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Jáñez Pedrayes A, Rymen D, Ghesquière B, Witters P. Glycosphingolipids in congenital disorders of glycosylation (CDG). Mol Genet Metab 2024; 142:108434. [PMID: 38489976 DOI: 10.1016/j.ymgme.2024.108434] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/19/2024] [Revised: 02/26/2024] [Accepted: 02/27/2024] [Indexed: 03/17/2024]
Abstract
Congenital disorders of glycosylation (CDG) are a large family of rare disorders affecting the different glycosylation pathways. Defective glycosylation can affect any organ, with varying symptoms among the different CDG. Even between individuals with the same CDG there is quite variable severity. Associating specific symptoms to deficiencies of certain glycoproteins or glycolipids is thus a challenging task. In this review, we focus on the glycosphingolipid (GSL) synthesis pathway, which is still rather unexplored in the context of CDG, and outline the functions of the main GSLs, including gangliosides, and their role in the central nervous system. We provide an overview of GSL studies that have been performed in CDG and show that abnormal GSL levels are not only observed in CDG directly affecting GSL synthesis, but also in better known CDG, such as PMM2-CDG. We highlight the importance of studying GSLs in CDG in order to better understand the pathophysiology of these disorders.
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Affiliation(s)
- Andrea Jáñez Pedrayes
- Laboratory of Applied Mass Spectrometry, Department of Cellular and Molecular Medicine, Katholieke Universiteit Leuven, 3000 Leuven, Belgium; Metabolomics Expertise Center, Center for Cancer Biology VIB, 3000 Leuven, Belgium; Department of Development and Regeneration, Katholieke Universiteit Leuven, 3000 Leuven, Belgium.
| | - Daisy Rymen
- Center for Metabolic Diseases, Department of Paediatrics, University Hospitals Leuven, 3000 Leuven, Belgium.
| | - Bart Ghesquière
- Laboratory of Applied Mass Spectrometry, Department of Cellular and Molecular Medicine, Katholieke Universiteit Leuven, 3000 Leuven, Belgium; Metabolomics Expertise Center, Center for Cancer Biology VIB, 3000 Leuven, Belgium.
| | - Peter Witters
- Department of Development and Regeneration, Katholieke Universiteit Leuven, 3000 Leuven, Belgium; Center for Metabolic Diseases, Department of Paediatrics, University Hospitals Leuven, 3000 Leuven, Belgium.
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Mo C, Jia S, Luo G, Ji Y. Identification of a novel A4GALT*299A allele associated with the rare p phenotype in one Chinese family. Transfusion 2024; 64:E13-E15. [PMID: 38501748 DOI: 10.1111/trf.17795] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2023] [Revised: 02/02/2024] [Accepted: 03/08/2024] [Indexed: 03/20/2024]
Affiliation(s)
- Chunyan Mo
- Institute of Clinical Blood Transfusion, Guangzhou Blood Center, Guangzhou, China
| | - Shuangshuang Jia
- Institute of Clinical Blood Transfusion, Guangzhou Blood Center, Guangzhou, China
| | - Guangping Luo
- Institute of Clinical Blood Transfusion, Guangzhou Blood Center, Guangzhou, China
| | - Yanli Ji
- Institute of Clinical Blood Transfusion, Guangzhou Blood Center, Guangzhou, China
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Cui S, Shin YJ, Fang X, Lee H, Eum SH, Ko EJ, Lim SW, Shin E, Lee KI, Lee JY, Lee CB, Bae SK, Yang CW, Chung BH. CRISPR/Cas9-mediated A4GALT suppression rescues Fabry disease phenotypes in a kidney organoid model. Transl Res 2023:S1931-5244(23)00025-7. [PMID: 36805562 DOI: 10.1016/j.trsl.2023.02.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/17/2022] [Revised: 01/28/2023] [Accepted: 02/13/2023] [Indexed: 02/20/2023]
Abstract
The objective of this study was to investigate whether CRISPR/Cas9-mediated suppression of A4GALT could rescue phenotype of Fabry disease nephropathy (FDN) using human induced pluripotent stem cells (hiPSCs) derived kidney organoid system. We generated FDN patient-derived hiPSC (CMC-Fb-002) and FD-specific hiPSCs (GLA-KO) by knock-out (KO) of GLA in wild-type (WT) hiPSCs using CRISPR/Cas9. We then performed A4GALT KO in both CMC-Fb-002 and GLA-KO to make Fb-002-A4GALT-KO and GLA/A4GALT-KO, respectively. Using these hiPSCs, we generated kidney organoids and compared alpha-galactosidase-A enzyme (α-GalA) activity, globotriaosylceramide (Gb-3) deposition, and zebra body formation under electron microscopy (EM). We also compared mRNA expression levels using RNA-seq and qPCR. Generated hiPSCs showed typical pluripotency markers without chromosomal disruption. Expression levels of GLA in CMC-Fb-002 and GLA-KO and expression levels of A4GALT in Fb-002-A4GALT-KO and GLA/A4GALT-KO were successfully decreased compared to those in WT-hiPSCs, respectively. Generated kidney organoids using these hiPSCs expressed typical nephron markers. In CMC-Fb-002 and GLA-KO organoids, α-GalA activity was significantly decreased along with increased deposition of Gb-3 in comparison with WT organoids. Intralysosomal inclusion body was also detected under EM. However, these disease phenotypes were rescued by KO of A4GALT in both GLA/A4GALT-KO and Fb-002-A4GALT-KO kidney organoids. RNA-seq showed increased expression levels of genes related to FDN progression in both GLA-mutant organoids compared to those in WT. Such increases were rescued in GLA/A4GALT-KO or Fb-002-A4GALT-KO organoids. CRISPR/Cas9 mediated suppression of A4GALT could rescue FDN phenotype. Hence, it can be proposed as a therapeutic approach to treat FDN.
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Affiliation(s)
- Sheng Cui
- Transplantation Research Center, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - Yoo Jin Shin
- Transplantation Research Center, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - Xianying Fang
- Transplantation Research Center, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - Hanbi Lee
- Transplantation Research Center, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea; Division of Nephrology, Department of Internal Medicine, Seoul St. Mary's Hospital, The College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - Sang Hun Eum
- Transplantation Research Center, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea; Division of Nephrology, Department of Internal Medicine, Incheon St. Mary's Hospital, The College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - Eun Jeong Ko
- Transplantation Research Center, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea; Division of Nephrology, Department of Internal Medicine, Seoul St. Mary's Hospital, The College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - Sun Woo Lim
- Transplantation Research Center, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | | | | | | | - Chae Bin Lee
- College of Pharmacy and Integrated Research Institute of Pharmaceutical Sciences, The Catholic University of Korea, Bucheon, Republic of Korea
| | - Soo Kyung Bae
- College of Pharmacy and Integrated Research Institute of Pharmaceutical Sciences, The Catholic University of Korea, Bucheon, Republic of Korea
| | - Chul Woo Yang
- Transplantation Research Center, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea; Division of Nephrology, Department of Internal Medicine, Seoul St. Mary's Hospital, The College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - Byung Ha Chung
- Transplantation Research Center, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea; Division of Nephrology, Department of Internal Medicine, Seoul St. Mary's Hospital, The College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea.
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Kok K, Zwiers KC, Boot RG, Overkleeft HS, Aerts JMFG, Artola M. Fabry Disease: Molecular Basis, Pathophysiology, Diagnostics and Potential Therapeutic Directions. Biomolecules 2021; 11:271. [PMID: 33673160 PMCID: PMC7918333 DOI: 10.3390/biom11020271] [Citation(s) in RCA: 50] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 02/05/2021] [Accepted: 02/06/2021] [Indexed: 02/06/2023] Open
Abstract
Fabry disease (FD) is a lysosomal storage disorder (LSD) characterized by the deficiency of α-galactosidase A (α-GalA) and the consequent accumulation of toxic metabolites such as globotriaosylceramide (Gb3) and globotriaosylsphingosine (lysoGb3). Early diagnosis and appropriate timely treatment of FD patients are crucial to prevent tissue damage and organ failure which no treatment can reverse. LSDs might profit from four main therapeutic strategies, but hitherto there is no cure. Among the therapeutic possibilities are intravenous administered enzyme replacement therapy (ERT), oral pharmacological chaperone therapy (PCT) or enzyme stabilizers, substrate reduction therapy (SRT) and the more recent gene/RNA therapy. Unfortunately, FD patients can only benefit from ERT and, since 2016, PCT, both always combined with supportive adjunctive and preventive therapies to clinically manage FD-related chronic renal, cardiac and neurological complications. Gene therapy for FD is currently studied and further strategies such as substrate reduction therapy (SRT) and novel PCTs are under investigation. In this review, we discuss the molecular basis of FD, the pathophysiology and diagnostic procedures, together with the current treatments and potential therapeutic avenues that FD patients could benefit from in the future.
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Affiliation(s)
- Ken Kok
- Department of Medical Biochemistry, Leiden Institute of Chemistry, Leiden University, P.O. Box 9502, 2300 RA Leiden, The Netherlands
| | - Kimberley C Zwiers
- Department of Medical Biochemistry, Leiden Institute of Chemistry, Leiden University, P.O. Box 9502, 2300 RA Leiden, The Netherlands
| | - Rolf G Boot
- Department of Medical Biochemistry, Leiden Institute of Chemistry, Leiden University, P.O. Box 9502, 2300 RA Leiden, The Netherlands
| | - Hermen S Overkleeft
- Department of Bio-organic Synthesis, Leiden Institute of Chemistry, Leiden University, P.O. Box 9502, 2300 RA Leiden, The Netherlands
| | - Johannes M F G Aerts
- Department of Medical Biochemistry, Leiden Institute of Chemistry, Leiden University, P.O. Box 9502, 2300 RA Leiden, The Netherlands
| | - Marta Artola
- Department of Medical Biochemistry, Leiden Institute of Chemistry, Leiden University, P.O. Box 9502, 2300 RA Leiden, The Netherlands
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Shastry S, Satyamoorthy K, Acharya KV, Reddy VR, Mohan G, Deepika C, Reghunathan D, Joshi MB. Deletion in the A4GALT Gene Associated with Rare "P null" Phenotype: The First Report from India. Transfus Med Hemother 2020; 47:186-189. [PMID: 32355479 DOI: 10.1159/000501916] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Accepted: 07/03/2019] [Indexed: 12/22/2022] Open
Abstract
Background The present report illustrates a case with rare "P null" phenotype due to a large deletion in chromosome 22q13.2 and with clinically significant anti-PP1P<sup>k</sup> antibody. Patient blood management in such cases is challenging. Case Report The transfusion center supporting the tertiary care referral center in the southern part of India received a blood sample from a trauma case for pre-transfusion testing. An antibody to a high-frequency blood group antigen was initially suspected. Following extensive immune-hematological workup, the patient was diagnosed to have naturally occurring anti-PP1P<sup>k</sup> antibody and a rare "P null" phenotype. The genomic DNA of the patient was analyzed by exome sequencing followed by Sanger's sequencing. Molecular diagnostics revealed a large 21-bp deletion in chromosome 22q13.2 which encodes the A4GALT gene, resulting in truncation of seven amino acids I245-251P and resulted in rare "P null" phenotype. Patient blood management strategies were adopted to manage the patient conservatively without blood transfusion. Conclusion A large deletion in chromosome 22q13.2 had resulted in a rare "P null" phenotype in the present case. The patient was a victim of a road traffic accident, required emergency hospitalization, as well as surgical intervention, and his plasma had antibodies to high-frequency antigens. A rare donor registry plays a major role in providing transfusion support to such cases.
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Affiliation(s)
- Shamee Shastry
- Department of Immunohematology and Blood Transfusion, Kasturba Medical College, Manipal, India
| | - Kapaettu Satyamoorthy
- Manipal School of Life Sciences, Manipal Academy of Higher Education, Manipal, India
| | - Kiran V Acharya
- Department of Orthopedics, Kasturba Medical College, Manipal Academy of Higher Education, Manipal, India
| | - Vijay Ram Reddy
- Department of Immunohematology and Blood Transfusion, Kasturba Medical College, Manipal, India
| | - Ganesh Mohan
- Department of Immunohematology and Blood Transfusion, Kasturba Medical College, Manipal, India
| | - Chenna Deepika
- Department of Immunohematology and Blood Transfusion, Kasturba Medical College, Manipal, India
| | - Dinesh Reghunathan
- Manipal School of Life Sciences, Manipal Academy of Higher Education, Manipal, India
| | - Manjunath B Joshi
- Manipal School of Life Sciences, Manipal Academy of Higher Education, Manipal, India
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Wu H, Li G, Tang Q, Tian L, Liu Q, Zhou X, He H, Xiong L. The mutation and one-base insertion of the α(1,4)galactosyltransferase gene responsible for the p phenotype. Transfus Clin Biol 2018; 26:358-360. [PMID: 30361135 DOI: 10.1016/j.tracli.2018.08.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Accepted: 08/02/2018] [Indexed: 11/20/2022]
Affiliation(s)
- H Wu
- Institute of Blood Transfusion, Jiangxi Province Blood Center, Nanchang, Jiangxi 330077, People's Republic of China.
| | - G Li
- Institute of Blood Transfusion, Jiangxi Province Blood Center, Nanchang, Jiangxi 330077, People's Republic of China
| | - Q Tang
- Institute of Blood Transfusion, Jiangxi Province Blood Center, Nanchang, Jiangxi 330077, People's Republic of China
| | - L Tian
- Institute of Blood Transfusion, Chinese Academy of Medical Sciences, Chengdu 610052, People's Republic of China
| | - Q Liu
- Institute of Blood Transfusion, Jiangxi Province Blood Center, Nanchang, Jiangxi 330077, People's Republic of China
| | - X Zhou
- Institute of Blood Transfusion, Jiangxi Province Blood Center, Nanchang, Jiangxi 330077, People's Republic of China
| | - H He
- Institute of Blood Transfusion, Jiangxi Province Blood Center, Nanchang, Jiangxi 330077, People's Republic of China
| | - L Xiong
- Institute of Blood Transfusion, Jiangxi Province Blood Center, Nanchang, Jiangxi 330077, People's Republic of China
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Affiliation(s)
- A. K. Hult
- Division of Laboratory Medicine; Clinical Immunology and Transfusion Medicine; Office of Medical Services; Lund Sweden
- Division of Hematology and Transfusion Medicine; Department of Laboratory Medicine; Lund University; Lund Sweden
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Reeves HM, Cary V, Mino MA, McGrath C, Westra JA, Piccone C, Downes KA. Unexpected Non-Maternally Derived Anti-PP1P k in an 11-Week-Old Patient. J Pediatr 2017; 181:302-305. [PMID: 27852457 DOI: 10.1016/j.jpeds.2016.10.042] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2016] [Revised: 07/18/2016] [Accepted: 10/11/2016] [Indexed: 11/16/2022]
Abstract
Alloantibody formation at less than 4 months of age is rare. Most antibodies identified in these patients are maternally derived. Anti-PP1Pk was detected in an 11-week-old infant that was not maternally derived. A multidisciplinary team approach led to appropriate testing, diagnosis, and transfusion management in this critically ill infant.
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Affiliation(s)
- Hollie M Reeves
- Department of Pathology, University Hospitals Cleveland Medical Center, Rainbow Babies and Children's Hospital, Case Western Reserve University School of Medicine, Cleveland, OH.
| | - Victoria Cary
- Department of Pathology, University Hospitals Cleveland Medical Center, Rainbow Babies and Children's Hospital, Case Western Reserve University School of Medicine, Cleveland, OH
| | - Mary Ann Mino
- American Red Cross Northern Ohio Region, Cleveland, OH
| | | | | | - Connie Piccone
- Department of Pediatric Hematology and Oncology, University Hospitals Cleveland Medical Center and Rainbow Babies and Children's Hospital, Case Western Reserve University School of Medicine, Cleveland, OH
| | - Katharine A Downes
- Department of Pathology, University Hospitals Cleveland Medical Center, Rainbow Babies and Children's Hospital, Case Western Reserve University School of Medicine, Cleveland, OH
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Astudillo L, Sabourdy F, Therville N, Bode H, Ségui B, Andrieu-Abadie N, Hornemann T, Levade T. Human genetic disorders of sphingolipid biosynthesis. J Inherit Metab Dis 2015; 38:65-76. [PMID: 25141825 DOI: 10.1007/s10545-014-9736-1] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/06/2014] [Accepted: 06/12/2014] [Indexed: 12/19/2022]
Abstract
Monogenic defects of sphingolipid biosynthesis have been recently identified in human patients. These enzyme deficiencies affect the synthesis of sphingolipid precursors, ceramides or complex glycosphingolipids. They are transmitted as autosomal recessive or dominant traits, and their resulting phenotypes often replicate the abnormalities seen in murine models deficient for the corresponding enzymes. In quite good agreement with the known critical roles of sphingolipids in cells from the nervous system and the epidermis, these genetic defects clinically manifest as neurological disorders, including paraplegia, epilepsy or peripheral neuropathies, or present with ichthyosis. The present review summarizes the genetic alterations, biochemical changes and clinical symptoms of this new group of inherited metabolic disorders. Hypotheses regarding the molecular pathophysiology and potential treatments of these diseases are also discussed.
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Affiliation(s)
- Leonardo Astudillo
- Centre de Recherches en Cancérologie de Toulouse (CRCT), Institut National de la Santé et de la Recherche Médicale (INSERM) UMR1037, Team n 4, CHU Rangueil, BP, 84225, 31432, Toulouse, France
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P1PK, GLOB, and FORS Blood Group Systems and GLOB Collection: Biochemical and Clinical Aspects. Do We Understand It All Yet? Transfus Med Rev 2014; 28:126-36. [DOI: 10.1016/j.tmrv.2014.04.007] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2014] [Revised: 04/15/2014] [Accepted: 04/17/2014] [Indexed: 01/09/2023]
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Westman JS, Hellberg A, Peyrard T, Hustinx H, Thuresson B, Olsson ML. P1/P2 genotyping of known and novel null alleles in the P1PK and GLOB histo-blood group systems. Transfusion 2013; 53:2928-39. [PMID: 23927681 DOI: 10.1111/trf.12355] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2013] [Revised: 05/30/2013] [Accepted: 06/16/2013] [Indexed: 12/14/2022]
Abstract
BACKGROUND The rare but clinically important null phenotypes of the P1PK and GLOB blood group systems are due to alterations in A4GALT and B3GALNT1, respectively. A recently identified single-nucleotide polymorphism in Exon 2a of A4GALT predicts the common P1 and P2 phenotypes but rare variants have not been tested. STUDY DESIGN AND METHODS The aim of this study was to analyze 84 p, P1 (k) , and P2 (k) samples, with special emphasis on unknown alleles and the P(1) /P(2) marker. Of these, 27 samples came from individuals not previously investigated genetically and were therefore subjected to sequencing of A4GALT or B3GALNT1, and a subset was tested by flow cytometry. RESULTS The P(1) /P(2) genotyping linked 20 p-inducing mutations in A4GALT to P(1) or P(2) allelic background. Eight p alleles remain unlinked due to compound heterozygosity. For 23 of 25 P(k) samples, concordant results were observed: P1 (k) samples had at least one P(1) allele while P2 (k) had P(2) only. The two remaining samples typed as P1+ and P1+(w) but were genetically P(2) /P(2) . A tendency toward higher P(k) antigen expression was observed on P1 (k) cells compared to P2 (k) . In total, six previously unknown null mutations were found and characterized in A4GALT while four new changes were revealed in B3GALNT1. CONCLUSION For the first time, p alleles were shown to occur on both P(1) and P(2) allelic backgrounds. Furthermore, P(1) /P(2) genotyping predicted the P1 (k) versus P2 (k) phenotype in more than 90% of globoside-deficient samples. The number of GLOB-null alleles was increased by 50% and several P1PK-null alleles were identified.
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Affiliation(s)
- Julia S Westman
- Division of Hematology and Transfusion Medicine, Department of Laboratory Medicine, Lund University, Lund, Sweden
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Suchanowska A, Kaczmarek R, Duk M, Lukasiewicz J, Smolarek D, Majorczyk E, Jaskiewicz E, Laskowska A, Wasniowska K, Grodecka M, Lisowska E, Czerwinski M. A single point mutation in the gene encoding Gb3/CD77 synthase causes a rare inherited polyagglutination syndrome. J Biol Chem 2012; 287:38220-30. [PMID: 22965229 DOI: 10.1074/jbc.m112.408286] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Rare polyagglutinable NOR erythrocytes contain three unique globoside (Gb4Cer) derivatives, NOR1, NOR(int), and NOR2, in which Gal(α1-4), GalNAc(β1-3)Gal(α1-4), and Gal(α1-4)GalNAc(β1-3)Gal(α1-4), respectively, are linked to the terminal GalNAc residue of Gb4Cer. NOR1 and NOR2, which both terminate with a Gal(α1-4)GalNAc- sequence, react with anti-NOR antibodies commonly present in human sera. While searching for an enzyme responsible for the biosynthesis of Gal(α1-4)GalNAc, we identified a mutation in the A4GALT gene encoding Gb3/CD77 synthase (α1,4-galactosyltransferase). Fourteen NOR-positive donors were heterozygous for the C>G mutation at position 631 of the open reading frame of the A4GALT gene, whereas 495 NOR-negative donors were homozygous for C at this position. The enzyme encoded by the mutated gene contains glutamic acid instead of glutamine at position 211 (substitution Q211E). To determine whether this mutation could change the enzyme specificity, we transfected a teratocarcinoma cell line (2102Ep) with vectors encoding the consensus Gb3/CD77 synthase and Gb3/CD77 synthase with Glu at position 211. The cellular glycolipids produced by these cells were analyzed by flow cytometry, high-performance thin-layer chromatography, enzymatic degradation, and MALDI-TOF mass spectrometry. Cells transfected with either vector expressed the P1 blood group antigen, which was absent from untransfected cells. Cells transfected with the vector encoding the Gb3/CD77 synthase with Glu at position 211 expressed both P1 and NOR antigens. Collectively, these results suggest that the C631G mutation alters the acceptor specificity of Gb3/CD77 synthase, rendering it able to catalyze synthesis of the Gal(α1-4)Gal and Gal(α1-4)GalNAc moieties.
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Affiliation(s)
- Anna Suchanowska
- Laboratory of Glycoconjugate Immunochemistry, Ludwik Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, 53-114 Wrocław, Poland
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Identification of a novel A4GALT exon reveals the genetic basis of the P1/P2 histo-blood groups. Blood 2011; 117:678-87. [DOI: 10.1182/blood-2010-08-301333] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Abstract
The A4GALT locus encodes a glycosyltransferase that synthesizes the terminal Galα1-4Gal of the Pk (Gb3/CD77) glycosphingolipid, important in transfusion medicine, obstetrics, and pathogen susceptibility. Critical nucleotide changes in A4GALT not only abolish Pk formation but also another Galα1-4Gal–defined antigen, P1, which belongs to the only blood group system for which the responsible locus remains undefined. Since known A4GALT polymorphisms do not explain the P1−Pk+ phenotype, P2, we set out to elucidate the genetic basis of P1/P2. Despite marked differences (P1 > P2) in A4GALT transcript levels in blood, luciferase experiments showed no difference between P1/P2-related promoter sequences. Investigation of A4GALT mRNA in cultured human bone marrow cells revealed novel transcripts containing only the noncoding exon 1 and a sequence (here termed exon 2a) from intron 1. These 5′-capped transcripts include poly-A tails and 3 polymorphic sites, one of which was P1/P2-specific among > 200 donors and opens a short reading frame in P2 alleles. We exploited these data to devise the first genotyping assays to predict P1 status. P1/P2 genotypes correlated with both transcript levels and P1/Pk expression on red cells. Thus, P1 zygosity partially explains the well-known interindividual variation in P1 strength. Future investigations need to focus on regulatory mechanisms underlying P1 synthesis.
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Benidt GR, Jaben EA, Winters JL, Stubbs JR. Identification of anti-PP1Pk in a blood donor and her family: A case report following her pregnancy and review. Transfus Apher Sci 2010; 43:369-374. [DOI: 10.1016/j.transci.2010.10.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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15
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Wang YC, Chang CF, Lin HC, Lin KS, Lin KT, Hung CM, Lin TM. Functional characterisation of a complex mutation in the α(1,4)galactosyltransferase gene in Taiwanese individuals with p phenotype. Transfus Med 2010; 21:84-9. [PMID: 21092013 DOI: 10.1111/j.1365-3148.2010.01055.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
BACKGROUND AND OBJECTIVE Individuals with p phenotype lack P1, P(k) and P antigens on red blood cells, presumably as a result of deficiency in the enzyme α(1,4)galactosyltransferase (A4GALT). The aim of this study was to explore the molecular background of a Taiwanese family with p phenotype. MATERIALS AND METHODS Blood samples from two p siblings and seven family members were investigated. The coding region of the A4GALT gene was analysed by polymerase chain reaction and direct sequencing. The wild- and mutant-complementary DNAs (cDNAs) of A4GALT were cloned into an expression vector and transfected to Chinese hamster ovary (CHO) cells. P(k) expression on the transfected cells was analysed by flow cytometry and the activities of A4GALT were measured by high-performance liquid chromatography. RESULTS The two individuals with p phenotype were homozygous for the complex mutation, which was caused by a combined deletion and insertion between nt 418 and 428. No expression of P(k) and no enzyme activity were observed in cells transfected with the mutant construct. CONCLUSION The first case of p phenotype in Taiwan was caused by a non-functional allele resulting from a homozygous complex mutation of A4GALT gene.
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Affiliation(s)
- Y-C Wang
- Kaohsiung Blood Center, Taiwan Blood Services Foundation, Kaohsiung, Taiwan
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Hellberg Å, Chester MA, Olsson ML. Two previously proposed P1/P2-differentiating and nine novel polymorphisms at the A4GALT (Pk) locus do not correlate with the presence of the P1 blood group antigen. BMC Genet 2005; 6:49. [PMID: 16212661 PMCID: PMC1282566 DOI: 10.1186/1471-2156-6-49] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2005] [Accepted: 10/07/2005] [Indexed: 11/24/2022] Open
Abstract
Background The molecular genetics of the P blood group system and the absence of P1 antigen in the p phenotype are still enigmatic. One theory proposes that the same gene encodes for both the P1 and Pk glycosyltransferases, but no polymorphisms in the coding region of the Pk gene explain the P1/P2 phenotypes. We investigated the potential regulatory regions up- and downstream of the A4GALT (Pk) gene exons. Results P1 (n = 18) and P2 (n = 9) samples from donors of mainly Swedish descent were analysed by direct sequencing of PCR-amplified 5'- and 3'-fragments surrounding the Pk coding region. Seventy-eight P1 and P2 samples were investigated with PCR using allele-specific primers (ASP) for two polymorphisms previously proposed as P2-related genetic markers (-551_-550insC, -160A>G). Haplotype analysis of single nucleotide polymorphisms was also performed with PCR-ASP. In ~1.5 kbp of the 3'-untranslated region one new insertion and four new substitutions compared to a GenBank sequence (AL049757) were found. In addition to the polymorphisms at positions -550 and -160, one insertion, two deletions and one substitution were found in ~1.0 kbp of the 5'-upstream region. All 20 P2 samples investigated with PCR-ASP were homozygous for -550insC. However, so were 18 of the 58 P1 samples investigated. Both the 20 P2 and the 18 P1 samples were also homozygous for -160G. Conclusion The proposed P2-specific polymorphisms, -551_-550insC and -160G, found in P2 samples in a Japanese study were found here in homozygous form in both P1 and P2 donors. Since P2 is the null allele in the P blood group system it is difficult to envision how these mutations would cause the P2 phenotype. None of the novel polymorphisms reported in this study correlated with P1/P2 status and the P1/p mystery remains unsolved.
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Affiliation(s)
- Åsa Hellberg
- Division of Hematology and Transfusion Medicine, Department of Laboratory Medicine, Lund University and the Blood Centre, Lund University Hospital, Lund, Sweden
| | - M Alan Chester
- Division of Hematology and Transfusion Medicine, Department of Laboratory Medicine, Lund University and the Blood Centre, Lund University Hospital, Lund, Sweden
| | - Martin L Olsson
- Division of Hematology and Transfusion Medicine, Department of Laboratory Medicine, Lund University and the Blood Centre, Lund University Hospital, Lund, Sweden
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