. FINDINGS Between Dec 19, 2000, and March 8, 2005, 26 106 patients were enrolled in the study, 25 893 of whom had their transfusion status recorded and were included in the primary analysis. 8513 (32·8%) patients received a blood transfusion. Patients were followed-up until discharge from hospital for a median of 2 days (IQR 1-4). 405 (4·8%) of 8513 patients who received a transfusion died compared with 689 (4·0%) of 17 380 patients who did not receive a transfusion. Transfusion was associated with decreased odds of death in site-adjusted analysis (odds ratio [OR] 0·82 [95% CI 0·71-0·94]) and after adjusting for the increased disease severity of patients who received a transfusion (0·50 [0·42-0·60]). Severe anaemia, elevated lactate concentration, respiratory distress, and parasite density were associated with greater odds of receiving a transfusion. Among all study participants, transfusion was associated with improved survival when the admission haemoglobin concentration was up to 77 g/L (95% CI 65-110). Among those with impaired consciousness (Blantyre Coma Score ≤4), transfusion was associated with improved survival at haemoglobin concentrations up to 105 g/L (95% CI 71-115). Among those with hyperlactataemia (blood lactate ≥5·0 mmol/L), transfusion was not significantly associated with harm at any haemoglobin concentration-ie, the OR of death comparing transfused versus not transfused was less than 1 at all haemoglobin concentrations (lower bound of the 95% CI for the haemoglobin concentration at which the OR of death equals 1: 90 g/L; no upper bound). INTERPRETATION Our findings suggest that whole blood transfusion was associated with improved survival among children hospitalised with P falciparum malaria. Among those with impaired consciousness or hyperlactataemia, transfusion was associated with improved survival at haemoglobin concentrations above the currently recommended transfusion threshold. These findings highlight the need to do randomised controlled trials to test higher transfusion thresholds among African children with severe malaria complicated by these factors. FUNDING US National Institute of Allergy and Infectious Diseases.
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3
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Moussa EM, Huang H, Thézénas ML, Fischer R, Ramaprasad A, Sisay-Joof F, Jallow M, Pain A, Kwiatkowski D, Kessler BM, Casals-Pascual C. Proteomic profiling of the plasma of Gambian children with cerebral malaria. Malar J 2018; 17:337. [PMID: 30249265 PMCID: PMC6154937 DOI: 10.1186/s12936-018-2487-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Accepted: 09/19/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Cerebral malaria (CM) is a severe neurological complication of Plasmodium falciparum infection. A number of pathological findings have been correlated with pediatric CM including sequestration, platelet accumulation, petechial haemorrhage and retinopathy. However, the molecular mechanisms leading to death in CM are not yet fully understood. METHODS A shotgun plasma proteomic study was conducted using samples form 52 Gambian children with CM admitted to hospital. Based on clinical outcome, children were assigned to two groups: reversible and fatal CM. Label-free liquid chromatography-tandem mass spectrometry was used to identify and compare plasma proteins that were differentially regulated in children who recovered from CM and those who died. Candidate biomarkers were validated using enzyme immunoassays. RESULTS The plasma proteomic signature of children with CM identified 266 proteins differentially regulated in children with fatal CM. Proteins from the coagulation cascade were consistently decreased in fatal CM, whereas the plasma proteomic signature associated with fatal CM underscored the importance of endothelial activation, tissue damage, inflammation, haemolysis and glucose metabolism. The concentration of circulating proteasomes or PSMB9 in plasma was not significantly different in fatal CM when compared with survivors. Plasma PSMB9 concentration was higher in patients who presented with seizures and was significantly correlated with the number of seizures observed in patients with CM during admission. CONCLUSIONS The results indicate that increased tissue damage and hypercoagulability may play an important role in fatal CM. The diagnostic value of this molecular signature to identify children at high risk of dying to optimize patient referral practices should be validated prospectively.
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Affiliation(s)
- Ehab M Moussa
- Wellcome Trust Centre for Human Genetics, Oxford, UK
- King Abdulla University of Science and Technology, Thuwal, Saudi Arabia
| | - Honglei Huang
- Wellcome Trust Centre for Human Genetics, Oxford, UK
| | | | - Roman Fischer
- Wellcome Trust Centre for Human Genetics, Oxford, UK
| | - Abhinay Ramaprasad
- Wellcome Trust Centre for Human Genetics, Oxford, UK
- King Abdulla University of Science and Technology, Thuwal, Saudi Arabia
| | | | | | - Arnab Pain
- King Abdulla University of Science and Technology, Thuwal, Saudi Arabia
| | | | | | - Climent Casals-Pascual
- Wellcome Trust Centre for Human Genetics, Oxford, UK.
- Hospital Clinic i Provincial de Barcelona, CDB and ISGlobal, Barcelona, Spain.
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4
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Cominetti O, Smith D, Hoffman F, Jallow M, Thézénas ML, Huang H, Kwiatkowski D, Maini PK, Casals-Pascual C. Identification of a Novel Clinical Phenotype of Severe Malaria using a Network-Based Clustering Approach. Sci Rep 2018; 8:12849. [PMID: 30150696 PMCID: PMC6110866 DOI: 10.1038/s41598-018-31320-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Accepted: 08/14/2018] [Indexed: 11/29/2022] Open
Abstract
The parasite Plasmodium falciparum is the main cause of severe malaria (SM). Despite treatment with antimalarial drugs, more than 400,000 deaths are reported every year, mainly in African children. The diversity of clinical presentations associated with SM highlights important differences in disease pathogenesis that often require specific therapeutic options. The clinical heterogeneity of SM is largely unresolved. Here we report a network-based analysis of clinical phenotypes associated with SM in 2,915 Gambian children admitted to hospital with Plasmodium falciparum malaria. We used a network-based clustering method which revealed a strong correlation between disease heterogeneity and mortality. The analysis identified four distinct clusters of SM and respiratory distress that departed from the WHO definition. Patients in these clusters characteristically presented with liver enlargement and high concentrations of brain natriuretic peptide (BNP), giving support to the potential role of circulatory overload and/or right-sided heart failure as a mechanism of disease. The role of heart failure is controversial in SM and our work suggests that standard clinical management may not be appropriate. We find that our clustering can be a powerful data exploration tool to identify novel disease phenotypes and therapeutic options to reduce malaria-associated mortality.
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Affiliation(s)
- Ornella Cominetti
- Wolfson Centre for Mathematical Biology, Mathematical Institute, University of Oxford, Oxford, UK
- Nestlé Institute of Health Sciences, Lausanne, Switzerland
| | - David Smith
- London School of Hygiene and Tropical Medicine, Keppel Street, London, UK
| | - Fred Hoffman
- Department of Computer Science, University of Oxford, Oxford, UK
- XL Catlin, London, UK
| | | | - Marie L Thézénas
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, UK
| | - Honglei Huang
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, UK
| | | | - Philip K Maini
- Wolfson Centre for Mathematical Biology, Mathematical Institute, University of Oxford, Oxford, UK
| | - Climent Casals-Pascual
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, UK.
- ISGlobal, Hospital Clínic i Provincial de Barcelona, Centre Diagnòstic Biomèdic- Universitat de Barcelona, Barcelona, Spain.
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5
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Leffler EM, Band G, Busby GBJ, Kivinen K, Le QS, Clarke GM, Bojang KA, Conway DJ, Jallow M, Sisay-Joof F, Bougouma EC, Mangano VD, Modiano D, Sirima SB, Achidi E, Apinjoh TO, Marsh K, Ndila CM, Peshu N, Williams TN, Drakeley C, Manjurano A, Reyburn H, Riley E, Kachala D, Molyneux M, Nyirongo V, Taylor T, Thornton N, Tilley L, Grimsley S, Drury E, Stalker J, Cornelius V, Hubbart C, Jeffreys AE, Rowlands K, Rockett KA, Spencer CCA, Kwiatkowski DP. Resistance to malaria through structural variation of red blood cell invasion receptors. Science 2017; 356:science.aam6393. [PMID: 28522690 DOI: 10.1126/science.aam6393] [Citation(s) in RCA: 95] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Accepted: 05/08/2017] [Indexed: 12/29/2022]
Abstract
The malaria parasite Plasmodium falciparum invades human red blood cells by a series of interactions between host and parasite surface proteins. By analyzing genome sequence data from human populations, including 1269 individuals from sub-Saharan Africa, we identify a diverse array of large copy-number variants affecting the host invasion receptor genes GYPA and GYPB We find that a nearby association with severe malaria is explained by a complex structural rearrangement involving the loss of GYPB and gain of two GYPB-A hybrid genes, which encode a serologically distinct blood group antigen known as Dantu. This variant reduces the risk of severe malaria by 40% and has recently increased in frequency in parts of Kenya, yet it appears to be absent from west Africa. These findings link structural variation of red blood cell invasion receptors with natural resistance to severe malaria.
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Affiliation(s)
- Ellen M Leffler
- Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK.,Wellcome Trust Sanger Institute, Hinxton, Cambridge CB10 1SA, UK
| | - Gavin Band
- Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK.,Wellcome Trust Sanger Institute, Hinxton, Cambridge CB10 1SA, UK
| | - George B J Busby
- Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK
| | - Katja Kivinen
- Wellcome Trust Sanger Institute, Hinxton, Cambridge CB10 1SA, UK
| | - Quang Si Le
- Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK
| | - Geraldine M Clarke
- Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK
| | - Kalifa A Bojang
- Medical Research Council Unit, Atlantic Boulevard, Fajara, Post Office Box 273, The Gambia
| | - David J Conway
- Medical Research Council Unit, Atlantic Boulevard, Fajara, Post Office Box 273, The Gambia.,Department of Pathogen Molecular Biology, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK
| | - Muminatou Jallow
- Medical Research Council Unit, Atlantic Boulevard, Fajara, Post Office Box 273, The Gambia.,Royal Victoria Teaching Hospital, Independence Drive, Post Office Box 1515, Banjul, The Gambia
| | - Fatoumatta Sisay-Joof
- Medical Research Council Unit, Atlantic Boulevard, Fajara, Post Office Box 273, The Gambia
| | - Edith C Bougouma
- Centre National de Recherche et de Formation sur le Paludisme (CNRFP), 01 BP 2208 Ouagadougou 01, Burkina Faso
| | | | - David Modiano
- University of Rome La Sapienza, Piazzale Aldo Moro 5, 00185 Rome, Italy
| | - Sodiomon B Sirima
- Centre National de Recherche et de Formation sur le Paludisme (CNRFP), 01 BP 2208 Ouagadougou 01, Burkina Faso
| | - Eric Achidi
- Department of Medical Laboratory Sciences, University of Buea, Post Office Box 63, Buea, South West Region, Cameroon
| | - Tobias O Apinjoh
- Department of Biochemistry and Molecular Biology, University of Buea, Post Office Box 63, Buea, South West Region, Cameroon
| | - Kevin Marsh
- Kenyan Medical Research Institute (KEMRI)-Wellcome Trust Research Programme, Post Office Box 230-80108, Kilifi, Kenya.,Nuffield Department of Medicine, NDM Research Building, Roosevelt Drive, Headington, Oxford OX3 7FZ, UK
| | - Carolyne M Ndila
- Kenyan Medical Research Institute (KEMRI)-Wellcome Trust Research Programme, Post Office Box 230-80108, Kilifi, Kenya
| | - Norbert Peshu
- Kenyan Medical Research Institute (KEMRI)-Wellcome Trust Research Programme, Post Office Box 230-80108, Kilifi, Kenya
| | - Thomas N Williams
- Kenyan Medical Research Institute (KEMRI)-Wellcome Trust Research Programme, Post Office Box 230-80108, Kilifi, Kenya.,Faculty of Medicine, Department of Medicine, Imperial College, Exhibition Road, London SW7 2AZ, UK
| | - Chris Drakeley
- Joint Malaria Programme, Kilimanjaro Christian Medical Centre, Post Office Box 2228, Moshi, Tanzania.,Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK
| | - Alphaxard Manjurano
- Joint Malaria Programme, Kilimanjaro Christian Medical Centre, Post Office Box 2228, Moshi, Tanzania.,Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK.,National Institute for Medical Research, Mwanza Research Centre, Mwanza City, Tanzania
| | - Hugh Reyburn
- Joint Malaria Programme, Kilimanjaro Christian Medical Centre, Post Office Box 2228, Moshi, Tanzania.,Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK
| | - Eleanor Riley
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK
| | - David Kachala
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Queen Elizabeth Central Hospital, College of Medicine, Post Office Box 30096, Chichiri, Blantyre 3, Malawi
| | - Malcolm Molyneux
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Queen Elizabeth Central Hospital, College of Medicine, Post Office Box 30096, Chichiri, Blantyre 3, Malawi.,Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK
| | - Vysaul Nyirongo
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Queen Elizabeth Central Hospital, College of Medicine, Post Office Box 30096, Chichiri, Blantyre 3, Malawi
| | - Terrie Taylor
- Blantyre Malaria Project, Queen Elizabeth Central Hospital, College of Medicine, Post Office Box 30096, Chichiri, Blantyre 3, Malawi.,College of Osteopathic Medicine, Michigan State University, East Lansing, MI 48824, USA
| | - Nicole Thornton
- International Blood Group Reference Laboratory, National Health Service (NHS) Blood and Transplant, 500 North Bristol Park, Filton, Bristol BS34 7QH, UK
| | - Louise Tilley
- International Blood Group Reference Laboratory, National Health Service (NHS) Blood and Transplant, 500 North Bristol Park, Filton, Bristol BS34 7QH, UK
| | - Shane Grimsley
- International Blood Group Reference Laboratory, National Health Service (NHS) Blood and Transplant, 500 North Bristol Park, Filton, Bristol BS34 7QH, UK
| | - Eleanor Drury
- Wellcome Trust Sanger Institute, Hinxton, Cambridge CB10 1SA, UK
| | - Jim Stalker
- Wellcome Trust Sanger Institute, Hinxton, Cambridge CB10 1SA, UK
| | - Victoria Cornelius
- Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK
| | - Christina Hubbart
- Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK
| | - Anna E Jeffreys
- Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK
| | - Kate Rowlands
- Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK
| | - Kirk A Rockett
- Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK.,Wellcome Trust Sanger Institute, Hinxton, Cambridge CB10 1SA, UK
| | - Chris C A Spencer
- Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK.
| | - Dominic P Kwiatkowski
- Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK. .,Wellcome Trust Sanger Institute, Hinxton, Cambridge CB10 1SA, UK
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6
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Clarke GM, Rockett K, Kivinen K, Hubbart C, Jeffreys AE, Rowlands K, Jallow M, Conway DJ, Bojang KA, Pinder M, Usen S, Sisay-Joof F, Sirugo G, Toure O, Thera MA, Konate S, Sissoko S, Niangaly A, Poudiougou B, Mangano VD, Bougouma EC, Sirima SB, Modiano D, Amenga-Etego LN, Ghansah A, Koram KA, Wilson MD, Enimil A, Evans J, Amodu OK, Olaniyan S, Apinjoh T, Mugri R, Ndi A, Ndila CM, Uyoga S, Macharia A, Peshu N, Williams TN, Manjurano A, Sepúlveda N, Clark TG, Riley E, Drakeley C, Reyburn H, Nyirongo V, Kachala D, Molyneux M, Dunstan SJ, Phu NH, Quyen NN, Thai CQ, Hien TT, Manning L, Laman M, Siba P, Karunajeewa H, Allen S, Allen A, Davis TME, Michon P, Mueller I, Molloy SF, Campino S, Kerasidou A, Cornelius VJ, Hart L, Shah SS, Band G, Spencer CCA, Agbenyega T, Achidi E, Doumbo OK, Farrar J, Marsh K, Taylor T, Kwiatkowski DP. Characterisation of the opposing effects of G6PD deficiency on cerebral malaria and severe malarial anaemia. eLife 2017; 6:e15085. [PMID: 28067620 PMCID: PMC5222559 DOI: 10.7554/elife.15085] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2016] [Accepted: 11/03/2016] [Indexed: 01/27/2023] Open
Abstract
Glucose-6-phosphate dehydrogenase (G6PD) deficiency is believed to confer protection against Plasmodium falciparum malaria, but the precise nature of the protective effecthas proved difficult to define as G6PD deficiency has multiple allelic variants with different effects in males and females, and it has heterogeneous effects on the clinical outcome of P. falciparum infection. Here we report an analysis of multiple allelic forms of G6PD deficiency in a large multi-centre case-control study of severe malaria, using the WHO classification of G6PD mutations to estimate each individual's level of enzyme activity from their genotype. Aggregated across all genotypes, we find that increasing levels of G6PD deficiency are associated with decreasing risk of cerebral malaria, but with increased risk of severe malarial anaemia. Models of balancing selection based on these findings indicate that an evolutionary trade-off between different clinical outcomes of P. falciparum infection could have been a major cause of the high levels of G6PD polymorphism seen in human populations.
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Affiliation(s)
- Geraldine M Clarke
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom,MRC Centre for Genomics and Global Health, University of Oxford, Oxford, United Kingdom, (GMC)
| | - Kirk Rockett
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom,MRC Centre for Genomics and Global Health, University of Oxford, Oxford, United Kingdom,The Wellcome Trust Sanger Institute, Cambridge, United Kingdom, (KRoc)
| | - Katja Kivinen
- The Wellcome Trust Sanger Institute, Cambridge, United Kingdom
| | - Christina Hubbart
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - Anna E Jeffreys
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - Kate Rowlands
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - Muminatou Jallow
- Medical Research Council Unit The Gambia, Fajara, Gambia,Edward Francis Small Teaching Hospital, Independence Drive, Banjul, Gambia
| | - David J Conway
- Medical Research Council Unit The Gambia, Fajara, Gambia,Department of Pathogen Molecular Biology, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | | | | | - Stanley Usen
- Medical Research Council Unit The Gambia, Fajara, Gambia
| | | | - Giorgio Sirugo
- Medical Research Council Unit The Gambia, Fajara, Gambia
| | - Ousmane Toure
- Malaria Research and Training Centre, University of Bamako, Bamako, Mali
| | - Mahamadou A Thera
- Malaria Research and Training Centre, University of Bamako, Bamako, Mali
| | - Salimata Konate
- Malaria Research and Training Centre, University of Bamako, Bamako, Mali
| | - Sibiry Sissoko
- Malaria Research and Training Centre, University of Bamako, Bamako, Mali
| | - Amadou Niangaly
- Malaria Research and Training Centre, University of Bamako, Bamako, Mali
| | - Belco Poudiougou
- Malaria Research and Training Centre, University of Bamako, Bamako, Mali
| | | | - Edith C Bougouma
- Centre National de Recherche et de Formation sur le Paludisme (CNRFP), Ouagadougou, Burkina Faso
| | - Sodiomon B Sirima
- Centre National de Recherche et de Formation sur le Paludisme (CNRFP), Ouagadougou, Burkina Faso
| | | | | | - Anita Ghansah
- Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana
| | - Kwadwo A Koram
- Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana
| | - Michael D Wilson
- Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana
| | | | - Jennifer Evans
- Department of Molecular Medicine, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany,Kumasi Centre for Collaborative Research, Kumasi, Ghana
| | | | | | - Tobias Apinjoh
- Department of Biochemistry and Molecular Biology, University of Buea, Buea, Cameroon
| | - Regina Mugri
- Department of Medical Laboratory Sciences, University of Buea, Buea, Cameroon
| | - Andre Ndi
- Department of Medical Laboratory Sciences, University of Buea, Buea, Cameroon
| | | | - Sophie Uyoga
- KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
| | | | - Norbert Peshu
- KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Thomas N Williams
- KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya,Department of Medicine, Faculty of Medicine, Imperial College, London, United Kingdom
| | - Alphaxard Manjurano
- Joint Malaria Programme, Kilimanjaro Christian Medical College, Moshi, Tanzania,Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Nuno Sepúlveda
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Taane G Clark
- Department of Pathogen Molecular Biology, London School of Hygiene and Tropical Medicine, London, United Kingdom,Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Eleanor Riley
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Chris Drakeley
- Joint Malaria Programme, Kilimanjaro Christian Medical College, Moshi, Tanzania,Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Hugh Reyburn
- Joint Malaria Programme, Kilimanjaro Christian Medical College, Moshi, Tanzania,Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Vysaul Nyirongo
- Malawi-Liverpool Wellcome Trust Clinical Research Programme, University of Malawi, Blantyre, Malawi
| | - David Kachala
- Oxford University Clinical Research Unit, University of Oxford, Ho Chi Minh City, Vietnam
| | - Malcolm Molyneux
- Malawi-Liverpool Wellcome Trust Clinical Research Programme, University of Malawi, Blantyre, Malawi,Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, United Kingdom
| | - Sarah J Dunstan
- The Peter Doherty Institute for Infection and Immunity, The University of Melbourne, Melbourne, Australia
| | - Nguyen Hoan Phu
- Oxford University Clinical Research Unit, University of Oxford, Ho Chi Minh City, Vietnam,Hospital for Tropical Diseases, Ho Chi Minh City, Viet Nam
| | - Nguyen Ngoc Quyen
- Oxford University Clinical Research Unit, University of Oxford, Ho Chi Minh City, Vietnam
| | - Cao Quang Thai
- Oxford University Clinical Research Unit, University of Oxford, Ho Chi Minh City, Vietnam,Hospital for Tropical Diseases, Ho Chi Minh City, Viet Nam
| | - Tran Tinh Hien
- Oxford University Clinical Research Unit, University of Oxford, Ho Chi Minh City, Vietnam,Hospital for Tropical Diseases, Ho Chi Minh City, Viet Nam,Papua New Guinea Institute of Medical Research, Goroka, Papua New Guinea
| | - Laurens Manning
- Papua New Guinea Institute of Medical Research, Goroka, Papua New Guinea
| | - Moses Laman
- Papua New Guinea Institute of Medical Research, Goroka, Papua New Guinea
| | - Peter Siba
- Papua New Guinea Institute of Medical Research, Goroka, Papua New Guinea
| | | | | | - Angela Allen
- Weatherall Institute of Molecular Medicine, Oxford University, Oxford, United Kingdom
| | | | - Pascal Michon
- Papua New Guinea Institute of Medical Research, Goroka, Papua New Guinea,Faculty of Medicine and Health Sciences, Divine Word University, Madang, Papua New Guinea
| | - Ivo Mueller
- Papua New Guinea Institute of Medical Research, Goroka, Papua New Guinea,Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia,Barcelona Centre for International Health Research, Barcelona, Spain
| | - Síle F Molloy
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - Susana Campino
- The Wellcome Trust Sanger Institute, Cambridge, United Kingdom
| | - Angeliki Kerasidou
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom,Nuffield Department of Population Health, The Ethox Centre, University of Oxford, Oxford, United Kingdom
| | - Victoria J Cornelius
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom,MRC Centre for Genomics and Global Health, University of Oxford, Oxford, United Kingdom
| | - Lee Hart
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - Shivang S Shah
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom,Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, United States
| | - Gavin Band
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom,MRC Centre for Genomics and Global Health, University of Oxford, Oxford, United Kingdom
| | - Chris CA Spencer
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - Tsiri Agbenyega
- Komfo Anoyke Teaching Hospital, Kumasi, Ghana,Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| | - Eric Achidi
- Department of Medical Laboratory Sciences, University of Buea, Buea, Cameroon
| | - Ogobara K Doumbo
- Malaria Research and Training Centre, University of Bamako, Bamako, Mali
| | - Jeremy Farrar
- Oxford University Clinical Research Unit, University of Oxford, Ho Chi Minh City, Vietnam,Nuffield Department of Clinical Medicine, Center for Tropical Medicine, Oxford University, Oxford, United Kingdom
| | - Kevin Marsh
- KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Terrie Taylor
- Blantyre Malaria Project at the College of Medicine, University of Malawi, Blantyre, Malawi
| | - Dominic P Kwiatkowski
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom,MRC Centre for Genomics and Global Health, University of Oxford, Oxford, United Kingdom,The Wellcome Trust Sanger Institute, Cambridge, United Kingdom, (DPK)
| | - MalariaGEN Consortium
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom,The Wellcome Trust Sanger Institute, Cambridge, United Kingdom
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7
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Howie SRC, Schellenberg J, Chimah O, Ideh RC, Ebruke BE, Oluwalana C, Mackenzie G, Jallow M, Njie M, Donkor S, Dionisio KL, Goldberg G, Fornace K, Bottomley C, Hill PC, Grant CC, Corrah T, Prentice AM, Ezzati M, Greenwood BM, Smith PG, Adegbola RA, Mulholland K. Childhood pneumonia and crowding, bed-sharing and nutrition: a case-control study from The Gambia. Int J Tuberc Lung Dis 2016; 20:1405-1415. [PMID: 27725055 PMCID: PMC5019143 DOI: 10.5588/ijtld.15.0993] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2015] [Accepted: 05/19/2016] [Indexed: 12/03/2022] Open
Abstract
SETTING Greater Banjul and Upper River Regions, The Gambia. OBJECTIVE To investigate tractable social, environmental and nutritional risk factors for childhood pneumonia. DESIGN A case-control study examining the association of crowding, household air pollution (HAP) and nutritional factors with pneumonia was undertaken in children aged 2-59 months: 458 children with severe pneumonia, defined according to the modified WHO criteria, were compared with 322 children with non-severe pneumonia, and these groups were compared to 801 neighbourhood controls. Controls were matched by age, sex, area and season. RESULTS Strong evidence was found of an association between bed-sharing with someone with a cough and severe pneumonia (adjusted OR [aOR] 5.1, 95%CI 3.2-8.2, P < 0.001) and non-severe pneumonia (aOR 7.3, 95%CI 4.1-13.1, P < 0.001), with 18% of severe cases estimated to be attributable to this risk factor. Malnutrition and pneumonia had clear evidence of association, which was strongest between severe malnutrition and severe pneumonia (aOR 8.7, 95%CI 4.2-17.8, P < 0.001). No association was found between pneumonia and individual carbon monoxide exposure as a measure of HAP. CONCLUSION Bed-sharing with someone with a cough is an important risk factor for severe pneumonia, and potentially tractable to intervention, while malnutrition remains an important tractable determinant.
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Affiliation(s)
- S R C Howie
- Medical Research Council Unit, Fajara, The Gambia; Department of Paediatrics: Child & Youth Health, University of Auckland, Auckland, Centre for International Health, University of Otago, Dunedin, New Zealand
| | - J Schellenberg
- London School of Hygiene & Tropical Medicine, London, UK
| | - O Chimah
- Medical Research Council Unit, Fajara, The Gambia
| | - R C Ideh
- Medical Research Council Unit, Fajara, The Gambia; Child Health Department, University of Benin, Teaching Hospital, Benin City, Nigeria
| | - B E Ebruke
- Medical Research Council Unit, Fajara, The Gambia
| | - C Oluwalana
- Medical Research Council Unit, Fajara, The Gambia
| | - G Mackenzie
- Medical Research Council Unit, Fajara, The Gambia
| | - M Jallow
- Ministry of Health and Social Welfare, Banjul, The Gambia
| | - M Njie
- Ministry of Health and Social Welfare, Banjul, The Gambia
| | - S Donkor
- Medical Research Council Unit, Fajara, The Gambia
| | - K L Dionisio
- Harvard School of Public Health, Department of Global Health and Population, Boston, and Harvard School of Public Health, Department of Environmental Health, Boston, Massachusetts, USA; National Exposure Research Laboratory, US Environmental Protection Agency, Research Triangle Park, North Carolina, USA
| | - G Goldberg
- MRC-Public Health England Centre for Environment and Health, Imperial College London, London, UK
| | - K Fornace
- Medical Research Council Unit, Fajara, The Gambia, London School of Hygiene & Tropical Medicine, London, UK
| | - C Bottomley
- London School of Hygiene & Tropical Medicine, London, UK
| | - P C Hill
- Centre for International Health, University of Otago, Dunedin, New Zealand
| | - C C Grant
- Department of Paediatrics: Child & Youth Health, University of Auckland, Auckland, New Zealand
| | - T Corrah
- Medical Research Council Unit, Fajara, The Gambia
| | - A M Prentice
- Medical Research Council Unit, Fajara, The Gambia, London School of Hygiene & Tropical Medicine, London, UK
| | - M Ezzati
- Medical Research Council (MRC) Human Nutrition Research, Cambridge, UK
| | - B M Greenwood
- London School of Hygiene & Tropical Medicine, London, UK
| | - P G Smith
- London School of Hygiene & Tropical Medicine, London, UK
| | - R A Adegbola
- Medical Research Council Unit, Fajara, The Gambia, GlaxoSmithKline Vaccines, Wavre, Belgium
| | - K Mulholland
- London School of Hygiene & Tropical Medicine, London, UK, Harvard School of Public Health, Department of Global Health and Population, Boston, and Harvard School of Public Health, Department of Environmental Health, Boston, Massachusetts, USA
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8
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Busby GB, Band G, Si Le Q, Jallow M, Bougama E, Mangano VD, Amenga-Etego LN, Enimil A, Apinjoh T, Ndila CM, Manjurano A, Nyirongo V, Doumba O, Rockett KA, Kwiatkowski DP, Spencer CC. Admixture into and within sub-Saharan Africa. eLife 2016; 5. [PMID: 27324836 PMCID: PMC4915815 DOI: 10.7554/elife.15266] [Citation(s) in RCA: 94] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Accepted: 05/17/2016] [Indexed: 12/27/2022] Open
Abstract
Similarity between two individuals in the combination of genetic markers along their chromosomes indicates shared ancestry and can be used to identify historical connections between different population groups due to admixture. We use a genome-wide, haplotype-based, analysis to characterise the structure of genetic diversity and gene-flow in a collection of 48 sub-Saharan African groups. We show that coastal populations experienced an influx of Eurasian haplotypes over the last 7000 years, and that Eastern and Southern Niger-Congo speaking groups share ancestry with Central West Africans as a result of recent population expansions. In fact, most sub-Saharan populations share ancestry with groups from outside of their current geographic region as a result of gene-flow within the last 4000 years. Our in-depth analysis provides insight into haplotype sharing across different ethno-linguistic groups and the recent movement of alleles into new environments, both of which are relevant to studies of genetic epidemiology. DOI:http://dx.doi.org/10.7554/eLife.15266.001 Our genomes contain a record of historical events. This is because when groups of people are separated for generations, the DNA sequence in the two groups’ genomes will change in different ways. Looking at the differences in the genomes of people from the same population can help researchers to understand and reconstruct the historical interactions that brought their ancestors together. The mixing of two populations that were previously separate is known as admixture. Africa as a continent has few written records of its history. This means that it is somewhat unknown which important movements of people in the past generated the populations found in modern-day Africa. Busby et al. have now attempted to use DNA to look into this and reconstruct the last 4000 years of genetic history in African populations. As has been shown in other regions of the world, the new analysis showed that all African populations are the result of historical admixture events. However, Busby et al. could characterize these events to unprecedented level of detail. For example, multiple ethnic groups from The Gambia and Mali all show signs of sharing the same set of ancestors from West Africa, Europe and Asia who mixed around 2000 years ago. Evidence of a migration of people from Central West Africa, known as the Bantu expansion, could also be detected, and was shown to carry genes to the south and east. An important next step will be to now look at the consequences of the observed gene-flow, and ask if it has contributed to spreading beneficial, or detrimental, mutations around Africa. DOI:http://dx.doi.org/10.7554/eLife.15266.002
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Affiliation(s)
- George Bj Busby
- Wellcome Trust Centre for Human Genetics, Oxford, United Kingdom
| | - Gavin Band
- Wellcome Trust Centre for Human Genetics, Oxford, United Kingdom.,Wellcome Trust Sanger Institute, Cambridge, United Kingdom
| | - Quang Si Le
- Wellcome Trust Centre for Human Genetics, Oxford, United Kingdom
| | - Muminatou Jallow
- Medical Research Council Unit, Serrekunda, The Gambia.,Royal Victoria Teaching Hospital, Banjul, The Gambia
| | - Edith Bougama
- Centre National de Recherche et de Formation sur le Paludisme, Ouagadougou, Burkina Faso
| | - Valentina D Mangano
- Dipartimento di Sanita Publica e Malattie Infettive, University of Rome La Sapienza, Rome, Italy
| | | | | | - Tobias Apinjoh
- Department of Biochemistry and Molecular Biology, University of Buea, Buea, Cameroon
| | | | - Alphaxard Manjurano
- Joint Malaria Programme, Kilimanjaro Christian Medical College, Moshi, Tanzania.,Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Vysaul Nyirongo
- Malawi-Liverpool Wellcome Trust Clinical Research Programme, College of Medicine, University of Malawi, Blantyre, Malawi
| | - Ogobara Doumba
- Malaria Research and Training Centre, University of Bamako, Bamako, Mali
| | - Kirk A Rockett
- Wellcome Trust Centre for Human Genetics, Oxford, United Kingdom.,Wellcome Trust Sanger Institute, Cambridge, United Kingdom
| | - Dominic P Kwiatkowski
- Wellcome Trust Centre for Human Genetics, Oxford, United Kingdom.,Wellcome Trust Sanger Institute, Cambridge, United Kingdom
| | - Chris Ca Spencer
- Wellcome Trust Centre for Human Genetics, Oxford, United Kingdom
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9
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Shah SS, Rockett KA, Jallow M, Sisay-Joof F, Bojang KA, Pinder M, Jeffreys A, Craik R, Hubbart C, Wellems TE, Kwiatkowski DP. Heterogeneous alleles comprising G6PD deficiency trait in West Africa exert contrasting effects on two major clinical presentations of severe malaria. Malar J 2016; 15:13. [PMID: 26738565 PMCID: PMC4704392 DOI: 10.1186/s12936-015-1045-0] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Accepted: 12/09/2015] [Indexed: 11/11/2022] Open
Abstract
Background Glucose-6-phosphate dehydrogenase (G6PD) deficiency exhibits considerable allelic heterogeneity which manifests with variable biochemical and clinical penetrance. It has long been thought that G6PD deficiency confers partial protection against severe malaria, however prior genetic association studies have disagreed with regard to the strength and specificity of a protective effect, which might reflect differences in the host genetic background, environmental influences, or in the specific clinical phenotypes considered. Methods A case-control association study of severe malaria was conducted in The Gambia, a region in West Africa where there is considerable allelic heterogeneity underlying expression of G6PD deficiency trait, evaluating the three major nonsynonymous polymorphisms known to be associated with enzyme deficiency (A968G, T542A, and C202T) in a cohort of 3836 controls and 2379 severe malaria cases. Results Each deficiency allele exhibited a similar trend toward protection against severe malaria overall (15–26 % reduced risk); however, in stratifying severe malaria to two of its constituent clinical subphenotypes, severe malarial anaemia (SMA) and cerebral malaria (CM), the three deficiency alleles exhibited trends of opposing effect, with risk conferred to SMA and protection with respect to CM. To assess the overall effect of G6PD deficiency trait, deficiency alleles found across all three loci were pooled. G6PD deficiency trait was found to be significantly associated with protection from severe malaria overall (OR 0.83 [0.75–0.92], \documentclass[12pt]{minimal}
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\begin{document}$$P = 0.0006$$\end{document}P=0.0006), but this was limited to CM (OR 0.73 [0.61–0.87], \documentclass[12pt]{minimal}
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\begin{document}$$P = 0.0005$$\end{document}P=0.0005), with a trend toward increased risk for SMA, especially in fully-deficient individuals (OR 1.43 [0.99–2.08], \documentclass[12pt]{minimal}
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\begin{document}$$P = 0.056$$\end{document}P=0.056). Sex-stratified testing largely comported with these results, with evidence suggesting that protection by G6PD deficiency trait is conferred to both males and females, though susceptibility to SMA may be restricted to fully-deficient male hemizygotes. Conclusions In a part of Africa where multiple alleles contribute to expression of G6PD deficiency trait, these findings clarify and extend previous work done in populations where a single variant predominates, and taken together suggest a causal role for G6PD deficiency trait itself with respect to severe malaria, with opposing effects seen on two major clinical subphenotypes.
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Affiliation(s)
- Shivang S Shah
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, UK. .,Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA.
| | - Kirk A Rockett
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, UK.
| | - Muminatou Jallow
- Medical Research Council Laboratories, Banjul, Fajara, The Gambia.
| | - Fatou Sisay-Joof
- Medical Research Council Laboratories, Banjul, Fajara, The Gambia.
| | - Kalifa A Bojang
- Medical Research Council Laboratories, Banjul, Fajara, The Gambia.
| | - Margaret Pinder
- Medical Research Council Laboratories, Banjul, Fajara, The Gambia.
| | - Anna Jeffreys
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, UK.
| | - Rachel Craik
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, UK.
| | - Christina Hubbart
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, UK.
| | - Thomas E Wellems
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA.
| | - Dominic P Kwiatkowski
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, UK. .,Wellcome Trust Sanger Institute, Hinxton, UK.
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10
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Gurdasani D, Carstensen T, Tekola-Ayele F, Pagani L, Tachmazidou I, Hatzikotoulas K, Karthikeyan S, Iles L, Pollard MO, Choudhury A, Ritchie GRS, Xue Y, Asimit J, Nsubuga RN, Young EH, Pomilla C, Kivinen K, Rockett K, Kamali A, Doumatey AP, Asiki G, Seeley J, Sisay-Joof F, Jallow M, Tollman S, Mekonnen E, Ekong R, Oljira T, Bradman N, Bojang K, Ramsay M, Adeyemo A, Bekele E, Motala A, Norris SA, Pirie F, Kaleebu P, Kwiatkowski D, Tyler-Smith C, Rotimi C, Zeggini E, Sandhu MS. The African Genome Variation Project shapes medical genetics in Africa. Nature 2014; 517:327-32. [PMID: 25470054 PMCID: PMC4297536 DOI: 10.1038/nature13997] [Citation(s) in RCA: 370] [Impact Index Per Article: 37.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2014] [Accepted: 10/23/2014] [Indexed: 12/27/2022]
Abstract
Given the importance of Africa to studies of human origins and disease susceptibility, detailed characterization of African genetic diversity is needed. The African Genome Variation Project provides a resource with which to design, implement and interpret genomic studies in sub-Saharan Africa and worldwide. The African Genome Variation Project represents dense genotypes from 1,481 individuals and whole-genome sequences from 320 individuals across sub-Saharan Africa. Using this resource, we find novel evidence of complex, regionally distinct hunter-gatherer and Eurasian admixture across sub-Saharan Africa. We identify new loci under selection, including loci related to malaria susceptibility and hypertension. We show that modern imputation panels (sets of reference genotypes from which unobserved or missing genotypes in study sets can be inferred) can identify association signals at highly differentiated loci across populations in sub-Saharan Africa. Using whole-genome sequencing, we demonstrate further improvements in imputation accuracy, strengthening the case for large-scale sequencing efforts of diverse African haplotypes. Finally, we present an efficient genotype array design capturing common genetic variation in Africa.
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Affiliation(s)
- Deepti Gurdasani
- 1] Wellcome Trust Sanger Institute, Genome Campus, Hinxton, Cambridge CB10 1SA, UK [2] Department of Public Health and Primary Care, University of Cambridge, 2 Wort's Causeway, Cambridge, CB1 8RN, UK
| | - Tommy Carstensen
- 1] Wellcome Trust Sanger Institute, Genome Campus, Hinxton, Cambridge CB10 1SA, UK [2] Department of Public Health and Primary Care, University of Cambridge, 2 Wort's Causeway, Cambridge, CB1 8RN, UK
| | - Fasil Tekola-Ayele
- Centre for Research on Genomics and Global Health, National Human Genome Research Institute, National Institutes of Health, 12 South Drive, MSC 5635, Bethesda, Maryland 20891-5635, USA
| | - Luca Pagani
- 1] Wellcome Trust Sanger Institute, Genome Campus, Hinxton, Cambridge CB10 1SA, UK [2] Department of Biological, Geological and Environmental Sciences, University of Bologna, Via Selmi 3, 40126 Bologna, Italy
| | - Ioanna Tachmazidou
- Wellcome Trust Sanger Institute, Genome Campus, Hinxton, Cambridge CB10 1SA, UK
| | | | - Savita Karthikeyan
- 1] Wellcome Trust Sanger Institute, Genome Campus, Hinxton, Cambridge CB10 1SA, UK [2] Department of Public Health and Primary Care, University of Cambridge, 2 Wort's Causeway, Cambridge, CB1 8RN, UK
| | - Louise Iles
- 1] Wellcome Trust Sanger Institute, Genome Campus, Hinxton, Cambridge CB10 1SA, UK [2] Department of Public Health and Primary Care, University of Cambridge, 2 Wort's Causeway, Cambridge, CB1 8RN, UK [3] Department of Archaeology, University of York, King's Manor, York YO1 7EP, UK
| | - Martin O Pollard
- Wellcome Trust Sanger Institute, Genome Campus, Hinxton, Cambridge CB10 1SA, UK
| | - Ananyo Choudhury
- Sydney Brenner Institute of Molecular Bioscience (SBIMB), University of the Witwatersrand, The Mount, 9 Jubilee Road, Parktown 2193, Johannesburg, Gauteng, South Africa
| | - Graham R S Ritchie
- 1] Wellcome Trust Sanger Institute, Genome Campus, Hinxton, Cambridge CB10 1SA, UK [2] Vertebrate Genomics, European Molecular Biology Laboratory, European Bioinformatics Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SD, UK
| | - Yali Xue
- Wellcome Trust Sanger Institute, Genome Campus, Hinxton, Cambridge CB10 1SA, UK
| | - Jennifer Asimit
- Wellcome Trust Sanger Institute, Genome Campus, Hinxton, Cambridge CB10 1SA, UK
| | - Rebecca N Nsubuga
- Medical Research Council/Uganda Virus Research Institute, Plot 51-57 Nakiwogo Road, Uganda
| | - Elizabeth H Young
- 1] Wellcome Trust Sanger Institute, Genome Campus, Hinxton, Cambridge CB10 1SA, UK [2] Department of Public Health and Primary Care, University of Cambridge, 2 Wort's Causeway, Cambridge, CB1 8RN, UK
| | - Cristina Pomilla
- 1] Wellcome Trust Sanger Institute, Genome Campus, Hinxton, Cambridge CB10 1SA, UK [2] Department of Public Health and Primary Care, University of Cambridge, 2 Wort's Causeway, Cambridge, CB1 8RN, UK
| | - Katja Kivinen
- Wellcome Trust Sanger Institute, Genome Campus, Hinxton, Cambridge CB10 1SA, UK
| | - Kirk Rockett
- Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Headington, Oxford OX3 7BN, UK
| | - Anatoli Kamali
- Medical Research Council/Uganda Virus Research Institute, Plot 51-57 Nakiwogo Road, Uganda
| | - Ayo P Doumatey
- Centre for Research on Genomics and Global Health, National Human Genome Research Institute, National Institutes of Health, 12 South Drive, MSC 5635, Bethesda, Maryland 20891-5635, USA
| | - Gershim Asiki
- Medical Research Council/Uganda Virus Research Institute, Plot 51-57 Nakiwogo Road, Uganda
| | - Janet Seeley
- Medical Research Council/Uganda Virus Research Institute, Plot 51-57 Nakiwogo Road, Uganda
| | - Fatoumatta Sisay-Joof
- Medical Research Council Unit, Atlantic Boulevard, SerrekundaPO Box 273, Banjul, The Gambia
| | - Muminatou Jallow
- Medical Research Council Unit, Atlantic Boulevard, SerrekundaPO Box 273, Banjul, The Gambia
| | - Stephen Tollman
- 1] Medical Research Council/Wits Rural Public Health and Health Transitions Unit, School of Public Health, Education Campus, 27 St Andrew's Road, Parktown 2192, Johannesburg, Gauteng, South Africa [2] INDEPTH Network, 38/40 Mensah Wood Street, East Legon, PO Box KD 213, Kanda, Accra, Ghana
| | - Ephrem Mekonnen
- Institute of Biotechnology, Addis Ababa University, Entoto Avenue, Arat Kilo, 16087 Addis Ababa, Ethiopia
| | - Rosemary Ekong
- Department of Genetics Evolution and Environment, University College, London, Gower Street, London WC1E 6BT, UK
| | - Tamiru Oljira
- University of Haramaya, Department of Biology, PO Box 138, Dire Dawa, Ethiopia
| | - Neil Bradman
- Henry Stewart Group, 28/30 Little Russell Street, London WC1A 2HN, UK
| | - Kalifa Bojang
- Medical Research Council Unit, Atlantic Boulevard, SerrekundaPO Box 273, Banjul, The Gambia
| | - Michele Ramsay
- 1] Sydney Brenner Institute of Molecular Bioscience (SBIMB), University of the Witwatersrand, The Mount, 9 Jubilee Road, Parktown 2193, Johannesburg, Gauteng, South Africa [2] Division of Human Genetics, National Health Laboratory Service, C/O Hospital and de Korte Streets, Braamfontein 2000, Johannesburg, South Africa [3] School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Braamfontein 2000, Johannesburg, South Africa
| | - Adebowale Adeyemo
- Centre for Research on Genomics and Global Health, National Human Genome Research Institute, National Institutes of Health, 12 South Drive, MSC 5635, Bethesda, Maryland 20891-5635, USA
| | - Endashaw Bekele
- Department of Microbial, Cellular and Molecular Biology, College of Natural Sciences, Arat Kilo Campus, Addis Ababa University, PO Box 1176, Addis Ababa, Ethiopia
| | - Ayesha Motala
- Department of Diabetes and Endocrinology, University of KwaZulu-Natal, 719 Umbilo Road, Congella, Durban 4013, South Africa
| | - Shane A Norris
- Department of Paediatrics, University of Witwatersrand, 7 York Road, Parktown 2198, Johannesburg, Gauteng, South Africa
| | - Fraser Pirie
- Department of Diabetes and Endocrinology, University of KwaZulu-Natal, 719 Umbilo Road, Congella, Durban 4013, South Africa
| | - Pontiano Kaleebu
- Medical Research Council/Uganda Virus Research Institute, Plot 51-57 Nakiwogo Road, Uganda
| | - Dominic Kwiatkowski
- 1] Wellcome Trust Sanger Institute, Genome Campus, Hinxton, Cambridge CB10 1SA, UK [2] Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Headington, Oxford OX3 7BN, UK
| | - Chris Tyler-Smith
- Wellcome Trust Sanger Institute, Genome Campus, Hinxton, Cambridge CB10 1SA, UK
| | - Charles Rotimi
- Centre for Research on Genomics and Global Health, National Human Genome Research Institute, National Institutes of Health, 12 South Drive, MSC 5635, Bethesda, Maryland 20891-5635, USA
| | - Eleftheria Zeggini
- Wellcome Trust Sanger Institute, Genome Campus, Hinxton, Cambridge CB10 1SA, UK
| | - Manjinder S Sandhu
- 1] Wellcome Trust Sanger Institute, Genome Campus, Hinxton, Cambridge CB10 1SA, UK [2] Department of Public Health and Primary Care, University of Cambridge, 2 Wort's Causeway, Cambridge, CB1 8RN, UK
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11
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Huang H, Ideh RC, Gitau E, Thézénas ML, Jallow M, Ebruke B, Chimah O, Oluwalana C, Karanja H, Mackenzie G, Adegbola RA, Kwiatkowski D, Kessler BM, Berkley JA, Howie SRC, Casals-Pascual C. Discovery and validation of biomarkers to guide clinical management of pneumonia in African children. Clin Infect Dis 2014; 58:1707-15. [PMID: 24696240 PMCID: PMC4036688 DOI: 10.1093/cid/ciu202] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Lipocalin 2 distinguishes severe and bacterial pneumonia from nonsevere and nonbacterial pneumonia with a high level of precision. The clinical impact of this biomarker requires large-scale clinical evaluation. Background. Pneumonia is the leading cause of death in children globally. Clinical algorithms remain suboptimal for distinguishing severe pneumonia from other causes of respiratory distress such as malaria or distinguishing bacterial pneumonia and pneumonia from others causes, such as viruses. Molecular tools could improve diagnosis and management. Methods. We conducted a mass spectrometry–based proteomic study to identify and validate markers of severity in 390 Gambian children with pneumonia (n = 204) and age-, sex-, and neighborhood-matched controls (n = 186). Independent validation was conducted in 293 Kenyan children with respiratory distress (238 with pneumonia, 41 with Plasmodium falciparum malaria, and 14 with both). Predictive value was estimated by the area under the receiver operating characteristic curve (AUC). Results. Lipocalin 2 (Lpc-2) was the best protein biomarker of severe pneumonia (AUC, 0.71 [95% confidence interval, .64–.79]) and highly predictive of bacteremia (78% [64%–92%]), pneumococcal bacteremia (84% [71%–98%]), and “probable bacterial etiology” (91% [84%–98%]). These results were validated in Kenyan children with severe malaria and respiratory distress who also met the World Health Organization definition of pneumonia. The combination of Lpc-2 and haptoglobin distinguished bacterial versus malaria origin of respiratory distress with high sensitivity and specificity in Gambian children (AUC, 99% [95% confidence interval, 99%–100%]) and Kenyan children (82% [74%–91%]). Conclusions. Lpc-2 and haptoglobin can help discriminate the etiology of clinically defined pneumonia and could be used to improve clinical management. These biomarkers should be further evaluated in prospective clinical studies.
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Affiliation(s)
| | - Readon C Ideh
- Child Survival Theme, Medical Research Council Unit, The Gambia
| | - Evelyn Gitau
- Liverpool School of Tropical Medicine, United Kingdom Kenya Medical Research Institute, Centre for Geographical Medicine Research (Coast), Kilifi
| | | | | | - Bernard Ebruke
- Child Survival Theme, Medical Research Council Unit, The Gambia
| | - Osaretin Chimah
- Child Survival Theme, Medical Research Council Unit, The Gambia
| | | | - Henri Karanja
- Kenya Medical Research Institute, Centre for Geographical Medicine Research (Coast), Kilifi
| | - Grant Mackenzie
- Child Survival Theme, Medical Research Council Unit, The Gambia
| | | | | | | | - James A Berkley
- Centre for Clinical Vaccinology and Tropical Medicine, Nuffield Department of Medicine, University of Oxford Kenya Medical Research Institute, Centre for Geographical Medicine Research (Coast), Kilifi
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James A, Darboe S, Ceesay B, Jallow M. A new perspective to invasive bacterial infections in The Gambia: Surveillance of etiological agents responsible for admission of patients in the clinic. Int J Infect Dis 2014. [DOI: 10.1016/j.ijid.2014.03.1000] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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13
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Amambua-Ngwa A, Tetteh KKA, Manske M, Gomez-Escobar N, Stewart LB, Deerhake ME, Cheeseman IH, Newbold CI, Holder AA, Knuepfer E, Janha O, Jallow M, Campino S, MacInnis B, Kwiatkowski DP, Conway DJ. Population genomic scan for candidate signatures of balancing selection to guide antigen characterization in malaria parasites. PLoS Genet 2012; 8:e1002992. [PMID: 23133397 PMCID: PMC3486833 DOI: 10.1371/journal.pgen.1002992] [Citation(s) in RCA: 130] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2012] [Accepted: 08/13/2012] [Indexed: 11/19/2022] Open
Abstract
Acquired immunity in vertebrates maintains polymorphisms in endemic pathogens, leading to identifiable signatures of balancing selection. To comprehensively survey for genes under such selection in the human malaria parasite Plasmodium falciparum, we generated paired-end short-read sequences of parasites in clinical isolates from an endemic Gambian population, which were mapped to the 3D7 strain reference genome to yield high-quality genome-wide coding sequence data for 65 isolates. A minority of genes did not map reliably, including the hypervariable var, rifin, and stevor families, but 5,056 genes (90.9% of all in the genome) had >70% sequence coverage with minimum read depth of 5 for at least 50 isolates, of which 2,853 genes contained 3 or more single nucleotide polymorphisms (SNPs) for analysis of polymorphic site frequency spectra. Against an overall background of negatively skewed frequencies, as expected from historical population expansion combined with purifying selection, the outlying minority of genes with signatures indicating exceptionally intermediate frequencies were identified. Comparing genes with different stage-specificity, such signatures were most common in those with peak expression at the merozoite stage that invades erythrocytes. Members of clag, PfMC-2TM, surfin, and msp3-like gene families were highly represented, the strongest signature being in the msp3-like gene PF10_0355. Analysis of msp3-like transcripts in 45 clinical and 11 laboratory adapted isolates grown to merozoite-containing schizont stages revealed surprisingly low expression of PF10_0355. In diverse clonal parasite lines the protein product was expressed in a minority of mature schizonts (<1% in most lines and ∼10% in clone HB3), and eight sub-clones of HB3 cultured separately had an intermediate spectrum of positive frequencies (0.9 to 7.5%), indicating phase variable expression of this polymorphic antigen. This and other identified targets of balancing selection are now prioritized for functional study.
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Affiliation(s)
| | - Kevin K. A. Tetteh
- Department of Pathogen Molecular Biology, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Magnus Manske
- Wellcome Trust Sanger Institute, Hinxton, United Kingdom
| | | | - Lindsay B. Stewart
- Department of Pathogen Molecular Biology, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - M. Elizabeth Deerhake
- Department of Pathogen Molecular Biology, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Ian H. Cheeseman
- Medical Research Council Unit, Fajara, Banjul, The Gambia
- Department of Pathogen Molecular Biology, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Christopher I. Newbold
- Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, United Kingdom
| | - Anthony A. Holder
- Division of Parasitology, MRC National Institute for Medical Research, London, United Kingdom
| | - Ellen Knuepfer
- Division of Parasitology, MRC National Institute for Medical Research, London, United Kingdom
| | - Omar Janha
- Medical Research Council Unit, Fajara, Banjul, The Gambia
| | | | - Susana Campino
- Wellcome Trust Sanger Institute, Hinxton, United Kingdom
| | | | - Dominic P. Kwiatkowski
- Wellcome Trust Sanger Institute, Hinxton, United Kingdom
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - David J. Conway
- Medical Research Council Unit, Fajara, Banjul, The Gambia
- Department of Pathogen Molecular Biology, London School of Hygiene and Tropical Medicine, London, United Kingdom
- * E-mail:
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de Vries J, Jallow M, Williams TN, Kwiatkowski D, Parker M, Fitzpatrick R. Investigating the potential for ethnic group harm in collaborative genomics research in Africa: is ethnic stigmatisation likely? Soc Sci Med 2012; 75:1400-7. [PMID: 22749442 PMCID: PMC3632260 DOI: 10.1016/j.socscimed.2012.05.020] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2011] [Revised: 03/28/2012] [Accepted: 05/11/2012] [Indexed: 01/09/2023]
Abstract
A common assumption in genomics research is that the use of ethnic categories has the potential to lead to ethnic stigmatisation - particularly when the research is done on minority populations. Yet few empirical studies have sought to investigate the relation between genomics and stigma, and fewer still with a focus on Africa. In this paper, we investigate the potential for genomics research to lead to harms to ethnic groups. We carried out 49 semi-structured, open-ended interviews with stakeholders in a current medical genomics research project in Africa, MalariaGEN. Interviews were conducted with MalariaGEN researchers, fieldworkers, members of three ethics committees who reviewed MalariaGEN project proposals, and with members of the two funding bodies providing support to the MalariaGEN project. Interviews were conducted in Kenya, The Gambia and the UK between June 2008 and October 2009. They covered a range of aspects relating to the use of ethnicity in the genomics project, including views on adverse effects of the inclusion of ethnicity in such research. Drawing on the empirical data, we argue that the risk of harm to ethnic groups is likely to be more acute in specific types of genomics research. We develop a typology of research questions and projects that carry a greater risk of harm to the populations included in genomics research. We conclude that the potential of generating harm to ethnic groups in genomics research is present if research includes populations that are already stigmatised or discriminated against, or where the research investigates questions with particular normative implications. We identify a clear need for genomics researchers to take account of the social context of the work they are proposing to do, including understanding the local realities and relations between ethnic groups, and whether diseases are already stigmatised.
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Affiliation(s)
- Jantina de Vries
- The Ethox Centre, Department of Public Health, University of Oxford, UK.
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15
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Jallow M, Casals-Pascual C, Ackerman H, Walther B, Walther M, Pinder M, Sisay-Joof F, Usen S, Jallow M, Abubakar I, Olaosebikan R, Jobarteh A, Conway DJ, Bojang K, Kwiatkowski D. Clinical features of severe malaria associated with death: a 13-year observational study in the Gambia. PLoS One 2012; 7:e45645. [PMID: 23029157 PMCID: PMC3460946 DOI: 10.1371/journal.pone.0045645] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2012] [Accepted: 08/21/2012] [Indexed: 11/18/2022] Open
Abstract
Background Severe malaria (SM) is a major cause of death in sub-Saharan Africa. Identification of both specific and sensitive clinical features to predict death is needed to improve clinical management. Methods A 13-year observational study was conducted from 1997 through 2009 of 2,901 children with SM enrolled at the Royal Victoria Teaching Hospital in The Gambia to identify sensitive and specific predictors of poor outcome in Gambian children with severe malaria between the ages 4 months to 14 years. We have measured the sensitivity and specificity of clinical features that predict death or development of neurological sequelae. Findings Impaired consciousness (odds ratio {OR} 4.4 [95% confidence interval {CI}, 2.7–7.3]), respiratory distress (OR 2.4 [95%CI, 1.7–3.2]), hypoglycemia (OR 1.7 [95%CI, 1.2–2.3]), jaundice (OR 1.9 [95%CI, 1.2–2.9]) and renal failure (OR 11.1 [95%CI, 3.3–36.5]) were independently associated with death in children with SM. The clinical features that showed the highest sensitivity and specificity to predict death were respiratory distress (area under the curve 0.63 [95%CI, 0.60–0.65]) and impaired consciousness (AUC 0.61[95%CI, 0.59–0.63]), which were comparable to the ability of hyperlactatemia (blood lactate>5 mM) to predict death (AUC 0.64 [95%CI, 0.55–0.72]). A Blantyre coma score (BCS) of 2 or less had a sensitivity of 74% and specificity of 67% to predict death (AUC 0.70 [95% C.I. 0.68–0.72]), and sensitivity and specificity of 74% and 69%, respectively to predict development of neurological sequelae (AUC 0.72 [95% CI, 0.67–0.76]).The specificity of this BCS threshold to identify children at risk of dying improved in children less than 3 years of age (AUC 0.74, [95% C.I 0.71–0.76]). Conclusion The BCS is a quantitative predictor of death. A BCS of 2 or less is the most sensitive and specific clinical feature to predict death or development of neurological sequelae in children with SM.
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Affiliation(s)
- Muminatou Jallow
- Malaria Programme, MRC Laboratories, Banjul, The Gambia
- Royal Victoria Teaching Hospital, Banjul, The Gambia
| | | | - Hans Ackerman
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, Rockville, Maryland, United States of America
| | | | - Michael Walther
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, Rockville, Maryland, United States of America
| | | | | | - Stanley Usen
- Malaria Programme, MRC Laboratories, Banjul, The Gambia
| | | | | | | | | | - David J. Conway
- London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Kalifa Bojang
- Malaria Programme, MRC Laboratories, Banjul, The Gambia
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16
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Yindom LM, Forbes R, Aka P, Janha O, Jeffries D, Jallow M, Conway DJ, Walther M. Killer-cell immunoglobulin-like receptors and malaria caused by Plasmodium falciparum in The Gambia. ACTA ACUST UNITED AC 2012; 79:104-13. [PMID: 22220719 PMCID: PMC3320664 DOI: 10.1111/j.1399-0039.2011.01818.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The relevance of innate immune responses to Plasmodium falciparum infection, in particular the central role of natural killer (NK) cell-derived interferon gamma (IFN-γ), is becoming increasingly recognised. Recently, it has been shown that IFN-γ production in response to P. falciparum antigens is in part regulated by killer-cell immunoglobulin-like receptor (KIR) genes, and a study from malaria-exposed Melanesians suggested an association between KIR genotypes and susceptibility to infection. This prompted us to determine and compare the frequencies of 15 KIR genes in Gambian children presenting with either severe malaria (n = 133) or uncomplicated malaria (n = 188) and in cord-blood population control samples (n = 314) collected from the same area. While no significant differences were observed between severe and uncomplicated cases, proportions of individuals with KIR2DS2+C1 and KIR2DL2+C1 were significantly higher among malaria cases overall than in population control samples. In an exploratory analysis, activating KIR genes KIR2DS2, KIR3DS1 and KIR2DS5 were slightly higher in children in disease subgroups associated with the highest mortality. In addition, our data suggest that homozygosity for KIR genotype A might be associated with different malaria outcomes including protection from infection and higher blood parasitaemia levels in those that do get infected. These findings are consistent with a probable role of KIR genes in determining susceptibility to malaria, and further studies are warranted in different populations.
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Affiliation(s)
- L-M Yindom
- Medical Research Council Laboratories, Fajara, Banjul, The Gambia.
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Auburn S, Fry AE, Clark TG, Campino S, Diakite M, Green A, Richardson A, Jallow M, Sisay-Joof F, Pinder M, Molyneux ME, Taylor TE, Haldar K, Rockett KA, Kwiatkowski DP. Further evidence supporting a role for gs signal transduction in severe malaria pathogenesis. PLoS One 2010; 5:e10017. [PMID: 20386734 PMCID: PMC2850389 DOI: 10.1371/journal.pone.0010017] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2009] [Accepted: 02/11/2010] [Indexed: 11/25/2022] Open
Abstract
With the functional demonstration of a role in erythrocyte invasion by Plasmodium falciparum parasites, implications in the aetiology of common conditions that prevail in individuals of African origin, and a wealth of pharmacological knowledge, the stimulatory G protein (Gs) signal transduction pathway presents an exciting target for anti-malarial drug intervention. Having previously demonstrated a role for the G-alpha-s gene, GNAS, in severe malaria disease, we sought to identify other important components of the Gs pathway. Using meta-analysis across case-control and family trio (affected child and parental controls) studies of severe malaria from The Gambia and Malawi, we sought evidence of association in six Gs pathway candidate genes: adenosine receptor 2A (ADORA2A) and 2B (ADORA2B), beta-adrenergic receptor kinase 1 (ADRBK1), adenylyl cyclase 9 (ADCY9), G protein beta subunit 3 (GNB3), and regulator of G protein signalling 2 (RGS2). Our study amassed a total of 2278 cases and 2364 controls. Allele-based models of association were investigated in all genes, and genotype and haplotype-based models were investigated where significant allelic associations were identified. Although no significant associations were observed in the other genes, several were identified in ADORA2A. The most significant association was observed at the rs9624472 locus, where the G allele (∼20% frequency) appeared to confer enhanced risk to severe malaria [OR = 1.22 (1.09–1.37); P = 0.001]. Further investigation of the ADORA2A gene region is required to validate the associations identified here, and to identify and functionally characterize the responsible causal variant(s). Our results provide further evidence supporting a role of the Gs signal transduction pathway in the regulation of severe malaria, and request further exploration of this pathway in future studies.
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Affiliation(s)
- Sarah Auburn
- Wellcome Trust Centre for Human Genetics, Oxford, United Kingdom.
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Hill SE, Njie O, Sanneh M, Jallow M, Peel D, Njie M, Weber M, Hill PC, Adegbola RA, Howie SRC. Oxygen for treatment of severe pneumonia in The Gambia, West Africa: a situational analysis. Int J Tuberc Lung Dis 2009; 13:587-593. [PMID: 19383191] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/27/2023] Open
Abstract
SETTING Health facilities in The Gambia, West Africa. OBJECTIVES Oxygen treatment is vital in pneumonia, the leading cause of death in children globally. There are shortages of oxygen in developing countries, but little information is available on the extent of the problem. We assessed national oxygen availability and use in The Gambia, a sub-Saharan African country. METHODS A government-led team visited 12 health facilities in The Gambia. A modified World Health Organization assessment tool was used to determine oxygen requirements, current provision and capacity to support effective oxygen use. RESULTS Eleven of the 12 facilities managed severe pneumonia. Oxygen was reliable in three facilities. Requirement and supply were often mismatched. Both oxygen concentrators and oxygen cylinders were used. Suboptimal electricity and maintenance made using concentrators difficult, while logistical problems and cost hampered cylinder use. Children were usually triaged by trained nurses who reported lack of training in oxygen use. Oxygen was given typically by nasal prongs; pulse oximetry was available in two facilities. CONCLUSIONS National data showed that oxygen availability did not meet needs in most Gambian health facilities. Remedial options must be carefully assessed for real costs, reliability and site-by-site usability. Training is needed to support oxygen use and equipment maintenance.
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Affiliation(s)
- S E Hill
- Department of Public Health, University of Otago, Wellington, New Zealand
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19
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Fry AE, Ghansa A, Small KS, Palma A, Auburn S, Diakite M, Green A, Campino S, Teo YY, Clark TG, Jeffreys AE, Wilson J, Jallow M, Sisay-Joof F, Pinder M, Griffiths MJ, Peshu N, Williams TN, Newton CR, Marsh K, Molyneux ME, Taylor TE, Koram KA, Oduro AR, Rogers WO, Rockett KA, Sabeti PC, Kwiatkowski DP. Positive selection of a CD36 nonsense variant in sub-Saharan Africa, but no association with severe malaria phenotypes. Hum Mol Genet 2009; 18:2683-92. [PMID: 19403559 PMCID: PMC2701331 DOI: 10.1093/hmg/ddp192] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
The prevalence of CD36 deficiency in East Asian and African populations suggests that the causal variants are under selection by severe malaria. Previous analysis of data from the International HapMap Project indicated that a CD36 haplotype bearing a nonsense mutation (T1264G; rs3211938) had undergone recent positive selection in the Yoruba of Nigeria. To investigate the global distribution of this putative selection event, we genotyped T1264G in 3420 individuals from 66 populations. We confirmed the high frequency of 1264G in the Yoruba (26%). However, the 1264G allele is less common in other African populations and absent from all non-African populations without recent African admixture. Using long-range linkage disequilibrium, we studied two West African groups in depth. Evidence for recent positive selection at the locus was demonstrable in the Yoruba, although not in Gambians. We screened 70 variants from across CD36 for an association with severe malaria phenotypes, employing a case–control study of 1350 subjects and a family study of 1288 parent–offspring trios. No marker was significantly associated with severe malaria. We focused on T1264G, genotyping 10 922 samples from four African populations. The nonsense allele was not associated with severe malaria (pooled allelic odds ratio 1.0; 95% confidence interval 0.89–1.12; P = 0.98). These results suggest a range of possible explanations including the existence of alternative selection pressures on CD36, co-evolution between host and parasite or confounding caused by allelic heterogeneity of CD36 deficiency.
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Affiliation(s)
- Andrew E Fry
- Wellcome Trust Centre for Human Genetics, Roosevelt Drive, Oxford OX3 7BN, UK.
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Clark TG, Fry AE, Auburn S, Campino S, Diakite M, Green A, Richardson A, Teo YY, Small K, Wilson J, Jallow M, Sisay-Joof F, Pinder M, Sabeti P, Kwiatkowski DP, Rockett KA. Allelic heterogeneity of G6PD deficiency in West Africa and severe malaria susceptibility. Eur J Hum Genet 2009; 17:1080-5. [PMID: 19223928 DOI: 10.1038/ejhg.2009.8] [Citation(s) in RCA: 97] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Several lines of evidence link glucose-6-phosphate dehydrogenase (G6PD) deficiency to protection from severe malaria. Early reports suggested most G6PD deficiency in sub-Saharan Africa was because of the 202A/376G G6PD A- allele, and recent association studies of G6PD deficiency have employed genotyping as a convenient way to determine enzyme status. However, further work has suggested that other G6PD deficiency alleles are relatively common in some regions of West Africa. To investigate the consequences of unrecognized allelic heterogeneity on association studies, in particular studies of G6PD deficiency and malaria, we carried out a case-control analysis of 2488 Gambian children with severe malaria and 3875 controls. No significant association was found between severe malaria and the 202A/376G G6PD A- allele when analyzed alone, but pooling 202A/376G with other deficiency alleles revealed the signal of protection (male odds ratio (OR) 0.77, 95% CI 0.62-0.95, P=0.016; female OR 0.71, 95% CI 0.56-0.89, P=0.004). We have identified the 968C mutation as the most common G6PD A- allele in The Gambia. Our results highlight some of the consequences of allelic heterogeneity, particularly the increased type I error. They also suggest that G6PD-deficient male hemizygotes and female heterozygotes are protected from severe malaria.
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Affiliation(s)
- Taane G Clark
- Wellcome Trust Centre for Human Genetics, University of Oxford, UK.
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Clark TG, Diakite M, Auburn S, Campino S, Fry AE, Green A, Richardson A, Small K, Teo YY, Wilson J, Jallow M, Sisay-Joof F, Pinder M, Griffiths MJ, Peshu N, Williams TN, Marsh K, Molyneux ME, Taylor TE, Rockett KA, Kwiatkowski DP. Tumor necrosis factor and lymphotoxin-alpha polymorphisms and severe malaria in African populations. J Infect Dis 2009; 199:569-75. [PMID: 19281305 PMCID: PMC2742199 DOI: 10.1086/596320] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
The tumor necrosis factor gene (TNF) and lymphotoxin-alpha gene (LTA) have long attracted attention as candidate genes for susceptibility traits for malaria, and several of their polymorphisms have been found to be associated with severe malaria (SM) phenotypes. In a large study involving >10,000 individuals and encompassing 3 African populations, we found evidence to support the reported associations between the TNF -238 polymorphism and SM in The Gambia. However, no TNF/LTA polymorphisms were found to be associated with SM in cohorts in Kenya and Malawi. It has been suggested that the causal polymorphisms regulating the TNF and LTA responses may be located some distance from the genes. Therefore, more-detailed mapping of variants across TNF/LTA genes and their flanking regions in the Gambian and allied populations may need to be undertaken to find any causal polymorphisms.
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Affiliation(s)
- Taane G Clark
- Wellcome Trust Centre for Human Genetics, University of Oxford, Nuffield Department of Medicine, John Radcliffe Hospital, Oxford, United Kingdom.
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Mangano VD, Clark TG, Auburn S, Campino S, Diakite M, Fry AE, Green A, Richardson A, Jallow M, Sisay-Joof F, Pinder M, Griffiths MJ, Newton C, Peshu N, Williams TN, Marsh K, Molyneux ME, Taylor TE, Modiano D, Kwiatkowski DP, Rockett KA. Lack of association of interferon regulatory factor 1 with severe malaria in affected child-parental trio studies across three African populations. PLoS One 2009; 4:e4206. [PMID: 19145247 PMCID: PMC2621088 DOI: 10.1371/journal.pone.0004206] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2008] [Accepted: 11/26/2008] [Indexed: 11/30/2022] Open
Abstract
Interferon Regulatory Factor 1 (IRF-1) is a member of the IRF family of transcription factors, which have key and diverse roles in the gene-regulatory networks of the immune system. IRF-1 has been described as a critical mediator of IFN-gamma signalling and as the major player in driving TH1 type responses. It is therefore likely to be crucial in both innate and adaptive responses against intracellular pathogens such as Plasmodium falciparum. Polymorphisms at the human IRF1 locus have been previously found to be associated with the ability to control P. falciparum infection in populations naturally exposed to malaria. In order to test whether genetic variation at the IRF1 locus also affects the risk of developing severe malaria, we performed a family-based test of association for 18 Single Nucleotide Polymorphisms (SNPs) across the gene in three African populations, using genotype data from 961 trios consisting of one affected child and his/her two parents (555 from The Gambia, 204 from Kenya and 202 from Malawi). No significant association with severe malaria or severe malaria subphenotypes (cerebral malaria and severe malaria anaemia) was observed for any of the SNPs/haplotypes tested in any of the study populations. Our results offer no evidence that the molecular pathways regulated by the transcription factor IRF-1 are involved in the immune-based pathogenesis of severe malaria.
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Affiliation(s)
- Valentina D Mangano
- Childhood Infection Group, The Wellcome Trust Centre for Human Genetics, Oxford, United Kingdom.
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23
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Fry AE, Auburn S, Diakite M, Green A, Richardson A, Wilson J, Jallow M, Sisay-Joof F, Pinder M, Griffiths MJ, Peshu N, Williams TN, Marsh K, Molyneux ME, Taylor TE, Rockett KA, Kwiatkowski DP. Variation in the ICAM1 gene is not associated with severe malaria phenotypes. Genes Immun 2008; 9:462-9. [PMID: 18528404 DOI: 10.1038/gene.2008.38] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Evidence from autopsy and in vitro binding studies suggests that adhesion of erythrocytes infected with Plasmodium falciparum to the human host intercellular adhesion molecule (ICAM)-1 receptor is important in the pathogenesis of severe malaria. Previous association studies between polymorphisms in the ICAM1 gene and susceptibility to severe malarial phenotypes have been inconclusive and often contradictory. We performed genetic association studies with 15 single nucleotide polymorphisms (SNPs) around the ICAM1 locus. All SNPs were screened in a family study of 1071 trios from The Gambia, Malawi and Kenya. Two key non-synonymous SNPs with previously reported associations, rs5491 (K56M or 'ICAM-1(Kilifi)') and rs5498 (K469E), were tested in an additional 708 Gambian trios and a case-control study of 4058 individuals. None of the polymorphisms were associated with severe malaria phenotypes. Pooled results across our studies for ICAM-1(Kilifi) were, in severe malaria, odds ratio (OR) 1.02, 95% confidence interval (CI) 0.96-1.09, P=0.54, and cerebral malaria OR 1.07, CI 0.97-1.17, P=0.17. We assess the available epidemiological, population genetic and functional evidence that links ICAM-1(Kilifi) to severe malaria susceptibility.
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Affiliation(s)
- A E Fry
- The Wellcome Trust Centre for Human Genetics, Roosevelt Drive, Oxford, UK.
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24
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Fry AE, Griffiths MJ, Auburn S, Diakite M, Forton JT, Green A, Richardson A, Wilson J, Jallow M, Sisay-Joof F, Pinder M, Peshu N, Williams TN, Marsh K, Molyneux ME, Taylor TE, Rockett KA, Kwiatkowski DP. Common variation in the ABO glycosyltransferase is associated with susceptibility to severe Plasmodium falciparum malaria. Hum Mol Genet 2007; 17:567-76. [PMID: 18003641 PMCID: PMC2657867 DOI: 10.1093/hmg/ddm331] [Citation(s) in RCA: 112] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
There is growing epidemiological and molecular evidence that ABO blood group affects host susceptibility to severe Plasmodium falciparum infection. The high frequency of common ABO alleles means that even modest differences in susceptibility could have a significant impact on the health of people living in malaria endemic regions. We performed an association study, the first to utilize key molecular genetic variation underlying the ABO system, genotyping >9000 individuals across three African populations. Using population- and family-based tests, we demonstrated that alleles producing functional ABO enzymes are associated with greater risk of severe malaria phenotypes (particularly malarial anemia) in comparison with the frameshift deletion underlying blood group O: case-control allelic odds ratio (OR), 1.2; 95% confidence interval (CI), 1.09-1.32; P = 0.0003; family-studies allelic OR, 1.19; 95% CI, 1.08-1.32; P = 0.001; pooled across all studies allelic OR, 1.18; 95% CI, 1.11-1.26; P = 2 x 10(-7). We found suggestive evidence of a parent-of-origin effect at the ABO locus by analyzing the family trios. Non-O haplotypes inherited from mothers, but not fathers, are significantly associated with severe malaria (likelihood ratio test of Weinberg, P = 0.046). Finally, we used HapMap data to demonstrate a region of low F(ST) (-0.001) between the three main HapMap population groups across the ABO locus, an outlier in the empirical distribution of F(ST) across chromosome 9 (approximately 99.5-99.9th centile). This low F(ST) region may be a signal of long-standing balancing selection at the ABO locus, caused by multiple infectious pathogens including P. falciparum.
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Affiliation(s)
- Andrew E Fry
- The Wellcome Trust Centre for Human Genetics, Roosevelt Drive, Oxford OX3 7BN, UK.
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25
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Hanchard N, Elzein A, Trafford C, Rockett K, Pinder M, Jallow M, Harding R, Kwiatkowski D, McKenzie C. Classical sickle beta-globin haplotypes exhibit a high degree of long-range haplotype similarity in African and Afro-Caribbean populations. BMC Genet 2007; 8:52. [PMID: 17688704 PMCID: PMC1997132 DOI: 10.1186/1471-2156-8-52] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2007] [Accepted: 08/10/2007] [Indexed: 11/24/2022] Open
Abstract
Background The sickle (βs) mutation in the beta-globin gene (HBB) occurs on five "classical" βs haplotype backgrounds in ethnic groups of African ancestry. Strong selection in favour of the βs allele – a consequence of protection from severe malarial infection afforded by heterozygotes – has been associated with a high degree of extended haplotype similarity. The relationship between classical βs haplotypes and long-range haplotype similarity may have both anthropological and clinical implications, but to date has not been explored. Here we evaluate the haplotype similarity of classical βs haplotypes over 400 kb in population samples from Jamaica, The Gambia, and among the Yoruba of Nigeria (Hapmap YRI). Results The most common βs sub-haplotype among Jamaicans and the Yoruba was the Benin haplotype, while in The Gambia the Senegal haplotype was observed most commonly. Both subtypes exhibited a high degree of long-range haplotype similarity extending across approximately 400 kb in all three populations. This long-range similarity was significantly greater than that seen for other haplotypes sampled in these populations (P < 0.001), and was independent of marker choice and marker density. Among the Yoruba, Benin haplotypes were highly conserved, with very strong linkage disequilibrium (LD) extending a megabase across the βs mutation. Conclusion Two different classical βs haplotypes, sampled from different populations, exhibit comparable and extensive long-range haplotype similarity and strong LD. This LD extends across the adjacent recombination hotspot, and is discernable at distances in excess of 400 kb. Although the multi-centric geographic distribution of βs haplotypes indicates strong subdivision among early Holocene sub-Saharan populations, we find no evidence that selective pressures imposed by falciparum malaria varied in intensity or timing between these subpopulations. Our observations also suggest that cis-acting loci, which may influence outcomes in sickle cell disease, could lie considerable distances away from β-globin.
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Affiliation(s)
- Neil Hanchard
- Tropical Metabolism Research Unit, Tropical Medicine Research Institute, University of the West Indies, Kingston, Jamaica
- Department of Pediatric and Adolescent Medicine, Mayo Clinic, Rochester, USA
| | - Abier Elzein
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, UK
| | - Clare Trafford
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, UK
| | - Kirk Rockett
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, UK
| | | | | | - Rosalind Harding
- Departments of Zoology and Statistics, University of Oxford, Oxford, UK
| | | | - Colin McKenzie
- Tropical Metabolism Research Unit, Tropical Medicine Research Institute, University of the West Indies, Kingston, Jamaica
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Wilson JN, Rockett K, Keating B, Jallow M, Pinder M, Sisay-Joof F, Newport M, Kwiatkowski D. A hallmark of balancing selection is present at the promoter region of interleukin 10. Genes Immun 2006; 7:680-3. [PMID: 16943796 DOI: 10.1038/sj.gene.6364336] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
As an anti-inflammatory mediator IL10 is beneficial in certain contexts and deleterious in others. As increased production of IL10 favours protection against inflammatory disease, whereas low production promotes elimination of foreign pathogens by the host, we investigated the possible influence of balancing selection at this locus. We began by resequencing 48 European and 48 African chromosomes across 2.2 kb of the IL10 promoter region, and compared this with four neighbouring gene regions: MK2, IL19, IL20 and IL24. Analysis of nucleotide diversity showed a positive Tajima's D-test for IL10 in Europeans, of borderline statistical significance (1.89, P=0.05). Analysis of F(st) values showed significant population divergence at MK2, IL19, IL20 and IL24 (P<0.01) but not at IL10. Taken together, these findings are consistent with the hypothesis that balancing selection has played a role in the evolution of polymorphisms in the IL10 promoter region.
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Affiliation(s)
- J N Wilson
- Wellcome Trust Centre for Human Genetics, Oxford, UK.
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27
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Hanchard N, Diakite M, Koch O, Keating B, Pinder M, Jallow M, Sisay-Joof F, Nijnik A, Wilson J, Udalova I, Kwiatkowski D, Rockett K. Implications of inter-population linkage disequilibrium patterns on the approach to a disease association study in the human MHC class III. Immunogenetics 2006; 58:465-70. [PMID: 16738941 DOI: 10.1007/s00251-006-0118-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2005] [Accepted: 04/03/2006] [Indexed: 10/24/2022]
Abstract
There is presently much interest in utilizing patterns of linkage disequilibrium (LD) to further genetic association studies. This is particularly pertinent in the class III region of the human major histocompatibility complex (MHC), which has been extensively studied as a disease susceptibility locus in a number of ethnic groups. To date, however, few studies of LD in the MHC have considered non-Caucasian populations. With the advent of large-scale haplotyping of the human genome, the question of utilizing LD patterns across populations has come to the fore. We have previously used LD mapping to direct an MHC class III association study in a UK Caucasian population. As an extension of this, we sought to determine to what extent the pattern of LD observed in that study could be used to conduct a similar study in a West African Gambian population. We found that broad patterns of LD were similar in the two populations, resulting in similar candidate region delineations, but at a higher resolution, marker-specific patterns of LD and population-dependent allele frequencies confounded the choice of regional tagging SNPs. Our results have implications for the applicability of large-scale haplotype maps such as the HapMap to complex regions like the MHC.
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Affiliation(s)
- Neil Hanchard
- Wellcome Trust Centre for Human Genetics, Oxford, UK.
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28
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Luoni G, Forton J, Jallow M, Sadighi Akha E, Sisay-Joof F, Pinder M, Hanchard N, Herbert M, Kimber M, Mott R, Hull J, Rockett K, Kwiatkowski D. Population-specific patterns of linkage disequilibrium in the human 5q31 region. Genes Immun 2006; 6:723-7. [PMID: 16052173 DOI: 10.1038/sj.gene.6364250] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Linkage disequilibrium across the human genome is generally lower in West Africans than Europeans. However in the 5q31 region, which is rich in immune genes, we find significantly more examples of apparent nonrecombination between distant marker pairs in West Africans. Much of this effect is due to SNPs that are absent in Europeans, possibly reflecting recent positive selection in the West African population.
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Affiliation(s)
- G Luoni
- University Department of Paediatrics, Wellcome Trust Centre for Human Genetics, Roosevelt Drive, Oxford, Oxon OX3 7BN, UK
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29
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Hanchard NA, Rockett KA, Spencer C, Coop G, Pinder M, Jallow M, Kimber M, McVean G, Mott R, Kwiatkowski DP. Screening for recently selected alleles by analysis of human haplotype similarity. Am J Hum Genet 2006; 78:153-9. [PMID: 16385459 PMCID: PMC1380214 DOI: 10.1086/499252] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2005] [Accepted: 10/17/2005] [Indexed: 11/03/2022] Open
Abstract
There is growing interest in the use of haplotype-based methods for detecting recent selection. Here, we describe a method that uses a sliding window to estimate similarity among the haplotypes associated with any given single-nucleotide polymorphism (SNP) allele. We used simulations of natural selection to provide estimates of the empirical power of the method to detect recently selected alleles and found it to be comparable in power to the popular long-range haplotype test and more powerful than methods based on nucleotide diversity. We then applied the method to a recently selected allele--the sickle mutation at the HBB locus--and found it to have a signal of selection that was significantly stronger than that of simulated models both with and without strong selection. Using this method, we also evaluated >4,000 SNPs on chromosome 20, indicating the applicability of the method to regional data sets.
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Affiliation(s)
- Neil A Hanchard
- Wellcome Trust Centre for Human Genetics, Oxford, United Kingdom.
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30
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Ackerman H, Usen S, Jallow M, Sisay-Joof F, Pinder M, Kwiatkowski DP. A comparison of case-control and family-based association methods: the example of sickle-cell and malaria. Ann Hum Genet 2005; 69:559-65. [PMID: 16138914 DOI: 10.1111/j.1529-8817.2005.00180.x] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
There has been much debate about the relative merits of population- and family-based strategies for testing genetic association, yet there is little empirical data that directly compare the two approaches. Here we compare case-control and transmission/disequilibrium test (TDT) study designs using a well-established genetic association, the protective effect of the sickle-cell trait against severe malaria. We find that the two methods give similar estimates of the level of protection (case-control odds ratio = 0.10, 95% confidence interval 0.03-0.23; family-based estimate of the odds ratio = 0.11, 95% confidence interval 0.04-0.25) and similar statistical significance of the result (case-control: chi2= 41.26, p= 10(-10), TDT: chi2= 39.06, p= 10(-10)) when 315 TDT cases are compared to 583 controls. We propose a family plus population control study design, which allows both case-control and TDT analysis of the cases. This combination is robust against the respective weaknesses of the case-control and TDT study designs, namely population structure and segregation distortion. The combined study design is especially cost-effective when cases are difficult to ascertain and, when the case-control and TDT results agree, offers greater confidence in the result.
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Affiliation(s)
- H Ackerman
- Wellcome Trust Centre for Human Genetics, Roosevelt Drive, Oxford, OX3 7BN, UK
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31
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Wilson JN, Rockett K, Jallow M, Pinder M, Sisay-Joof F, Newport M, Newton J, Kwiatkowski D. Analysis of IL10 haplotypic associations with severe malaria. Genes Immun 2005; 6:462-6. [PMID: 15933743 DOI: 10.1038/sj.gene.6364227] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
We investigated the association between severe malaria and genetic variation of IL10 in Gambian children, as several lines of evidence indicate that IL10 is protective against severe malaria and that IL10 production is genetically determined. We began by identifying five informative SNPs in the Gambian population that were genotyped in a combined case-control and intrafamilial study including 654 cases of severe malaria, 579 sets of parents and 459 ethnically matched controls. No significant associations were identified with individual SNPs. One haplotype of frequency 0.11 was strongly associated with protection against severe malaria in the case-control analysis (odds ratio 0.52, P=0.00002), but the transmission disequilibrium test in families showed no significant effect. These findings raise the question of whether IL10 associations with severe malaria might be confounded by foetal survival rates or other sources of transmission bias.
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Affiliation(s)
- J N Wilson
- Wellcome Trust Centre for Human Genetics, Oxford, UK.
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32
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Koch O, Rockett K, Jallow M, Pinder M, Sisay-Joof F, Kwiatkowski D. Investigation of malaria susceptibility determinants in the IFNG/IL26/IL22 genomic region. Genes Immun 2005; 6:312-8. [PMID: 15858598 DOI: 10.1038/sj.gene.6364214] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Interferon-gamma, encoded by IFNG, is a key immunological mediator that is believed to play both a protective and a pathological role in malaria. Here, we investigate the relationship between IFNG variation and susceptibility to malaria. We began by analysing West African and European haplotype structure and patterns of linkage disequilibrium across a 100 kb genomic region encompassing IFNG and its immediate neighbours IL22 and IL26. A large case-control study of severe malaria in a West Africa population identified several weak associations with individual single-nucleotide polymorphisms in the IFNG and IL22 genes, and defined two IL22 haplotypes that are, respectively, associated with resistance and susceptibility. These data provide a starting point for functional and genetic analysis of the IFNG genomic region in malaria and other infectious and inflammatory conditions affecting African populations.
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Affiliation(s)
- O Koch
- Wellcome Trust Centre for Human Genetics, Oxford, UK
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33
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Sirugo G, Schim van der Loeff M, Sam O, Nyan O, Pinder M, Hill AV, Kwiatkowski D, Prentice A, de Toma C, Cann HM, Diatta M, Jallow M, Morgan G, Clarke M, Corrah T, Whittle H, McAdam K. A national DNA bank in The Gambia, West Africa, and genomic research in developing countries. Nat Genet 2004; 36:785-6. [PMID: 15284842 DOI: 10.1038/ng0804-785] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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34
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Ackerman HC, Ribas G, Jallow M, Mott R, Neville M, Sisay-Joof F, Pinder M, Campbell RD, Kwiatkowski DP. Complex haplotypic structure of the central MHC region flanking TNF in a West African population. Genes Immun 2004; 4:476-86. [PMID: 14551600 DOI: 10.1038/sj.gene.6364008] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
TNF polymorphisms have been associated with susceptibility to malaria and other infectious and inflammatory conditions. We investigated a sample of 150 West African chromosomes to determine linkage disequilibrium (LD) between 25 SNP markers located in an 80 kb segment of the MHC Class III region encompassing TNF and eight neighbouring genes. We observed 45 haplotypes, and 22 of them comprise 80% of the sample. The pattern of LD is remarkably patchy, such that many markers show no LD with adjacent markers but high LD with markers that are much further away. We introduce a method of examining the implications of LD data for disease association studies based on sample size considerations: this shows that certain TNF polymorphisms would be likely to yield positive associations if the true disease allele resided in LTA or BAT1. We conclude that detailed marker maps are needed to resolve the causal origin of disease associations observed at the TNF locus.
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Affiliation(s)
- H C Ackerman
- Wellcome Trust Centre for Human Genetics, Roosevelt Drive, Oxford, UK.
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35
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Burgner D, Usen S, Rockett K, Jallow M, Ackerman H, Cervino A, Pinder M, Kwiatkowski DP. Nucleotide and haplotypic diversity of the NOS2A promoter region and its relationship to cerebral malaria. Hum Genet 2004. [DOI: 10.1007/s00439-003-1068-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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36
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Burgner D, Usen S, Rockett K, Jallow M, Ackerman H, Cervino A, Pinder M, Kwiatkowski DP. Nucleotide and haplotypic diversity of the NOS2A promoter region and its relationship to cerebral malaria. Hum Genet 2003; 112:379-86. [PMID: 12552317 DOI: 10.1007/s00439-002-0882-4] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2002] [Accepted: 11/05/2002] [Indexed: 11/29/2022]
Abstract
To assess the hypothesis that nitric oxide is critical in the pathogenesis of cerebral malaria, we analysed genetic variation in the proximal promoter region of NOS2A, the gene encoding inducible nitric oxide synthase. Sequencing 72 Gambian chromosomes revealed 11 single nucleotide polymorphisms in 2.5 kB (theta=8.6 x 10(-4)). Genotyping 104 nuclear families identified six common haplotypes. A single haplotype, uniquely defined by the NOS2A-1659T allele, was associated with cerebral malaria by a transmission disequilibrium test of 334 affected children and their parents (P=0.02). An independent case-control study of 505 different children from the same population replicated the allelic association with cerebral malaria (odds ratio: 1.31, P=0.04). Taken together these data indicate a weak but significant association of the NOS2A locus with susceptibility to cerebral malaria. Despite high linkage disequilibrium across the region studied, this association would not have been detected without the initial construction of a dense marker set for haplotype tagging.
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Affiliation(s)
- David Burgner
- Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford, OX2 7BN, UK
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37
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Sabeti P, Usen S, Farhadian S, Jallow M, Doherty T, Newport M, Pinder M, Ward R, Kwiatkowski D. CD40L association with protection from severe malaria. Genes Immun 2002; 3:286-91. [PMID: 12140747 DOI: 10.1038/sj.gene.6363877] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2001] [Revised: 02/19/2002] [Accepted: 02/19/2002] [Indexed: 11/09/2022]
Abstract
CD40 ligand (CD40L), a glycoprotein involved in B cell proliferation, antigen presenting cell activation, and Ig class switching, is important in the immune response to infection. Rare coding mutations in CD40L can lead to life-threatening immunodeficiency but the potential for common variants to alter disease susceptibility remains to be explored. To identify polymorphisms in CD40L, we sequenced 2.3 kb of the 5' flanking region and the first exon of the gene in DNA samples from 36 Gambian females and one chimpanzee. Diversity was lower than the average reported for other areas of the X chromosome, and only two polymorphisms were identified. The polymorphisms were genotyped in DNA samples from 957 Gambian individuals, cases and controls from a study of severe malaria. A significant reduction in risk for severe malaria (OR = 0.52, P = 0.002) was associated with males hemizygous for the CD40L-726C. Analysis by transmission disequilibrium test of 371 cases, for whom DNA from both parents was also available, confirmed the result was not due to stratification (P = 0.04). A similar but non-significant trend was found in females. This preliminary association of a common variant in CD40L with a malaria resistance phenotype encourages further genetic characterization of the role of CD40L in infectious disease.
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Affiliation(s)
- P Sabeti
- Wellcome Trust Centre for Human Genetics, Oxford, UK
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38
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Koch O, Awomoyi A, Usen S, Jallow M, Richardson A, Hull J, Pinder M, Newport M, Kwiatkowski D. IFNGR1 gene promoter polymorphisms and susceptibility to cerebral malaria. J Infect Dis 2002; 185:1684-7. [PMID: 12023780 DOI: 10.1086/340516] [Citation(s) in RCA: 86] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2001] [Revised: 01/24/2002] [Indexed: 11/03/2022] Open
Abstract
Interferon (IFN)-gamma is a critical mediator of immunity to malaria. This study explored the relationship between polymorphisms in the promoter region of the gene encoding IFN-gamma receptor 1 (IFNGR1) and susceptibility to malaria in African children. Four polymorphisms were found in the region between -1400 and +100 nt of the translational start site by sequencing, and analysis of 562 nuclear families revealed 6 haplotypes. Case-control analysis of 562 Gambian children with severe malaria and 569 umbilical cord blood samples (controls) showed that in Mandinka, the major Gambian ethnic group, heterozygotes for the IFNGR1-56 polymorphism were protected against cerebral malaria (odds ratio, 0.54; P=.016) and against death resulting from cerebral malaria (odds ratio, 0.22; P=.006). Analysis of a family study by transmission disequilibrium testing revealed a similar result. Further data are needed to validate this finding, but these results are reminiscent of those for other well-established heterozygote advantages, such as that associated with hemoglobin S.
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Affiliation(s)
- Oliver Koch
- Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, United Kingdom.
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Deming MS, Jaiteh KO, Otten MW, Flagg EW, Jallow M, Cham M, Brogan D, N'jie H. Epidemic poliomyelitis in The Gambia following the control of poliomyelitis as an endemic disease. II. Clinical efficacy of trivalent oral polio vaccine. Am J Epidemiol 1992; 135:393-408. [PMID: 1550091 DOI: 10.1093/oxfordjournals.aje.a116300] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
An epidemic of poliomyelitis caused by poliovirus type 1 occurred in The Gambia from May to November 1986. Descriptive findings and vaccination coverage levels are reported in part I. This article (part II) describes a case-control study to estimate the clinical efficacy of three or more doses of trivalent oral polio vaccine compared with zero doses. "Cases" were 1- to 7-year-old children paralyzed during the epidemic who were diagnosed as having poliomyelitis by designated referral physicians. They were identified by reports from referral physicians during the epidemic and by a nationwide village-to-village search after the epidemic. Up to five controls were randomly selected for each case from among children of the same age and sex living in neighboring households. In a matched analysis of 195 cases and 839 controls, the efficacy of three or more doses of trivalent oral polio vaccine was 72% (95% confidence interval 57-82) when children without vaccination cards were considered unvaccinated. The efficacy of three or more doses in 1- to 2-year-old children, in whom the determination of vaccination status was considered to be more accurate than in older children, was 81% (95% confidence interval 66-90). Vaccine failure was not associated with short intervals between doses. Higher levels of vaccination coverage and efficacy than those achieved in The Gambia may be needed in African countries to prevent the return of poliomyelitis as an epidemic disease after it has been controlled as an endemic disease.
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Affiliation(s)
- M S Deming
- International Health Program Office, Centers for Disease Control, Atlanta, GA 30333
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