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Vercellati C, Marcello AP, Fattizzo B, Zaninoni A, Seresini A, Barcellini W, Bianchi P, Fermo E. Effect of primary lesions in cytoskeleton proteins on red cell membrane stability in patients with hereditary spherocytosis. Front Physiol 2022; 13:949044. [PMID: 36035481 PMCID: PMC9413078 DOI: 10.3389/fphys.2022.949044] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Accepted: 07/08/2022] [Indexed: 11/30/2022] Open
Abstract
We investigated by targeted next generation sequencing the genetic bases of hereditary spherocytosis in 25 patients and compared the molecular results with the biochemical lesion of RBC membrane obtained by SDS-PAGE analysis. The HS diagnosis was based on available guidelines for diagnosis of congenital hemolytic anemia, and patients were selected because of atypical clinical presentation or intra-family variability, or because presented discrepancies between laboratory investigation and biochemical findings. In all patients but 5 we identified pathogenic variants in SPTA1, SPTB, ANK1, SLC4A1, EPB42 genes able to justify the clinical phenotype. Interestingly, a correspondence between the biochemical lesion and the molecular defect was identified in only 11/25 cases, mostly with band 3 deficiency due to SLC4A1 mutations. Most of the mutations in SPTB and ANK1 gene didn’t hesitate in abnormalities of RBC membrane protein; conversely, in two cases the molecular lesion didn’t correspond to the biochemical defect, suggesting that a mutation in a specific cytoskeleton protein may result in a more complex RBC membrane damage or suffering. Finally, in two cases the HS diagnosis was maintained despite absence of both protein defect and molecular lesion, basing on clinical and family history, and on presence of clear laboratory markers of HS. The study revealed complex relationships between the primary molecular lesion and the final effect in the RBC membrane cytoskeleton, and further underlines the concept that there is not a unique approach to the diagnosis of HS.
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Affiliation(s)
- Cristina Vercellati
- Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico Milano—UOC Ematologia, UOS Fisiopatologia Delle Anemie, Milan, Italy
| | - Anna Paola Marcello
- Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico Milano—UOC Ematologia, UOS Fisiopatologia Delle Anemie, Milan, Italy
| | - Bruno Fattizzo
- Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico Milano—UOC Ematologia, UOS Fisiopatologia Delle Anemie, Milan, Italy
| | - Anna Zaninoni
- Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico Milano—UOC Ematologia, UOS Fisiopatologia Delle Anemie, Milan, Italy
| | - Agostino Seresini
- Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico Milano—UOC Laboratorio Centrale, UOS Laboratorio Genetica Medica, Milan, Italy
| | - Wilma Barcellini
- Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico Milano—UOC Ematologia, UOS Fisiopatologia Delle Anemie, Milan, Italy
| | - Paola Bianchi
- Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico Milano—UOC Ematologia, UOS Fisiopatologia Delle Anemie, Milan, Italy
- *Correspondence: Paola Bianchi,
| | - Elisa Fermo
- Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico Milano—UOC Ematologia, UOS Fisiopatologia Delle Anemie, Milan, Italy
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Bogusławska DM, Skulski M, Machnicka B, Potoczek S, Kraszewski S, Kuliczkowski K, Sikorski AF. Identification of a Novel Mutation of β-Spectrin in Hereditary Spherocytosis Using Whole Exome Sequencing. Int J Mol Sci 2021; 22:ijms222011007. [PMID: 34681667 PMCID: PMC8540824 DOI: 10.3390/ijms222011007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Revised: 10/05/2021] [Accepted: 10/09/2021] [Indexed: 11/17/2022] Open
Abstract
Hereditary spherocytosis (HS), the most commonly inherited hemolytic anemia in northern Europeans, comprises a group of diseases whose heterogeneous genetic basis results in a variable clinical presentation. High-throughput genome sequencing methods have made a leading contribution to the recent progress in research on and diagnostics of inherited diseases and inspired us to apply whole exome sequencing (WES) to identify potential mutations in HS. The data presented here reveal a novel mutation probably responsible for HS in a single Polish family. Patients with clinical evidence of HS (clinical symptoms, hematological data, and EMA test) were enrolled in the study. The examination of the resulting WES data showed a number of polymorphisms in 71 genes associated with known erythrocyte pathologies (including membranopathies, enzymopathies, and hemoglobinopathies). Only a single SPTB gene variant indicated the possible molecular mechanism of the disease in the studied family. The new missense mutation p.C183Y was identified using WES in the SPTB gene, which is most likely the cause of clinical symptoms typical of hereditary spherocytosis (membranopathy) due to structural and functional impairments of human β-spectrin. This mutation allows for a better understanding of the molecular mechanism(s) of one of the membranopathies, hereditary spherocytosis.
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Affiliation(s)
- Dżamila M. Bogusławska
- Department of Biotechnology, Institute of Biological Sciences, University of Zielona Góra, Prof. Szafrana St. 1, 65-516 Zielona Góra, Poland; (D.M.B.); (B.M.)
| | - Michał Skulski
- Department of Cytobiochemistry, Faculty of Biotechnology, University of Wrocław, ul. Fryderyka Joliot-Curie 14a, 50-383 Wrocław, Poland;
| | - Beata Machnicka
- Department of Biotechnology, Institute of Biological Sciences, University of Zielona Góra, Prof. Szafrana St. 1, 65-516 Zielona Góra, Poland; (D.M.B.); (B.M.)
| | - Stanisław Potoczek
- Department and Clinic of Haematology, Blood Neoplasms, and Bone Marrow Transplantation, Wroclaw Medical University, Wybrzeże L. Pasteura 4, 50-367 Wroclaw, Poland;
| | - Sebastian Kraszewski
- Department of Biomedical Engineering, Wrocław University of Science and Technology, Plac Grunwaldzki 13 (D-1), 50-377 Wrocław, Poland;
| | - Kazimierz Kuliczkowski
- Silesian Park of Medical Technology Kardio-Med Silesia, ul. M. Curie-Skłodowskiej 10c, 41-800 Zabrze, Poland;
| | - Aleksander F. Sikorski
- Research and Development Centre, Regional Specialist Hospital, Kamieńskiego 73a, 51-154 Wroclaw, Poland
- Correspondence: ; Tel.: +48-71-327-05-16; Fax: +48-71-375-62-08
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Luo Y, Li Z, Huang L, Tian J, Xiong M, Yang Z. Spectrum of Ankyrin Mutations in Hereditary Spherocytosis: A Case Report and Review of the Literature. Acta Haematol 2018; 140:77-86. [PMID: 30227413 DOI: 10.1159/000492024] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Accepted: 07/06/2018] [Indexed: 12/15/2022]
Abstract
BACKGROUND/AIMS Hereditary spherocytosis (HS) is a common pediatric hemolytic anemia caused by congenital red blood cell defects. HS due to ankyrin 1 (ANK1) mutations is the most common type. We explored an ANK1 mutation from an HS patient and reviewed the literature. METHODS We detected the mutation in a Chinese family in which 2 members were diagnosed with HS by next-generation sequencing. The proband was diagnosed with HS in the newborn period, based on clinical manifestations, laboratory data, and family history. The mutation spectrum of the ANK1 gene was summarized based on 85 patients diagnosed with HS carrying ANK1 mutations, and the ANK1 mutation spectrum was summarized and analyzed. RESULTS We identified a novel mutation affecting ANK1 gene splicing (a splicing mutation) in both the patient and her mother, which is a substitution of T>G 2 nt after exon 25 in intron 26. The study expands our knowledge of the ANK1 gene mutation spectrum, providing a molecular basis for HS. CONCLUSION A novel ANK1 mutation (NM_000037.3, c.2960+2T>G, intron 26) that is potentially associated with HS was identified. To date, 80 ANK1 mutations have been reported to be associated with HS in humans.
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Affiliation(s)
- Yeping Luo
- Department of Pediatrics, Third Xiangya Hospital of Central South University, Changsha, China
| | - Zhuoying Li
- Department of Pediatrics, Third Xiangya Hospital of Central South University, Changsha, China
| | - Lihua Huang
- Center for Medical Experiments, Third Xiangya Hospital of Central South University, Changsha, China
| | - Jing Tian
- Department of Pediatrics, Third Xiangya Hospital of Central South University, Changsha, China
| | - Menglong Xiong
- Department of Pediatrics, Third Xiangya Hospital of Central South University, Changsha, China
| | - Zuocheng Yang
- Department of Pediatrics, Third Xiangya Hospital of Central South University, Changsha, China
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Guan H, Liang X, Zhang R, Wang H, Liu W, Zhang R, Yang J, Liu S. Identification of a de novo ANK1 mutation in a Chinese family with hereditary spherocytosis. Hematology 2017; 23:357-361. [PMID: 29099659 DOI: 10.1080/10245332.2017.1398210] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
Affiliation(s)
- Hongzai Guan
- Department of Clinical Hematology, The Medical College of Qingdao University, Qingdao, People’s Republic of China
| | - Xinping Liang
- Department of Clinical Hematology, The Medical College of Qingdao University, Qingdao, People’s Republic of China
| | - Rong Zhang
- Department of Clinical Laboratory, The Qingdao Central Hospital, Qingdao, People’s Republic of China
| | - Haiyan Wang
- Department of Blood Transfusion, The Affiliated Hospital of Qingdao University, Qingdao, People’s Republic of China
| | - Wenmiao Liu
- Prenatal Diagnosis Center, The Affiliated Hospital of Qingdao University, Qingdao, People’s Republic of China
| | - Ru Zhang
- Prenatal Diagnosis Center, The Affiliated Hospital of Qingdao University, Qingdao, People’s Republic of China
| | - Jie Yang
- Department of Hematology, The Affiliated Hospital of Qingdao University, Qingdao, People’s Republic of China
| | - Shiguo Liu
- Prenatal Diagnosis Center, The Affiliated Hospital of Qingdao University, Qingdao, People’s Republic of China
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Satchwell TJ, Bell AJ, Hawley BR, Pellegrin S, Mordue KE, van Deursen CTBM, Braak NHT, Huls G, Leers MPG, Overwater E, Tamminga RYJ, van der Zwaag B, Fermo E, Bianchi P, van Wijk R, Toye AM. Severe Ankyrin-R deficiency results in impaired surface retention and lysosomal degradation of RhAG in human erythroblasts. Haematologica 2016; 101:1018-27. [PMID: 27247322 DOI: 10.3324/haematol.2016.146209] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2016] [Accepted: 05/25/2016] [Indexed: 11/09/2022] Open
Abstract
Ankyrin-R provides a key link between band 3 and the spectrin cytoskeleton that helps to maintain the highly specialized erythrocyte biconcave shape. Ankyrin deficiency results in fragile spherocytic erythrocytes with reduced band 3 and protein 4.2 expression. We use in vitro differentiation of erythroblasts transduced with shRNAs targeting ANK1 to generate erythroblasts and reticulocytes with a novel ankyrin-R 'near null' human phenotype with less than 5% of normal ankyrin expression. Using this model, we demonstrate that absence of ankyrin negatively impacts the reticulocyte expression of a variety of proteins, including band 3, glycophorin A, spectrin, adducin and, more strikingly, protein 4.2, CD44, CD47 and Rh/RhAG. Loss of band 3, which fails to form tetrameric complexes in the absence of ankyrin, alongside GPA, occurs due to reduced retention within the reticulocyte membrane during erythroblast enucleation. However, loss of RhAG is temporally and mechanistically distinct, occurring predominantly as a result of instability at the plasma membrane and lysosomal degradation prior to enucleation. Loss of Rh/RhAG was identified as common to erythrocytes with naturally occurring ankyrin deficiency and demonstrated to occur prior to enucleation in cultures of erythroblasts from a hereditary spherocytosis patient with severe ankyrin deficiency but not in those exhibiting milder reductions in expression. The identification of prominently reduced surface expression of Rh/RhAG in combination with direct evaluation of ankyrin expression using flow cytometry provides an efficient and rapid approach for the categorization of hereditary spherocytosis arising from ankyrin deficiency.
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Affiliation(s)
- Timothy J Satchwell
- School of Biochemistry, University of Bristol, UK National Institute for Health Research Blood and Transplant Research Unit (NIHR BTRU) in Red Blood Cell Products, University of Bristol, UK
| | | | - Bethan R Hawley
- School of Biochemistry, University of Bristol, UK National Institute for Health Research Blood and Transplant Research Unit (NIHR BTRU) in Red Blood Cell Products, University of Bristol, UK
| | - Stephanie Pellegrin
- School of Biochemistry, University of Bristol, UK National Institute for Health Research Blood and Transplant Research Unit (NIHR BTRU) in Red Blood Cell Products, University of Bristol, UK
| | - Kathryn E Mordue
- School of Biochemistry, University of Bristol, UK National Institute for Health Research Blood and Transplant Research Unit (NIHR BTRU) in Red Blood Cell Products, University of Bristol, UK
| | | | | | - Gerwin Huls
- Department of Hematology, University Medical Center Groningen, The Netherlands
| | - Mathie P G Leers
- Department of Clinical Chemistry and Hematology, Atrium Medical Center Parkstad, Heerlen, The Netherlands
| | - Eline Overwater
- Department of Clinical Genetics, VU University Medical Center, and Department of Clinical Genetics, Academic Medical Center, Amsterdam, The Netherlands
| | - Rienk Y J Tamminga
- Department of Pediatric Hematology, Beatrix Childrens Hospital, University Medical Center Groningen, The Netherlands
| | - Bert van der Zwaag
- Department of Medical Genetics, University Medical Center Utrecht, The Netherlands
| | - Elisa Fermo
- Oncohematology Unit - Physiopathology of Anemias Unit, Foundation IRCCS Cà Granda, Ospedale Maggiore Policlinico, Milan, Italy
| | - Paola Bianchi
- Oncohematology Unit - Physiopathology of Anemias Unit, Foundation IRCCS Cà Granda, Ospedale Maggiore Policlinico, Milan, Italy
| | - Richard van Wijk
- Department of Clinical Chemistry and Haematology, Laboratory for Red Blood Cell Research, University Medical Center Utrecht, The Netherlands
| | - Ashley M Toye
- School of Biochemistry, University of Bristol, UK National Institute for Health Research Blood and Transplant Research Unit (NIHR BTRU) in Red Blood Cell Products, University of Bristol, UK
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6
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Park J, Jeong DC, Yoo J, Jang W, Chae H, Kim J, Kwon A, Choi H, Lee JW, Chung NG, Kim M, Kim Y. Mutational characteristics of ANK1 and SPTB genes in hereditary spherocytosis. Clin Genet 2016; 90:69-78. [PMID: 26830532 DOI: 10.1111/cge.12749] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2015] [Revised: 01/04/2016] [Accepted: 01/25/2016] [Indexed: 12/18/2022]
Abstract
The aim of this study was to describe the mutational characteristics in Korean hereditary spherocytosis (HS) patients. Relevant literatures including genetically confirmed cases with well-documented clinical summaries and relevant information were also reviewed to investigate the mutational gene- or domain-specific laboratory and clinical association. Twenty-five HS patients carried one heterozygous mutation of ANK1 (n = 13) or SPTB (n = 12) but not in SPTA1, SLC4A1, or EPB42. Deleterious mutations including frameshift, nonsense, and splice site mutations were identified in 91% (21/23), and non-hotspot mutations were dispersed across multiple exons. Genotype-phenotype correlation was clarified after combined analysis of the cases and the literature review; anemia was most severe in HS patients with mutations on the ANK1 spectrin-binding domain (p < 0.05), and SPTB mutations in HS patients spared the tetramerization domain in which mutations of hereditary elliptocytosis and pyropoikilocytosis are located. Splenectomy (17/75) was more frequent in ANK1 mutant HS (32%) than in HS with SPTB mutation (10%) (p = 0.028). Aplastic crisis occurred in 32.0% of the patients (8/25; 3 ANK1 and 5 SPTB), and parvovirus B19 was detected in 88%. The study clarifies ANK1 or SPTB mutational characteristics in HS Korean patients. The genetic association of laboratory and clinical aspects suggests comprehensive considerations for genetic-based management of HS.
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Affiliation(s)
- J Park
- Department of Laboratory Medicine, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea.,Catholic Genetic Laboratory Center, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - D-C Jeong
- Department of Pediatrics, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea.,The Vaccine Bio Research Institute, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - J Yoo
- Department of Laboratory Medicine, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea.,Catholic Genetic Laboratory Center, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - W Jang
- Catholic Genetic Laboratory Center, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea.,Division of Laboratory Medicine, Samkwang Medical Laboratories, Seoul, Republic of Korea
| | - H Chae
- Department of Laboratory Medicine, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea.,Catholic Genetic Laboratory Center, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - J Kim
- Catholic Genetic Laboratory Center, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - A Kwon
- Catholic Genetic Laboratory Center, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - H Choi
- Catholic Genetic Laboratory Center, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - J W Lee
- Department of Pediatrics, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - N-G Chung
- Department of Pediatrics, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - M Kim
- Department of Laboratory Medicine, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea.,Catholic Genetic Laboratory Center, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - Y Kim
- Department of Laboratory Medicine, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea.,Catholic Genetic Laboratory Center, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
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7
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Han JH, Kim S, Jang H, Kim SW, Lee MG, Koh H, Lee JH. Identification of a novel p.Q1772X ANK1 mutation in a Korean family with hereditary spherocytosis. PLoS One 2015; 10:e0131251. [PMID: 26107955 PMCID: PMC4480973 DOI: 10.1371/journal.pone.0131251] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2014] [Accepted: 05/31/2015] [Indexed: 12/13/2022] Open
Abstract
Hereditary spherocytosis (HS), a common form of inherited hemolytic anemia, is a heterogeneous group of disorders with regard to clinical severity, protein defects, and mode of inheritance. Causal mutations in at least five genes have been reported so far. Because multiple genes have been associated with HS, clinical genetic testing that relies on direct sequencing will be a challenge. In this study, we used whole exome sequencing to identify a novel nonsense mutation in ANK1 (p.Q1772X, NM_020476) that resulted in a truncated protein in a Korean patient with HS. Sanger sequencing confirmed the two affected individuals in the patient's family were heterozygous for the mutation. This is the first report of a Korean family that carries an ANK1 mutation responsible for HS. Our results demonstrate that next generation sequencing is a powerful approach for rapidly determining the genetic etiology of HS.
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Affiliation(s)
| | - Seung Kim
- Department of Pediatrics, Severance Children’s Hospital, Yonsei University College of Medicine, Seoul, Korea
| | - Hoon Jang
- Department of Chemistry, Yonsei University, Seoul, Korea
| | - So Won Kim
- Department of Pharmacology and PharmacoGenomics Research Center, Inje University College of Medicine, Busan, Korea
- Department of Clinical Pharmacology, Inje University, Busan Paik Hospital, Busan, Korea
| | - Min Goo Lee
- Department of Pharmacology, Pharmacogenomic Research Center for Membrane Transporters, Brain Korea 21 PLUS Project for Medical Sciences, Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul, Korea
| | - Hong Koh
- Department of Pediatrics, Severance Children’s Hospital, Yonsei University College of Medicine, Seoul, Korea
- * E-mail: (JHL); (HK)
| | - Ji Hyun Lee
- Department of Oral Biology, Yonsei University College of Dentistry, Seoul, Korea
- * E-mail: (JHL); (HK)
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8
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Gallagher PG. Hematologically important mutations: Ankyrin variants in hereditary spherocytosis. Blood Cells Mol Dis 2005; 35:345-7. [PMID: 16223590 DOI: 10.1016/j.bcmd.2005.08.008] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2005] [Accepted: 08/30/2005] [Indexed: 11/28/2022]
Abstract
The primary defect in the hereditary spherocytosis (HS) syndromes is a qualitative or quantitative alteration in one or more erythrocyte membrane proteins. Mutation of the erythrocyte membrane protein ankyrin are the most common cause of typical, dominant HS. Ankyrin mutations also cause nondominant spherocytosis due to ankyrin gene promoter or de novo mutations. In most cases, HS-related ankyrin mutations are private. A summary of reported HS-associated ankyrin gene mutations is provided in this report.
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Affiliation(s)
- Patrick G Gallagher
- Department of Pediatrics, Yale University School of Medicine, 333 Cedar Street, P.O. Box 208064, New Haven, CT 06520-8064, USA.
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Eber S, Lux SE. Hereditary spherocytosis—defects in proteins that connect the membrane skeleton to the lipid bilayer. Semin Hematol 2004; 41:118-41. [PMID: 15071790 DOI: 10.1053/j.seminhematol.2004.01.002] [Citation(s) in RCA: 185] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The molecular causes of hereditary spherocytosis (HS) have been unraveled in the past decade. No frequent defect is found, and nearly every family has a unique mutation. In dominant HS, nonsense and frameshift mutations of ankyrin, band 3, and beta-spectrin predominate. Recessive HS is most often due to compound heterozygosity of defects in ankyrin, alpha-spectrin, or protein 4.2. Common combinations include a defect in the promoter or 5'-untranslated region of ankyrin paired with a missense mutation, a low expression allele of alpha-spectrin plus a missense mutation, and various mutations in the gene for protein 4.2. In most patients' red cells, no abnormal protein is present. Only rare missense mutations, like ankyrin Walsrode (V463I) or beta-spectrin Kissimmee (W202R), have given any insight into the functional domains of the respective proteins. Although the eminent role of the spleen in the premature hemolysis of red cells in HS is unquestioned, the molecular events that cause splenic conditioning of spherocytes are unclear. Electron micrographs show that small membrane vesicles are shed during the formation of spherocytes. Animal models give further insight into the pathogenetic consequences of membrane protein defects as well as the causes of the variability of disease severity.
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Affiliation(s)
- Stefan Eber
- Division of Hematology/Oncology, Children's Hospital-Boston, Harvard Medical School, Boston, MA, USA.
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10
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Miraglia del Giudice E, Nobili B, Francese M, D'Urso L, Iolascon A, Eber S, Perrotta S. Clinical and molecular evaluation of non-dominant hereditary spherocytosis. Br J Haematol 2001; 112:42-7. [PMID: 11167781 DOI: 10.1046/j.1365-2141.2001.02501.x] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
About 75% of hereditary spherocytosis (HS) patients have the autosomal dominant form of the disease, whereas both parents of the remaining HS patients are clinically and haematologically normal. These patients could have either the autosomal recessive form of the disease or a de novo mutation. We studied 80 randomly chosen, Italian HS children with normal parents. They had different clinical phenotypes (16 mild, 40 moderate, 16 moderately severe and eight severe). These patients were screened for the occurrence of ankyrin or beta-spectrin de novo mutations. To search for ankyrin de novo mutations affecting mRNA accumulation, we studied a (AC)(n) microsatellite located in the non-coding sequence of the last exon of the ankyrin gene, and four different exonic polymorphisms in the beta-spectrin gene were utilized for the detection of de novo mutations influencing beta-spectrin mRNA stability. They were also screened for the presence of alpha-spectrin(LEPRA) as well as for the mutation -108T-->C in the ankyrin promoter, two variants previously found in some cases of genuinely recessive HS. Twenty-five patients showed ankyrin de novo mutations and 10 HS subjects had beta-spectrin de novo mutations. Furthermore, we found five patients to be heterozygous for alpha-spectrin(LEPRA) and one heterozygous for the mutation in the ankyrin promoter. Therefore, a molecular diagnosis was achieved in about 50% of the cases. Our data demonstrate that, among HS patients with normal parents, de novo dominant mutants are six times more common than recessive mutations. These results should be considered in view of the genetic counselling of a normal couple with a HS child.
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11
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Dooner GJ, Barker JE, Gallagher PG, Debatis ME, Brown AH, Forget BG, Becker PS. Gene transfer to ankyrin-deficient bone marrow corrects spherocytosis in vitro. Exp Hematol 2000; 28:765-74. [PMID: 10907638 DOI: 10.1016/s0301-472x(00)00185-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
OBJECTIVE The goal of this study was to transfer by retroviral vector the cDNA for ankyrin to progenitors from normal bone marrow and from the nb/nb spherocytosis mutant deficient in expression of full-length ankyrin to achieve erythroid expression of functional ankyrin protein. MATERIALS AND METHODS A minigene composed of the human ankyrin promoter, murine ankyrin cDNA, and the 3' human domain corresponding to the ankyrin 2.2 isoform was assembled in the retroviral vector, pG1. Murine erythroleukemia (MEL) cells, normal murine bone marrow cells, 3T3 fibroblasts, and nb/nb mutant bone marrow and spleen cells were transduced with the retroviral supernatant. Transduced mutant cells were induced to differentiate in liquid culture. Gene transfer was assessed by colony polymerase chain reaction (PCR) and reverse transcriptase (RT)-PCR, immunofluorescence, and Southern, Northern, and Western blot analysis. RESULTS MEL cells, normal bone marrow progenitors, and nb/nb cells were all successfully transduced and expressed ankyrin by RT-PCR and Western blot. Transduced murine 3T3 fibroblasts and MEL cells exhibited cell membrane staining by immunofluorescence. Colony RT-PCR demonstrated dependence of expression on erythropoietin. In vitro, the transduced nb/nb cells matured to polychromatophils, whereas nontransduced nb/nb cells matured to microspherocytes. CONCLUSION Retroviral transfer of ankyrin corrected the defect leading to formation of microspherocytes in erythroid differentiation cultures from the nb/nb mutant. The human ankyrin promoter conferred erythropoietin-dependent expression in normal and mutant erythroid progenitors, which could have implications for the gene therapy of human hemolytic anemias.
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Affiliation(s)
- G J Dooner
- Cancer Center and Gene Therapy Link Laboratory, University of Massachusetts Medical School, Worcester, USA
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12
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Abstract
The recent discovery of the specific molecular defects in many patients with hereditary spherocytosis and hereditary elliptocytosis/pyropoikilocytosis partially clarifies the molecular pathology of these diseases. HE and HPP are caused by defects in the horizontal interactions that hold the membrane skeleton together, particularly the critical spectrin self-association reaction. Single gene defects cause red cells to elongate as they circulate, by a unknown mechanism, and are clinically harmless. The combination of two defective genes or one severe alpha spectrin defect and a thalassaemia-like defect in the opposite allele (alphaLELY) results in fragile cells that fragment into bizarre shapes in the circulation, with haemolysis and sometimes life-threatening anaemia. A few of the alpha spectrin defects are common, suggesting they provide an advantage against malaria or some other threat. HS, in contrast, is nearly always caused by family-specific private mutations. These involve the five proteins that link the membrane skeleton to the overlying lipid bilayer: alpha and beta spectrin, ankyrin, band 3 and protein 4.2. Somehow, perhaps through loss of the anchorage band 3 provides its lipid neighbours (Peters et al, 1996), microvesiculation of the membrane surface ensues, leading to spherocytosis, splenic sequestration and haemolysis. Future research will need to focus on how each type of defect causes its associated disease, how the spleen aggravates membrane skeleton defects (a process termed 'conditioning'), how defective red, cells are recognized and removed in the spleen, and why patients with similar or even identical defects can have different clinical severity. Emphasis also needs to be given to improving diagnostic tests, particularly for HS, and exploring new options for therapy, like partial splenectomy, which can ameliorate symptoms while better protecting patients from bacterial sepsis and red cell parasites, and perhaps from atherosclerosis (Robinette & Franmeni, 1977) and venous thrombosis (Stewart et al, 1996).
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Affiliation(s)
- W T Tse
- Division of Hematology/Oncology, Children's Hospital and Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts 02115, USA
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13
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Gallagher PG, Forget BG. Hematologically important mutations: spectrin and ankyrin variants in hereditary spherocytosis. Blood Cells Mol Dis 1998; 24:539-43. [PMID: 9887280 DOI: 10.1006/bcmd.1998.0217] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- P G Gallagher
- Department of Pediatrics, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520-8064, USA
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Abstract
Some genes that contain premature nonsense codons express alternatively-spliced mRNA that has skipped the exon containing the nonsense codon. This paradoxical association of translation signals (nonsense codons) and RNA splicing has inspired numerous explanations. The first is based on the fact that premature nonsense codons often reduce mRNA abundance. The reduction in abundance of full-length mRNA then allows more efficient amplification during PCR of normal, minor, exon-deleted products. This mechanism has been demonstrated to explain an extensive correlation between nonsense codons and exon-skipping for the hamster Hprt gene. The second explanation is that the mutation producing an in-frame nonsense codon has an effect on exon definition. This has been demonstrated for the Mup and hamster Hprt gene by virtue of the fact that missense mutations at the same sites also are associated with the same exon-deleted mRNA. The third general explanation is that a hypothetical process takes place in the nucleus that recognizes nonsense codons, termed 'nuclear scanning', which then has an effect on mRNA splicing. Definitive evidence for nuclear scanning is lacking. My analysis of both nonsense and missense mutations associated with exon skipping in a large number of genes revealed that both types of mutations frequently introduce a T into a purine-rich DNA sequence and are often within 30 base pairs of the nearest exon boundary. This is intriguing given that purine-rich splicing enhancers are known to be inhibited by the introduction of a T. Almost all mutations associated with exon skipping occur in purine-rich or A/C-rich sequences, also characteristics of splicing enhancers. I conclude that most cases of exon skipping associated with premature termination codons may be adequately explained either by a structural effect on exon definition or by nonquantitative methods to measure mRNA, rather than an effect on a putative nuclear scanning mechanism.
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Affiliation(s)
- C R Valentine
- Division of Genetic and Reproductive Toxicology, National Center for Toxicological Research, Jefferson, AR 72079-9502, USA.
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Hayette S, Carré G, Bozon M, Alloisio N, Maillet P, Wilmotte R, Pascal O, Reynaud J, Reman O, Stéphan JL, Morlé L, Delaunay J. Two distinct truncated variants of ankyrin associated with hereditary spherocytosis. Am J Hematol 1998; 58:36-41. [PMID: 9590147 DOI: 10.1002/(sici)1096-8652(199805)58:1<36::aid-ajh7>3.0.co;2-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
We present two distinct truncated variants of ankyrin associated with mild to moderate hereditary spherocytosis. Ankyrin Saint-Etienne 1 was manifested by an additional band located between bands 2.1 and 2.2. It was associated with a nonsense mutation in exon 39: TGG-->TGA; W1721X. Ankyrin Saint-Etienne 2 appeared as two faint bands underlining bands 2.1 and 2.2. It was associated with a nonsense mutation in exon 41: CGA-->TGA; R1833X. Overall ankyrin was diminished in splenectomized patients. Messenger RNAs Saint-Etienne 1 and 2 amounted to 20 and 37% of the total ankyrin mRNA, respectively. Ankyrin molecules truncated in their C-terminal region retain some ability to bind to the membrane whereas the bulk of nonsense mutations, located in more upstream regions, result in the mere disappearance of one haploid set of ankyrin. In the present cases, it was not possible to apportion the roles of ankyrin reduction and truncation in the pathogenesis of hereditary spherocytosis.
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Affiliation(s)
- S Hayette
- Laboratoire de Génétique Moléculaire Humaine, CNRS URA 1171, Institut Pasteur de Lyon, France
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Miraglia del Giudice E, Francese M, Nobili B, Morlé L, Cutillo S, Delaunay J, Perrotta S. High frequency of de novo mutations in ankyrin gene (ANK1) in children with hereditary spherocytosis. J Pediatr 1998; 132:117-20. [PMID: 9470011 DOI: 10.1016/s0022-3476(98)70495-0] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
OBJECTIVE To evaluate the frequency of de novo monoallelic expression of the ANK1 gene in hereditary spherocytosis individuals appearing as recessive. STUDY DESIGN We studied 40 unrelated children with spherocytosis and their normal parents. The genomic distribution of the ankyrin (AC)n dinucleotide repeats was evaluated in the patients showing combined ankyrin and spectrin deficiency. To search for the absence of mRNA derived from one of the two ANK1 genes, cDNA from the heterozygous patients was amplified using polymerase chain reaction. This was analyzed for the (AC)n dinucleotide repeats. RESULTS Thirty-three hereditary spherocytosis subjects had variable degrees of combined ankyrin and spectrin reduction; 19 were found to be heterozygous for the AC repeat lengths and were further studied. In 12, we found a cDNA polymerase chain reaction product from one ankyrin gene alone. These findings strongly suggested the nonexpression of one of the two ANK1 genes because of the de novo mutational events. CONCLUSION The de novo loss of an ankyrin allele expression is a frequent cause of hereditary spherocytosis in children with normal parents. Therefore the category of genuinely recessive hereditary spherocytosis cases is further reduced compared with spherocytosis cases because of de novo mutations. The determination of the (AC)n microsatellite polymorphisms appears as a helpful and reliable tool for the discrimination between these two categories.
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Gallagher PG, Tse WT, Scarpa AL, Lux SE, Forget BG. Structure and organization of the human ankyrin-1 gene. Basis for complexity of pre-mRNA processing. J Biol Chem 1997; 272:19220-8. [PMID: 9235914 DOI: 10.1074/jbc.272.31.19220] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Ankyrin-1 (ANK-1) is an erythrocyte membrane protein that is defective in many patients with hereditary spherocytosis, a common hemolytic anemia. In the red cell, ankyrin-1 provides the primary linkage between the membrane skeleton and the plasma membrane. To gain additional insight into the structure and function of this protein and to provide the necessary tools for further genetic studies of hereditary spherocytosis patients, we cloned the human ANK-1 chromosomal gene. Characterization of the ANK-1 gene genomic structure revealed that the erythroid transcript is composed of 42 exons distributed over approximately 160 kilobase pairs of DNA. Comparison of the genomic structure with the protein domains reveals a near-absolute correlation between the tandem repeats encoding the membrane-binding domain of ankyrin with the location of the intron/exon boundaries in the corresponding part of the gene. Erythroid stage-specific, complex patterns of alternative splicing were identified in the region encoding the regulatory domain of ankyrin-1. Novel brain-specific transcripts were also identified in this region, as well as in the "hinge" region between the membrane-binding and spectrin-binding domains. Utilization of alternative polyadenylation signals was found to be the basis for the previously described, stage-specific 9.0- and 7.2-kilobase pair transcripts of the ANK-1 gene.
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Affiliation(s)
- P G Gallagher
- Department of Pediatrics, Yale University School of Medicine, New Haven, Connecticut 06510, USA.
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18
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Morlé L, Bozon M, Alloisio N, Vallier A, Hayette S, Pascal O, Monier D, Philippe N, Forget BG, Delaunay J. Ankyrin Bugey: a de novo deletional frameshift variant in exon 6 of the ankyrin gene associated with spherocytosis. Am J Hematol 1997; 54:242-8. [PMID: 9067504 DOI: 10.1002/(sici)1096-8652(199703)54:3<242::aid-ajh11>3.0.co;2-f] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
We describe a case of spherocytosis in a French child splenectomized at age 10 years. The parents were devoid of any clinical, hematological, or biochemical abnormalities. Following splenectomy, the proposita exhibited a reduction of red cell membrane ankyrin. The variable number of dinucleotide repeats associated with the erythroid ankyrin gene (ANK1) were studied at the genomic level. The father, the mother, and the proposita had the AC14/AC11, AC14/AC14, and AC14/AC11 genotypes, respectively, although the proposita exhibited a pattern consistent with an AC14,-combination at the cDNA level. We thought there could be a de novo mutation in the ANK1 allele of paternal origin (AC11). A false paternity seemed most unlikely. Based on PCR-amplification of exons, SSCP analysis, and, when appropriate, nucleotide sequencing, we found a one-nucleotide deletion in codon 146 (exon 6): 521delC, ACG-->AG. This placed in phase a TAG triplet normally overlapping codons 150 and 151. Early interruption of translation presumably accounted for the premature degradation of mutant mRNA. Restriction analysis confirmed the presence of the mutation in the proposita and its absence in the parents. The variant was designated ankyrin Bugey.
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Affiliation(s)
- L Morlé
- Laboratoire de Génétique Moleculaire Humaine, CNRS URA 1171, InstitutPasteur de Lyon, France
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Stoya G, Baumann E, Junker U, Hermann J, Linss W. Flow cytometric analysis of band 3 protein of human erythrocytes. Acta Histochem 1997; 99:29-36. [PMID: 9150794 DOI: 10.1016/s0065-1281(97)80005-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Flow cytometry was used to quantify the transmembrane anion exchanger (band 3 protein) of human erythrocytes by covalently bound eosin-5-maleimide. In vitro and in vivo vesiculated red blood cells were investigated. The fluorescence and light scatter signals of cells after heat induced vesiculation, in vivo ageing, and in patients with hereditary spherocytosis were decreased. These results reflect a deficiency of band 3 protein which is presumably caused by membrane surface area loss. It was possible to distinguish control erythrocytes, erythrocytes from patients with hereditary spherocytosis, and from other forms of haemolytic anaemias on the basis of their light scatter and fluorescence signals characteristics.
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Affiliation(s)
- G Stoya
- Institute of Anatomy I, Friedrich Schiller University Jena, Germany
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20
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Bedell MA, Largaespada DA, Jenkins NA, Copeland NG. Mouse models of human disease. Part II: recent progress and future directions. Genes Dev 1997; 11:11-43. [PMID: 9000048 DOI: 10.1101/gad.11.1.11] [Citation(s) in RCA: 141] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Affiliation(s)
- M A Bedell
- Mammalian Genetics Laboratory, ABL-Basic Research Program, NCI-Frederick Cancer Research and Development Center, Frederick, Maryland 21702-1201, USA
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Wichterle H, Hanspal M, Palek J, Jarolim P. Combination of two mutant alpha spectrin alleles underlies a severe spherocytic hemolytic anemia. J Clin Invest 1996; 98:2300-7. [PMID: 8941647 PMCID: PMC507680 DOI: 10.1172/jci119041] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
We studied a patient with a severe spherocytic hemolytic anemia without family history of spherocytosis. Analysis of patient's erythrocyte membrane proteins revealed spectrin deficiency and a truncated alpha spectrin protein. We determined that the patient is a compound heterozygote with two mutations in alpha spectrin gene. Mutation in the paternal allele, designated alpha spectrin(PRAGUE), is a transition A to G in the penultimate position of intron 36 that leads to skipping of exon 37, frameshift, and production of the truncated alpha spectrin protein. The maternal allele, designated alpha spectrin(LEPRA), contains transition C-->T in position -99 of intron 30. This mutation enhances an alternative acceptor splice site 70 nucleotides upstream from the regular site. The alternative splicing causes a frameshift and premature termination of translation leading to a significant decrease in alpha spectrin production. The alpha(LEPRA) mutation is linked to a spectrin alphaIIa marker that was found to be associated with recessive or nondominant spectrin-deficient hereditary spherocytosis in approximately 50% of studied families. We conclude that the alpha(LEPRA) mutation combined in trans with the alpha(PRAGUE) mutation underlie the severe hemolytic anemia in the proband. We suggest that allele alpha spectrin(LEPRA) may be frequently involved in pathogenesis of recessive or nondominant spectrin-deficient hereditary spherocytosis.
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Affiliation(s)
- H Wichterle
- Department of Biomedical Research, St. Elizabeth's Medical Center, Boston, Massachusetts 02135, USA
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22
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Eber SW, Gonzalez JM, Lux ML, Scarpa AL, Tse WT, Dornwell M, Herbers J, Kugler W, Ozcan R, Pekrun A, Gallagher PG, Schröter W, Forget BG, Lux SE. Ankyrin-1 mutations are a major cause of dominant and recessive hereditary spherocytosis. Nat Genet 1996; 13:214-8. [PMID: 8640229 DOI: 10.1038/ng0696-214] [Citation(s) in RCA: 141] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Hereditary spherocytosis (HS) is the most common inherited haemolytic anaemia in Northern Europeans. The primary molecular defects reside in the red blood cell (RBC) membrane, particularly in proteins that link the membrane skeleton to the overlying lipid bilayer and its integral membrane constituents. Ankyrin-1 is the predominant linker molecule. It attaches spectrin, the major skeletal protein, to the cytoplasmic domain of band 3, the RBC anion exchanger. Two-thirds of patients with HS have combined spectrin and ankyrin-1 deficiency; deficiency of band 3 occurs in about 15 to 20% (ref.1). These data suggest that ankyrin-1 or band 3 defects may be common in HS. To test this we screened all 42 coding exons plus the 5' untranslated/promoter region of ankyrin-1 and the 19 coding exons of band 3 in 46 HS families. Twelve ankyrin-1 mutations and five band 3 mutations were identified. Missense mutations and a mutation in the putative ankyrin-1 promoter were common in recessive HS. In contrast, ankyrin-1 and band 3 frameshift and nonsense null mutations prevailed in dominant HS. Increased accumulation of the normal protein product partially compensated for the ankyrin-1 or band 3 defects in some of these null mutations. Our findings indicate that ankyrin-1 mutations are a major cause of dominant and recessive HS (approximately 35 to 65%), that band 3 mutations are less common (approximately 15 to 25%), and that the severity of HS is modified by factors other than the primary gene defect.
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Affiliation(s)
- S W Eber
- Division of Hematology/Oncology, Children's Hospital, Boston, Massachusetts 02115, USA
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23
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Jarolim P, Wichterle H, Hanspal M, Murray J, Rubin HL, Palek J. Beta spectrin PRAGUE: a truncated beta spectrin producing spectrin deficiency, defective spectrin heterodimer self-association and a phenotype of spherocytic elliptocytosis. Br J Haematol 1995; 91:502-10. [PMID: 8547102 DOI: 10.1111/j.1365-2141.1995.tb05330.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Spherocytic elliptocytosis is a phenotypic hybrid between hereditary spherocytosis (HS) and hereditary elliptocytosis (HE) characterized by the presence of spheroovalocytes and spherocytes which exhibit increased osmotic fragility, indicating a deficiency of surface area. Both the spherocytic red cell morphology and the increased osmotic fragility distinguish this clinical entity from common HE. In contrast to common HE, the molecular basis of spherocytic elliptocytosis is unknown. Here we describe two members of a family who both have the characteristic features of spherocytic HE. We show that the underlying defect involves a G to C transversion at the -1 position of the acceptor splice site upstream of exon X of beta spectrin leading to skipping of exon X from the mutant beta spectrin mRNA allele. The mutant mRNA is present in reticulocytes in similar amounts as the normal mRNA. Pulse-labelling of erythroblasts prepared from peripheral blood in a two-phase liquid-culture system reveals a decreased synthesis of the truncated beta spectrin, a finding which is likely to underlie the moderately severe spectrin deficiency in the two patients. In addition, this mutant spectrin, similar to the previously reported spectrins, is defective in spectrin heterodimer self-association. The spectrin deficiency, which represents a common finding in the majority of patients with HS, together with weakened spectrin heterodimer self-association, as found in the majority of patients with common HE, provides a molecular explanation for the phenotype of spherocytic elliptocytosis in this kindred and, most likely, in other patients carrying similar beta spectrin mutations.
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Affiliation(s)
- P Jarolim
- Department of Biomedical Research, St Elizabeth's Medical Center, Tufts University School of Medicine, Boston, Massachusetts, USA
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Abstract
The red cell membrane is comprised of a lipid bilayer studded with transmembrane proteins, and laminated by a protein network, the membrane skeleton, at the surface of the inner monolayer. The erythrocyte owes its mechanical properties to the membrane skeleton. Hereditary spherocytosis, hereditary elliptocytosis or poikilocytosis, Southeast Asian ovalocytosis are hereditary hemolytic anemias, due to mutations in the genes encoding ankyrin, the anion exchanger, spectrin, protein 4.1 or protein 4.2, which are main proteins of the membrane. Recent advances in the field have led to fundamental questions.
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Affiliation(s)
- J Delaunay
- Laboratoire de Génétique Moléculaire Humaine (CNRS URA 1171), Institut Pasteur de Lyon, France
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