1
|
Srivastava K, Yin Q, Makuria AT, Rios M, Gebremedhin A, Flegel WA. CD59 gene: 143 haplotypes of 22,718 nucleotides length by computational phasing in 113 individuals from different ethnicities. Transfusion 2024; 64:1296-1305. [PMID: 38817044 PMCID: PMC11251854 DOI: 10.1111/trf.17869] [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: 11/18/2023] [Revised: 03/22/2024] [Accepted: 04/30/2024] [Indexed: 06/01/2024]
Abstract
BACKGROUND CD59 deficiency due to rare germline variants in the CD59 gene causes disabilities, ischemic strokes, neuropathy, and hemolysis. CD59 deficiency due to common somatic variants in the PIG-A gene in hematopoietic stem cells causes paroxysmal nocturnal hemoglobinuria. The ISBT database lists one nonsense and three missense germline variants that are associated with the CD59-null phenotype. To analyze the genetic diversity of the CD59 gene, we determined long-range CD59 haplotypes among individuals from different ethnicities. METHODS We determined a 22.7 kb genomic fragment of the CD59 gene in 113 individuals using next-generation sequencing (NGS), which covered the whole NM_203330.2 mRNA transcript of 7796 base pairs. Samples came from an FDA reference repository and our Ethiopia study cohorts. The raw genotype data were computationally phased into individual haplotype sequences. RESULTS Nucleotide sequencing of the CD59 gene of 226 chromosomes identified 216 positions with single nucleotide variants. Only three haplotypes were observed in homozygous form, which allowed us to assign them unambiguously as experimentally verified CD59 haplotypes. They were also the most frequent haplotypes among both cohorts. An additional 140 haplotypes were imputed computationally. DISCUSSION We provided a large set of haplotypes and proposed three verified long-range CD59 reference sequences, based on a population approach, using a generalizable rationale for our choice. Correct long-range haplotypes are useful as template sequences for allele calling in high-throughput NGS and precision medicine approaches, thus enhancing the reliability of clinical diagnostics. Long-range haplotypes can also be used to evaluate the influence of genetic variation on the risk of transfusion reactions or diseases.
Collapse
Affiliation(s)
- Kshitij Srivastava
- Department of Transfusion Medicine, NIH Clinical Center, National Institutes of Health, Bethesda, MD, USA
| | - Qinan Yin
- Department of Transfusion Medicine, NIH Clinical Center, National Institutes of Health, Bethesda, MD, USA
| | - Addisalem Taye Makuria
- Department of Transfusion Medicine, NIH Clinical Center, National Institutes of Health, Bethesda, MD, USA
- Department of Pathology and Laboratory Services, ECU Health Medical Center, Greenville, NC, USA
| | - Maria Rios
- Office of Blood Research and Review, Center for Biologics Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, MD, USA
| | - Amha Gebremedhin
- School of Medicine, College of Health Sciences, Addis Ababa University, Ethiopia
| | - Willy Albert Flegel
- Department of Transfusion Medicine, NIH Clinical Center, National Institutes of Health, Bethesda, MD, USA
| |
Collapse
|
2
|
Srivastava K, Fratzscher AS, Lan B, Flegel WA. Cataloguing experimentally confirmed 80.7 kb-long ACKR1 haplotypes from the 1000 Genomes Project database. BMC Bioinformatics 2021; 22:273. [PMID: 34039276 PMCID: PMC8150616 DOI: 10.1186/s12859-021-04169-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Accepted: 05/04/2021] [Indexed: 12/18/2022] Open
Abstract
Background Clinically effective and safe genotyping relies on correct reference sequences, often represented by haplotypes. The 1000 Genomes Project recorded individual genotypes across 26 different populations and, using computerized genotype phasing, reported haplotype data. In contrast, we identified long reference sequences by analyzing the homozygous genomic regions in this online database, a concept that has rarely been reported since next generation sequencing data became available. Study design and methods Phased genotype data for a 80.6 kb region of chromosome 1 was downloaded for all 2,504 unrelated individuals of the 1000 Genome Project Phase 3 cohort. The data was centered on the ACKR1 gene and bordered by the CADM3 and FCER1A genes. Individuals with heterozygosity at a single site or with complete homozygosity allowed unambiguous assignment of an ACKR1 haplotype. A computer algorithm was developed for extracting these haplotypes from the 1000 Genome Project in an automated fashion. A manual analysis validated the data extracted by the algorithm. Results We confirmed 902 ACKR1 haplotypes of varying lengths, the longest at 80,584 nucleotides and shortest at 1,901 nucleotides. The combined length of haplotype sequences comprised 19,895,388 nucleotides with a median of 16,014 nucleotides. Based on our approach, all haplotypes can be considered experimentally confirmed and not affected by the known errors of computerized genotype phasing. Conclusions Tracts of homozygosity can provide definitive reference sequences for any gene. They are particularly useful when observed in unrelated individuals of large scale sequence databases. As a proof of principle, we explored the 1000 Genomes Project database for ACKR1 gene data and mined long haplotypes. These haplotypes are useful for high throughput analysis with next generation sequencing. Our approach is scalable, using automated bioinformatics tools, and can be applied to any gene. Supplementary Information The online version contains supplementary material available at 10.1186/s12859-021-04169-6.
Collapse
Affiliation(s)
- Kshitij Srivastava
- Laboratory Services Section, Department of Transfusion Medicine, NIH Clinical Center, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Anne-Sophie Fratzscher
- Laboratory Services Section, Department of Transfusion Medicine, NIH Clinical Center, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Bo Lan
- Laboratory Services Section, Department of Transfusion Medicine, NIH Clinical Center, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Willy Albert Flegel
- Laboratory Services Section, Department of Transfusion Medicine, NIH Clinical Center, National Institutes of Health, Bethesda, MD, 20892, USA.
| |
Collapse
|
3
|
Srivastava K, Albasri J, Alsuhaibani OM, Aljasem HA, Bueno MU, Antonacci T, Branch DR, Denomme GA, Flegel WA. SCAR: The high-prevalence antigen 013.008 in the Scianna blood group system. Transfusion 2021; 61:246-254. [PMID: 33098316 PMCID: PMC9067365 DOI: 10.1111/trf.16152] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2020] [Revised: 08/31/2020] [Accepted: 09/24/2020] [Indexed: 12/16/2022]
Abstract
BACKGROUND The Scianna (SC) blood group system comprises seven antigens. They reside on the erythroblast membrane-associated glycoprotein (ERMAP). The ERMAP and RHCE genes are juxtaposed to each other on chromosome 1. We report a novel SC antigen. STUDY DESIGN AND METHODS Blood samples came from a patient and his two sisters in Saudi Arabia. To investigate the antibody specificity we used the column agglutination technique and soluble recombinant ERMAP protein. The significance of anti-SCAR was evaluated by the transfusion history and a monocyte monolayer assay. We determined the genomic sequence of ERMAP and RHCE genes. RESULTS The patient's serum showed an antibody of titer 8 against a high-prevalence antigen. The soluble recombinant ERMAP protein inhibited the antibody. The propositus genotyped homozygous for an ERMAP:c.424C>G variant, for which his sisters were heterozygous. The c.424C>G variant occurred in the SC*01 allele in one haplotype with the RHCE*03 (RHCE*cE) allele. No signs of hemolysis occurred following an incompatible blood transfusion. The monocyte monolayer assay was negative. CONCLUSIONS We characterized a high-prevalence antigen, with the proposed name "SCAR," which is the eighth antigen of the Scianna blood group system (proposed designation 013.008). Individuals homozygous for ERMAP:p.(Gln142Glu) protein variant can produce anti-SCAR. Although we did not observe any sign of hemolysis at this time, the anti-SCAR prompted a change of the treatment regimen. A review of the known reports indicated that all SC alloantibodies of sufficient titer should be considered capable of causing hemolysis.
Collapse
Affiliation(s)
- Kshitij Srivastava
- Department of Transfusion Medicine, NIH Clinical Center, National Institutes of Health, Bethesda, Maryland
| | - Jasem Albasri
- Blood Bank Laboratory, Prince Sultan Military Medical City, Riyadh, Saudi Arabia
| | - Omar M. Alsuhaibani
- Blood Bank Laboratory, Prince Sultan Military Medical City, Riyadh, Saudi Arabia
| | - Hassan A. Aljasem
- Blood Bank Laboratory, Prince Sultan Military Medical City, Riyadh, Saudi Arabia
| | - Marina U. Bueno
- Department of Transfusion Medicine, NIH Clinical Center, National Institutes of Health, Bethesda, Maryland
| | - Tania Antonacci
- Versiti Blood Research Institute and Diagnostic Laboratories, Versiti, Milwaukee, Wisconsin
| | - Donald R. Branch
- Department of Medicine, University of Toronto, and Centre for Innovation, Canadian Blood Services, Toronto, Ontario, Canada
| | - Gregory A. Denomme
- Versiti Blood Research Institute and Diagnostic Laboratories, Versiti, Milwaukee, Wisconsin
| | - Willy A. Flegel
- Department of Transfusion Medicine, NIH Clinical Center, National Institutes of Health, Bethesda, Maryland
| |
Collapse
|
4
|
Srivastava K, Khil PP, Sippert E, Volkova E, Dekker JP, Rios M, Flegel WA. ACKR1 Alleles at 5.6 kb in a Well-Characterized Renewable US Food and Drug Administration (FDA) Reference Panel for Standardization of Blood Group Genotyping. J Mol Diagn 2020; 22:1272-1279. [PMID: 32688055 DOI: 10.1016/j.jmoldx.2020.06.014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Revised: 06/17/2020] [Accepted: 06/26/2020] [Indexed: 12/18/2022] Open
Abstract
The glycoprotein encoded by the ACKR1 gene expresses the Duffy blood group antigens and is a receptor for malaria parasites. We recently described 18 long-range ACKR1 alleles in an autochthonous population of a malaria endemic region. Extending this work, we sequenced the gene in a 53-sample repository established by the US Food and Drug Administration (FDA) as reference reagents for blood group genotyping. The FDA samples have been characterized for 19 genes; however, long-range haplotype information for these genes, including ACKR1, was lacking. We used a hybrid approach, novel for this type of gene, to characterize ACKR1 by combining two next-generation sequencing technologies, the short-read massively parallel sequencing and the long-read nanopore sequencing. The expedient integration of data from both next-generation sequencing systems were necessary and sufficient to allow determination of all 25 long-range ACKR1 alleles found in the 53 samples accurately. All 25 alleles identified in our current FDA cohort were novel and, unexpectedly, none had been observed among the 18 alleles in our previous study. The alleles will be useful for validation, calibration, and proficiency testing of red cell genotyping. The lack of any overlap between the ACKR1 alleles in the two studies documents differences in mutation rate and recombination frequency among populations. The exact haplotype and their interethnic or interpopulation dissimilarities can influence disease susceptibility and therapy.
Collapse
Affiliation(s)
- Kshitij Srivastava
- Department of Transfusion Medicine, NIH Clinical Center, NIH, Bethesda, Maryland
| | - Pavel P Khil
- Laboratory Medicine, NIH Clinical Center, NIH, Bethesda, Maryland
| | - Emilia Sippert
- Office of Blood Research and Review, Center for Biologics Evaluation and Research, US Food and Drug Administration, Silver Spring, Maryland
| | - Evgeniya Volkova
- Office of Blood Research and Review, Center for Biologics Evaluation and Research, US Food and Drug Administration, Silver Spring, Maryland
| | - John P Dekker
- Laboratory of Clinical Immunology and Microbiology, National Institute of Allergy and Infectious Diseases, Bethesda, Maryland
| | - Maria Rios
- Office of Blood Research and Review, Center for Biologics Evaluation and Research, US Food and Drug Administration, Silver Spring, Maryland
| | - Willy A Flegel
- Department of Transfusion Medicine, NIH Clinical Center, NIH, Bethesda, Maryland.
| |
Collapse
|
5
|
Myc/Max dependent intronic long antisense noncoding RNA, EVA1A-AS, suppresses the expression of Myc/Max dependent anti-proliferating gene EVA1A in a U2 dependent manner. Sci Rep 2019; 9:17319. [PMID: 31754186 PMCID: PMC6872820 DOI: 10.1038/s41598-019-53944-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Accepted: 10/22/2019] [Indexed: 01/26/2023] Open
Abstract
The Myc gene has been implicated in the pathogenesis of most types of human cancerous tumors. Myc/Max activates large numbers of pro-tumor genes; however it also induces anti-proliferation genes. When anti-proliferation genes are activated by Myc, cancer cells can only survive if they are downregulated. Hepatocellular carcinoma (HCC) specific intronic long noncoding antisense (lnc-AS) RNA, the EVA1A-AS gene, is located within the second intron (I2) of the EVA1A gene (EVA-1 homolog A) that encodes an anti-proliferation factor. Indeed, EVA1A, but not EVA1A-AS, is expressed in normal liver. Depletion of EVA1A-AS suppressed cell proliferation of HepG2 cells by upregulation of EVA1A. Overexpression of EVA1A caused cell death at the G2/M phase via microtubule catastrophe. Furthermore, suppressed EVA1A expression levels are negatively correlated with differentiation grade in 365 primary HCCs, while EVA1A-AS expression levels are positively correlated with patient survival. Notably, both EVA1A and EVA1A-AS were activated by the Myc/Max complex. Eva1A-AS is transcribed in the opposite direction near the 3′splice site of EVA1A I2. The second intron did not splice out in a U2 dependent manner and EVA1A mRNA is not exported. Thus, the Myc/Max dependent anti-proliferating gene, EVA1A, is controlled by Myc/Max dependent anti-sense noncoding RNA for HCC survival.
Collapse
|
6
|
Brunker PAR, Flegel WA. An update on the Scianna blood group system. Immunohematology 2019; 35:48-50. [PMID: 31246487 PMCID: PMC6684214] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
This update of the Scianna blood group system (Brunker PA, Flegel WA. Scianna: the lucky 13th blood group system. Immunohematology 2011;27:41-57) provides the recent work on the genetic variation of ERMAP across more world populations, the elucidation of the molecular basis of an historical serologic case, new cases of antibodies in the system, the development of new serologic reagents, and new discoveries in the biology of the erythroid membrane associated protein (ERMAP). Although genetic variation in ERMAP has been extensively cataloged, nonsynonymous variants associated with alloantigens have remained limited, and no new antigens have been identified. The first case of a severe hemolytic transfusion reaction to anti-Sc2 has recently been reported, highlighting the importance of pursuing the possibility of antibodies to low-prevalence antigens via indirect antiglobulin testing as a routine component of all transfusion reaction investigations. The expanding use of molecular testing in blood centers and transfusion services has uncovered a wider population distribution of Scianna antigens and heightened the awareness of this blood group system. The International Society of Blood Transfusion recognizes seven antigens in the Scianna blood group system 13.
Collapse
Affiliation(s)
- Patricia A R Brunker
- Medical Director, American Red Cross, Biomedical Services, Greater Chesapeake and Potomac Region
| | - Willy A Flegel
- Chief, Laboratory Services Section, DTM/CC/NIH, Bethesda, MD
| |
Collapse
|
7
|
Srivastava K, Wollenberg KR, Flegel WA. The phylogeny of 48 alleles, experimentally verified at 21 kb, and its application to clinical allele detection. J Transl Med 2019; 17:43. [PMID: 30744658 PMCID: PMC6371619 DOI: 10.1186/s12967-019-1791-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2019] [Accepted: 02/04/2019] [Indexed: 01/19/2023] Open
Abstract
Background Sequence information generated from next generation sequencing is often computationally phased using haplotype-phasing algorithms. Utilizing experimentally derived allele or haplotype information improves this prediction, as routinely used in HLA typing. We recently established a large dataset of long ERMAP alleles, which code for protein variants in the Scianna blood group system. We propose the phylogeny of this set of 48 alleles and identify evolutionary steps to derive the observed alleles. Methods The nucleotide sequence of > 21 kb each was used for all physically confirmed 48 ERMAP alleles that we previously published. Full-length sequences were aligned and variant sites were extracted manually. The Bayesian coalescent algorithm implemented in BEAST v1.8.3 was used to estimate a coalescent phylogeny for these variants and the allelic ancestral states at the internal nodes of the phylogeny. Results The phylogenetic analysis allowed us to identify the evolutionary relationships among the 48 ERMAP alleles, predict 4243 potential ancestral alleles and calculate a posterior probability for each of these unobserved alleles. Some of them coincide with observed alleles that are extant in the population. Conclusions Our proposed strategy places known alleles in a phylogenetic framework, allowing us to describe as-yet-undiscovered alleles. In this new approach, which relies heavily on the accuracy of the alleles used for the phylogenetic analysis, an expanded set of predicted alleles can be used to infer alleles when large genotype data are analyzed, as typically generated by high-throughput sequencing. The alleles identified by studies like ours may be utilized in designing of microarray technologies, imputing of genotypes and mapping of next generation sequencing data. Electronic supplementary material The online version of this article (10.1186/s12967-019-1791-9) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Kshitij Srivastava
- Laboratory Services Section, Department of Transfusion Medicine, NIH Clinical Center, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Kurt R Wollenberg
- Bioinformatics and Computational Biosciences Branch, Office of Cyber Infrastructure and Computational Biology, National Institute of Allergy and Infectious Diseases, Bethesda, MD, USA
| | - Willy A Flegel
- Laboratory Services Section, Department of Transfusion Medicine, NIH Clinical Center, National Institutes of Health, Bethesda, MD, 20892, USA.
| |
Collapse
|
8
|
Lemay AS, Tong TN, Branch DR, Huang M, Sumner C, Oldfield L, Hawes J, Cserti-Gazdewich CM, Lau W. The first case of severe acute hemolytic transfusion reaction caused by anti-Sc2. Transfusion 2018; 58:2506-2512. [PMID: 30299537 DOI: 10.1111/trf.14867] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2017] [Revised: 04/28/2018] [Accepted: 05/09/2018] [Indexed: 01/01/2023]
Abstract
BACKGROUND Alloantibodies to the low-frequency antigen Scianna-2 (Sc2) have been implicated in cases of hemolytic disease of the fetus and newborn but never in hemolytic transfusion reactions (HTRs); thus, the clinical significance of anti-Sc2 has yet to be fully addressed. STUDY DESIGN AND METHODS A 26-year-old woman with thalassemia presented rigors, fever, nausea, abdominal pain, and hemolytic biochemistry after exposure to 75 mL of plasma-reduced red blood cells (RBCs). The RBC unit was issued by electronic crossmatch but was 3+ incompatible on recrossmatch by gel indirect antiglobulin test (IAT). The patient had anti-Sc2 previously identified, but considered to be clinically insignificant. The transfusion history was reviewed and a monocyte monolayer assay (MMA) was performed. RESULTS The patient was investigated for a RBC reaction 9 years prior, when she developed symptoms of HTR. The RBC unit was crossmatched by immediate spin due to consistent screen negativity. Full crossmatch found the RBC 1+ incompatible by gel IAT with both pre/post samples, while direct antiglobulin test was negative (pre) and 1+ immunoglobulin G positive (post). The antibody remained unidentified and she was committed to gel IAT crossmatch. Two-years later, the specificity to Sc2 was deduced when one RBC unit was found 3+ incompatible. Finally, the transfusion reaction reported herein occurred when she received by happenstance RBCs from the same donor who was associated with the remote reaction 9 years earlier. MMA yielded highly positive phagocytic indices only for Sc2+ RBCs, including the donor's RBCs that triggered the severe HTR. CONCLUSION This is the first case of HTR caused by anti-Sc2 confirmed by clinical findings and MMA.
Collapse
Affiliation(s)
- Anne-Sophie Lemay
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada
| | - Tik Nga Tong
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada.,the Centre for Innovation, Toronto, Ontario, Canada
| | - Donald R Branch
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada.,the Centre for Innovation, Toronto, Ontario, Canada.,University Health Network, Toronto, Ontario, Canada
| | - Mary Huang
- Diagnostic Services, Canadian Blood Services, Toronto, Ontario, Canada
| | | | - Lynne Oldfield
- Diagnostic Services, Canadian Blood Services, Toronto, Ontario, Canada
| | - Janice Hawes
- University Health Network, Toronto, Ontario, Canada
| | | | - Wendy Lau
- Diagnostic Services, Canadian Blood Services, Toronto, Ontario, Canada.,The Hospital for Sick Children, Toronto, Ontario, Canada
| |
Collapse
|
9
|
Yin Q, Srivastava K, Gebremedhin A, Makuria AT, Flegel WA. Long-range haplotype analysis of the malaria parasite receptor gene ACKR1 in an East-African population. Hum Genome Var 2018; 5:26. [PMID: 30245840 PMCID: PMC6138691 DOI: 10.1038/s41439-018-0024-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Accepted: 07/13/2018] [Indexed: 12/18/2022] Open
Abstract
The human ACKR1 gene encodes a glycoprotein expressing the Duffy blood group antigens (Fy). The Duffy protein acts as a receptor for distinct pro-inflammatory cytokines and malaria parasites. We determined the haplotypes of the ACKR1 gene in a population inhabiting a malaria-endemic area. We collected blood samples from 60 healthy volunteers in Ethiopia’s southwestern low-altitude tropical region. An assay was devised to amplify the ACKR1 gene as a single amplicon and determine its genomic sequence. All haplotypes were resolved at 5178 nucleotides each, covering the coding sequence (CDS) of the ACKR1 gene and including the 5′- and 3′-untranslated regions (UTR), intron 1, and the 5′- and 3′-flanking regions. When necessary, allele-specific PCR with nucleotide sequencing or length polymorphism analysis was applied. Among the 120 chromosomes analyzed, 18 ACKR1 alleles were confirmed without ambiguity. We found 18 single-nucleotide polymorphisms (SNPs); only one SNP was novel. The non-coding sequences harbored 14 SNPs. No SNP, other than c.-67T>C, indicative of a non-functional allele, was detected. We described haplotypes of the ACKR1 gene in an autochthonous East-African population and found 18 distinct ACKR1 alleles. These long-range alleles are useful as templates to phase and analyze next-generation sequencing data, thus enhancing the reliability of clinical diagnostics. Researchers have surveyed genetic diversity related to malaria resistance in a region of Ethiopia where malaria is endemic. Duffy antigens, a component of blood type, are encoded by the ACKR1 gene, and individuals with the Duffy-negative blood type are resistant to malaria. Although the genes encoding resistant types have been identified, they have not been fully surveyed in malaria-endemic regions, where novel types are most likely to be found. Willy Flegel at the National Institutes of Health, Bethesda, USA, and co-workers sequenced ACKR1 in 60 people from Gambela, Ethiopia, where malaria is endemic. They detected 18 variants, including one never before documented. Almost all (16 of 18) of the variants encoded the Duffy-negative blood type. The authors plan to compare the genetic diversity in this region with a nearby region where malaria is not endemic.
Collapse
Affiliation(s)
- Qinan Yin
- 1Department of Transfusion Medicine, NIH Clinical Center, National Institutes of Health, Bethesda, MD USA
| | - Kshitij Srivastava
- 1Department of Transfusion Medicine, NIH Clinical Center, National Institutes of Health, Bethesda, MD USA
| | | | - Addisalem Taye Makuria
- 1Department of Transfusion Medicine, NIH Clinical Center, National Institutes of Health, Bethesda, MD USA.,3U.S. Food and Drug Administration, Silver Spring, MD USA
| | - Willy Albert Flegel
- 1Department of Transfusion Medicine, NIH Clinical Center, National Institutes of Health, Bethesda, MD USA
| |
Collapse
|