1
|
Powell NR, Geck RC, Lai D, Shugg T, Skaar TC, Dunham M. Functional Analysis of G6PD Variants Associated With Low G6PD Activity in the All of Us Research Program. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2024:2024.04.12.24305393. [PMID: 38645242 PMCID: PMC11030488 DOI: 10.1101/2024.04.12.24305393] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/23/2024]
Abstract
Glucose-6-phosphate dehydrogenase (G6PD) protects red blood cells against oxidative damage through regeneration of NADPH. Individuals with G6PD polymorphisms (variants) that produce an impaired G6PD enzyme are usually asymptomatic, but at risk of hemolytic anemia from oxidative stressors, including certain drugs and foods. Prevention of G6PD deficiency-related hemolytic anemia is achievable through G6PD genetic testing or whole-genome sequencing (WGS) to identify affected individuals who should avoid hemolytic triggers. However, accurately predicting the clinical consequence of G6PD variants is limited by over 800 G6PD variants which remain of uncertain significance. There also remains significant variability in which deficiency-causing variants are included in pharmacogenomic testing arrays across institutions: many panels only include c.202G>A, even though dozens of other variants can also cause G6PD deficiency. Here, we seek to improve G6PD genotype interpretation using data available in the All of Us Research Program and using a yeast functional assay. We confirm that G6PD coding variants are the main contributor to decreased G6PD activity, and that 13% of individuals in the All of Us data with deficiency-causing variants would be missed if only the c.202G>A variant were tested for. We expand clinical interpretation for G6PD variants of uncertain significance; reporting that c.595A>G, known as G6PD Dagua or G6PD Açores, and the newly identified variant c.430C>G, reduce activity sufficiently to lead to G6PD deficiency. We also provide evidence that five missense variants of uncertain significance are unlikely to lead to G6PD deficiency, since they were seen in hemi- or homozygous individuals without a reduction in G6PD activity. We also applied the new WHO guidelines and were able to classify two synonymous variants as WHO class C. We anticipate these results will improve the accuracy, and prompt increased use, of G6PD genetic tests through a more complete clinical interpretation of G6PD variants. As the All of Us data increases from 245,000 to 1 million participants, and additional functional assays are carried out, we expect this research to serve as a template to enable complete characterization of G6PD deficiency genotypes. With an increased number of interpreted variants, genetic testing of G6PD will be more informative for preemptively identifying individuals at risk for drug- or food-induced hemolytic anemia.
Collapse
Affiliation(s)
- Nicholas R Powell
- Indiana University School of Medicine, Department of Medicine, Division of Clinical Pharmacology, Indianapolis IN
| | - Renee C Geck
- University of Washington, Department of Genome Sciences, Seattle WA
| | - Dongbing Lai
- Indiana University School of Medicine, Department of Medical and Molecular Genetics, Indianapolis IN
| | - Tyler Shugg
- Indiana University School of Medicine, Department of Medicine, Division of Clinical Pharmacology, Indianapolis IN
| | - Todd C Skaar
- Indiana University School of Medicine, Department of Medicine, Division of Clinical Pharmacology, Indianapolis IN
| | - Maitreya Dunham
- University of Washington, Department of Genome Sciences, Seattle WA
| |
Collapse
|
2
|
Geck RC, Powell NR, Dunham MJ. Functional interpretation, cataloging, and analysis of 1,341 glucose-6-phosphate dehydrogenase variants. Am J Hum Genet 2023; 110:228-239. [PMID: 36681081 PMCID: PMC9943724 DOI: 10.1016/j.ajhg.2023.01.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Accepted: 01/03/2023] [Indexed: 01/22/2023] Open
Abstract
Glucose-6-phosphate dehydrogenase (G6PD) deficiency affects over 500 million individuals who can experience anemia in response to oxidative stressors such as certain foods and drugs. Recently, the World Health Organization (WHO) called for revisiting G6PD variant classification as a priority to implement genetic medicine in low- and middle-income countries. Toward this goal, we sought to collect reports of G6PD variants and provide interpretations. We identified 1,341 G6PD variants in population and clinical databases. Using the ACMG standards and guidelines for the interpretation of sequence variants, we provided interpretations for 268 variants, including 186 variants that were not reported or of uncertain significance in ClinVar, bringing the total number of variants with non-conflicting interpretations to 400. For 414 variants with functional or clinical data, we analyzed associations between activity, stability, and current classification systems, including the new 2022 WHO classification. We corroborated known challenges with classification systems, including phenotypic variation, emphasizing the importance of comparing variant effects across individuals and studies. Biobank data made available by All of Us illustrate the benefit of large-scale sequencing and phenotyping by adding additional support connecting variants to G6PD-deficient anemia. By leveraging available data and interpretation guidelines, we created a repository for information on G6PD variants and nearly doubled the number of variants with clinical interpretations. These tools enable better interpretation of G6PD variants for the implementation of genetic medicine.
Collapse
Affiliation(s)
- Renee C Geck
- Department of Genome Sciences, University of Washington, Seattle, WA 98195, USA
| | - Nicholas R Powell
- Division of Clinical Pharmacology, Department of Medicine, School of Medicine, Indiana University, Indianapolis, IN 46202, USA
| | - Maitreya J Dunham
- Department of Genome Sciences, University of Washington, Seattle, WA 98195, USA.
| |
Collapse
|
3
|
Sudsumrit S, Chamchoy K, Songdej D, Adisakwattana P, Krudsood S, Adams ER, Imwong M, Leartsakulpanich U, Boonyuen U. Genotype-phenotype association and biochemical analyses of glucose-6-phosphate dehydrogenase variants: Implications for the hemolytic risk of using 8-aminoquinolines for radical cure. Front Pharmacol 2022; 13:1032938. [PMID: 36339627 PMCID: PMC9631214 DOI: 10.3389/fphar.2022.1032938] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Accepted: 10/11/2022] [Indexed: 09/02/2023] Open
Abstract
Background: Plasmodium vivax remains the malaria species posing a major threat to human health worldwide owing to its relapse mechanism. Currently, the only drugs of choice for radical cure are the 8-aminoquinolines (primaquine and tafenoquine), which are capable of killing hypnozoites and thus preventing P. vivax relapse. However, the therapeutic use of primaquine and tafenoquine is restricted because these drugs can cause hemolysis in individuals with glucose-6-phosphate dehydrogenase (G6PD) deficiency. This study aimed to assess and understand the hemolytic risk of using 8-aminoquinolines for radical treatment in a malaria endemic area of Thailand. Methods: The prevalence of G6PD deficiency was determined using a quantitative test in 1,125 individuals. Multiplexed high-resolution meltinging (HRM) assays were developed and applied to detect 12 G6PD mutations. Furthermore, biochemical and structural characterization of G6PD variants was carried out to understand the molecular basis of enzyme deficiency. Results: The prevalence of G6PD deficiency was 6.76% (76/1,125), as assessed by a phenotypic test. Multiplexed HRM assays revealed G6PD Mahidol in 15.04% (77/512) of males and 28.38% (174/613) of females, as well as G6PD Aures in one female. G6PD activity above the 30% cut-off was detected in those carrying G6PD Mahidol, even in hemizygous male individuals. Two variants, G6PD Murcia Oristano and G6PD Songklanagarind + Viangchan, were identified for the first time in Thailand. Biochemical characterization revealed that structural instability is the primary cause of enzyme deficiency in G6PD Aures, G6PD Murcia Oristano, G6PD Songklanagarind + Viangchan, and G6PD Chinese 4 + Viangchan, with double G6PD mutations causing more severe enzyme deficiency. Conclusion: In western Thailand, up to 22% of people may be ineligible for radical cure. Routine qualitative tests may be insufficient for G6PD testing, so quantitative tests should be implemented. G6PD genotyping should also be used to confirm G6PD status, especially in female individuals suspected of having G6PD deficiency. People with double G6PD mutations are more likely to have hemolysis than are those with single G6PD mutations because the double mutations significantly reduce the catalytic activity as well as the structural stability of the protein.
Collapse
Affiliation(s)
- Sirapapha Sudsumrit
- Department of Molecular Tropical Medicine and Genetics, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Kamonwan Chamchoy
- Princess Srisavangavadhana College of Medicine, Chulabhorn Royal Academy, Bangkok, Thailand
| | - Duantida Songdej
- Department of Pediatrics, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok, Thailand
| | - Poom Adisakwattana
- Department of Helminthology, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Srivicha Krudsood
- Department of Tropical Hygiene, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Emily R. Adams
- Research Centre for Drugs and Diagnostics, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Mallika Imwong
- Department of Molecular Tropical Medicine and Genetics, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Ubolsree Leartsakulpanich
- National Center for Genetic Engineering and Biotechnology, National Science and Technology Development Agency, Pathumthani, Thailand
| | - Usa Boonyuen
- Department of Molecular Tropical Medicine and Genetics, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| |
Collapse
|
4
|
Ganapathi M, Campbell P, Ofori K, Aggarwal V, Francis RO, Kratz A. Impact of preemptive rapid testing for glucose-6-phosphate dehydrogenase deficiency prior to rasburicase administration at a tertiary care center: a retrospective study. Br J Clin Pharmacol 2022; 88:4163-4170. [PMID: 35419830 DOI: 10.1111/bcp.15353] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Revised: 03/13/2022] [Accepted: 03/15/2022] [Indexed: 11/30/2022] Open
Abstract
AIM Glucose-6-phosphate dehydrogenase (G6PD) deficiency, the most common enzymopathy in humans, can cause acute hemolysis resulting from exposure to certain medications, chemicals, infections and fava beans. Rasburicase, used to manage elevated uric acid levels in the oncologic emergency of tumor lysis syndrome, is one such drug. The Food & Drug Administration (FDA) recommends testing of G6PD status prior to rasburicase administration for patients at higher risk for G6PD deficiency. METHODS We performed a retrospective chart review of all oncology patients for whom a semi-quantitative biochemical test for detecting G6PD deficiency was performed prior to rasburicase administration over a 2.5 year period, in a large academic metropolitan hospital. RESULTS We identified 16 out of 260 tested individuals as G6PD-deficient (6.1%), including six females. On average, test results were electronically available to health-care providers within 4 hours of sample collection, with most results available within 2-3 hours. Four G6PD-deficient patients developed elevated uric acid levels. Two of the G6PD-deficient patients were treated with rasburicase, and subsequently developed hemolysis, which was appropriately managed. CONCLUSION In summary, by providing information about G6PD status with a rapid turnaround time, we have taken a significant step towards personalized medicine in our institution. In spite of the test implementation, two out of four G6PD deficient patients, who were no longer candidates for rasburicase use, still received the drug, highlighting the need for improved provider education.
Collapse
Affiliation(s)
- Mythily Ganapathi
- Department of Pathology & Cell Biology, Columbia University Irving Medical Center, New York, NY, USA
| | - Peter Campbell
- Department of Pharmacy, New York-Presbyterian Hospital, Columbia University Irving Medical Center, New York, NY
| | - Kenneth Ofori
- Department of Pathology & Cell Biology, Columbia University Irving Medical Center, New York, NY, USA
| | - Vimla Aggarwal
- Department of Pathology & Cell Biology, Columbia University Irving Medical Center, New York, NY, USA
| | - Richard O Francis
- Department of Pathology & Cell Biology, Columbia University Irving Medical Center, New York, NY, USA
| | - Alexander Kratz
- Department of Pathology & Cell Biology, Columbia University Irving Medical Center, New York, NY, USA
| |
Collapse
|
5
|
Genzen JR, Nwosu A, Long T, Murphy H, Alter DN. An International Survey of Glucose-6-Phosphate Dehydrogenase Laboratory Reporting Practices. Arch Pathol Lab Med 2022; 146:477172. [PMID: 35090003 DOI: 10.5858/arpa.2021-0276-cp] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/20/2021] [Indexed: 02/21/2024]
Abstract
CONTEXT.— Glucose-6-phosphate dehydrogenase (G6PD) activity is used in the evaluation of hemolysis risk in patients being assessed for G6PD deficiency. A long-acting 8-aminoquinoline drug (tafenoquine) used in malaria treatment is contraindicated in patients with G6PD deficiency (<70% normal G6PD activity). The current state of G6PD reporting practices to support clinical eligibility assessment is poorly understood. OBJECTIVE.— To assess clinical laboratory reporting practices for G6PD testing. DESIGN.— In October 2019 and October 2020, voluntary questionnaires were distributed to 327 and 324 laboratories participating in the College of American Pathologists G6PD proficiency testing (PT). RESULTS.— Two hundred fifty-seven and 119 laboratories responded to the 2019 and 2020 questionnaires, respectively. Few laboratories have received clinical questions about average normal G6PD activity (US/Canada, 2.0% [3 of 149]; international, 8.4% [9 of 107]), whereas slightly more have determined the average normal G6PD activity for their own assay and patient populations (US/Canada, 6.7% [10 of 149]; international, 19.4% [21 of 108]). Few laboratories report G6PD activity in percent of normal format (US/Canada, 2.7% [4 of 149]; international, 8.3% [9 of 108]). The most common unit of measurement in use for quantitative G6PD reporting is unit per gram of hemoglobin. Reference intervals vary based on assay, reaction temperature, and participant laboratory and demonstrate moderate correlation (r = .46-.51) to G6PD activity measured from a "normal" PT challenge specimen. Nearly half of participants (47.8% [85 of 178]) categorized a quantitatively "intermediate" G6PD PT challenge as "normal" when using qualitative assays. CONCLUSIONS.— Percent of normal G6PD activity reporting would facilitate patient eligibility assessment for drugs, such as tafenoquine. Quantitative assays are better able to differentiate "intermediate" specimens than qualitative assays.
Collapse
Affiliation(s)
- Jonathan R Genzen
- From the Department of Pathology, University of Utah, Salt Lake City, Utah (Genzen)
- ARUP Laboratories, Salt Lake City, Utah (Genzen)
| | - Ann Nwosu
- The Division of Biostatistics (Nwosu, Long), College of American Pathologists, Northfield, Illinois
| | - Thomas Long
- The Division of Biostatistics (Nwosu, Long), College of American Pathologists, Northfield, Illinois
| | - Hilda Murphy
- Proficiency Testing (Murphy), College of American Pathologists, Northfield, Illinois
| | - David N Alter
- The Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, Georgia (Alter)
| |
Collapse
|
6
|
Wang X, Xia Z, He Y, Zhou X, Zhang H, Gao C, Ge Y, Cai X, Zhou Y, Guo Q. Newborn Screening for G6PD Deficiency in Xiamen, China: Prevalence, Variant Spectrum, and Genotype-Phenotype Correlations. Front Genet 2021; 12:718503. [PMID: 34659341 PMCID: PMC8517332 DOI: 10.3389/fgene.2021.718503] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Accepted: 09/20/2021] [Indexed: 01/12/2023] Open
Abstract
Background: Glucose-6-phosphate dehydrogenase (G6PD) deficiency is a common inherited enzymatic defect. The purpose of this study was to evaluate the profile of G6PD deficiency and investigate the factors associated with the accuracy of newborn screening (NBS) in Xiamen, China. Methods: A total of 99,546 newborns were screened by modified fluorescent spot test at the Women and Children’s Hospital, Xiamen University. High-risk neonates were recalled for diagnosis by either a measurement of G6PD activity or genetic testing for the presence of pathogenic G6PD variants using a quantitative G6PD enzymatic assay or the MeltPro® G6PD assay, respectively. Results: In the first-tier screening, 1,256 newborns were categorized as high risk. Of these, 1,051 were diagnosed with G6PD deficiency, indicating a prevalence of 1.39% in Xiamen, China. Among the 1,013 neonates who underwent genotyping, 851 carried hemizygous, heterozygous, homozygous, or compound heterozygous variants, for a positive predictive value (PPV) of 84.01%. In total, 12 variants and 32 genotypes were identified, and the six most common variants were c.1376G>T, c.1388G>A, c.95A>G, c.1024C>T, c.871G>A, and c.392G>T, which accounted for approximately 94% of the identified alleles. Different variants showed characteristic enzymatic activities, although high phenotypic heterogeneity was observed for each variant. The use of cold-chain transportation significantly improved the PPV of NBS. Conclusions: We determined the profile of G6PD deficiency in Xiamen, including the prevalence, variant spectrum, and genotype-phenotype correlations and confirmed that maintaining a low temperature during sample transport is essential to ensure the high screening accuracy of NBS. Our data provides epidemiological, genotypic, phenotypic, and clinical practice references to standardize future interventions for G6PD deficiency.
Collapse
Affiliation(s)
- Xudong Wang
- United Diagnostic and Research Center for Clinical Genetics, Women and Children's Hospital, School of Medicine and School of Public Health, Xiamen University, Xiamen, China.,Xiamen Newborn Screening Center, Women and Children's Hospital, School of Medicine, Xiamen University, Xiamen, China
| | - Zhongmin Xia
- United Diagnostic and Research Center for Clinical Genetics, Women and Children's Hospital, School of Medicine and School of Public Health, Xiamen University, Xiamen, China
| | - Ying He
- Xiamen Newborn Screening Center, Women and Children's Hospital, School of Medicine, Xiamen University, Xiamen, China
| | - Xiaoman Zhou
- School of Medicine, Xiamen University, Xiamen, China
| | - Haixia Zhang
- School of Public Health, Xiamen University, Xiamen, China
| | - Chunliu Gao
- School of Public Health, Xiamen University, Xiamen, China
| | - Yunsheng Ge
- United Diagnostic and Research Center for Clinical Genetics, Women and Children's Hospital, School of Medicine and School of Public Health, Xiamen University, Xiamen, China
| | - Xiaofang Cai
- Xiamen Newborn Screening Center, Women and Children's Hospital, School of Medicine, Xiamen University, Xiamen, China
| | - Yulin Zhou
- United Diagnostic and Research Center for Clinical Genetics, Women and Children's Hospital, School of Medicine and School of Public Health, Xiamen University, Xiamen, China.,Xiamen Newborn Screening Center, Women and Children's Hospital, School of Medicine, Xiamen University, Xiamen, China
| | - Qiwei Guo
- United Diagnostic and Research Center for Clinical Genetics, Women and Children's Hospital, School of Medicine and School of Public Health, Xiamen University, Xiamen, China
| |
Collapse
|
7
|
Pal S, Myburgh J, Bansil P, Hann A, Robertson L, Gerth-Guyette E, Ambler G, Bizilj G, Kahn M, Zobrist S, Manis MR, Styke NA, Allan V, Ansbro R, Akingbade T, Bryan A, Murphy SC, Kublin JG, Layton M, Domingo GJ. Reference and point-of-care testing for G6PD deficiency: Blood disorder interference, contrived specimens, and fingerstick equivalence and precision. PLoS One 2021; 16:e0257560. [PMID: 34543346 PMCID: PMC8452025 DOI: 10.1371/journal.pone.0257560] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2021] [Accepted: 09/05/2021] [Indexed: 11/30/2022] Open
Abstract
Certain clinical indications and treatments such as the use of rasburicase in cancer therapy and 8-aminoquinolines for Plasmodium vivax malaria treatment would benefit from a point-of-care test for glucose-6-phosphate dehydrogenase (G6PD) deficiency. Three studies were conducted to evaluate the performance of one such test: the STANDARD™ G6PD Test (SD BIOSENSOR, South Korea). First, biological interference on the test performance was evaluated in specimens with common blood disorders, including high white blood cell (WBC) counts. Second, the test precision on fingerstick specimens was evaluated against five individuals of each, deficient, intermediate, and normal G6PD activity status. Third, clinical performance of the test was evaluated at three point-of-care settings in the United States. The test performed equivalently to the reference assay in specimens with common blood disorders. High WBC count blood samples resulted in overestimation of G6PD activity in both the reference assay and the STANDARD G6PD Test. The STANDARD G6PD Test showed good precision on multiple fingerstick specimens from the same individual. The same G6PD threshold values (U/g Hb) were applied for a semiquantitative interpretation for fingerstick- and venous-derived results. The sensitivity/specificity values (95% confidence intervals) for the test for G6PD deficiency were 100 (92.3–100.0)/97 (95.2–98.2) and 100 (95.7–100.0)/97.4 (95.7–98.5) for venous and capillary specimens, respectively. The same values for females with intermediate (> 30% to ≤ 70%) G6PD activity were 94.1 (71.3–99.9)/88.2 (83.9–91.7) and 82.4 (56.6–96.2)/87.6(83.3–91.2) for venous and capillary specimens, respectively. The STANDARD G6PD Test enables point-of-care testing for G6PD deficiency.
Collapse
Affiliation(s)
- Sampa Pal
- PATH, Seattle, Washington, United States of America
| | - Jane Myburgh
- Special Haematology Laboratory, Hammersmith Hospital, London, United Kingdom
| | - Pooja Bansil
- PATH, Seattle, Washington, United States of America
| | - Amanda Hann
- Special Haematology Laboratory, Hammersmith Hospital, London, United Kingdom
| | - Lynn Robertson
- Special Haematology Laboratory, Hammersmith Hospital, London, United Kingdom
| | | | - Gwen Ambler
- PATH, Seattle, Washington, United States of America
| | - Greg Bizilj
- PATH, Seattle, Washington, United States of America
| | - Maria Kahn
- PATH, Seattle, Washington, United States of America
| | | | - Michelle R. Manis
- Departments of Laboratory Medicine and Microbiology, University of Washington School of Medicine, Seattle, Washington, United States of America
| | - Nickolas A. Styke
- Departments of Laboratory Medicine and Microbiology, University of Washington School of Medicine, Seattle, Washington, United States of America
| | - Vajra Allan
- PATH, Seattle, Washington, United States of America
| | | | - Tobi Akingbade
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
| | - Andrew Bryan
- Departments of Laboratory Medicine and Microbiology, University of Washington School of Medicine, Seattle, Washington, United States of America
| | - Sean C. Murphy
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, Washington, United States of America
- Center for Emerging and Re-emerging Infectious Diseases, University of Washington, Seattle, Washington, United States of America
| | - James G. Kublin
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
| | - Mark Layton
- Special Haematology Laboratory, Hammersmith Hospital, London, United Kingdom
| | | |
Collapse
|
8
|
Higgins V, Cheng PL, Selvaratnam R, Brinc D. Optimizing Measurement and Interpretation of the G6PD/Hb Ratio. J Appl Lab Med 2021; 6:1251-1263. [PMID: 33755132 DOI: 10.1093/jalm/jfab008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Accepted: 01/25/2021] [Indexed: 11/12/2022]
Abstract
BACKGROUND Glucose-6-phosphate dehydrogenase (G6PD)/hemoglobin (Hb) ratio helps detect G6PD deficiency, an X-linked disorder that can be asymptomatic or cause acute hemolytic anemia and chronic hemolysis. We investigated preanalytical, analytical, and postanalytical aspects to optimize G6PD/Hb measurement and interpretation. METHODS G6PD was measured with the Pointe Scientific assay and Hb with Drabkin's reagent on Alinity c® (Abbott Diagnostics). Stability of G6PD/Hb was assessed after 7 and 14 days while stored at 2-8 °C. Stability of hemolysate prepared for G6PD analysis was assessed using QC and patient samples up to 4 h at room temperature or 2-8 °C. Analytical performance specifications including precision, method comparison, linearity, LOQ, and carry-over were established for the enzymatic reaction of G6PD and spectrophotometric reading of Hb. G6PD/Hb reference interval and cut-offs were established indirectly using truncated maximum likelihood method (TML) using retrospective data (n = 4715 patient data points). RESULTS Samples were stable after 7 days at 2-8°C, unless grossly hemolyzed. Hemolysate prepared for G6PD measurement remained stable for up to 4 h for QC at room temperature and 2-8°C, but up to 30 min-1 h at room temperature and 1-2 h at 2-8 °C for patient samples. Precision, linearity, LOQ, and carryover were acceptable. G6PD/Hb cut-offs were <3.3, ≥3.3, 3.3-8.9, and ≥8.9 U/g Hb for deficient males/females, normal males, intermediate females, and normal females, respectively. CONCLUSIONS In vitro hemolysis and delayed hemolysate analysis significantly reduce G6PD/Hb stability. QC material cannot detect the impact of delayed hemolysate analysis. These findings were foundational for optimizing G6PD/Hb protocols for a new platform and establishing laboratory-specific G6PD/Hb cut-offs.
Collapse
Affiliation(s)
- Victoria Higgins
- Department of Laboratory Medicine & Pathobiology, University of Toronto, Toronto, ON, Canada
| | - Pow Lee Cheng
- Department of Laboratory Medicine, University Health Network, Toronto, ON, Canada
| | - Rajeevan Selvaratnam
- Department of Laboratory Medicine & Pathobiology, University of Toronto, Toronto, ON, Canada.,Department of Laboratory Medicine, University Health Network, Toronto, ON, Canada
| | - Davor Brinc
- Department of Laboratory Medicine & Pathobiology, University of Toronto, Toronto, ON, Canada.,Department of Laboratory Medicine, University Health Network, Toronto, ON, Canada
| |
Collapse
|
9
|
Boonyuen U, Songdej D, Tanyaratsrisakul S, Phuanukoonnon S, Chamchoy K, Praoparotai A, Pakparnich P, Sudsumrit S, Edwards T, Williams CT, Byrne RL, Adams ER, Imwong M. Glucose-6-phosphate dehydrogenase mutations in malaria endemic area of Thailand by multiplexed high-resolution melting curve analysis. Malar J 2021; 20:194. [PMID: 33879156 PMCID: PMC8056697 DOI: 10.1186/s12936-021-03731-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Accepted: 04/08/2021] [Indexed: 12/26/2022] Open
Abstract
Background Glucose-6-phosphate dehydrogenase (G6PD) deficiency, the most common enzymopathy in humans, is prevalent in tropical and subtropical areas where malaria is endemic. Anti-malarial drugs, such as primaquine and tafenoquine, can cause haemolysis in G6PD-deficient individuals. Hence, G6PD testing is recommended before radical treatment against vivax malaria. Phenotypic assays have been widely used for screening G6PD deficiency, but in heterozygous females, the random lyonization causes difficulty in interpreting the results. Over 200 G6PD variants have been identified, which form genotypes associated with differences in the degree of G6PD deficiency and vulnerability to haemolysis. This study aimed to assess the frequency of G6PD mutations using a newly developed molecular genotyping test. Methods A multiplexed high-resolution melting (HRM) assay was developed to detect eight G6PD mutations, in which four mutations can be tested simultaneously. Validation of the method was performed using 70 G6PD-deficient samples. The test was then applied to screen 725 blood samples from people living along the Thai–Myanmar border. The enzyme activity of these samples was also determined using water-soluble tetrazolium salts (WST-8) assay. Then, the correlation between genotype and enzyme activity was analysed. Results The sensitivity of the multiplexed HRM assay for detecting G6PD mutations was 100 % [95 % confidence interval (CI): 94.87–100 %] with specificity of 100 % (95 % CI: 87.66–100 %). The overall prevalence of G6PD deficiency in the studied population as revealed by phenotypic WST-8 assay was 20.55 % (149/725). In contrast, by the multiplexed HRM assay, 27.17 % (197/725) of subjects were shown to have G6PD mutations. The mutations detected in this study included four single variants, G6PD Mahidol (187/197), G6PD Canton (4/197), G6PD Viangchan (3/197) and G6PD Chinese-5 (1/197), and two double mutations, G6PD Mahidol + Canton (1/197) and G6PD Chinese-4 + Viangchan (1/197). A broad range of G6PD enzyme activities were observed in individuals carrying G6PD Mahidol, especially in females. Conclusions The multiplexed HRM-based assay is sensitive and reliable for detecting G6PD mutations. This genotyping assay can facilitate the detection of heterozygotes, which could be useful as a supplementary approach for high-throughput screening of G6PD deficiency in malaria endemic areas before the administration of primaquine and tafenoquine.
Collapse
Affiliation(s)
- Usa Boonyuen
- Department of Molecular Tropical Medicine and Genetics, Faculty of Tropical Medicine, Mahidol University, Bangkok, 10400, Thailand.
| | - Duantida Songdej
- Department of Pediatrics, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok, 10400, Thailand
| | | | - Suparat Phuanukoonnon
- Department of Social and Environmental Medicine, Faculty of Tropical Medicine, Mahidol University, Bangkok, 10400, Thailand
| | - Kamonwan Chamchoy
- Faculty of Medicine and Public Health, HRH Princess Chulabhorn College of Medical Science, Chulabhorn Royal Academy, Bangkok, 10210, Thailand
| | - Aun Praoparotai
- Department of Molecular Tropical Medicine and Genetics, Faculty of Tropical Medicine, Mahidol University, Bangkok, 10400, Thailand
| | - Phonchanan Pakparnich
- Department of Molecular Tropical Medicine and Genetics, Faculty of Tropical Medicine, Mahidol University, Bangkok, 10400, Thailand
| | - Sirapapha Sudsumrit
- Department of Molecular Tropical Medicine and Genetics, Faculty of Tropical Medicine, Mahidol University, Bangkok, 10400, Thailand
| | - Thomas Edwards
- Centre for Drugs and Diagnostics, Liverpool School of Tropical Medicine, L3 5QA, Liverpool, UK
| | - Christopher T Williams
- Centre for Drugs and Diagnostics, Liverpool School of Tropical Medicine, L3 5QA, Liverpool, UK
| | - Rachel L Byrne
- Centre for Drugs and Diagnostics, Liverpool School of Tropical Medicine, L3 5QA, Liverpool, UK
| | - Emily R Adams
- Centre for Drugs and Diagnostics, Liverpool School of Tropical Medicine, L3 5QA, Liverpool, UK
| | - Mallika Imwong
- Department of Molecular Tropical Medicine and Genetics, Faculty of Tropical Medicine, Mahidol University, Bangkok, 10400, Thailand
| |
Collapse
|
10
|
Youssef JG, Zahiruddin F, Youssef G, Padmanabhan S, Ensor J, Pingali SR, Zu Y, Sahay S, Iyer SP. G6PD deficiency and severity of COVID19 pneumonia and acute respiratory distress syndrome: tip of the iceberg? Ann Hematol 2021; 100:667-673. [PMID: 33439304 PMCID: PMC7804896 DOI: 10.1007/s00277-021-04395-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Accepted: 01/03/2021] [Indexed: 01/08/2023]
Abstract
Abstract The severe pneumonia caused by the human coronavirus (hCoV)-SARS-CoV-2 has inflicted heavy casualties, especially among the elderly and those with co-morbid illnesses irrespective of their age. The high mortality in African-Americans and males, in general, raises the concern for a possible X-linked mediated process that could affect the viral pathogenesis and the immune system. We hypothesized that G6PD, the most common X-linked enzyme deficiency, associated with redox status, may have a role in severity of pneumonia. Retrospective chart review was performed in hospitalized patients with COVID19 pneumonia needing supplemental oxygen. A total of 17 patients were evaluated: six with G6PD deficiency (G6PDd) and 11 with normal levels. The two groups (normal and G6PDd) were comparable in terms of age, sex, co-morbidities, and laboratory parameters—LDH, IL-6, CRP, and ferritin, respectively. Thirteen patients needed ventilatory support ; 8 in the normal group and 5 in the G6PDd group (72% vs.83%). The main differences indicating increasing severity in normal vs. G6PDd groups included G6PD levels (12.2 vs. 5.6, P = 0.0002), PaO2/FiO2 ratio (159 vs. 108, P = 0.05), days on mechanical ventilation (10.25 vs. 21 days P = 0.04), hemoglobin level (10 vs. 8.1 P = 0.03), and hematocrit (32 vs. 26 P = 0.015). Only one patient with G6PDd died; 16 were discharged home. Our clinical series ascribes a possible biological role for G6PDd in SARS-CoV2 viral proliferation. It is imperative that further studies are performed to understand the interplay between the viral and host factors in G6PDd that may lead to disparity in outcomes. Key Points • COVID19 studies show higher mortality in men, due to severe pneumonia and ARDS, indicating possible X-linked mediated differences • G6PD, the most common X-linked enzymopathy, highly prevalent in African Americans and Italians, maintains redox homeostasis. • Preclinical studies using G6PD deficient (G6PDd) cells infected with human coronavirus (hCoV), show impaired cellular responses, viral proliferation and worsening oxidative damage. • Retrospective chart review in hospitalized patients with COVID19 pneumonia needing supplemental oxygen shows differences between the two groups (Normal and G6PDd) in hematological indices; the G6PDdgroup demonstrated prolonged PaO2/FiO2 ratio, and longer days on mechanical ventilation indicating the severity of the pneumonia.
Collapse
Affiliation(s)
- Jihad G Youssef
- Division of Pulmonary and Critical Care Medicine, Houston Methodist Pulmonary Transplant Center, Houston Methodist Hospital, Houston, TX, USA
| | - Faisal Zahiruddin
- Division of Pulmonary and Critical Care Medicine, Houston Methodist Pulmonary Transplant Center, Houston Methodist Hospital, Houston, TX, USA
| | - George Youssef
- College of Natural Sciences and Mathematics, University of Houston, Houston, TX, USA
| | - Sriram Padmanabhan
- Collaborative Action for SARS-CoV-2 Eradication (CARE), Houston, TX, USA
| | - Joe Ensor
- Houston Methodist Cancer Center, Houston Methodist Research Institute, Houston Methodist Hospital, Houston, TX, USA
| | - Sai Ravi Pingali
- Houston Methodist Cancer Center, Houston Methodist Research Institute, Houston Methodist Hospital, Houston, TX, USA
| | - Youli Zu
- Houston Methodist Department of Pathology and Genomic Medicine, Houston Methodist Research Institute, Houston Methodist Hospital, Houston, TX, USA
| | - Sandeep Sahay
- Division of Pulmonary and Critical Care Medicine, Houston Methodist Lung Center, Houston Methodist Research Institute, Houston Methodist Hospital, Houston, TX, USA
| | - Swaminathan P Iyer
- Collaborative Action for SARS-CoV-2 Eradication (CARE), Houston, TX, USA. .,Department of Lymphoma/Myeloma, Division of Cancer Medicine, University of Texas MD Anderson Cancer Center, 1400 Unit 429, Holcombe Blvd, Houston, TX, 77030, USA.
| |
Collapse
|
11
|
He Y, Zhang Y, Chen X, Wang Q, Ling L, Xu Y. Glucose-6-phosphate dehydrogenase deficiency in the Han Chinese population: molecular characterization and genotype-phenotype association throughout an activity distribution. Sci Rep 2020; 10:17106. [PMID: 33051526 PMCID: PMC7555859 DOI: 10.1038/s41598-020-74200-y] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Accepted: 09/28/2020] [Indexed: 11/09/2022] Open
Abstract
Glucose-6-phosphate dehydrogenase (G6PD) deficiency is a common hereditary disorder in China. The existing prevalence and molecular epidemiology of G6PD deficiency in China were geographically limited. In this study, the spectrum of G6PD gene mutations was well characterized in a large and diverse population all over the country; and the correlation of genotype and enzyme activity phenotype was explored for the first time. The results showed that the overall prevalence of G6PD deficiency in China was 2.10% at the national level. The top six common mutations were c.1388 G>A, c.1376 G>T, c.95 A>G, c.392 G>T, c.871 G>A and c.1024 C>T, accounting for more than 90% of G6PD deficient alleles. Compound mutation patterns were frequently observed in females with severe deficiency. The distribution of G6PD activities depended on the type of mutation patterns and genders. Hemizygote, homozygote, and compound heterozygote were predominantly associated with severe G6PD deficiency, whereas heterozygotes with single mutation mainly presented moderate enzyme deficiency. A significant gap between G6PD activities in hemizygous and normal males was observed, and yet, the overall distribution of that in females carrying missense mutations was a continuum from G6PD severely deficient to normal. This is the first report of discussing the association between G6PD genetic variants in the Chinese and enzyme activity phenotypes.
Collapse
Affiliation(s)
- Ying He
- Department of Laboratory Medicine, The Eighth Affiliated Hospital, Sun Yat-Sen University, Shenzhen, Guangdong Province, China
| | - Yinhui Zhang
- Department of Laboratory Medicine, The Eighth Affiliated Hospital, Sun Yat-Sen University, Shenzhen, Guangdong Province, China
| | - Xionghao Chen
- Maternity and Children, Healthcare Hospital of Futian, Shenzhen, Guangdong Province, China
| | - Qiong Wang
- Department of Laboratory Medicine, The Eighth Affiliated Hospital, Sun Yat-Sen University, Shenzhen, Guangdong Province, China
| | - Lifen Ling
- Department of Laboratory Medicine, The Eighth Affiliated Hospital, Sun Yat-Sen University, Shenzhen, Guangdong Province, China
| | - Yuhong Xu
- Department of Clinical Pharmacy, The Eighth Affiliated Hospital, Sun Yat-Sen University, Shenzhen, Guangdong Province, China.
| |
Collapse
|
12
|
Calvaresi EC, Genzen JR. Evaluating Percentage-Based Reporting of Glucose-6-Phosphate Dehydrogenase (G6PD) Enzymatic Activity. Am J Clin Pathol 2020; 154:248-254. [PMID: 32405645 DOI: 10.1093/ajcp/aqaa040] [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] [Indexed: 01/06/2023] Open
Abstract
OBJECTIVES The World Health Organization recommends measurement of glucose-6-phosphate dehydrogenase (G6PD) activity before initiation of 8-aminoquinoline therapy. A new drug for malaria prophylaxis and treatment (tafenoquine) is contraindicated in patients with G6PD deficiency or unknown G6PD status given its prolonged half-life. Assessments of percentage of normal G6PD activity using laboratory-specific result distributions are not widely available, making tafenoquine-eligibility decisions potentially challenging. METHODS Using an institutional review board-exempt protocol, a data set of quantitative G6PD results was retrieved from a national reference laboratory. G6PD testing was previously performed at 37 °C using an automated enzymatic assay configured on a Roche cobas c501 chemistry analyzer. RESULTS Overall, 52,216 results from patients 18 years and older and 6,397 results from patients younger than 18 years were obtained. A modified adjusted male median of 12.7 U/g Hb was derived for adult males in this assay configuration. Result distributions showed higher G6PD activity in neonates. CONCLUSIONS Retrospective data analysis can be used to determine laboratory-specific normal G6PD activity values in clinical populations and thus can assist in clinical-eligibility considerations for 8-aminoquinoline treatment.
Collapse
Affiliation(s)
| | - Jonathan R Genzen
- Department of Pathology, University of Utah, Salt Lake City
- ARUP Laboratories, Salt Lake City, UT
| |
Collapse
|