1
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Ghosh S, Oldenburg J, Czogalla-Nitsche KJ. The Role of GRP and MGP in the Development of Non-Hemorrhagic VKCFD1 Phenotypes. Int J Mol Sci 2022; 23:798. [PMID: 35054981 PMCID: PMC8775833 DOI: 10.3390/ijms23020798] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Revised: 01/05/2022] [Accepted: 01/08/2022] [Indexed: 11/21/2022] Open
Abstract
Vitamin K dependent coagulation factor deficiency type 1 (VKCFD1) is a rare hereditary bleeding disorder caused by mutations in γ-Glutamyl carboxylase (GGCX) gene. The GGCX enzyme catalyzes the γ-carboxylation of 15 different vitamin K dependent (VKD) proteins, which have function in blood coagulation, calcification, and cell signaling. Therefore, in addition to bleedings, some VKCFD1 patients develop diverse non-hemorrhagic phenotypes such as skin hyper-laxity, skeletal dysmorphologies, and/or cardiac defects. Recent studies showed that GGCX mutations differentially effect γ-carboxylation of VKD proteins, where clotting factors are sufficiently γ-carboxylated, but not certain non-hemostatic VKD proteins. This could be one reason for the development of diverse phenotypes. The major manifestation of non-hemorrhagic phenotypes in VKCFD1 patients are mineralization defects. Therefore, the mechanism of regulation of calcification by specific VKD proteins as matrix Gla protein (MGP) and Gla-rich protein (GRP) in physiological and pathological conditions is of high interest. This will also help to understand the patho-mechanism of VKCFD1 phenotypes and to deduce new treatment strategies. In the present review article, we have summarized the recent findings on the function of GRP and MGP and how these proteins influence the development of non-hemorrhagic phenotypes in VKCFD1 patients.
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Affiliation(s)
- Suvoshree Ghosh
- Institute of Experimental Haematology and Transfusion Medicine, Venusberg Campus 1, University Clinic Bonn, 53127 Bonn, Germany; (S.G.); (J.O.)
| | - Johannes Oldenburg
- Institute of Experimental Haematology and Transfusion Medicine, Venusberg Campus 1, University Clinic Bonn, 53127 Bonn, Germany; (S.G.); (J.O.)
- Center for Rare Diseases Bonn, Venusberg Campus 1, University Clinic Bonn, 53127 Bonn, Germany
| | - Katrin J. Czogalla-Nitsche
- Institute of Experimental Haematology and Transfusion Medicine, Venusberg Campus 1, University Clinic Bonn, 53127 Bonn, Germany; (S.G.); (J.O.)
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2
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Lofaro FD, Mucciolo DP, Murro V, Pavese L, Quaglino D, Boraldi F. From Clinical Diagnosis to the Discovery of Multigene Rare Sequence Variants in Pseudoxanthoma elasticum: A Case Report. Front Med (Lausanne) 2021; 8:726856. [PMID: 34513887 PMCID: PMC8427021 DOI: 10.3389/fmed.2021.726856] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Accepted: 07/30/2021] [Indexed: 12/03/2022] Open
Abstract
Pseudoxanthoma elasticum (PXE) is a rare autosomal recessive disease clinically characterised by early cutaneous alterations, and by late clinically relevant ocular, and cardiovascular manifestations. ABCC6 genetic tests are used to confirm clinical PXE diagnosis, but this strategy may be rather challenging when only one ABCC6 pathogenic variant is found. A next-generation sequencing approach focusing on 362 genes related to the calcification process and/or to inherited retinal diseases was performed on a patient with clinical PXE diagnosis (skin papules and laxity, angioid streaks, and atrophy) who was carrier of only one ABCC6 rare sequence variant. Beside ABCC6, several rare sequence variants were detected which can contribute either to the occurrence of calcification (GGCX and SERPINF1 genes) and/or to ophthalmological manifestations (ABCA4, AGBL5, CLUAP1, and KCNV2 genes). This wide-spectrum analysis approach facilitates the identification of rare variants possibly involved in PXE, thus avoiding invasive skin biopsy as well as expensive and time-consuming diagnostic odyssey and allows to broaden and to deepen the knowledge on this complex rare disease and to improve patients' counselling, also with a future perspective of personalised medicine.
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Affiliation(s)
| | - Dario Pasquale Mucciolo
- Department of Neuroscience, Psychology, Drug Research and Child Health, University of Florence, Eye Clinic, Florence, Italy
| | - Vittoria Murro
- Department of Neuroscience, Psychology, Drug Research and Child Health, University of Florence, Eye Clinic, Florence, Italy
| | - Laura Pavese
- Department of Neuroscience, Psychology, Drug Research and Child Health, University of Florence, Eye Clinic, Florence, Italy
| | - Daniela Quaglino
- Department of Life Science, University of Modena and Reggio Emilia, Modena, Italy
| | - Federica Boraldi
- Department of Life Science, University of Modena and Reggio Emilia, Modena, Italy
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3
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Molecular Genetics and Modifier Genes in Pseudoxanthoma Elasticum, a Heritable Multisystem Ectopic Mineralization Disorder. J Invest Dermatol 2020; 141:1148-1156. [PMID: 33341249 DOI: 10.1016/j.jid.2020.10.013] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Revised: 10/19/2020] [Accepted: 10/23/2020] [Indexed: 01/08/2023]
Abstract
In the past two decades, there has been great progress in identifying the molecular basis and pathomechanistic details in pseudoxanthoma elasticum (PXE), a heritable multisystem ectopic mineralization disorder. Although the identification of pathogenic variants in ABCC6 has been critical for understanding the disease process, genetic modifiers have been disclosed that explain the phenotypic heterogeneity of PXE. Adding to the genetic complexity of PXE are PXE-like phenotypes caused by pathogenic variants in other ectopic mineralization-associated genes. This review summarizes the current knowledge of the genetics and candidate modifier genes in PXE, a multifactorial disease at the genome-environment interface.
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4
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Naima J, Abir RA, Hosen MJ. Homology Modeling and Virtual Screening of Proteins Related to PXE and PXE-like Diseases: Insights for Overlapping Metabolites. Curr Pharm Biotechnol 2020; 21:1470-1478. [DOI: 10.2174/1389201021666200519115032] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Revised: 03/28/2020] [Accepted: 05/20/2020] [Indexed: 11/22/2022]
Abstract
Background:
The molecular etiology of Pseudoxanthoma Elasticum (PXE), an autosomal
recessive connective tissue disorder, has become increasingly complex as not only mutations in the
ABCC6, but also in ENPP1 and GGCX, can cause resembling phenotypes.
Methods:
To get insights on the common pathway, the overlapping metabolites for these three proteins
were predicted through 3D homology modeling and virtual screening. 3D homology models of
ABCC6, ENPP1, and GGCX were generated by the MODELLER program, which were further validated
using RAMPAGE and ERRAT servers. Substrate binding sites of ABCC6 were predicted using
blind docking of reported in vitro substrates.
Results:
Virtual screening against the substrate binding site of ABCC6 using metabolites listed in Human
Metabolome Databases (HMDB) revealed the best possible substrate of ABCC6. Those listed metabolites
were further docked against predicted substrate binding sites of GGCX and ENPP1. Molecular
docking and virtual screening revealed a list of 133 overlapping metabolites of these three proteins.
Most of them are Phosphatidylinositol (PI), Phosphatidylserine (PS), Diacylglycerol (DAG), phosphatidic
acid, oleanolic acid metabolites and were found to have links with calcification.
Conclusion:
These predicted overlapping metabolites may give novel insights for searching common
pathomechanism for PXE and PXE-like diseases.
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Affiliation(s)
- Jannatul Naima
- Department of Genetic Engineering and Biotechnology, Shahjalal University of Science & Technology, Sylhet, Bangladesh
| | - Ruhshan A. Abir
- Department of Genetic Engineering and Biotechnology, Shahjalal University of Science & Technology, Sylhet, Bangladesh
| | - Mohammad J. Hosen
- Department of Genetic Engineering and Biotechnology, Shahjalal University of Science & Technology, Sylhet, Bangladesh
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5
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Verschuere S, Van Gils M, Nollet L, Vanakker OM. From membrane to mineralization: the curious case of the ABCC6 transporter. FEBS Lett 2020; 594:4109-4133. [PMID: 33131056 DOI: 10.1002/1873-3468.13981] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Revised: 10/12/2020] [Accepted: 10/16/2020] [Indexed: 12/13/2022]
Abstract
ATP-binding cassette subfamily C member 6 gene/protein (ABCC6) is an ATP-dependent transmembrane transporter predominantly expressed in the liver and the kidney. ABCC6 first came to attention in human medicine when it was discovered in 2000 that mutations in its encoding gene, ABCC6, caused the autosomal recessive multisystemic mineralization disease pseudoxanthoma elasticum (PXE). Since then, the physiological and pathological roles of ABCC6 have been the subject of intense research. In the last 20 years, significant findings have clarified ABCC6 structure as well as its physiological role in mineralization homeostasis in humans and animal models. Yet, several facets of ABCC6 biology remain currently incompletely understood, ranging from the precise nature of its substrate(s) to the increasingly complex molecular genetics. Nonetheless, advances in our understanding of pathophysiological mechanisms causing mineralization lead to several treatment options being suggested or already tested in pilot clinical trials for ABCC6 deficiency. This review highlights current knowledge of ABCC6 and the challenges ahead, particularly the attempts to translate basic science into clinical practice.
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Affiliation(s)
- Shana Verschuere
- Center for Medical Genetics, Ghent University Hospital, Belgium.,Department of Biomolecular Medicine, Ghent University, Belgium.,Ectopic Mineralization Research Group Ghent, Ghent, Belgium
| | - Matthias Van Gils
- Center for Medical Genetics, Ghent University Hospital, Belgium.,Department of Biomolecular Medicine, Ghent University, Belgium.,Ectopic Mineralization Research Group Ghent, Ghent, Belgium
| | - Lukas Nollet
- Center for Medical Genetics, Ghent University Hospital, Belgium.,Department of Biomolecular Medicine, Ghent University, Belgium.,Ectopic Mineralization Research Group Ghent, Ghent, Belgium
| | - Olivier M Vanakker
- Center for Medical Genetics, Ghent University Hospital, Belgium.,Department of Biomolecular Medicine, Ghent University, Belgium.,Ectopic Mineralization Research Group Ghent, Ghent, Belgium
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6
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Li D, Ryu E, Saeidian AH, Youssefian L, Oliphant E, Terry SF, Tong PL, Uitto J, Haass NK, Li Q. GGCX mutations in a patient with overlapping pseudoxanthoma elasticum/cutis laxa-like phenotype. Br J Dermatol 2020; 184:1170-1174. [PMID: 33000479 DOI: 10.1111/bjd.19576] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Revised: 09/25/2020] [Accepted: 09/27/2020] [Indexed: 12/15/2022]
Abstract
Pseudoxanthoma elasticum (PXE) is a multisystem disorder characterized by ectopic mineralization of connective tissues with primary manifestations in the skin, eyes and the cardiovascular system. The classic forms of PXE are caused by mutations in the ABCC6 gene encoding the ABCC6 protein, expressed primarily in the liver. Cutis laxa (CL) manifests with loose and sagging skin with loss of recoil. In 2009 we investigated a 19-year-old patient with overlapping cutaneous features of PXE and CL, together with alpha thalassaemia. Genetic analysis failed to identify pathogenic mutations in ABCC6. More recently we developed a gene-targeted panel of next-generation sequencing technology. This panel has 29 genes, 22 of which, including ABCC6 and GGCX, are associated with ectopic mineralization phenotypes. Mutation analysis in the patient identified two heterozygous GGCX mutations: c.200_201delTT in exon 2 and c.763G>A, p.V255M in exon 7. The GGCX gene encodes a γ-glutamyl carboxylase necessary for activation of blood coagulation factors in the liver. The p.V255M mutation was previously reported to result in reduced γ-glutamyl carboxylase activity in vitro, while the c.200_201delTT mutation is novel. Previous studies reported that mutations in GGCX cause overlapping PXE/CL skin phenotypes in association with or without multiple vitamin K-dependent coagulation factor deficiency. Our patient had loose redundant skin, moderate-to-severe angioid streaks and characteristic calcification of elastic structures in the mid dermis, consistent with PXE/CL overlap, but no coagulation abnormalities. Our studies expand the GGCX mutation landscape in patients with PXE-like phenotypes.
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Affiliation(s)
- D Li
- Department of Dermatology and Cutaneous Biology, Sidney Kimmel Medical College, and PXE International Center of Excellence in Research and Clinical Care, Jefferson Institute of Molecular Medicine, Thomas Jefferson University, Philadelphia, PA, 19107, USA
| | - E Ryu
- Department of Dermatology and Cutaneous Biology, Sidney Kimmel Medical College, and PXE International Center of Excellence in Research and Clinical Care, Jefferson Institute of Molecular Medicine, Thomas Jefferson University, Philadelphia, PA, 19107, USA
| | - A H Saeidian
- Department of Dermatology and Cutaneous Biology, Sidney Kimmel Medical College, and PXE International Center of Excellence in Research and Clinical Care, Jefferson Institute of Molecular Medicine, Thomas Jefferson University, Philadelphia, PA, 19107, USA.,Genetics, Genomics and Cancer Biology PhD Program, Thomas Jefferson University, Philadelphia, PA, USA
| | - L Youssefian
- Department of Dermatology and Cutaneous Biology, Sidney Kimmel Medical College, and PXE International Center of Excellence in Research and Clinical Care, Jefferson Institute of Molecular Medicine, Thomas Jefferson University, Philadelphia, PA, 19107, USA
| | - E Oliphant
- PXE International, Inc, Washington, DC, 20008, USA
| | - S F Terry
- PXE International, Inc, Washington, DC, 20008, USA
| | - P L Tong
- Discipline of Dermatology, University of Sydney, Camperdown, NSW, Australia.,Department of Dermatology, Royal Prince Alfred Hospital, Camperdown, NSW, Australia
| | - J Uitto
- Department of Dermatology and Cutaneous Biology, Sidney Kimmel Medical College, and PXE International Center of Excellence in Research and Clinical Care, Jefferson Institute of Molecular Medicine, Thomas Jefferson University, Philadelphia, PA, 19107, USA
| | - N K Haass
- Discipline of Dermatology, University of Sydney, Camperdown, NSW, Australia.,Department of Dermatology, Royal Prince Alfred Hospital, Camperdown, NSW, Australia.,The University of Queensland Diamantina Institute, The University of Queensland, Brisbane, QLD, Australia
| | - Q Li
- Department of Dermatology and Cutaneous Biology, Sidney Kimmel Medical College, and PXE International Center of Excellence in Research and Clinical Care, Jefferson Institute of Molecular Medicine, Thomas Jefferson University, Philadelphia, PA, 19107, USA
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7
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Talib M, Boon CJF. Retinal Dystrophies and the Road to Treatment: Clinical Requirements and Considerations. Asia Pac J Ophthalmol (Phila) 2020; 9:159-179. [PMID: 32511120 PMCID: PMC7299224 DOI: 10.1097/apo.0000000000000290] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Accepted: 04/01/2020] [Indexed: 12/15/2022] Open
Abstract
: Retinal dystrophies (RDs) comprise relatively rare but devastating causes of progressive vision loss. They represent a spectrum of diseases with marked genetic and clinical heterogeneity. Mutations in the same gene may lead to different diagnoses, for example, retinitis pigmentosa or cone dystrophy. Conversely, mutations in different genes may lead to the same phenotype. The age at symptom onset, and the rate and characteristics of peripheral and central vision decline, may vary widely per disease group and even within families. For most RD cases, no effective treatment is currently available. However, preclinical studies and phase I/II/III gene therapy trials are ongoing for several RD subtypes, and recently the first retinal gene therapy has been approved by the US Food and Drug Administration for RPE65-associated RDs: voretigene neparvovec-rzyl (Luxturna). With the rapid advances in gene therapy studies, insight into the phenotypic spectrum and long-term disease course is crucial information for several RD types. The vast clinical heterogeneity presents another important challenge in the evaluation of potential efficacy in future treatment trials, and in establishing treatment candidacy criteria. This perspective describes these challenges, providing detailed clinical descriptions of several forms of RD that are caused by genes of interest for ongoing and future gene or cell-based therapy trials. Several ongoing and future treatment options will be described.
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Affiliation(s)
- Mays Talib
- Department of Ophthalmology, Leiden, The Netherlands
| | - Camiel J F Boon
- Department of Ophthalmology, Leiden, The Netherlands
- Department of Ophthalmology, Amsterdam UMC, Academic Medical Center, University of Amsterdam. Amsterdam, The Netherlands
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8
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Quaglino D, Boraldi F, Lofaro FD. The biology of vascular calcification. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2020; 354:261-353. [PMID: 32475476 DOI: 10.1016/bs.ircmb.2020.02.007] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Vascular calcification (VC), characterized by different mineral deposits (i.e., carbonate apatite, whitlockite and hydroxyapatite) accumulating in blood vessels and valves, represents a relevant pathological process for the aging population and a life-threatening complication in acquired and in genetic diseases. Similarly to bone remodeling, VC is an actively regulated process in which many cells and molecules play a pivotal role. This review aims at: (i) describing the role of resident and circulating cells, of the extracellular environment and of positive and negative factors in driving the mineralization process; (ii) detailing the types of VC (i.e., intimal, medial and cardiac valve calcification); (iii) analyzing rare genetic diseases underlining the importance of altered pyrophosphate-dependent regulatory mechanisms; (iv) providing therapeutic options and perspectives.
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Affiliation(s)
- Daniela Quaglino
- Department of Life Sciences, University of Modena and Reggio Emilia, Modena, Italy.
| | - Federica Boraldi
- Department of Life Sciences, University of Modena and Reggio Emilia, Modena, Italy
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9
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Van Gils M, Nollet L, Verly E, Deianova N, Vanakker OM. Cellular signaling in pseudoxanthoma elasticum: an update. Cell Signal 2019; 55:119-129. [PMID: 30615970 DOI: 10.1016/j.cellsig.2018.12.009] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Revised: 12/20/2018] [Accepted: 12/20/2018] [Indexed: 12/27/2022]
Abstract
Pseudoxanthoma elasticum is an autosomal recessive genodermatosis with variable expression, due to mutations in the ABCC6 or ENPP1 gene. It is characterized by elastic fiber mineralization and fragmentation, resulting in skin, eye and cardiovascular symptoms. Significant advances have been made in the last 20 years with respect to the phenotypic characterization and pathophysiological mechanisms leading to elastic fiber mineralization. Nonetheless, the substrates of the ABCC6 transporter - the main cause of PXE - remain currently unknown. Though the precise mechanisms linking the ABCC6 transporter to mineralization of the extracellular matrix are unclear, several studies have looked into the cellular consequences of ABCC6 deficiency in PXE patients and/or animal models. In this paper, we compile the evidence on cellular signaling in PXE, which seems to revolve mainly around TGF-βs, BMPs and inorganic pyrophosphate signaling cascades. Where conflicting results or fragmented data are present, we address these with novel signaling data. This way, we aim to better understand the up- and down-stream signaling of TGF-βs and BMPs in PXE and we demonstrate that ANKH deficiency can be an additional mechanism contributing to decreased serum PPi levels in PXE patients.
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Affiliation(s)
- M Van Gils
- Center for Medical Genetics, Ghent University Hospital, Ghent, Belgium; Department of Biomolecular Medicine, Ghent University, Belgium
| | - L Nollet
- Center for Medical Genetics, Ghent University Hospital, Ghent, Belgium
| | - E Verly
- Center for Medical Genetics, Ghent University Hospital, Ghent, Belgium
| | - N Deianova
- Center for Medical Genetics, Ghent University Hospital, Ghent, Belgium
| | - O M Vanakker
- Center for Medical Genetics, Ghent University Hospital, Ghent, Belgium; Department of Biomolecular Medicine, Ghent University, Belgium.
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10
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Okubo Y, Masuyama R, Iwanaga A, Koike Y, Kuwatsuka Y, Ogi T, Yamamoto Y, Endo Y, Tamura H, Utani A. Calcification in dermal fibroblasts from a patient with GGCX syndrome accompanied by upregulation of osteogenic molecules. PLoS One 2017; 12:e0177375. [PMID: 28494010 PMCID: PMC5426700 DOI: 10.1371/journal.pone.0177375] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Accepted: 04/26/2017] [Indexed: 12/21/2022] Open
Abstract
Gamma-glutamyl carboxylase (GGCX) gene mutation causes GGCX syndrome (OMIM: 137167), which is characterized by pseudoxanthoma elasticum (PXE)-like symptoms and coagulation impairment. Here, we present a 55-year-old male with a novel homozygous deletion mutation, c.2,221delT, p.S741LfsX100, in the GGCX gene. Histopathological examination revealed calcium deposits in elastic fibers and vessel walls, and collagen accumulation in the mid-dermis. Studies of dermal fibroblasts from the patient (GGCX dermal fibroblasts) demonstrated that the mutated GGCX protein was larger, but its expression level and intracellular distribution were indistinguishable from those of the wild-type GGCX protein. Immunostaining and an enzyme-linked immunosorbent assay showed an increase in undercarboxylated matrix gamma-carboxyglutamic acid protein (ucMGP), a representative substrate of GGCX and a potent calcification inhibitor, indicating that mutated GGCX was enzymatically inactive. Under osteogenic conditions, calcium deposition was exclusively observed in GGCX dermal fibroblasts. Furthermore, GGCX dermal fibroblast cultures contained 23- and 7.7-fold more alkaline phosphatase (ALP)-positive cells than normal dermal fibroblast cultures (n = 3), without and with osteogenic induction, respectively. Expression and activity of ALP were higher in GGCX dermal fibroblasts than in normal dermal fibroblasts upon osteogenic induction. mRNA levels of other osteogenic markers were also higher in GGCX dermal fibroblasts than in normal dermal fibroblasts, which including bone morphogenetic protein 6, runt-related transcription factor 2, and periostin (POSTN) without osteogenic induction; and osterix, collagen type I alpha 2, and POSTN with osteogenic induction. Together, these data indicate that GGCX dermal fibroblasts trans-differentiate into the osteogenic lineage. This study proposes another mechanism underlying aberrant calcification in patients with GGCX syndrome.
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Affiliation(s)
- Yumi Okubo
- Department of Dermatology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan
- Research and Clinical Center for Yusho and Dioxin (ReCYD), Kyushu University Hospital, Fukuoka, Japan
| | - Ritsuko Masuyama
- Department of Molecular Bone Biology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan
| | - Akira Iwanaga
- Department of Dermatology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan
| | - Yuta Koike
- Department of Dermatology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan
| | - Yutaka Kuwatsuka
- Department of Dermatology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan
| | - Tomoo Ogi
- Department of Genetics, Research Institute of Environmental Medicine (RIeM), Nagoya University, Aichi, Japan
| | - Yosuke Yamamoto
- Department of Healthcare Epidemiology Research, Graduate School of Medicine Kyoto University, Kyoto, Japan
- Department of Dermatology, Graduate School of Medicine Kyoto University, Kyoto, Japan
| | - Yuichiro Endo
- Department of Dermatology, Graduate School of Medicine Kyoto University, Kyoto, Japan
| | - Hiroshi Tamura
- Department of Ophthalmology and Visual Sciences, Graduate School of Medicine Kyoto University, Kyoto, Japan
| | - Atsushi Utani
- Department of Dermatology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan
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Abstract
Pseudoxanthoma elasticum (PXE) is a genetic metabolic disease with autosomal recessive inheritance caused by mutations in the ABCC6 gene. The lack of functional ABCC6 protein leads to ectopic mineralization that is most apparent in the elastic tissues of the skin, eyes and blood vessels. The clinical prevalence of PXE has been estimated at between 1 per 100,000 and 1 per 25,000, with slight female predominance. The first clinical sign of PXE is almost always small yellow papules on the nape and sides of the neck and in flexural areas. The papules coalesce, and the skin becomes loose and wrinkled. The mid-dermal elastic fibers are short, fragmented, clumped and calcified. Dystrophic calcification of Bruch's membrane, revealed by angioid streaks, may trigger choroidal neovascularization and, ultimately, loss of central vision and blindness in late-stage disease. Lesions in small and medium-sized artery walls may result in intermittent claudication and peripheral artery disease. Cardiac complications (myocardial infarction, angina pectoris) are thought to be relatively rare but merit thorough investigation. Ischemic strokes have been reported. PXE is a metabolic disease in which circulating levels of an anti-mineralization factor are low. There is good evidence to suggest that the factor is inorganic pyrophosphate (PPi), and that the circulating low levels of PPi and decreased PPi/Pi ratio result from the lack of ATP release by hepatocytes harboring the mutant ABCC6 protein. However, the substrate(s) bound, transported or modulated by the ABCC6 protein remain unknown. More than 300 sequence variants of the ABCC6 gene have been identified. There is no cure for PXE; the main symptomatic treatments are vascular endothelial growth factor inhibitor therapy (for ophthalmic manifestations), lifestyle, lipid-lowering and dietary measures (for reducing vascular risk factors), and vascular surgery (for severe cardiovascular manifestations). Future treatment options may include gene therapy/editing and pharmacologic chaperone therapy.
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Affiliation(s)
- Dominique P Germain
- Division of Medical Genetics, University of Versailles - Saint Quentin en Yvelines, Paris-Saclay University, 2 avenue de la source de la Bièvre, F-78180, Montigny, France.
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12
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GGCX-Associated Phenotypes: An Overview in Search of Genotype-Phenotype Correlations. Int J Mol Sci 2017; 18:ijms18020240. [PMID: 28125048 PMCID: PMC5343777 DOI: 10.3390/ijms18020240] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Revised: 12/21/2016] [Accepted: 01/13/2017] [Indexed: 11/16/2022] Open
Abstract
Gamma-carboxylation, performed by gamma-glutamyl carboxylase (GGCX), is an enzymatic process essential for activating vitamin K-dependent proteins (VKDP) with important functions in various biological processes. Mutations in the encoding GGCX gene are associated with multiple phenotypes, amongst which vitamin K-dependent coagulation factor deficiency (VKCFD1) is best known. Other patients have skin, eye, heart or bone manifestations. As genotype–phenotype correlations were never described, literature was systematically reviewed in search of patients with at least one GGCX mutation with a phenotypic description, resulting in a case series of 47 patients. Though this number was too low for statistically valid correlations—a frequent problem in orphan diseases—we demonstrate the crucial role of the horizontally transferred transmembrane domain in developing cardiac and bone manifestations. Moreover, natural history suggests ageing as the principal determinant to develop skin and eye symptoms. VKCFD1 symptoms seemed more severe in patients with both mutations in the same protein domain, though this could not be linked to a more perturbed coagulation factor function. Finally, distinct GGCX functional domains might be dedicated to carboxylation of very specific VKDP. In conclusion, this systematic review suggests that there indeed may be genotype–phenotype correlations for GGCX-related phenotypes, which can guide patient counseling and management.
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13
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Nair P, Hamzeh AR, Malik EM, Oberoi D, Al-Ali MT, Bastaki F. Novel PDE6A mutation in an Emirati patient with retinitis pigmentosa. Oman J Ophthalmol 2017; 10:228-231. [PMID: 29118501 PMCID: PMC5657168 DOI: 10.4103/ojo.ojo_213_2016] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Mutations in the PDE6A gene are known to cause a form of retinitis pigmentosa (RP43), characterized by progressive retinal degeneration. We describe an Emirati patient with RP caused by a novel mutation in PDE6A. Clinical diagnosis of RP was made based on clinical evaluation and electroretinograms. The molecular analysis involved performing whole-exome sequencing, which enabled the identification of a homozygous 2-bp deletion (c.1358_1359delAT) in PDE6A, which was predicted to result in a frameshift and premature termination (p.Ile452Serfs*7). The mutation completely removed the catalytic PDEase domain in the protein. The parents were found to be heterozygous carriers of the variant. We thus report the first known case of a pathological variant in the PDE6A gene from the Arabian Peninsula.
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Affiliation(s)
| | | | - Ethar Mustafa Malik
- Department of Pediatric, Latifa Hospital, Dubai Health Authority, Dubai, UAE
| | | | | | - Fatma Bastaki
- Department of Pediatric, Latifa Hospital, Dubai Health Authority, Dubai, UAE
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Dasi MA, Gonzalez-Conejero R, Izquierdo S, Padilla J, Garcia JL, Garcia-Barberá N, Argilés B, de la Morena-Barrio ME, Hernández-Sánchez JM, Hernández-Rivas JM, Vicente V, Corral J. Uniparental disomy causes deficiencies of vitamin K-dependent proteins. J Thromb Haemost 2016; 14:2410-2418. [PMID: 27681307 DOI: 10.1111/jth.13517] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Accepted: 08/08/2016] [Indexed: 08/31/2023]
Abstract
Essentials Vitamin K-dependent coagulant factor deficiency (VKCFD) is a rare autosomal recessive disorder. We describe a case of inherited VKCFD due to uniparental disomy. The homozygous mutation caused the absence of GGCX isoform 1 and overexpression of Δ2GGCX. Hepatic and non-hepatic vitamin K-dependent proteins must be assayed to monitor VKCFD treatment. SUMMARY Background Inherited deficiency of all vitamin K-dependent coagulant factors (VKCFD) is a rare autosomal recessive disorder caused by mutations in the γ-glutamyl carboxylase gene (GGCX) or the vitamin K epoxide reductase gene (VKORC1), with great heterogeneity in terms of both clinical presentation and response to treatment. Objective To characterize the molecular basis of VKCFD in a Spanish family. Methods and Results Sequencing of candidate genes, comparative genomic hybridization and massive sequencing identified a new mechanism causing VKCFD in the proband. Uniparental disomy (UPD) of chromosome 2 caused homozygosity of a mutation (c.44-1G>A) resulting in aberrant GGCX splicing. This change contributed to absent expression of the mRNA coding for the full-length protein, and to four-fold overexpression of the smaller mRNA isoform lacking exon 2 (Δ2GGCX). Δ2GGCX might be responsible for two unexpected clinical observations in the patient: (i) increased plasma osteocalcin levels following vitamin K1 supplementation; and (ii) a mild non-bleeding phenotype. Conclusions Our study identifies a new autosomal disease, VKCFD1, caused by UPD. These data suggest that the Δ2GGCX isoform may retain enzymatic activity, and strongly encourage the evaluation of both hepatic and non-hepatic vitamin K-dependent proteins to assess differing responses to vitamin K supplementation in VKCFD patients.
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Affiliation(s)
- M A Dasi
- Unidad de Hematología Pediátrica, Hospital Universitario y Politécnico La Fe, Valencia, Spain
| | | | - S Izquierdo
- Unidad de Hematología Pediátrica, Hospital Universitario y Politécnico La Fe, Valencia, Spain
| | - J Padilla
- Centro Regional de Hemodonación, Universidad de Murcia-IMIB, Murcia, Spain
| | - J L Garcia
- Centro de Investigación del Cáncer-Universidad de Salamanca-CSIC, Salamanca, Spain
| | - N Garcia-Barberá
- Centro Regional de Hemodonación, Universidad de Murcia-IMIB, Murcia, Spain
| | - B Argilés
- Unidad de Hematología Pediátrica, Hospital Universitario y Politécnico La Fe, Valencia, Spain
| | - M E de la Morena-Barrio
- Centro Regional de Hemodonación, Universidad de Murcia-IMIB, Murcia, Spain
- Grupo CB15/00055 del Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Instituto de Salud Carlos III (ISCIII), Madrid, Spain
| | | | - J M Hernández-Rivas
- Centro de Investigación del Cáncer-Universidad de Salamanca-CSIC, Salamanca, Spain
| | - V Vicente
- Centro Regional de Hemodonación, Universidad de Murcia-IMIB, Murcia, Spain
- Grupo CB15/00055 del Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Instituto de Salud Carlos III (ISCIII), Madrid, Spain
| | - J Corral
- Centro Regional de Hemodonación, Universidad de Murcia-IMIB, Murcia, Spain
- Grupo CB15/00055 del Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Instituto de Salud Carlos III (ISCIII), Madrid, Spain
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Jin DY, Vermeer C, Stafford DW, Tie JK. Splice-Site Mutation of Exon 3 Deletion in the Gamma-Glutamyl Carboxylase Gene Causes Inactivation of the Enzyme. J Invest Dermatol 2016; 136:2314-2317. [PMID: 27394683 DOI: 10.1016/j.jid.2016.05.128] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2016] [Revised: 05/04/2016] [Accepted: 05/10/2016] [Indexed: 01/26/2023]
Affiliation(s)
- Da-Yun Jin
- Department of Biology, University of North Carolina at Chapel Hill, North Carolina, USA
| | - Cees Vermeer
- R&D Group VitaK, Maastricht University, Maastricht, The Netherlands
| | - Darrel W Stafford
- Department of Biology, University of North Carolina at Chapel Hill, North Carolina, USA
| | - Jian-Ke Tie
- Department of Biology, University of North Carolina at Chapel Hill, North Carolina, USA.
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16
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Gusdorf L, Mitcov M, Maradeix S, Cunat S, Martin L, Cribier B. [Pseudoxanthoma elasticum-like disease with deficiency of vitamin K-dependent clotting factors and cutis laxa features]. Ann Dermatol Venereol 2016; 143:279-83. [PMID: 26944767 DOI: 10.1016/j.annder.2015.11.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2015] [Accepted: 11/09/2015] [Indexed: 11/30/2022]
Abstract
BACKGROUND Pseudoxanthoma elasticum (PXE)-like syndrome is characterized by the association of PXE and cutis laxa (CL) features with a deficiency of vitamin K-dependent clotting factors. It was first described in 1971 and was identified as a distinct genetic entity in 2007 with analysis of the GGCX (γ-glutamyl carboxylase) gene, which is involved in congenital deficiency in vitamin K-dependent clotting factors. Here we report a new case of this extremely rare syndrome. PATIENTS AND METHODS A 23-year-old female patient was seen for the emergence of loose and redundant skin following extensive weight loss. She also presented a deficiency of vitamin K-dependent clotting factors. Physical examination revealed excessive, leathery skin folds in the axillary and neck regions. A skin biopsy revealed polymorphous and fragmented elastic fibers in the reticular dermis. These were mineralized, as was demonstrated by Von Kossa staining. The clinical features of CL associated with the histopathological features of PXE and vitamin K-dependent clotting factor deficiency led us to a diagnosis of PXE-like syndrome. A molecular study of the GGCX gene showed compound heterozygosity. DISCUSSION The GGCX gene is usually responsible for PXE-like syndrome. GGCX encodes a γ-glutamyl carboxylase necessary for activation of gla-proteins. Gla-proteins are involved both in coagulation factors in the liver and in the prevention of ectopic mineralization of soft tissues. Uncarboxylated forms of gla-proteins in fibroblast would thus enable mineralization and fragmentation of elastic fibers.
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Affiliation(s)
- L Gusdorf
- Clinique dermatologique, hôpitaux universitaires de Strasbourg, 1, place de l'Hôpital, 67000 Strasbourg, France.
| | - M Mitcov
- Clinique dermatologique, hôpitaux universitaires de Strasbourg, 1, place de l'Hôpital, 67000 Strasbourg, France
| | - S Maradeix
- Cabinet de dermatologie, 11, rue du Maréchal-Foch, 67500 Haguenau, France
| | - S Cunat
- Laboratoire d'hématologie, CHU de Montpellier, 80, avenue Augustin-Fliche, 34090 Montpellier, France
| | - L Martin
- Service de dermatologie, CHU d'Angers, 4, rue Larrey, 49100 Angers, France
| | - B Cribier
- Clinique dermatologique, hôpitaux universitaires de Strasbourg, 1, place de l'Hôpital, 67000 Strasbourg, France
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17
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Tie JK, Stafford DW. Structural and functional insights into enzymes of the vitamin K cycle. J Thromb Haemost 2016; 14:236-47. [PMID: 26663892 PMCID: PMC5073812 DOI: 10.1111/jth.13217] [Citation(s) in RCA: 68] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Accepted: 11/25/2015] [Indexed: 12/20/2022]
Abstract
Vitamin K-dependent proteins require carboxylation of certain glutamates for their biological functions. The enzymes involved in the vitamin K-dependent carboxylation include: gamma-glutamyl carboxylase (GGCX), vitamin K epoxide reductase (VKOR) and an as-yet-unidentified vitamin K reductase (VKR). Due to the hydrophobicity of vitamin K, these enzymes are likely to be integral membrane proteins that reside in the endoplasmic reticulum. Therefore, structure-function studies on these enzymes have been challenging, and some of the results are notably controversial. Patients with naturally occurring mutations in these enzymes, who mainly exhibit bleeding disorders or are resistant to oral anticoagulant treatment, provide valuable information for the functional study of the vitamin K cycle enzymes. In this review, we discuss: (i) the discovery of the enzymatic activities and gene identifications of the vitamin K cycle enzymes; (ii) the identification of their functionally important regions and their active site residues; (iii) the membrane topology studies of GGCX and VKOR; and (iv) the controversial issues regarding the structure and function studies of these enzymes, particularly, the membrane topology, the role of the conserved cysteines and the mechanism of active site regeneration of VKOR. We also discuss the possibility that a paralogous protein of VKOR, VKOR-like 1 (VKORL1), is involved in the vitamin K cycle, and the importance of and possible approaches for identifying the unknown VKR. Overall, we describe the accomplishments and the remaining questions in regard to the structure and function studies of the enzymes in the vitamin K cycle.
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Affiliation(s)
- J-K Tie
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - D W Stafford
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
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Vanakker O, Callewaert B, Malfait F, Coucke P. The Genetics of Soft Connective Tissue Disorders. Annu Rev Genomics Hum Genet 2015; 16:229-55. [DOI: 10.1146/annurev-genom-090314-050039] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Olivier Vanakker
- Center for Medical Genetics, Ghent University Hospital, 9000 Ghent, Belgium;
| | - Bert Callewaert
- Center for Medical Genetics, Ghent University Hospital, 9000 Ghent, Belgium;
| | - Fransiska Malfait
- Center for Medical Genetics, Ghent University Hospital, 9000 Ghent, Belgium;
| | - Paul Coucke
- Center for Medical Genetics, Ghent University Hospital, 9000 Ghent, Belgium;
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