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Olupot-Olupot P, Tomlinson G, Williams TN, Tshilolo L, Santos B, Smart LR, McElhinney K, Howard TA, Aygun B, Stuber SE, Lane A, Latham TS, Ware RE. Hydroxyurea treatment is associated with lower malaria incidence in children with sickle cell anemia in sub-Saharan Africa. Blood 2023; 141:1402-1410. [PMID: 36375125 PMCID: PMC10273078 DOI: 10.1182/blood.2022017051] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Revised: 10/05/2022] [Accepted: 10/24/2022] [Indexed: 11/16/2022] Open
Abstract
Realizing Effectiveness Across Continents with Hydroxyurea (REACH, NCT01966731) provides hydroxyurea at maximum tolerated dose (MTD) for children with sickle cell anemia (SCA) in sub-Saharan Africa. Beyond reducing SCA-related clinical events, documented treatment benefits include ∼50% reduction in malaria incidence. To identify associations and propose mechanisms by which hydroxyurea could be associated with lower malaria rates, infections were recorded across all clinical sites (Angola, Democratic Republic of Congo, Kenya, and Uganda). Hazard ratios (HR) with 95% confidence intervals (CIs) for baseline demographics, and time-varying laboratory and clinical parameters were estimated in a modified Cox gap-time model for repeated events. Over 3387 patient-years of hydroxyurea treatment, 717 clinical malaria episodes occurred in 336 of 606 study participants; over half were confirmed by blood smear and/or rapid diagnostic testing with 97.8% Plasmodium falciparum. In univariate analysis limited to 4 confirmed infections per child, malaria risk was significantly associated with absolute neutrophil count (ANC), splenomegaly, hemoglobin, and achieving MTD; age, malaria season, MTD dose, fetal hemoglobin, α-thalassemia, and glucose-6-phosphate dehydrogenase deficiency had no effect. In multivariable regression of confirmed infections, ANC was significant (HR, 1.37 per doubled value; 95% CI, 1.10-1.70; P = .0052), and ANC values <3.0 × 109/L were associated with lower malaria incidence. Compared with nonpalpable spleen, 1- to 4-cm splenomegaly also was associated with higher malaria risk (HR, 2.01; 95% CI, 1.41-2.85; P = .0001). Hydroxyurea at MTD is associated with lower malaria incidence in SCA through incompletely defined mechanisms, but treatment-associated mild myelosuppression with ANC <3.0 × 109/L is salutary. Splenomegaly is an unexplained risk factor for malaria infections among children with SCA in Africa.
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Affiliation(s)
- Peter Olupot-Olupot
- Mbale Clinical Research Institute, Mbale, Uganda
- Mbale Regional Referral and Teaching Hospital/Busitema University, Mbale, Uganda
| | - George Tomlinson
- Department of Medicine, University Health Network and Mt Sinai Hospital, Toronto, ON, Canada
- University of Toronto, Toronto, ON, Canada
| | - Thomas N. Williams
- KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
- Institute of Global Health Innovation, Imperial College, London, United Kingdom
| | - Léon Tshilolo
- Institut de Recherche Biomédicale in CEFA/Centre Hospitalier Monkole, Kinshasa, Democratic Republic of Congo
| | | | - Luke R. Smart
- Division of Hematology, Department of Pediatrics, Cincinnati Children’s Hospital, Cincinnati, OH
- University of Cincinnati College of Medicine, Cincinnati, OH
- Global Health Center, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH
| | - Kathryn McElhinney
- Division of Hematology, Department of Pediatrics, Cincinnati Children’s Hospital, Cincinnati, OH
| | - Thad A. Howard
- Division of Hematology, Department of Pediatrics, Cincinnati Children’s Hospital, Cincinnati, OH
| | - Banu Aygun
- Cohen Children’s Medical Center, New Hyde Park, NY
- Donald and Barbara Zucker School of Medicine at Hofstra/Northwell, Hempstead, NY
| | - Susan E. Stuber
- Division of Hematology, Department of Pediatrics, Cincinnati Children’s Hospital, Cincinnati, OH
- Global Health Center, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH
| | - Adam Lane
- Division of Hematology, Department of Pediatrics, Cincinnati Children’s Hospital, Cincinnati, OH
- University of Cincinnati College of Medicine, Cincinnati, OH
| | - Teresa S. Latham
- Division of Hematology, Department of Pediatrics, Cincinnati Children’s Hospital, Cincinnati, OH
| | - Russell E. Ware
- Division of Hematology, Department of Pediatrics, Cincinnati Children’s Hospital, Cincinnati, OH
- University of Cincinnati College of Medicine, Cincinnati, OH
- Global Health Center, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH
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2
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Pombo G, Gray R, Cardoso MJ, Ourselin S, Rees G, Ashburner J, Nachev P. Equitable modelling of brain imaging by counterfactual augmentation with morphologically constrained 3D deep generative models. Med Image Anal 2023; 84:102723. [PMID: 36542907 PMCID: PMC10591114 DOI: 10.1016/j.media.2022.102723] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Revised: 11/21/2022] [Accepted: 12/02/2022] [Indexed: 12/12/2022]
Abstract
We describe CounterSynth, a conditional generative model of diffeomorphic deformations that induce label-driven, biologically plausible changes in volumetric brain images. The model is intended to synthesise counterfactual training data augmentations for downstream discriminative modelling tasks where fidelity is limited by data imbalance, distributional instability, confounding, or underspecification, and exhibits inequitable performance across distinct subpopulations. Focusing on demographic attributes, we evaluate the quality of synthesised counterfactuals with voxel-based morphometry, classification and regression of the conditioning attributes, and the Fréchet inception distance. Examining downstream discriminative performance in the context of engineered demographic imbalance and confounding, we use UK Biobank and OASIS magnetic resonance imaging data to benchmark CounterSynth augmentation against current solutions to these problems. We achieve state-of-the-art improvements, both in overall fidelity and equity. The source code for CounterSynth is available at https://github.com/guilherme-pombo/CounterSynth.
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Affiliation(s)
- Guilherme Pombo
- UCL Queen Square Institute of Neurology, University College London, London, UK.
| | - Robert Gray
- UCL Queen Square Institute of Neurology, University College London, London, UK
| | - M Jorge Cardoso
- School of Biomedical Engineering & Imaging Sciences, King's College London, London, UK
| | - Sebastien Ourselin
- School of Biomedical Engineering & Imaging Sciences, King's College London, London, UK
| | - Geraint Rees
- UCL Queen Square Institute of Neurology, University College London, London, UK
| | - John Ashburner
- UCL Queen Square Institute of Neurology, University College London, London, UK
| | - Parashkev Nachev
- UCL Queen Square Institute of Neurology, University College London, London, UK
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3
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Mahmoud O, Dudbridge F, Davey Smith G, Munafo M, Tilling K. A robust method for collider bias correction in conditional genome-wide association studies. Nat Commun 2022; 13:619. [PMID: 35110547 PMCID: PMC8810923 DOI: 10.1038/s41467-022-28119-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Accepted: 01/04/2022] [Indexed: 11/26/2022] Open
Abstract
Estimated genetic associations with prognosis, or conditional on a phenotype (e.g. disease incidence), may be affected by collider bias, whereby conditioning on the phenotype induces associations between causes of the phenotype and prognosis. We propose a method, ‘Slope-Hunter’, that uses model-based clustering to identify and utilise the class of variants only affecting the phenotype to estimate the adjustment factor, assuming this class explains more variation in the phenotype than any other variant classes. Simulation studies show that our approach eliminates the bias and outperforms alternatives even in the presence of genetic correlation. In a study of fasting blood insulin levels (FI) conditional on body mass index, we eliminate paradoxical associations of the underweight loci: COBLLI; PPARG with increased FI, and reveal an association for the locus rs1421085 (FTO). In an analysis of a case-only study for breast cancer mortality, a single region remains associated with more pronounced results. Genetic associations can be biased by conditioning on a phenotype. This study presents ‘Slope-Hunter’, a method which uses model-based clustering to correct this bias, even in the presence of genetic correlation, assuming the class of SNPs affecting only the collider explains more variation in the collider than any other class of SNPs.
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Affiliation(s)
- Osama Mahmoud
- Department of Mathematical Sciences, University of Essex, Colchester, UK. .,Department of Applied Statistics, Helwan University, Helwan, Egypt.
| | - Frank Dudbridge
- Department of Health Sciences, University of Leicester, Leicester, UK
| | - George Davey Smith
- MRC Integrative Epidemiology Unit, University of Bristol, Bristol, UK.,Department of Population Health Sciences, Bristol Medical School, University of Bristol, Bristol, UK
| | - Marcus Munafo
- MRC Integrative Epidemiology Unit, University of Bristol, Bristol, UK.,School of Psychological Science, University of Bristol, Bristol, UK
| | - Kate Tilling
- MRC Integrative Epidemiology Unit, University of Bristol, Bristol, UK.,Department of Population Health Sciences, Bristol Medical School, University of Bristol, Bristol, UK
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4
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Jezewski AJ, Lin YH, Reisz JA, Culp-Hill R, Barekatain Y, Yan VC, D'Alessandro A, Muller FL, Odom John AR. Targeting Host Glycolysis as a Strategy for Antimalarial Development. Front Cell Infect Microbiol 2021; 11:730413. [PMID: 34604112 PMCID: PMC8482815 DOI: 10.3389/fcimb.2021.730413] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Accepted: 08/17/2021] [Indexed: 11/13/2022] Open
Abstract
Glycolysis controls cellular energy, redox balance, and biosynthesis. Antiglycolytic therapies are under investigation for treatment of obesity, cancer, aging, autoimmunity, and microbial diseases. Interrupting glycolysis is highly valued as a therapeutic strategy, because glycolytic disruption is generally tolerated in mammals. Unfortunately, anemia is a known dose-limiting side effect of these inhibitors and presents a major caveat to development of antiglycolytic therapies. We developed specific inhibitors of enolase – a critical enzyme in glycolysis – and validated their metabolic and cellular effects on human erythrocytes. Enolase inhibition increases erythrocyte susceptibility to oxidative damage and induces rapid and premature erythrocyte senescence, rather than direct hemolysis. We apply our model of red cell toxicity to address questions regarding erythrocyte glycolytic disruption in the context of Plasmodium falciparum malaria pathogenesis. Our study provides a framework for understanding red blood cell homeostasis under normal and disease states and clarifies the importance of erythrocyte reductive capacity in malaria parasite growth.
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Affiliation(s)
- Andrew J Jezewski
- Department of Pediatrics, Washington University School of Medicine, St. Louis, MO, United States.,Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO, United States
| | - Yu-Hsi Lin
- Department of Cancer Systems Imaging, Division of Diagnostic Imaging, The University of Texas MD Anderson Cancer Center, Houston, TX, United States
| | - Julie A Reisz
- Department of Biochemistry and Molecular Genetics, Aurora, CO, United States
| | - Rachel Culp-Hill
- Department of Biochemistry and Molecular Genetics, Aurora, CO, United States
| | - Yasaman Barekatain
- Department of Cancer Systems Imaging, Division of Diagnostic Imaging, The University of Texas MD Anderson Cancer Center, Houston, TX, United States
| | - Victoria C Yan
- Department of Cancer Systems Imaging, Division of Diagnostic Imaging, The University of Texas MD Anderson Cancer Center, Houston, TX, United States
| | - Angelo D'Alessandro
- Department of Biochemistry and Molecular Genetics, Aurora, CO, United States
| | - Florian L Muller
- Department of Cancer Systems Imaging, Division of Diagnostic Imaging, The University of Texas MD Anderson Cancer Center, Houston, TX, United States.,Department of Neuro-Oncology, Division of Cancer Medicine, The University of Texas MD Anderson Cancer Center, Houston, TX, United States
| | - Audrey R Odom John
- Department of Pediatrics, Washington University School of Medicine, St. Louis, MO, United States.,Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO, United States
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5
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Amoah LE, Asare KK, Dickson D, Abankwa J, Busayo A, Bredu D, Annan S, Asumah GA, Peprah NY, Asamoah A, Laurencia Malm K. Genotypic glucose-6-phosphate dehydrogenase (G6PD) deficiency protects against Plasmodium falciparum infection in individuals living in Ghana. PLoS One 2021; 16:e0257562. [PMID: 34570821 PMCID: PMC8476035 DOI: 10.1371/journal.pone.0257562] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2021] [Accepted: 09/05/2021] [Indexed: 11/18/2022] Open
Abstract
INTRODUCTION The global effort to eradicate malaria requires a drastic measure to terminate relapse from hypnozoites as well as transmission via gametocytes in malaria-endemic areas. Primaquine has been recommended for the treatment of P. falciparum gametocytes and P. vivax hypnozoites, however, its implementation is challenged by the high prevalence of G6PD deficient (G6PDd) genotypes in malaria endemic countries. The objective of this study was to profile G6PDd genotypic variants and correlate them with malaria prevalence in Ghana. METHODS A cross-sectional survey of G6PDd genotypic variants was conducted amongst suspected malaria patients attending health care facilities across the entire country. Malaria was diagnosed using microscopy whilst G6PD deficiency was determined using restriction fragment length polymorphisms at position 376 and 202 of the G6PD gene. The results were analysed using GraphPad prism. RESULTS A total of 6108 subjects were enrolled in the study with females representing 65.59% of the population. The overall prevalence of malaria was 36.31%, with malaria prevalence among G6PDd genotypic variants were 0.07% for A-A- homozygous deficient females, 1.31% and 3.03% for AA- and BA- heterozygous deficient females respectively and 2.03% for A- hemizygous deficient males. The odd ratio (OR) for detecting P. falciparum malaria infection in the A-A- genotypic variant was 0.0784 (95% CI: 0.0265-0.2319, p<0.0001). Also, P. malariae and P. ovale parasites frequently were observed in G6PD B variants relative to G6PD A- variants. CONCLUSION G6PDd genotypic variants, A-A-, AA- and A- protect against P. falciparum, P. ovale and P. malariae infection in Ghana.
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Affiliation(s)
- Linda Eva Amoah
- Dept. of Immunology, Noguchi Memorial Institute of Medical Research, University of Ghana, Accra, Ghana
| | - Kwame Kumi Asare
- Dept. of Biomedical Science, School of Allied Health Sciences, College of Allied Health Sciences, University of Cape Coast, Cape Coast, Ghana
| | - Donu Dickson
- Dept. of Immunology, Noguchi Memorial Institute of Medical Research, University of Ghana, Accra, Ghana
| | - Joana Abankwa
- Dept. of Immunology, Noguchi Memorial Institute of Medical Research, University of Ghana, Accra, Ghana
| | - Abena Busayo
- Dept. of Immunology, Noguchi Memorial Institute of Medical Research, University of Ghana, Accra, Ghana
| | - Dorcas Bredu
- Dept. of Immunology, Noguchi Memorial Institute of Medical Research, University of Ghana, Accra, Ghana
| | - Sherifa Annan
- Dept. of Immunology, Noguchi Memorial Institute of Medical Research, University of Ghana, Accra, Ghana
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6
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Watson JA, Ndila CM, Uyoga S, Macharia A, Nyutu G, Mohammed S, Ngetsa C, Mturi N, Peshu N, Tsofa B, Rockett K, Leopold S, Kingston H, George EC, Maitland K, Day NPJ, Dondorp AM, Bejon P, Williams TN, Holmes CC, White NJ. Improving statistical power in severe malaria genetic association studies by augmenting phenotypic precision. eLife 2021; 10:e69698. [PMID: 34225842 PMCID: PMC8315799 DOI: 10.7554/elife.69698] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Accepted: 06/22/2021] [Indexed: 12/14/2022] Open
Abstract
Severe falciparum malaria has substantially affected human evolution. Genetic association studies of patients with clinically defined severe malaria and matched population controls have helped characterise human genetic susceptibility to severe malaria, but phenotypic imprecision compromises discovered associations. In areas of high malaria transmission, the diagnosis of severe malaria in young children and, in particular, the distinction from bacterial sepsis are imprecise. We developed a probabilistic diagnostic model of severe malaria using platelet and white count data. Under this model, we re-analysed clinical and genetic data from 2220 Kenyan children with clinically defined severe malaria and 3940 population controls, adjusting for phenotype mis-labelling. Our model, validated by the distribution of sickle trait, estimated that approximately one-third of cases did not have severe malaria. We propose a data-tilting approach for case-control studies with phenotype mis-labelling and show that this reduces false discovery rates and improves statistical power in genome-wide association studies.
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Affiliation(s)
- James A Watson
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol UniversityBangkokThailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of OxfordOxfordUnited Kingdom
| | - Carolyne M Ndila
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol UniversityBangkokThailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of OxfordOxfordUnited Kingdom
| | - Sophie Uyoga
- KEMRI-Wellcome Trust Research Programme, Centre for Geographic Medicine Research-CoastKilifiKenya
| | - Alexander Macharia
- KEMRI-Wellcome Trust Research Programme, Centre for Geographic Medicine Research-CoastKilifiKenya
| | - Gideon Nyutu
- KEMRI-Wellcome Trust Research Programme, Centre for Geographic Medicine Research-CoastKilifiKenya
| | - Shebe Mohammed
- KEMRI-Wellcome Trust Research Programme, Centre for Geographic Medicine Research-CoastKilifiKenya
| | - Caroline Ngetsa
- KEMRI-Wellcome Trust Research Programme, Centre for Geographic Medicine Research-CoastKilifiKenya
| | - Neema Mturi
- KEMRI-Wellcome Trust Research Programme, Centre for Geographic Medicine Research-CoastKilifiKenya
| | - Norbert Peshu
- KEMRI-Wellcome Trust Research Programme, Centre for Geographic Medicine Research-CoastKilifiKenya
| | - Benjamin Tsofa
- KEMRI-Wellcome Trust Research Programme, Centre for Geographic Medicine Research-CoastKilifiKenya
| | - Kirk Rockett
- The Wellcome Sanger InstituteCambridgeUnited Kingdom
- Wellcome Trust Centre for Human Genetics, University of OxfordOxfordUnited Kingdom
| | - Stije Leopold
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol UniversityBangkokThailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of OxfordOxfordUnited Kingdom
| | - Hugh Kingston
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol UniversityBangkokThailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of OxfordOxfordUnited Kingdom
| | - Elizabeth C George
- Medical Research Council Clinical Trials Unit, University College LondonLondonUnited Kingdom
| | - Kathryn Maitland
- KEMRI-Wellcome Trust Research Programme, Centre for Geographic Medicine Research-CoastKilifiKenya
- Institute of Global Health Innovation, Imperial College, LondonLondonUnited Kingdom
| | - Nicholas PJ Day
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol UniversityBangkokThailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of OxfordOxfordUnited Kingdom
| | - Arjen M Dondorp
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol UniversityBangkokThailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of OxfordOxfordUnited Kingdom
| | - Philip Bejon
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of OxfordOxfordUnited Kingdom
- KEMRI-Wellcome Trust Research Programme, Centre for Geographic Medicine Research-CoastKilifiKenya
| | - Thomas N Williams
- KEMRI-Wellcome Trust Research Programme, Centre for Geographic Medicine Research-CoastKilifiKenya
- Institute of Global Health Innovation, Imperial College, LondonLondonUnited Kingdom
| | - Chris C Holmes
- Nuffield Department of Medicine, University of OxfordOxfordUnited Kingdom
- Department of Statistics, University of OxfordOxfordUnited Kingdom
| | - Nicholas J White
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol UniversityBangkokThailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of OxfordOxfordUnited Kingdom
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7
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Glucose-6-phosphate dehydrogenase deficiency. Blood 2021; 136:1225-1240. [PMID: 32702756 DOI: 10.1182/blood.2019000944] [Citation(s) in RCA: 143] [Impact Index Per Article: 47.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Accepted: 12/12/2019] [Indexed: 11/20/2022] Open
Abstract
Glucose 6-phosphate dehydrogenase (G6PD) deficiency is 1 of the commonest human enzymopathies, caused by inherited mutations of the X-linked gene G6PD. G6PD deficiency makes red cells highly vulnerable to oxidative damage, and therefore susceptible to hemolysis. Over 200 G6PD mutations are known: approximately one-half are polymorphic and therefore common in various populations. Some 500 million persons with any of these mutations are mostly asymptomatic throughout their lifetime; however, any of them may develop acute and sometimes very severe hemolytic anemia when triggered by ingestion of fava beans, by any of a number of drugs (for example, primaquine, rasburicase), or, more rarely, by infection. Approximately one-half of the G6PD mutations are instead sporadic: rare patients with these mutations present with chronic nonspherocytic hemolytic anemia. Almost all G6PD mutations are missense mutations, causing amino acid replacements that entail deficiency of G6PD enzyme activity: they compromise the stability of the protein, the catalytic activity is decreased, or a combination of both mechanisms occurs. Thus, genotype-phenotype correlations have been reasonably well clarified in many cases. G6PD deficiency correlates remarkably, in its geographic distribution, with past/present malaria endemicity: indeed, it is a unique example of an X-linked human polymorphism balanced through protection of heterozygotes from malaria mortality. Acute hemolytic anemia can be managed effectively provided it is promptly diagnosed. Reliable diagnostic procedures are available, with point-of-care tests becoming increasingly important where primaquine and its recently introduced analog tafenoquine are required for the elimination of malaria.
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8
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Awab GR, Aaram F, Jamornthanyawat N, Suwannasin K, Pagornrat W, Watson JA, Woodrow CJ, Dondorp AM, Day NPJ, Imwong M, White NJ. Protective effect of Mediterranean-type glucose-6-phosphate dehydrogenase deficiency against Plasmodium vivax malaria. eLife 2021; 10:e62448. [PMID: 33543710 PMCID: PMC7884069 DOI: 10.7554/elife.62448] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Accepted: 02/03/2021] [Indexed: 01/19/2023] Open
Abstract
X-linked glucose-6-phosphate dehydrogenase (G6PD) deficiency is the most common human enzymopathy. The severe Mediterranean variant (G6PD Med) found across Europe and Asia is thought to confer protection against malaria, but its effect is unclear. We fitted a Bayesian statistical model to observed G6PD Med allele frequencies in 999 Pashtun patients presenting with acute Plasmodium vivax malaria and 1408 population controls. G6PD Med was associated with reductions in symptomatic P. vivax malaria incidence of 76% (95% credible interval [CI], 58-88) in hemizygous males and homozygous females combined and 55% (95% CI, 38-68) in heterozygous females. Unless there is very large population stratification within the Pashtun (confounding these results), the G6PD Med genotype confers a very large and gene-dose proportional protective effect against acute vivax malaria. The proportion of patients with vivax malaria at risk of haemolysis following 8-aminoquinoline radical cure is substantially overestimated by studies measuring G6PD deficiency prevalence in healthy subjects.
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Affiliation(s)
- Ghulam R Awab
- Mahidol Oxford Tropical Medicine Research Unit (MORU), Faculty of Tropical Medicine, Mahidol UniversityBangkokThailand
- Nangarhar Medical FacultyJalalabadAfghanistan
| | | | - Natsuda Jamornthanyawat
- Department of Molecular Tropical Medicine and Genetics, Faculty of Tropical Medicine, Mahidol UniversityBangkokThailand
| | - Kanokon Suwannasin
- Department of Molecular Tropical Medicine and Genetics, Faculty of Tropical Medicine, Mahidol UniversityBangkokThailand
| | - Watcharee Pagornrat
- Department of Molecular Tropical Medicine and Genetics, Faculty of Tropical Medicine, Mahidol UniversityBangkokThailand
| | - James A Watson
- Mahidol Oxford Tropical Medicine Research Unit (MORU), Faculty of Tropical Medicine, Mahidol UniversityBangkokThailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of OxfordOxfordUnited Kingdom
| | - Charles J Woodrow
- Mahidol Oxford Tropical Medicine Research Unit (MORU), Faculty of Tropical Medicine, Mahidol UniversityBangkokThailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of OxfordOxfordUnited Kingdom
| | - Arjen M Dondorp
- Mahidol Oxford Tropical Medicine Research Unit (MORU), Faculty of Tropical Medicine, Mahidol UniversityBangkokThailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of OxfordOxfordUnited Kingdom
| | - Nicholas PJ Day
- Mahidol Oxford Tropical Medicine Research Unit (MORU), Faculty of Tropical Medicine, Mahidol UniversityBangkokThailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of OxfordOxfordUnited Kingdom
| | - Mallika Imwong
- Department of Molecular Tropical Medicine and Genetics, Faculty of Tropical Medicine, Mahidol UniversityBangkokThailand
| | - Nicholas J White
- Mahidol Oxford Tropical Medicine Research Unit (MORU), Faculty of Tropical Medicine, Mahidol UniversityBangkokThailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of OxfordOxfordUnited Kingdom
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9
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Ryan K, Tekwani BL. Current investigations on clinical pharmacology and therapeutics of Glucose-6-phosphate dehydrogenase deficiency. Pharmacol Ther 2020; 222:107788. [PMID: 33326820 DOI: 10.1016/j.pharmthera.2020.107788] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Revised: 12/04/2020] [Accepted: 12/05/2020] [Indexed: 12/19/2022]
Abstract
Glucose-6-phospate dehydrogenase (G6PD) deficiency is estimated to affect more than 400 million people world-wide. This X-linked genetic deficiency puts stress on red blood cells (RBC), which may be further augmented under certain pathophysiological conditions and drug treatments. These conditions can cause hemolytic anemia and eventually lead to multi-organ failure and mortality. G6PD is involved in the rate-limiting step of the pentose phosphate pathway, which generates reduced nicotinamide adenine dinucleotide phosphate (NADPH). In RBCs, the NADPH/G6PD pathway is the only source for recycling reduced glutathione and provides protection from oxidative stress. Susceptibility of G6PD deficient populations to certain drug treatments and potential risks of hemolysis are important public health issues. A number of clinical trials are currently in progress investigating clinical factors associated with G6PD deficiency, validation of new diagnostic kits for G6PD deficiency, and evaluating drug safety, efficacy, and pathophysiology. More than 25 clinical studies in G6PD populations are currently in progress or have just been completed that have been examined for clinical pharmacology and potential therapeutic implications of G6PD deficiency. The information on clinical conditions, interventions, purpose, outcome, and status of these clinical trials has been studied. A critical review of ongoing clinical investigations on pharmacology and therapeutics of G6PD deficiency should be highly important for researchers, clinical pharmacologists, pharmaceutical companies, and global public health agencies. The information may be useful for developing strategies for treatment and control of hemolytic crisis and potential drug toxicities in G6PD deficient patients.
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Affiliation(s)
- Kaitlyn Ryan
- Department of Infectious Diseases, Division of Drug Discovery, Southern Research, 2000 9(th) Avenue South, Birmingham, AL 35205, United States of America.
| | - Babu L Tekwani
- Department of Infectious Diseases, Division of Drug Discovery, Southern Research, 2000 9(th) Avenue South, Birmingham, AL 35205, United States of America.
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10
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Gilchrist JJ, Uyoga S, Pirinen M, Rautanen A, Mwarumba S, Njuguna P, Mturi N, Hill AVS, Scott JAG, Williams TN. Risk of pneumococcal bacteremia in Kenyan children with glucose-6-phosphate dehydrogenase deficiency. BMC Med 2020; 18:148. [PMID: 32536341 PMCID: PMC7294654 DOI: 10.1186/s12916-020-01604-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Accepted: 04/23/2020] [Indexed: 01/12/2023] Open
Abstract
BACKGROUND Glucose-6-phosphate dehydrogenase (G6PD) deficiency is the most common enzyme deficiency state in humans. The clinical phenotype is variable and includes asymptomatic individuals, episodic hemolysis induced by oxidative stress, and chronic hemolysis. G6PD deficiency is common in malaria-endemic regions, an observation hypothesized to be due to balancing selection at the G6PD locus driven by malaria. G6PD deficiency increases risk of severe malarial anemia, a key determinant of invasive bacterial disease in malaria-endemic settings. The pneumococcus is a leading cause of invasive bacterial infection and death in African children. The effect of G6PD deficiency on risk of pneumococcal disease is undefined. We hypothesized that G6PD deficiency increases pneumococcal disease risk and that this effect is dependent upon malaria. METHODS We performed a genetic case-control study of pneumococcal bacteremia in Kenyan children stratified across a period of falling malaria transmission between 1998 and 2010. RESULTS Four hundred twenty-nine Kenyan children with pneumococcal bacteremia and 2677 control children were included in the study. Among control children, G6PD deficiency, secondary to the rs1050828 G>A mutation, was common, with 11.2% (n = 301 of 2677) being hemi- or homozygotes and 33.3% (n = 442 of 1329) of girls being heterozygotes. We found that G6PD deficiency increased the risk of pneumococcal bacteremia, but only during a period of high malaria transmission (P = 0.014; OR 2.33, 95% CI 1.19-4.57). We estimate that the population attributable fraction of G6PD deficiency on risk of pneumococcal bacteremia in areas under high malaria transmission is 0.129. CONCLUSIONS Our data demonstrate that G6PD deficiency increases risk of pneumococcal bacteremia in a manner dependent on malaria. At the population level, the impact of G6PD deficiency on invasive pneumococcal disease risk in malaria-endemic regions is substantial. Our study highlights the infection-associated morbidity and mortality conferred by G6PD deficiency in malaria-endemic settings and adds to our understanding of the potential indirect health benefits of improved malaria control.
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Affiliation(s)
- James J Gilchrist
- Wellcome Centre for Human Genetics, University of Oxford, Oxford, OX3 7BN, UK. .,Department of Paediatrics, University of Oxford, Oxford, OX3 9DU, UK.
| | - Sophie Uyoga
- KEMRI-Wellcome Trust Research Programme, Kilifi, 80108, Kenya
| | - Matti Pirinen
- Institute for Molecular Medicine Finland (FIMM), University of Helsinki, 00014, Helsinki, Finland
| | - Anna Rautanen
- Wellcome Centre for Human Genetics, University of Oxford, Oxford, OX3 7BN, UK
| | - Salim Mwarumba
- KEMRI-Wellcome Trust Research Programme, Kilifi, 80108, Kenya
| | | | - Neema Mturi
- KEMRI-Wellcome Trust Research Programme, Kilifi, 80108, Kenya
| | | | - Adrian V S Hill
- Wellcome Centre for Human Genetics, University of Oxford, Oxford, OX3 7BN, UK.,The Jenner Institute, University of Oxford, Old Road Campus Research Building, Oxford, OX3 7DQ, UK
| | - J Anthony G Scott
- KEMRI-Wellcome Trust Research Programme, Kilifi, 80108, Kenya.,Department of Infectious Disease Epidemiology, London School of Hygiene & Tropical Medicine, Keppel Street, London, WC1E 7HT, UK
| | - Thomas N Williams
- KEMRI-Wellcome Trust Research Programme, Kilifi, 80108, Kenya. .,Department of Medicine, Imperial College, Norfolk Place, London, W2 1PG, UK.
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Leopold SJ, Watson JA, Jeeyapant A, Simpson JA, Phu NH, Hien TT, Day NPJ, Dondorp AM, White NJ. Investigating causal pathways in severe falciparum malaria: A pooled retrospective analysis of clinical studies. PLoS Med 2019; 16:e1002858. [PMID: 31442221 PMCID: PMC6707545 DOI: 10.1371/journal.pmed.1002858] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Accepted: 07/25/2019] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Severe falciparum malaria is a medical emergency characterised by potentially lethal vital organ dysfunction. Patient fatality rates even with parenteral artesunate treatment remain high. Despite considerable research into adjuvant therapies targeting organ and tissue dysfunction, none have shown efficacy apart from renal replacement therapy. Understanding the causal contributions of clinical and laboratory abnormalities to mortality is essential for the design and evaluation of novel therapeutic interventions. METHODS AND FINDINGS We used a structural model causal inference approach to investigate causal relationships between epidemiological, laboratory, and clinical variables in patients with severe falciparum malaria enrolled in clinical trials and their in-hospital mortality. Under this causal model, we analysed records from 9,040 hospitalised children (0-12 years, n = 5,635) and adults (n = 3,405, 12-87 years) with severe falciparum malaria from 15 countries in Africa and Asia who were studied prospectively over the past 35 years. On admission, patient covariates associated with increased in-hospital mortality were severity of acidosis (odds ratio [OR] 2.10 for a 7-mEq/L increase in base deficit [95% CI 1.93-2.28]), renal impairment (OR 1.71 for a 2-fold increase in blood urea nitrogen [95% CI 1.58, 1.86]), coma (OR 3.59 [95% CI 3.07-4.21]), seizures (OR 1.40 [95% CI 1.16-1.68]), shock (OR 1.51 [95% CI 1.14-1.99]), and presumed pulmonary oedema (OR 1.58 [95% CI 1.04-2.39]). Lower in-hospital mortality was associated with moderate anaemia (OR 0.87 for a decrease of 10 percentage points in haematocrit [95% CI 0.80-0.95]). Circulating parasite density was not associated with mortality (OR 1.02 for a 6-fold increase [95% CI 0.94-1.11]), so the pathological effects of parasitaemia appear to be mediated entirely by the downstream effects of sequestration. Treatment with an artemisinin derivative decreased mortality compared with quinine (OR 0.64 [95% CI 0.56-0.74]). These estimates were consistent across children and adults (mainly representing African and Asian patients, respectively). Using inverse probability weighting, transfusion was not estimated to be beneficial in children with admission haematocrit values between 15% and 25% (OR 0.99 [95% CI 0.97-1.02]). Except for the effects of artemisinin treatment and transfusion, causal interpretations of these estimates could be biased by unmeasured confounding from severe bacterial sepsis, immunity, and duration of illness. CONCLUSION These data suggest that moderate anaemia is associated with a reduced risk of death in severe falciparum malaria. This is possibly a direct causal association. The severe anaemia threshold criteria for a definition of severe falciparum malaria should be reconsidered.
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Affiliation(s)
- Stije J. Leopold
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - James A. Watson
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Atthanee Jeeyapant
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Julie A. Simpson
- Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, The University of Melbourne, Melbourne, Victoria, Australia
| | - Nguyen H. Phu
- Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Programme, Ho Chi Minh City, Vietnam
| | - Tran T. Hien
- Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Programme, Ho Chi Minh City, Vietnam
| | - Nicholas P. J. Day
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Arjen M. Dondorp
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Nicholas J. White
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
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