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Novel mutations in the EPO-R, VHL and EPAS1 genes in the Congenital Erythrocytosis patients. Blood Cells Mol Dis 2020; 85:102479. [DOI: 10.1016/j.bcmd.2020.102479] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2020] [Revised: 07/18/2020] [Accepted: 07/19/2020] [Indexed: 12/11/2022]
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Gurnari C, Lombardi AM, Cosi E, Biagetti G, Buccisano F, Franceschini L, Di Veroli A, Falconi G, Fabiani E, Cantonetti M, Nasso D, Lo-Coco F, Randi ML, Voso MT. Genetic analysis of erythrocytosis reveals possible causative and modifier gene mutations. Br J Haematol 2019; 186:e100-e103. [PMID: 31016714 DOI: 10.1111/bjh.15931] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Carmelo Gurnari
- Department of Biomedicine and Prevention, University of Rome Tor Vergata, Rome, Italy
| | - Anna M Lombardi
- Department of Medicine, University of Padua Medical School, Padua, Italy
| | - Elisabetta Cosi
- Department of Medicine, University of Padua Medical School, Padua, Italy
| | - Giacomo Biagetti
- Department of Medicine, University of Padua Medical School, Padua, Italy
| | - Francesco Buccisano
- Department of Biomedicine and Prevention, University of Rome Tor Vergata, Rome, Italy
| | - Luca Franceschini
- Department of Biomedicine and Prevention, University of Rome Tor Vergata, Rome, Italy
| | - Ambra Di Veroli
- Department of Biomedicine and Prevention, University of Rome Tor Vergata, Rome, Italy
| | - Giulia Falconi
- Department of Biomedicine and Prevention, University of Rome Tor Vergata, Rome, Italy
| | - Emiliano Fabiani
- Department of Biomedicine and Prevention, University of Rome Tor Vergata, Rome, Italy
| | - Maria Cantonetti
- Department of Biomedicine and Prevention, University of Rome Tor Vergata, Rome, Italy
| | - Daniela Nasso
- Department of Biomedicine and Prevention, University of Rome Tor Vergata, Rome, Italy
| | - Francesco Lo-Coco
- Department of Biomedicine and Prevention, University of Rome Tor Vergata, Rome, Italy
| | - Maria L Randi
- Department of Medicine, University of Padua Medical School, Padua, Italy
| | - Maria T Voso
- Department of Biomedicine and Prevention, University of Rome Tor Vergata, Rome, Italy
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Camps C, Petousi N, Bento C, Cario H, Copley RR, McMullin MF, van Wijk R, Ratcliffe PJ, Robbins PA, Taylor JC. Gene panel sequencing improves the diagnostic work-up of patients with idiopathic erythrocytosis and identifies new mutations. Haematologica 2016; 101:1306-1318. [PMID: 27651169 PMCID: PMC5394871 DOI: 10.3324/haematol.2016.144063] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2016] [Accepted: 07/26/2016] [Indexed: 12/31/2022] Open
Abstract
Erythrocytosis is a rare disorder characterized by increased red cell mass and elevated hemoglobin concentration and hematocrit. Several genetic variants have been identified as causes for erythrocytosis in genes belonging to different pathways including oxygen sensing, erythropoiesis and oxygen transport. However, despite clinical investigation and screening for these mutations, the cause of disease cannot be found in a considerable number of patients, who are classified as having idiopathic erythrocytosis. In this study, we developed a targeted next-generation sequencing panel encompassing the exonic regions of 21 genes from relevant pathways (~79 Kb) and sequenced 125 patients with idiopathic erythrocytosis. The panel effectively screened 97% of coding regions of these genes, with an average coverage of 450×. It identified 51 different rare variants, all leading to alterations of protein sequence, with 57 out of 125 cases (45.6%) having at least one of these variants. Ten of these were known erythrocytosis-causing variants, which had been missed following existing diagnostic algorithms. Twenty-two were novel variants in erythrocytosis-associated genes (EGLN1, EPAS1, VHL, BPGM, JAK2, SH2B3) and in novel genes included in the panel (e.g. EPO, EGLN2, HIF3A, OS9), some with a high likelihood of functionality, for which future segregation, functional and replication studies will be useful to provide further evidence for causality. The rest were classified as polymorphisms. Overall, these results demonstrate the benefits of using a gene panel rather than existing methods in which focused genetic screening is performed depending on biochemical measurements: the gene panel improves diagnostic accuracy and provides the opportunity for discovery of novel variants.
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Affiliation(s)
- Carme Camps
- National Institute for Health Research (NIHR) Comprehensive Biomedical Research Centre, Oxford, UK
- Wellcome Trust Centre for Human Genetics, University of Oxford, UK
| | - Nayia Petousi
- Nuffield Department of Medicine, University of Oxford, UK
| | - Celeste Bento
- Hematology Department, Centro Hospitalar e Universitário de Coimbra, Portugal
| | - Holger Cario
- Department of Pediatrics and Adolescent Medicine, University Medical Center, Ulm, Germany
| | - Richard R Copley
- National Institute for Health Research (NIHR) Comprehensive Biomedical Research Centre, Oxford, UK
- Wellcome Trust Centre for Human Genetics, University of Oxford, UK
| | | | | | | | - Peter A Robbins
- Department of Physiology, Anatomy and Genetics, University of Oxford, UK
| | - Jenny C Taylor
- National Institute for Health Research (NIHR) Comprehensive Biomedical Research Centre, Oxford, UK
- Wellcome Trust Centre for Human Genetics, University of Oxford, UK
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Minervini G, Quaglia F, Tosatto SCE. Computational analysis of prolyl hydroxylase domain-containing protein 2 (PHD2) mutations promoting polycythemia insurgence in humans. Sci Rep 2016; 6:18716. [PMID: 26754054 PMCID: PMC4709589 DOI: 10.1038/srep18716] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Accepted: 11/06/2015] [Indexed: 12/18/2022] Open
Abstract
Idiopathic erythrocytosis is a rare disease characterized by an increase in red blood cell mass due to mutations in proteins of the oxygen-sensing pathway, such as prolyl hydroxylase 2 (PHD2). Here, we present a bioinformatics investigation of the pathological effect of twelve PHD2 mutations related to polycythemia insurgence. We show that few mutations impair the PHD2 catalytic site, while most localize to non-enzymatic regions. We also found that most mutations do not overlap the substrate recognition site, suggesting a novel PHD2 binding interface. After a structural analysis of both binding partners, we suggest that this novel interface is responsible for PHD2 interaction with the LIMD1 tumor suppressor.
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Affiliation(s)
- Giovanni Minervini
- Department of Biomedical Sciences and CRIBI Biotechnology Center, University of Padova, Viale G. Colombo 3, 35121, Padova, Italy
| | - Federica Quaglia
- Department of Biomedical Sciences and CRIBI Biotechnology Center, University of Padova, Viale G. Colombo 3, 35121, Padova, Italy
| | - Silvio C E Tosatto
- Department of Biomedical Sciences and CRIBI Biotechnology Center, University of Padova, Viale G. Colombo 3, 35121, Padova, Italy.,CNR Institute of Neuroscience, Viale G. Colombo 3, 35121, Padova, Italy
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Pressler BM, Williams LE, Ramos-Vara JA, Anderson KI. Sequencing of the von Hippel-Lindau gene in canine renal carcinoma. J Vet Intern Med 2009; 23:592-7. [PMID: 19422471 DOI: 10.1111/j.1939-1676.2009.0310.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND Similarities in human and canine renal cell carcinoma (RCC) epidemiology and biologic behavior suggest that molecular mechanisms of tumorigenesis may be similar in both species. Approximately 75% of RCC in people are of the clear cell subtype, up to 85% of which are associated with mutation of the von Hippel-Lindau (VHL) gene. The canine VHL coding deoxyribonucleic acid (DNA) shares 90% identity with the human VHL gene. OBJECTIVE To determine whether or not RCC in dogs are associated with VHL mutations, and if so determine the prevalence, type, and location of these mutations. ANIMALS Thirteen dogs with RCC, 2 dogs with primary renal sarcomas, and 10 dogs without neoplastic kidney disease. METHODS DNA was extracted from paraffin-embedded RCC tissue; DNA extracts from paraffin-embedded and snap-frozen nonneoplastic canine kidneys and canine whole blood were used as negative controls. Polymerase chain reaction and sequencing of the 3 VHL exons was performed, and results compared with the accessioned canine sequence. RESULTS All VHL exons were amplified from 9 of 13 canine RCC samples, both renal sarcomas, 8 of 10 nonneoplastic kidney samples, and canine whole blood; only exon 2 could be amplified from 2 RCC samples. Mutations were not identified in any exons. A maximal prevalence of 33.6% for VHL mutations in canine RCC was determined. CONCLUSION AND CLINICAL IMPORTANCE Although similarities between canine and human RCC merit further investigation of the dog as a model for some subtypes of renal tumors, the lower prevalence of VHL mutations suggests that oncogenesis in these 2 species differs.
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Affiliation(s)
- B M Pressler
- Department of Veterinary Clinical Sciences, School of Veterinary Medicine, Purdue University, West Lafayette, IN 47907, USA.
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Furlow PW, Percy MJ, Sutherland S, Bierl C, McMullin MF, Master SR, Lappin TRJ, Lee FS. Erythrocytosis-associated HIF-2alpha mutations demonstrate a critical role for residues C-terminal to the hydroxylacceptor proline. J Biol Chem 2009; 284:9050-8. [PMID: 19208626 PMCID: PMC2666553 DOI: 10.1074/jbc.m808737200] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2008] [Revised: 02/03/2009] [Indexed: 01/23/2023] Open
Abstract
A classic physiologic response to hypoxia in humans is the up-regulation of the ERYTHROPOIETIN (EPO) gene, which is the central regulator of red blood cell mass. The EPO gene, in turn, is activated by hypoxia inducible factor (HIF). HIF is a transcription factor consisting of an alpha subunit (HIF-alpha) and a beta subunit (HIF-beta). Under normoxic conditions, prolyl hydroxylase domain protein (PHD, also known as HIF prolyl hydroxylase and egg laying-defective nine protein) site specifically hydroxylates HIF-alpha in a conserved LXXLAP motif (where underlining indicates the hydroxylacceptor proline). This provides a recognition motif for the von Hippel Lindau protein, a component of an E3 ubiquitin ligase complex that targets hydroxylated HIF-alpha for degradation. Under hypoxic conditions, this inherently oxygen-dependent modification is arrested, thereby stabilizing HIF-alpha and allowing it to activate the EPO gene. We previously identified and characterized an erythrocytosis-associated HIF2A mutation, G537W. More recently, we reported two additional erythrocytosis-associated HIF2A mutations, G537R and M535V. Here, we describe the functional characterization of these two mutants as well as a third novel erythrocytosis-associated mutation, P534L. These mutations affect residues C-terminal to the LXXLAP motif. We find that all result in impaired degradation and thus aberrant stabilization of HIF-2alpha. However, each exhibits a distinct profile with respect to their effects on PHD2 binding and von Hippel Lindau interaction. These findings reinforce the importance of HIF-2alpha in human EPO regulation, demonstrate heterogeneity of functional defects arising from these mutations, and point to a critical role for residues C-terminal to the LXXLAP motif in HIF-alpha.
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Affiliation(s)
- Paul W Furlow
- Department of Pathology and Laboratory Medicine, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104, USA
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Abstract
Idiopathic erythrocytosis is an uncommon disease, and is defined by an increase in red blood cell mass. The differential diagnosis of erythrocytosis is extensive, and can be divided into primary and secondary forms. Primary erythrocytoses are due to intrinsic defects in erythroid precursor cells and are characterized by low erythropoietin levels. Secondary erythrocytoses are extrinsic to erythroid progenitors and are characterized by either high or inappropriately normal erythropoietin levels. A distinct subset of secondary erythrocytoses are due to genetic mutations in key proteins of the oxygen-sensing pathway. These proteins constitute the core molecular machinery of oxygen-sensing with respect to red blood cell control. Apart from assigning physiologic roles for these proteins, studies of these rare mutations have (i) revealed the exquisite sensitivity of this pathway to genetic perturbations, (ii) highlighted important functional regions of the proteins, and (iii) provided a basis for potentially targeting this pathway for therapeutic benefit.
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Affiliation(s)
- Frank S Lee
- Department of Pathology and Laboratory Medicine, University of Pennsylvania School of Medicine, 605 Stellar Chance Labs, 422 Curie Boulevard, Philadelphia, PA 19104, USA.
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Percy MJ, Furlow PW, Lucas GS, Li X, Lappin TRJ, McMullin MF, Lee FS. A gain-of-function mutation in the HIF2A gene in familial erythrocytosis. N Engl J Med 2008; 358:162-8. [PMID: 18184961 PMCID: PMC2295209 DOI: 10.1056/nejmoa073123] [Citation(s) in RCA: 248] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Hypoxia-inducible factor (HIF) alpha, which has three isoforms, is central to the continuous balancing of the supply and demand of oxygen throughout the body. HIF-alpha is a transcription factor that modulates a wide range of processes, including erythropoiesis, angiogenesis, and cellular metabolism. We describe a family with erythrocytosis and a mutation in the HIF2A gene, which encodes the HIF-2alpha protein. Our functional studies indicate that this mutation leads to stabilization of the HIF-2alpha protein and suggest that wild-type HIF-2alpha regulates erythropoietin production in adults.
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Percy MJ, Furlow PW, Beer PA, Lappin TRJ, McMullin MF, Lee FS. A novel erythrocytosis-associated PHD2 mutation suggests the location of a HIF binding groove. Blood 2007; 110:2193-6. [PMID: 17579185 PMCID: PMC1976349 DOI: 10.1182/blood-2007-04-084434] [Citation(s) in RCA: 125] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
The molecular basis of the erythrocytosis group of red cell disorders is incompletely defined. Some cases are due to dysregulation of erythropoietin (Epo) synthesis. The hypoxia inducible transcription factor (HIF) tightly regulates Epo synthesis. HIF in turn is regulated through its alpha subunit, which under normoxic conditions is hydroxylated on specific prolines and targeted for degradation by the von Hippel Lindau (VHL) protein. Several mutations in VHL have been reported in erythrocytosis, but only 1 mutation in the HIF prolyl hydroxylase PHD2 (prolyl hydroxylase domain protein 2) has been described. Here, we report a novel PHD2 mutation, Arg371His, which causes decreased HIF binding, HIF hydroxylase, and HIF inhibitory activities. In the tertiary structure of PHD2, Arg371 lies close to the previously described Pro317Arg mutation site. These findings substantiate PHD2 as a critical enzyme controlling HIF and therefore Epo in humans, and furthermore suggest the location of an active site groove in PHD2 that binds HIF.
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Affiliation(s)
- Melanie J Percy
- Department of Haematology, Belfast City Hospital, Belfast, United Kingdom.
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