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Ansh AJ, Stabach PR, Ciccone C, Cao W, De La Cruz EM, Sabbagh Y, Carpenter TO, Ferreira CR, Braddock DT. Quantitative correlation of ENPP1 pathogenic variants with disease phenotype. Bone 2024:117136. [PMID: 38806089 DOI: 10.1016/j.bone.2024.117136] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2024] [Revised: 04/07/2024] [Accepted: 05/24/2024] [Indexed: 05/30/2024]
Abstract
Ectonucleotide pyrophosphatase/phosphodiesterase 1 (ENPP1) codes for a type 2 transmembrane glycoprotein which hydrolyzes extracellular phosphoanhydrides into bio-active molecules that regulate, inter alia, ectopic mineralization, bone formation, vascular endothelial proliferation, and the innate immune response. The clinical phenotypes produced by ENPP1 deficiency are disparate, ranging from life-threatening arterial calcifications to cutaneous hypopigmentation. To investigate associations between disease phenotype and enzyme activity we quantified the enzyme velocities of 29 unique ENPP1 pathogenic variants in 41 patients enrolled in an NIH study along with 33 other variants reported in literature. We correlated the relative enzyme velocities with the presenting clinical diagnoses, performing the catalytic velocity measurements simultaneously in triplicate using a high-throughput assay to reduce experimental variation. We found that ENPP1 variants associated with autosomal dominant phenotypes reduced enzyme velocities by 50 % or more, whereas variants associated with insulin resistance had non-significant effects on enzyme velocity. In Cole's disease the catalytic velocities of ENPP1 variants associated with AD forms trended to lower values than those associated with autosomal recessive forms - 8-32 % vs. 33 % of WT, respectively. Additionally, ENPP1 variants leading to life-threatening vascular calcifications in GACI patients had widely variable enzyme activities, ranging from no significant differences compared to WT to the complete abolishment of enzyme velocity. Finally, disease severity in GACI did not correlate with the mean enzyme velocity of the variants present in affected compound heterozygotes but did correlate with the more severely damaging variant. In summary, correlation of ENPP1 enzyme velocity with disease phenotypes demonstrate that enzyme velocities below 50 % of WT levels are likely to occur in the context of autosomal dominant disease (due to a monoallelic variant), and that disease severity in GACI infants correlates with the more severely damaging ENPP1 variant in compound heterozygotes, not the mean velocity of the pathogenic variants present.
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Affiliation(s)
- Anenya Jai Ansh
- Department of Pathology, Yale University School of Medicine, New Haven, CT, USA
| | - Paul R Stabach
- Department of Pathology, Yale University School of Medicine, New Haven, CT, USA
| | - Carla Ciccone
- Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | - Wenxiang Cao
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA
| | - Enrique M De La Cruz
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA
| | - Yves Sabbagh
- Inozyme Pharma, 321 Summer St., Suite 400, Boston, MA 02201, USA
| | - Thomas O Carpenter
- Department of Pediatrics (Endocrinology), Yale University School of Medicine, New Haven, CT, USA
| | - Carlos R Ferreira
- Metabolic Medicine Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | - Demetrios T Braddock
- Department of Pathology, Yale University School of Medicine, New Haven, CT, USA.
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Hidaka N, Murata H, Tachikawa K, Osaki K, Sekiyama T, Kinoshita Y, Kato H, Hoshino Y, Kimura S, Sunouchi T, Watanabe S, Nangaku M, Makita N, Michigami T, Ito N. The Effect of Asfotase Alfa on Plasma and Urine Pyrophosphate Levels and Pseudofractures in a Patient With Adult-Onset Hypophosphatasia. JBMR Plus 2023; 7:e10842. [PMID: 38130758 PMCID: PMC10731098 DOI: 10.1002/jbm4.10842] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Revised: 10/07/2023] [Accepted: 10/25/2023] [Indexed: 12/23/2023] Open
Abstract
Hypophosphatasia (HPP) is an inherited disease caused by variants of the ALPL gene encoding tissue-nonspecific alkaline phosphatase. Adult-onset HPP (adult HPP), known as a mild form of HPP, develops symptoms involving osteomalacia after the age of 18 years. Asfotase alfa (AA) is a modulated recombinant human alkaline phosphatase (ALP) that has been established as a first-line therapy for severe forms of HPP, such as perinatal and infantile forms. We described a 64-year-old female who presented with pseudofractures in bilateral femur diaphyses and impaired mobility. Low serum ALP activity and a high concentration of urine phosphoethanolamine indicated the diagnosis of HPP, which was confirmed by the identification of a homozygous variant in the ALPL gene (c.319G > A; p.Val107Ile). An in vitro transfection experiment to measure the ALP activity of this novel variant protein was performed, resulting in 40% of the residual enzymatic activity compared with the wild type. AA was initiated to facilitate the union of pseudofracture and to improve mobility. After 6 months, radiographic images revealed the disappearance of fracture lines, and improvement of ambulatory ability was confirmed by the 6-minute walk test (525 to 606 m). The EQ-5D-5L index was also improved (0.757 to 0.895). Within a follow-up period, the levels of urine pyrophosphate corrected by urine creatinine (uPPi/Cre) declined in parallel with the level of plasma PPi (plasma PPi: 6.34 to 1.04 μM, uPPi/Cre: 226.8 to 75.4 nmol/mg). The beneficial effect of AA on pseudofracture healing in adult HPP was presented, although the application of AA should be restricted to patients exhibiting relatively severe manifestations. In addition, a novel pathogenic variant of the ALPL gene was identified with the supportive result of functional analysis. Furthermore, when monitoring patients with HPP treated with AA, uPPi/Cre might be a convenient substitute for plasma PPi, which requires immediate filtration after blood sampling. © 2023 The Authors. JBMR Plus published by Wiley Periodicals LLC. on behalf of American Society for Bone and Mineral Research.
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Affiliation(s)
- Naoko Hidaka
- Division of Nephrology and EndocrinologyThe University of Tokyo HospitalTokyoJapan
- Osteoporosis CenterThe University of Tokyo HospitalTokyoJapan
| | - Hiroaki Murata
- Department of Orthopaedic Surgery, Panasonic Health Insurance OrganizationMatsushita Memorial HospitalOsakaJapan
| | - Kanako Tachikawa
- Department of Bone and Mineral Research, Research InstituteOsaka Women's and Children's HospitalOsakaJapan
| | - Keiichi Osaki
- Department of Rehabilitation, Panasonic Health Insurance OrganizationMatsushita Memorial HospitalOsakaJapan
| | - Takashi Sekiyama
- Department of Rehabilitation, Panasonic Health Insurance OrganizationMatsushita Memorial HospitalOsakaJapan
| | - Yuka Kinoshita
- Division of Nephrology and EndocrinologyThe University of Tokyo HospitalTokyoJapan
- Osteoporosis CenterThe University of Tokyo HospitalTokyoJapan
| | - Hajime Kato
- Division of Nephrology and EndocrinologyThe University of Tokyo HospitalTokyoJapan
- Osteoporosis CenterThe University of Tokyo HospitalTokyoJapan
| | - Yoshitomo Hoshino
- Division of Nephrology and EndocrinologyThe University of Tokyo HospitalTokyoJapan
- Osteoporosis CenterThe University of Tokyo HospitalTokyoJapan
| | - Soichiro Kimura
- Division of Nephrology and EndocrinologyThe University of Tokyo HospitalTokyoJapan
- Osteoporosis CenterThe University of Tokyo HospitalTokyoJapan
| | - Takashi Sunouchi
- Division of Nephrology and EndocrinologyThe University of Tokyo HospitalTokyoJapan
- Osteoporosis CenterThe University of Tokyo HospitalTokyoJapan
| | - So Watanabe
- Osteoporosis CenterThe University of Tokyo HospitalTokyoJapan
- Department of Geriatric Medicine, Graduate School of MedicineThe University of TokyoTokyoJapan
| | - Masaomi Nangaku
- Division of Nephrology and EndocrinologyThe University of Tokyo HospitalTokyoJapan
| | - Noriko Makita
- Division of Nephrology and EndocrinologyThe University of Tokyo HospitalTokyoJapan
- Osteoporosis CenterThe University of Tokyo HospitalTokyoJapan
| | - Toshimi Michigami
- Department of Bone and Mineral Research, Research InstituteOsaka Women's and Children's HospitalOsakaJapan
| | - Nobuaki Ito
- Division of Nephrology and EndocrinologyThe University of Tokyo HospitalTokyoJapan
- Osteoporosis CenterThe University of Tokyo HospitalTokyoJapan
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3
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Kato H, Braddock DT, Ito N. Genetics of Diffuse Idiopathic Skeletal Hyperostosis and Ossification of the Spinal Ligaments. Curr Osteoporos Rep 2023; 21:552-566. [PMID: 37530996 PMCID: PMC10543536 DOI: 10.1007/s11914-023-00814-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 07/03/2023] [Indexed: 08/03/2023]
Abstract
PURPOSE OF REVIEW The study aims to provide updated information on the genetic factors associated with the diagnoses 'Diffuse Idiopathic Skeletal Hyperostosis' (DISH), 'Ossification of the Posterior Longitudinal Ligament' (OPLL), and in patients with spinal ligament ossification. RECENT FINDINGS Recent studies have advanced our knowledge of genetic factors associated with DISH, OPLL, and other spinal ossification (ossification of the anterior longitudinal ligament [OALL] and the yellow ligament [OYL]). Several case studies of individuals afflicted with monogenic disorders, such as X-linked hypophosphatemia (XLH), demonstrate the strong association of fibroblast growth factor 23-related hypophosphatemia with OPLL, suggesting that pathogenic variants in PHEX, ENPP1, and DMP1 are associated with FGF23-phosphate wasting phenotype and strong genetic factors placing patients at risk for OPLL. Moreover, emerging evidence demonstrates that heterozygous and compound heterozygous ENPP1 pathogenic variants inducing 'Autosomal Recessive Hypophosphatemic Rickets Type 2' (ARHR2) also place patients at risk for DISH and OPLL, possibly due to the loss of inhibitory plasma pyrophosphate (PPi) which suppresses ectopic calcification and enthesis mineralization. Our findings emphasize the importance of genetic and plasma biomarker screening in the clinical evaluation of DISH and OPLL patients, with plasma PPi constituting an important new biomarker for the identification of DISH and OPLL patients whose disease course may be responsive to ENPP1 enzyme therapy, now in clinical trials for rare calcification disorders.
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Affiliation(s)
- Hajime Kato
- Division of Nephrology and Endocrinology, The University of Tokyo Hospital, 7-3-1 Hongo, Bunkyo-Ku, Tokyo, 113-8655, Japan
- Osteoporosis Center, The University of Tokyo Hospital, Tokyo, Japan
| | | | - Nobuaki Ito
- Division of Nephrology and Endocrinology, The University of Tokyo Hospital, 7-3-1 Hongo, Bunkyo-Ku, Tokyo, 113-8655, Japan.
- Osteoporosis Center, The University of Tokyo Hospital, Tokyo, Japan.
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4
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Khursigara G, Huertas P, Wenkert D, O'Brien K, Sabbagh Y. Effects of food, fasting, and exercise on plasma pyrophosphate levels and ENPP1 activity in healthy adults. Bone 2023; 171:116750. [PMID: 37003563 DOI: 10.1016/j.bone.2023.116750] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Revised: 03/21/2023] [Accepted: 03/23/2023] [Indexed: 04/01/2023]
Abstract
BACKGROUND Inorganic pyrophosphate (PPi) is highly regulated as it plays a critical role in the regulation of physiological mineralization. Dysregulation of plasma PPi is associated with skeletal hypomineralization and pathogenic mineralization in soft connective tissue, arteries, and heart valves. There is no standard approach to measuring PPi, making it difficult to establish PPi as a biomarker of mineralization disorders. This study aims to determine the impact of time of day, meals, or exercise on plasma PPi homeostasis using a highly sensitive PPi assay. METHODS In this single-center trial, a clinical laboratory improvement amendment (CLIA) validated modified sulfurylase-based adenosine 5-triphosphate (ATP) assay was used to measure PPi levels throughout the day in 10 healthy adults under 3 conditions; normal diet (non-fasting), fasting, and normal diet with exercise. Serum ectonucleotide pyrophosphatase/phosphodiesterase 1 activity (ENPP1; an enzyme that produces PPi) was also measured to determine whether these conditions influence PPi levels through ENPP1 activity. RESULTS There is a circadian increase in mean PPi levels under fasting and non-fasting conditions between 8 am and 6 pm, followed by a rapid return to baseline overnight. A circadian increase in ENPP1 activity was also measured under fasting but was lost under non-fasting conditions. Meals increased the individual variability of PPi levels when compared to the same individual fasting. PPi levels and ENPP1 activity exhibited a short-term increase after intense exercise. We found PPi ranges from 1465 nM to 2969 nM (mean 2164 nM) after fasting overnight. Within this range, there was lower intra-subject variability in PPi, suggesting that each individual has a uniquely regulated normal PPi range. CONCLUSION Plasma levels of PPi can be reliably measured after an overnight fast and show promise as a biomarker of mineralization disorders.
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Affiliation(s)
- Gus Khursigara
- Inozyme Pharma, 321 Summer St, Suite 400, Boston, MA 02201, United States of America.
| | - Pedro Huertas
- Inozyme Pharma, 321 Summer St, Suite 400, Boston, MA 02201, United States of America
| | - Deborah Wenkert
- Inozyme Pharma, 321 Summer St, Suite 400, Boston, MA 02201, United States of America
| | - Kevin O'Brien
- Inozyme Pharma, 321 Summer St, Suite 400, Boston, MA 02201, United States of America
| | - Yves Sabbagh
- Inozyme Pharma, 321 Summer St, Suite 400, Boston, MA 02201, United States of America
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Maffeis V, Hürlimann D, Krywko-Cendrowska A, Schoenenberger CA, Housecroft CE, Palivan CG. A DNA-Micropatterned Surface for Propagating Biomolecular Signals by Positional on-off Assembly of Catalytic Nanocompartments. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2023; 19:e2202818. [PMID: 35869606 DOI: 10.1002/smll.202202818] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Revised: 06/17/2022] [Indexed: 06/15/2023]
Abstract
Signal transduction is pivotal for the transfer of information between and within living cells. The composition and spatial organization of specified compartments are key to propagating soluble signals. Here, a high-throughput platform mimicking multistep signal transduction which is based on a geometrically defined array of immobilized catalytic nanocompartments (CNCs) that consist of distinct polymeric nanoassemblies encapsulating enzymes and DNA or enzymes alone is presented. The dual role of single entities or tandem CNCs in providing confined but communicating spaces for complex metabolic reactions and in protecting encapsulated compounds from denaturation is explored. To support a controlled spatial organization of CNCs, CNCs are patterned by means of DNA hybridization to a microprinted glass surface. Specifically, CNC-functionalized DNA microarrays are produced where individual reaction compartments are kept in close proximity by a distinct geometrical arrangement to promote effective communication. Besides a remarkable versatility and robustness, the most prominent feature of this platform is the reversibility of DNA-mediated CNC-anchoring which renders it reusable. Micropatterns of polymer-based nanocompartment assemblies offer an ideal scaffold for the development of the next generation responsive and communicative soft-matter analytical devices for applications in catalysis and medicine.
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Affiliation(s)
- Viviana Maffeis
- Department of Chemistry, University of Basel, Mattenstrasse 24a, BPR 1096, Basel, 4058, Switzerland
- NCCR-Molecular Systems Engineering, BPR 1095, Mattenstrasse 24a, Basel, CH-4058, Switzerland
| | - Dimitri Hürlimann
- Department of Chemistry, University of Basel, Mattenstrasse 24a, BPR 1096, Basel, 4058, Switzerland
- NCCR-Molecular Systems Engineering, BPR 1095, Mattenstrasse 24a, Basel, CH-4058, Switzerland
| | - Agata Krywko-Cendrowska
- Department of Chemistry, University of Basel, Mattenstrasse 24a, BPR 1096, Basel, 4058, Switzerland
| | - Cora-Ann Schoenenberger
- Department of Chemistry, University of Basel, Mattenstrasse 24a, BPR 1096, Basel, 4058, Switzerland
- NCCR-Molecular Systems Engineering, BPR 1095, Mattenstrasse 24a, Basel, CH-4058, Switzerland
| | - Catherine E Housecroft
- Department of Chemistry, University of Basel, Mattenstrasse 24a, BPR 1096, Basel, 4058, Switzerland
- NCCR-Molecular Systems Engineering, BPR 1095, Mattenstrasse 24a, Basel, CH-4058, Switzerland
| | - Cornelia G Palivan
- Department of Chemistry, University of Basel, Mattenstrasse 24a, BPR 1096, Basel, 4058, Switzerland
- NCCR-Molecular Systems Engineering, BPR 1095, Mattenstrasse 24a, Basel, CH-4058, Switzerland
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6
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Lundkvist S, Niaziorimi F, Szeri F, Caffet M, Terry SF, Johansson G, Jansen RS, van de Wetering K. A new enzymatic assay to quantify inorganic pyrophosphate in plasma. Anal Bioanal Chem 2023; 415:481-492. [PMID: 36400967 PMCID: PMC9839608 DOI: 10.1007/s00216-022-04430-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Revised: 11/03/2022] [Accepted: 11/08/2022] [Indexed: 11/21/2022]
Abstract
Inorganic pyrophosphate (PPi) is a crucial extracellular mineralization regulator. Low plasma PPi concentrations underlie the soft tissue calcification present in several rare hereditary mineralization disorders as well as in more common conditions like chronic kidney disease and diabetes. Even though deregulated plasma PPi homeostasis is known to be linked to multiple human diseases, there is currently no reliable assay for its quantification. We here describe a PPi assay that employs the enzyme ATP sulfurylase to convert PPi into ATP. Generated ATP is subsequently quantified by firefly luciferase-based bioluminescence. An internal ATP standard was used to correct for sample-specific interference by matrix compounds on firefly luciferase activity. The assay was validated and shows excellent precision (< 3.5%) and accuracy (93-106%) of PPi spiked into human plasma samples. We found that of several anticoagulants tested only EDTA effectively blocked conversion of ATP into PPi in plasma after blood collection. Moreover, filtration over a 300,000-Da molecular weight cut-off membrane reduced variability of plasma PPi and removed ATP present in a membrane-enclosed compartment, possibly platelets. Applied to plasma samples of wild-type and Abcc6-/- rats, an animal model with established low circulating levels of PPi, the new assay showed lower variability than the assay that was previously in routine use in our laboratory. In conclusion, we here report a new and robust assay to determine PPi concentrations in plasma, which outperforms currently available assays because of its high sensitivity, precision, and accuracy.
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Affiliation(s)
- Stefan Lundkvist
- Department of Dermatology and Cutaneous Biology, Jefferson Institute of Molecular Medicine and PXE International Center of Excellence in Research and Clinical Care, Sidney Kimmel Medical College, Thomas Jefferson University, 233 S 10th Street, PA, 19107, Philadelphia, USA
- Department of Chemistry (BMC), Uppsala University, Uppsala, Sweden
| | - Fatemeh Niaziorimi
- Department of Dermatology and Cutaneous Biology, Jefferson Institute of Molecular Medicine and PXE International Center of Excellence in Research and Clinical Care, Sidney Kimmel Medical College, Thomas Jefferson University, 233 S 10th Street, PA, 19107, Philadelphia, USA
| | - Flora Szeri
- Department of Dermatology and Cutaneous Biology, Jefferson Institute of Molecular Medicine and PXE International Center of Excellence in Research and Clinical Care, Sidney Kimmel Medical College, Thomas Jefferson University, 233 S 10th Street, PA, 19107, Philadelphia, USA
- Research Centre for Natural Sciences, Institute of Enzymology, Budapest, Hungary
- Department of Biochemistry, Semmelweis University, Budapest, Hungary
| | | | | | - Gunnar Johansson
- Department of Chemistry (BMC), Uppsala University, Uppsala, Sweden
| | - Robert S Jansen
- Department of Microbiology, Radboud University, Nijmegen, The Netherlands
| | - Koen van de Wetering
- Department of Dermatology and Cutaneous Biology, Jefferson Institute of Molecular Medicine and PXE International Center of Excellence in Research and Clinical Care, Sidney Kimmel Medical College, Thomas Jefferson University, 233 S 10th Street, PA, 19107, Philadelphia, USA.
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7
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Liu J, Song X, Zhang D, Jiang Y, Ma M, Qiu Z, Xia W, Chen Y. Case report: Multiple arterial stenoses induced by autosomal-recessive hypophosphatemic rickets type 2 associated with mutation of ENPP1: a case study. Front Cardiovasc Med 2023; 10:1126445. [PMID: 37153460 PMCID: PMC10155832 DOI: 10.3389/fcvm.2023.1126445] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Accepted: 03/28/2023] [Indexed: 05/09/2023] Open
Abstract
Ectonucleotide pyrophosphatase/phosphodiesterase 1 (ENPP1)-related multiple arterial stenoses is a rare clinical syndrome in which global arterial calcification begins in infancy, with a high probability of early mortality, and hypophosphatemic rickets develops later in childhood. The vascular status of an ENPP1-mutated patient when they enter the rickets phase has not been thoroughly explored. In this study, we presented a case of an adolescent with an ENPP1 mutation who complained of uncontrolled hypertension. Systematic radiography showed renal, carotid, cranial, and aortic stenoses as well as random calcification foci on arterial walls. The patient was incorrectly diagnosed with Takayasu's arteritis, and cortisol therapy had little effect on reducing the vascular stenosis. As a result, phosphate replacement, calcitriol substitution, and antihypertensive medication were prescribed, and the patient was discharged for further examination. This research presented the vascular alterations of an ENPP1-mutanted patient, and while there is less calcification, intimal thickening may be the primary cause of arterial stenosis.
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Affiliation(s)
- Jie Liu
- Department of Neurosurgery, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China
| | - Xitao Song
- Department of Vascular Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China
| | - Daming Zhang
- Department of Radiology, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China
| | - Yan Jiang
- Department of Endocrinology, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China
| | - Mingsheng Ma
- Department of Pediatrics, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China
| | - Zhengqing Qiu
- Department of Pediatrics, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China
| | - Weibo Xia
- Department of Endocrinology, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China
| | - Yuexin Chen
- Department of Vascular Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China
- Correspondence: Yuexin Chen
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Adult Presentation of X-Linked Hypophosphatemia. ENDOCRINES 2022. [DOI: 10.3390/endocrines3030030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Adult X-linked hypophosphatemia (XLH) patients present with specific symptoms, including enthesopathies (e.g., ossification of longitudinal ligaments (OPLL), osteophytes around large joints, and enthesopathy in the Achilles tendons), early osteoarthritis, the development of severe secondary and tertiary hyperparathyroidism (SHPT/THPT), and the subsequent progression of chronic kidney disease (CKD). In addition, these patients exhibit the typical phenotypes of osteomalacia, such as pseudofracture and fracture in weight-bearing bones, odontitis, and tooth abscesses. The mechanism underlying enthesopathy development is unknown; however, a common underlying mechanism among XLH and autosomal recessive hypophosphatemic rickets (ARHR1/2) due to mutations in PHEX, DMP1, and ENPP1 is assumed. Clarification of the pathogenesis and drug discovery for this complication is an urgent issue, as many adult XLH patients suffer subsequent debilitating nervous symptoms or impingement syndrome, and existing treatments are ineffective. Severe SHPT and THPT are associated with conventional therapy, including active vitamin D and phosphate supplementation, and complicated and careful adjustment of dosages by experienced clinicians is required to avoid SHPT/THPT. Burosumab is a very effective therapy without risk for the development of SHPT/THPT. However, indications for this drug should be carefully considered, along with cost-effectiveness, guidelines or recommendations, and the health care system of each country.
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9
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Leftheriotis G, Navasiolava N, Clotaire L, Duranton C, Le Saux O, Bendahhou S, Laurain A, Rubera I, Martin L. Relationships between Plasma Pyrophosphate, Vascular Calcification and Clinical Severity in Patients Affected by Pseudoxanthoma Elasticum. J Clin Med 2022; 11:jcm11092588. [PMID: 35566717 PMCID: PMC9100273 DOI: 10.3390/jcm11092588] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Revised: 04/28/2022] [Accepted: 04/30/2022] [Indexed: 12/10/2022] Open
Abstract
Pseudoxanthoma elasticum (PXE; OMIM 264800) is an autosomal recessive metabolic disorder characterized by progressive calcification in the skin, the Bruch’s membrane, and the vasculature. Calcification in PXE results from a low level of circulating pyrophosphate (PPi) caused by ABCC6 deficiency. In this study, we used a cohort of 107 PXE patients to determine the pathophysiological relationship between plasma PPi, coronary calcification (CAC), lower limbs arterial calcification (LLAC), and disease severity. Overall, our data showed a deficit in plasma PPi in PXE patients compared to controls. Remarkably, affected females showed higher PPi levels than males, but a lower LLAC. There was a strong correlation between age and PPi in PXE patients (r = 0.423, p < 0.0001) but not in controls (r = 0.059, p = 0.828). A weak correlation was found between PPi and CAC (r = 0.266, p < 0.02); however, there was no statistically significant connection with LLAC (r = 0.068, p = 0.518) or a severity score (r = 0.077, p = 0.429). Surprisingly, we found no significant correlation between plasma alkaline phosphatase activity and PPi (r = 0.113, p = 0.252) or between a 10-year cardiovascular risk score and all other variables. Multivariate analysis confirmed that LLAC and CAC were strongly dependent on age, but not on PPi. Our data showed that arterial calcification is only weakly linked to circulating PPi levels and that time (i.e., age) appears to be the major determinant of disease severity and calcification in PXE. These data are important to better understand the natural history of this disease but also for the follow-up and management of patients, and the design of future clinical trials. Our results also show that PPi is not a good biomarker for the evaluation of disease severity and progression.
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Affiliation(s)
- Georges Leftheriotis
- University Hospital Nice, Vascular Physiology and Medicine Unit, 06000 Nice, France
- Université Côte d’Azur, LP2M, UMR CNRS 7370, LabEx ICST, 06107 Nice, France; (L.C.); (C.D.); (S.B.); (A.L.); (I.R.)
- Correspondence: or
| | - Nastassia Navasiolava
- PXE Reference Center, MAGEC Nord, University Hospital of Angers, 49000 Angers, France; (N.N.); (L.M.)
| | - Laetitia Clotaire
- Université Côte d’Azur, LP2M, UMR CNRS 7370, LabEx ICST, 06107 Nice, France; (L.C.); (C.D.); (S.B.); (A.L.); (I.R.)
| | - Christophe Duranton
- Université Côte d’Azur, LP2M, UMR CNRS 7370, LabEx ICST, 06107 Nice, France; (L.C.); (C.D.); (S.B.); (A.L.); (I.R.)
| | - Olivier Le Saux
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, HI 96817, USA;
| | - Saïd Bendahhou
- Université Côte d’Azur, LP2M, UMR CNRS 7370, LabEx ICST, 06107 Nice, France; (L.C.); (C.D.); (S.B.); (A.L.); (I.R.)
| | - Audrey Laurain
- Université Côte d’Azur, LP2M, UMR CNRS 7370, LabEx ICST, 06107 Nice, France; (L.C.); (C.D.); (S.B.); (A.L.); (I.R.)
| | - Isabelle Rubera
- Université Côte d’Azur, LP2M, UMR CNRS 7370, LabEx ICST, 06107 Nice, France; (L.C.); (C.D.); (S.B.); (A.L.); (I.R.)
| | - Ludovic Martin
- PXE Reference Center, MAGEC Nord, University Hospital of Angers, 49000 Angers, France; (N.N.); (L.M.)
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