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Heijboer AC, Cavalier E. The Measurement and Interpretation of Fibroblast Growth Factor 23 (FGF23) Concentrations. Calcif Tissue Int 2023; 112:258-270. [PMID: 35665817 PMCID: PMC9859838 DOI: 10.1007/s00223-022-00987-9] [Citation(s) in RCA: 20] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Accepted: 05/06/2022] [Indexed: 02/05/2023]
Abstract
Two decades after the discovery of the hormone FGF23, we know more about phosphate homeostasis as it turned out that FGF23 is the central hormone that regulates this. Hereditary hypophosphatemic rickets and tumor-induced osteomalacia could by then be explained, by autonomous FGF23 production, and the nephrology field was excited by this new marker as it turned out to be independently associated with mortality in people treated by hemodialysis. This led to the development of several immunoassays to be able to measure FGF23 in blood. In the past years we learned that FGF23 is a rather stable peptide, the precision of the assays is acceptable but assays are not standardized and therefore not comparable. This means that reference values and cutoff values need to be assay specific. For several assays reference values have been established and gender and age did not seem of high importance. The phosphate content of the diet, which can be culturally dependent, however, should be taken into account when interpreting results, but to what extent is not totally clear. Currently, clinical application of the immunoassays is established in the diagnosis of hereditary hypophosphatemic rickets and diagnosis and follow-up of tumor-induced osteomalacia. Definite conclusions on the usefulness of the FGF23 measurement in people with CKD either as a marker for risk prediction or a as target for treatment remains to be determined. The latter applications would require dedicated prospective clinical trials, which may take years, before providing answers. To improve the standardization of the FGF23 assays and to shed light on the biological functions that fragments might have we might aim for an LC-MS/MS-based method to quantify both intact and fragmented FGF23. In this literature review we will summarize the current knowledge on the physiological role of FGF23, its quantification, and the clinical usefulness of its determination.
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Affiliation(s)
- Annemieke C Heijboer
- Endocrine Laboratory, Department of Clinical Chemistry, Amsterdam Gastroenterology Endocrinology & Metabolism, Amsterdam UMC, Vrije Universiteit Amsterdam and University of Amsterdam, de Boelelaan 1117 and Meibergdreef 9, Amsterdam, The Netherlands.
| | - Etienne Cavalier
- Department of Clinical Chemistry, CHU de Liège, University of Liège, 4000, Liège, Belgium
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2
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Kritmetapak K, Kumar R. Phosphatonins: From Discovery to Therapeutics. Endocr Pract 2023; 29:69-79. [PMID: 36210014 DOI: 10.1016/j.eprac.2022.09.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Revised: 09/22/2022] [Accepted: 09/23/2022] [Indexed: 01/11/2023]
Abstract
OBJECTIVE Phosphate is crucial for cell signaling, energy metabolism, nucleotide synthesis, and bone mineralization. The gut-bone-parathyroid-kidney axis is influenced by parathyroid hormone, 1,25-dihydroxyvitamin D, and phosphatonins, especially fibroblast growth factor 23 (FGF23). These hormones facilitate maintenance of phosphate homeostasis. This review summarizes current knowledge regarding the phosphate homeostasis, phosphatonin pathophysiology, and clinical implications of FGF23-related hypophosphatemic disorders, with specific focus on burosumab treatment. METHOD A focused literature search of PubMed was conducted. RESULTS Phosphatonins including FGF23, secreted frizzled-related protein 4, matrix extracellular phosphoglycoprotein, and fibroblast growth factor 7 play a pathogenic role in several hypophosphatemic disorders. Excess FGF23 inhibits sodium-dependent phosphate cotransporters (NaPi-2a and NaPi-2c), resulting in hyperphosphaturia and hypophosphatemia. Additionally, FGF23 suppresses 1,25-dihydroxyvitamin D synthesis in the proximal renal tubule, and thus, it indirectly inhibits intestinal phosphate absorption. Disorders of FGF23-related hypophosphatemia include X-linked hypophosphatemia (XLH), autosomal dominant hypophosphatemic rickets, autosomal recessive hypophosphatemic rickets, fibrous dysplasia/McCune-Albright syndrome, and tumor-induced osteomalacia (TIO). Complications of conventional therapy with oral phosphate and vitamin D analogs comprise gastrointestinal distress, hypercalcemia, nephrocalcinosis, and secondary/tertiary hyperparathyroidism. In both children and adults with XLH and TIO, the anti-FGF23 antibody burosumab exhibits a favorable safety profile and is associated with healing of rickets in affected children and improvement of osteomalacia in both children and adults. CONCLUSION The treatment paradigm for XLH and TIO is changing based on data from recent clinical trials. Research suggest that burosumab is effective and safe for pediatric and adult patients with XLH or TIO.
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Affiliation(s)
| | - Rajiv Kumar
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, Minnesota.
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3
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Kato H, Okawa R, Ogasawara T, Hoshino Y, Hidaka N, Koga M, Kinoshita Y, Kobayashi H, Taniguchi Y, Fukumoto S, Nangaku M, Makita N, Hoshi K, Nakano K, Ito N. Effect of conventional treatment on dental complications and ectopic ossifications among 30 adults with XLH. J Clin Endocrinol Metab 2022; 108:1405-1414. [PMID: 36524341 DOI: 10.1210/clinem/dgac732] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Revised: 11/29/2022] [Accepted: 12/13/2022] [Indexed: 12/23/2022]
Abstract
CONTEXT Conventional treatment of XLH was reported to prevent dental complications, but whether the preventive effect was different among different types of teeth, including anterior teeth and molar teeth, is uncertain. Evidence of the preventive effect of conventional treatment on ectopic ossifications is also limited. OBJECTIVE To compare dental complications and ectopic ossifications among XLH adults with early (< 5 years old) or late (≥5 years old) conventional treatment. METHODS This retrospective observational study included a total of 30 adults with XLH using orthopantomograms, spinal computed tomography scans and X-rays of hip/knee joints. Dental complications, including decayed, missing filled (DMF) index and devitalized tooth, apical periodontitis, and periodontitis, were evaluated. The index of ossification of the anterior/posterior longitudinal ligament and yellow ligament (OA/OP/OY index) and the sum of the OA/OP/OY index (OS index) were utilized to evaluate the severity of spinal ligament ossification. The severity of the hip/knee osteophytes was evaluated by the Kellgren-Lawrence (KL) classification. RESULTS The number of sound teeth was significantly lower, and the DMF index was significantly higher in patients with late treatment. The severity of dental complications in the anterior tooth and molar tooth, OA/OP/OY/OS index, and KL grade were not significantly different among patients with early treatment and those with late treatment. CONCLUSION Early treatment could prevent dental complications but did not prevent ectopic ossification in adult patients with XLH. The difference in the preventive effect was not observed among different types of teeth.
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Affiliation(s)
- Hajime Kato
- Division of Nephrology and Endocrinology, The University of Tokyo Hospital, Tokyo, Japan
- Osteoporosis Center, The University of Tokyo Hospital, Tokyo, Japan
| | - Rena Okawa
- Department of Pediatric Dentistry, Osaka University Graduate School of Dentistry, Osaka, Japan
| | - Toru Ogasawara
- Department of Oral and Maxillofacial Surgery, The University of Tokyo Hospital, Tokyo, Japan
| | - Yoshitomo Hoshino
- Division of Nephrology and Endocrinology, The University of Tokyo Hospital, Tokyo, Japan
- Osteoporosis Center, The University of Tokyo Hospital, Tokyo, Japan
| | - Naoko Hidaka
- Division of Nephrology and Endocrinology, The University of Tokyo Hospital, Tokyo, Japan
- Osteoporosis Center, The University of Tokyo Hospital, Tokyo, Japan
| | - Minae Koga
- Division of Nephrology and Endocrinology, The University of Tokyo Hospital, Tokyo, Japan
- Osteoporosis Center, The University of Tokyo Hospital, Tokyo, Japan
| | - Yuka Kinoshita
- Division of Nephrology and Endocrinology, The University of Tokyo Hospital, Tokyo, Japan
| | - Hiroshi Kobayashi
- Department of Orthopedic Surgery, The University of Tokyo Hospital, Tokyo, Japan
| | - Yuki Taniguchi
- Department of Orthopedic Surgery, The University of Tokyo Hospital, Tokyo, Japan
| | - Seiji Fukumoto
- Fujii Memorial Institute of Medical Sciences, Institute of Advanced Medical Sciences, Tokushima University, Tokushima, Japan
| | - Masaomi Nangaku
- Division of Nephrology and Endocrinology, The University of Tokyo Hospital, Tokyo, Japan
| | - Noriko Makita
- Division of Nephrology and Endocrinology, The University of Tokyo Hospital, Tokyo, Japan
- Osteoporosis Center, The University of Tokyo Hospital, Tokyo, Japan
| | - Kazuto Hoshi
- Department of Oral and Maxillofacial Surgery, The University of Tokyo Hospital, Tokyo, Japan
| | - Kazuhiko Nakano
- Department of Pediatric Dentistry, Osaka University Graduate School of Dentistry, Osaka, Japan
| | - Nobuaki Ito
- Division of Nephrology and Endocrinology, The University of Tokyo Hospital, Tokyo, Japan
- Osteoporosis Center, The University of Tokyo Hospital, Tokyo, Japan
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4
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Kato H, Koga M, Kinoshita Y, Hidaka N, Hoshino Y, Takashi Y, Arai M, Kobayashi H, Katsura M, Nakamoto Y, Makise N, Ushiku T, Hoshi K, Nangaku M, Makita N, Fukumoto S, Ito N. Utility of Multimodality Approach Including Systemic FGF23 Venous Sampling in Localizing Phosphaturic Mesenchymal Tumors. J Endocr Soc 2022; 7:bvac181. [PMID: 36540156 PMCID: PMC9757682 DOI: 10.1210/jendso/bvac181] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Indexed: 11/27/2022] Open
Abstract
Context Tumor-induced osteomalacia (TIO) is one of the most common forms of acquired fibroblast growth factor 23 (FGF23)-related hypophosphatemia and is usually caused by phosphaturic mesenchymal tumors (PMTs). Although the complete resection of PMTs can cure TIO, preoperative localization of tumors by standard imaging modalities is often challenging. In addition to 18F-fluoro-2-deoxy-D-glucose positron emission tomography-computed tomography (FDG-PET) and 111In-pentetreotide scintigraphy (SRS), systemic FGF23 venous sampling (FGF23VS) has been used to help localize PMTs in specialized institutions. Objective This study aimed to evaluate the diagnostic performance of each imaging test and their combinations in localizing PMTs. Methods In an observational retrospective study of patients with adult-onset FGF23-related osteomalacia who underwent all 3 imaging studies (FDG-PET, SRS, and FGF23VS), the rate of successful preoperative localization of the tumors was evaluated only in the patients with pathological diagnoses of PMTs, considering the possibility that pathogenesis of patients without identified tumors might be due to other causes such as late-onset hereditary FGF23-related hypophosphatemia. Results A total of 30 Japanese patients with TIO (median age, 60 years [range, 28-87 years]; 10 women [33.3%]) were included in the study. The success rate of preoperative localization for each test and combinations of 2 or 3 tests among 18 patients with PMTs was as follows: 72% (FDG-PET), 72% (SRS), 94% (FGF23VS), 89% (FDG-PET, SRS), 100% (FDG-PET, FGF23VS), 94% (SRS, FGF23VS), and 100% (FDG-PET, SRS, and FGF23VS). Conclusion We observed the highest localization rate of PMTs in patients with identified PMTs with the combination of FDG-PET and FGF23VS.
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Affiliation(s)
| | | | - Yuka Kinoshita
- Division of Nephrology and Endocrinology, The University of Tokyo Hospital, Tokyo, 113-8655, Japan,Osteoporosis Center, The University of Tokyo Hospital, Tokyo, 113-8655, Japan
| | - Naoko Hidaka
- Division of Nephrology and Endocrinology, The University of Tokyo Hospital, Tokyo, 113-8655, Japan,Osteoporosis Center, The University of Tokyo Hospital, Tokyo, 113-8655, Japan
| | - Yoshitomo Hoshino
- Division of Nephrology and Endocrinology, The University of Tokyo Hospital, Tokyo, 113-8655, Japan,Osteoporosis Center, The University of Tokyo Hospital, Tokyo, 113-8655, Japan
| | - Yuichi Takashi
- Department of Endocrinology and Diabetes Mellitus, Fukuoka University School of Medicine, Fukuoka, 814-0180, Japan
| | - Makoto Arai
- Division of Molecular Physiology and Metabolism, Faculty of Medicine, Tohoku University, Miyagi, 980-8575, Japan
| | - Hiroshi Kobayashi
- Department of Orthopedic Surgery, The University of Tokyo Hospital, Tokyo, 113-8655, Japan
| | - Masaki Katsura
- Department of Radiology, Graduate School of Medicine, The University of Tokyo, Tokyo, 113-8655, Japan
| | - Yuji Nakamoto
- Department of Diagnostic Imaging and Nuclear Medicine, Graduate School of Medicine Kyoto University, Kyoto, 606-8507, Japan
| | - Naohiro Makise
- Department of Pathology, Graduate School of Medicine, The University of Tokyo, Tokyo, 113-8655, Japan,Division of Surgical Pathology, Chiba Cancer Center, Chiba, 260-8717, Japan
| | - Tetsuo Ushiku
- Department of Pathology, Graduate School of Medicine, The University of Tokyo, Tokyo, 113-8655, Japan
| | - Kazuto Hoshi
- Department of Oral-maxillofacial Surgery, Dentistry and Orthodontics, and Division of Tissue Engineering, The University of Tokyo Hospital, Tokyo, 113-8655, Japan
| | - Masaomi Nangaku
- Division of Nephrology and Endocrinology, The University of Tokyo Hospital, Tokyo, 113-8655, Japan
| | - Noriko Makita
- Division of Nephrology and Endocrinology, The University of Tokyo Hospital, Tokyo, 113-8655, Japan,Osteoporosis Center, The University of Tokyo Hospital, Tokyo, 113-8655, Japan
| | - Seiji Fukumoto
- Fujii Memorial Institute of Medical Sciences, Institute of Advanced Medical Sciences, Tokushima University, Tokushima, 770-8503, Japan
| | - Nobuaki Ito
- Correspondence: Nobuaki Ito, MD, PhD, Division of Nephrology and Endocrinology, The University of Tokyo Hospital, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655, Japan.
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Hartley IR, Gafni RI, Roszko KL, Brown SM, de Castro LF, Saikali A, Ferreira CR, Gahl WA, Pacak K, Blau JE, Boyce AM, Salusky IB, Collins MT, Florenzano P. Determination of FGF23 Levels for the Diagnosis of FGF23-Mediated Hypophosphatemia. J Bone Miner Res 2022; 37:2174-2185. [PMID: 36093861 PMCID: PMC9712269 DOI: 10.1002/jbmr.4702] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Revised: 08/22/2022] [Accepted: 09/05/2022] [Indexed: 11/09/2022]
Abstract
Fibroblast growth factor-23 (FGF23) measurement is a critical tool in the evaluation of patients with disordered phosphate homeostasis. Available laboratory reference ranges for blood FGF23 were developed using samples from normophosphatemic individuals. Reliance on such values can lead to misdiagnosis in patients with FGF23-mediated hypophosphatemia, such as X-linked hypophosphatemia (XLH) and tumor-induced osteomalacia (TIO), in whom pathology-driving FGF23 levels can be in the "normal range." To determine FGF23 levels that are diagnostic for the identification of patients with FGF23-mediated hypophosphatemic disorders, we studied 149 patients with various disorders of FGF23-mediated and FGF23-independent hypophosphatemia and defined cut-off levels for both intact FGF23 (iFGF23) and C-terminal FGF23 (cFGF23) that can accurately distinguish between FGF23-mediated and FGF23-independent hypophosphatemia. In addition, to demonstrate the relationship between FGF23 and phosphate across the spectrum of human physiology, we assessed blood levels of FGF23 and phosphate in 434 patients with various forms of hypophosphatemia, hyperphosphatemia, and normophosphatemia. An intact FGF23 cut point of 27 pg/mL was 100% sensitive and specific in distinguishing FGF23-mediated from FGF23-independent hypophosphatemia, and a cFGF23 cut point of 90 RU/mL was 100% sensitive and specific in distinguishing specifically TIO from FGF23-independent hypophosphatemia. There was overlap in the cFGF23 range of 45-90 RU/mL between genetic forms of FGF23 excess and FGF23-independent hypophosphatemia, substantiating the superiority of iFGF23 over cFGF23 in making the diagnosis of FGF23-mediated hypophosphatemia. In this cohort, using the laboratory upper limit of normal for cFGF23 (180 RU/mL) would result in a misdiagnosis in more than half of patients with FGF23-mediated hypophosphatemia. In this, the largest study of FGF23 in chronic hypophosphatemia to date, we established iFGF23 and cFGF23 cut-off values to assist in the evaluation and diagnosis of hypophosphatemic conditions. © 2022 American Society for Bone and Mineral Research (ASBMR). This article has been contributed to by US Government employees and their work is in the public domain in the USA.
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Affiliation(s)
- Iris R. Hartley
- Skeletal Disorders and Mineral Homeostasis Section, National Institutes of Dental and Craniofacial Research. National Institutes of Health, Bethesda, MD, USA
| | - Rachel I. Gafni
- Skeletal Disorders and Mineral Homeostasis Section, National Institutes of Dental and Craniofacial Research. National Institutes of Health, Bethesda, MD, USA
| | - Kelly L. Roszko
- Skeletal Disorders and Mineral Homeostasis Section, National Institutes of Dental and Craniofacial Research. National Institutes of Health, Bethesda, MD, USA
| | - Sydney M. Brown
- Skeletal Disorders and Mineral Homeostasis Section, National Institutes of Dental and Craniofacial Research. National Institutes of Health, Bethesda, MD, USA
| | - Luis F. de Castro
- Skeletal Disorders and Mineral Homeostasis Section, National Institutes of Dental and Craniofacial Research. National Institutes of Health, Bethesda, MD, USA
| | - Amanda Saikali
- Skeletal Disorders and Mineral Homeostasis Section, National Institutes of Dental and Craniofacial Research. National Institutes of Health, Bethesda, MD, USA
| | - Carlos R. Ferreira
- Metabolic Medicine Branch, National Human Genome Research Institute, National Institutes of Health
| | - William A. Gahl
- Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland
| | - Karel Pacak
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Jenny E. Blau
- National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Alison M. Boyce
- Skeletal Disorders and Mineral Homeostasis Section, National Institutes of Dental and Craniofacial Research. National Institutes of Health, Bethesda, MD, USA
| | - Isidro B. Salusky
- Division of Nephrology, Department of Pediatrics, David Geffen School of Medicine at University of California, Los Angeles, CA, USA
| | - Michael T. Collins
- Skeletal Disorders and Mineral Homeostasis Section, National Institutes of Dental and Craniofacial Research. National Institutes of Health, Bethesda, MD, USA
| | - Pablo Florenzano
- Department of Endocrinology, School of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile
- School of Medicine, Pontificia Universidad Catolica de Chile, Centro Traslacional en Endocrinología UC (CETREN-UC), Santiago, Chile
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6
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Abstract
Inorganic phosphate (Pi) in the mammalian body is balanced by its influx and efflux through the intestines, kidneys, bones, and soft tissues, at which several sodium/Pi co-transporters mediate its active transport. Pi homeostasis is achieved through the complex counter-regulatory feedback balance between fibroblast growth factor 23 (FGF23), 1,25-dihydroxyvitamin D (1,25(OH)2D), and parathyroid hormone. FGF23, which is mainly produced by osteocytes in bone, plays a central role in Pi homeostasis and exerts its effects by binding to the FGF receptor (FGFR) and αKlotho in distant target organs. In the kidneys, the main target, FGF23 promotes the excretion of Pi and suppresses the production of 1,25(OH)2D. Deficient and excess FGF23 result in hyperphosphatemia and hypophosphatemia, respectively. FGF23-related hypophosphatemic rickets/osteomalacia include tumor-induced osteomalacia and various genetic diseases, such as X-linked hypophosphatemic rickets. Coverage by the national health insurance system in Japan for the measurement of FGF23 and the approval of burosumab, an FGF23-neutralizing antibody, have had a significant impact on the diagnosis and treatment of FGF23-related hypophosphatemic rickets/osteomalacia. Some of the molecules responsible for genetic hypophosphatemic rickets/osteomalacia are highly expressed in osteocytes and function as local regulators of FGF23 production. A number of systemic factors also regulate FGF23 levels. Although the mechanisms responsible for Pi sensing in mammals have not yet been elucidated in detail, recent studies have suggested the involvement of FGFR1. The further clarification of the mechanisms by which osteocytes detect Pi levels and regulate FGF23 production will lead to the development of better strategies to treat hyperphosphatemic and hypophosphatemic conditions.
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Affiliation(s)
- Toshimi Michigami
- Department of Bone and Mineral Research, Research Institute, Osaka Women's and Children's Hospital, Osaka 594-1101, Japan
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7
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Hidaka N, Koga M, Kimura S, Hoshino Y, Kato H, Kinoshita Y, Makita N, Nangaku M, Horiguchi K, Furukawa Y, Ohnaka K, Inagaki K, Nakagawa A, Suzuki A, Takeuchi Y, Fukumoto S, Nakatani F, Ito N. Clinical Challenges in Diagnosis, Tumor Localization and Treatment of Tumor-Induced Osteomalacia: Outcome of a Retrospective Surveillance. J Bone Miner Res 2022; 37:1479-1488. [PMID: 35690913 DOI: 10.1002/jbmr.4620] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Revised: 05/27/2022] [Accepted: 06/04/2022] [Indexed: 01/02/2023]
Abstract
Tumor-induced osteomalacia (TIO) is an acquired fibroblast growth factor 23 (FGF23)-related hypophosphatemic osteomalacia caused by phosphaturic mesenchymal tumors (PMTs) developed in the bone or soft tissue. Diagnostic delay should be addressed, and ideal techniques to localize PMTs and efficient treatment options should be explored to improve the outcomes of this rare disease. To clarify the detailed clinical course and outcomes of TIO patients, retrospective questionnaire surveys were conducted among physicians from the Japanese Society for Bone and Mineral Research (JSBMR) and the Japan Endocrine Society (JES). The primary survey collected the number of TIO patients between January 2007 and December 2018. The secondary survey aimed to obtain the detailed characteristics, laboratory data, and outcomes. Eighty-eight patients (52 males, mean: 52 years old) were included, and 24 patients were clinically diagnosed with TIO without localized PMTs. The median duration from the onset to detection of high FGF23 levels was 3.4 years, with 77 patients being initially misdiagnosed. Among the methods used to detect small, localized PMTs (≤10 mm), fluorine-18-fluorodeoxyglucose-positron emission tomography/computed tomography and somatostatin receptor scintigraphy were less sensitive than somatostatin receptor positron emission tomography/computed tomography (SRPET/CT). Systemic venous sampling (SVS) of FGF23 was performed in 53 patients; among them, SVS was considered useful for detecting localized PMTs in 45 patients with diverse tumor sizes. Finally, 45 patients achieved biochemical remission by surgery, 39 patients continued pharmaceutical treatment, including burosumab (11 patients), and four patients died. These results encouraged us to further increase the awareness of TIO and to improve the accessibility of SRPET/CT and SVS. Further evidence about the efficacy of new pharmaceutical treatments is awaited. © 2022 American Society for Bone and Mineral Research (ASBMR).
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Affiliation(s)
- Naoko Hidaka
- Division of Nephrology and Endocrinology, The University of Tokyo Hospital, Tokyo, Japan.,Osteoporosis Center, The University of Tokyo Hospital, Tokyo, Japan
| | - Minae Koga
- Division of Nephrology and Endocrinology, The University of Tokyo Hospital, Tokyo, Japan.,Osteoporosis Center, The University of Tokyo Hospital, Tokyo, Japan
| | - Soichiro Kimura
- Division of Nephrology and Endocrinology, The University of Tokyo Hospital, Tokyo, Japan.,Toranomon Hospital Endocrine Center, Toranomon Hospital, Tokyo, Japan
| | - Yoshitomo Hoshino
- Division of Nephrology and Endocrinology, The University of Tokyo Hospital, Tokyo, Japan.,Osteoporosis Center, The University of Tokyo Hospital, Tokyo, Japan
| | - Hajime Kato
- Division of Nephrology and Endocrinology, The University of Tokyo Hospital, Tokyo, Japan.,Osteoporosis Center, The University of Tokyo Hospital, Tokyo, Japan
| | - Yuka Kinoshita
- Division of Nephrology and Endocrinology, The University of Tokyo Hospital, Tokyo, Japan.,Osteoporosis Center, The University of Tokyo Hospital, Tokyo, Japan
| | - Noriko Makita
- Division of Nephrology and Endocrinology, The University of Tokyo Hospital, Tokyo, Japan.,Osteoporosis Center, The University of Tokyo Hospital, Tokyo, Japan
| | - Masaomi Nangaku
- Division of Nephrology and Endocrinology, The University of Tokyo Hospital, Tokyo, Japan
| | - Kazuhiko Horiguchi
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Gunma University Graduate School of Medicine, Maebashi, Japan
| | - Yasushi Furukawa
- First Department of Internal Medicine, Wakayama Medical University, Wakayama, Japan
| | - Keizo Ohnaka
- Department of Geriatric Medicine, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Kenichi Inagaki
- Endocrine Center, Okayama University Hospital, Okayama, Japan
| | - Atsushi Nakagawa
- Department of Diabetology and Endocrinology, Kanazawa Medical University, Kahoku, Japan
| | - Atsushi Suzuki
- Department of Endocrinology, Diabetes and Metabolism, Fujita Health University, Toyoake, Japan
| | - Yasuhiro Takeuchi
- Toranomon Hospital Endocrine Center, Toranomon Hospital, Tokyo, Japan
| | - Seiji Fukumoto
- Fujii Memorial Institute of Medical Sciences, Institute of Advanced Medical Sciences, Tokushima University, Tokushima, Japan
| | - Fumihiko Nakatani
- Department of Musculoskeletal Oncology, National Cancer Center Hospital East, Kashiwa, Japan
| | - Nobuaki Ito
- Division of Nephrology and Endocrinology, The University of Tokyo Hospital, Tokyo, Japan.,Osteoporosis Center, The University of Tokyo Hospital, Tokyo, Japan
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8
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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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Kato H, Ansh AJ, Lester ER, Kinoshita Y, Hidaka N, Hoshino Y, Koga M, Taniguchi Y, Uchida T, Yamaguchi H, Niida Y, Nakazato M, Nangaku M, Makita N, Takamura T, Saito T, Braddock DT, Ito N. Identification of ENPP1 Haploinsufficiency in Patients With Diffuse Idiopathic Skeletal Hyperostosis and Early-Onset Osteoporosis. J Bone Miner Res 2022; 37:1125-1135. [PMID: 35340077 PMCID: PMC9177665 DOI: 10.1002/jbmr.4550] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Revised: 03/14/2022] [Accepted: 03/21/2022] [Indexed: 11/10/2022]
Abstract
Homozygous ENPP1 mutations are associated with autosomal recessive hypophosphatemic rickets type 2 (ARHR2), severe ossification of the spinal ligaments, and generalized arterial calcification of infancy type 1. There are a limited number of reports on phenotypes associated with heterozygous ENPP1 mutations. Here, we report a series of three probands and their families with heterozygous and compound heterozygous ENPP1 mutations. The first case (case 1) was a 47-year-old male, diagnosed with early-onset osteoporosis and low-normal serum phosphate levels, which invoked suspicion for hypophosphatemic rickets. The second and third cases were 77- and 54-year-old females who both presented with severe spinal ligament ossification and the presumptive diagnosis of diffuse idiopathic skeletal hyperostosis (DISH). Upon workup, fibroblast growth factor 23 (FGF23) was noted to be relatively high in case 2 and serum phosphorous was low-normal in case 3, and the diagnoses of X-linked hypophosphatemic rickets (XLH) and ARHR2 were considered. Genetic testing for genes related to congenital hypophosphatemic rickets was therefore performed, revealing heterozygous ENPP1 variants in cases 1 and 2 (case 1, c.536A>G, p.Asn179Ser; case 2, c.1352A>G, p.Tyr451Cys) and compound heterozygous ENPP1 variants in case 3 constituting the same variants present in cases 1 and 2 (c.536A>G, p.Asn179Ser and c.1352A>G, p.Tyr451Cys). Several in silico tools predicted the two variants to be pathogeneic, a finding confirmed by in vitro biochemical analysis demonstrating that the p.Asn179Ser and p.Tyr451Cys ENPP1 variants possessed a catalytic velocity of 45% and 30% compared with that of wild-type ENPP1, respectively. Both variants were therefore categorized as pathogenic loss-of-function mutations. Our findings suggest that ENPP1 mutational status should be evaluated in patients presenting with the diagnosis of idiopathic DISH, ossification of the posterior longitudinal ligament (OPLL), and early-onset osteoporosis. © 2022 American Society for Bone and Mineral Research (ASBMR).
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Affiliation(s)
- Hajime Kato
- Division of Nephrology and Endocrinology, The University of Tokyo Hospital, Tokyo, Japan
- Osteoporosis center, The University of Tokyo Hospital, Tokyo, Japan
| | - Anenya J. Ansh
- Department of Pathology, Yale University, New Haven, CT, USA
| | - Ethan R. Lester
- Department of Pathology, Yale University, New Haven, CT, USA
| | - Yuka Kinoshita
- Division of Nephrology and Endocrinology, The University of Tokyo Hospital, Tokyo, Japan
- Osteoporosis center, The University of Tokyo Hospital, Tokyo, Japan
| | - Naoko Hidaka
- Division of Nephrology and Endocrinology, The University of Tokyo Hospital, Tokyo, Japan
- Osteoporosis center, The University of Tokyo Hospital, Tokyo, Japan
| | - Yoshitomo Hoshino
- Division of Nephrology and Endocrinology, The University of Tokyo Hospital, Tokyo, Japan
- Osteoporosis center, The University of Tokyo Hospital, Tokyo, Japan
| | - Minae Koga
- Division of Nephrology and Endocrinology, The University of Tokyo Hospital, Tokyo, Japan
- Osteoporosis center, The University of Tokyo Hospital, Tokyo, Japan
| | - Yuki Taniguchi
- Department of Orthopedic Surgery, The University of Tokyo Hospital, Tokyo, Japan
| | - Taisuke Uchida
- Division of Neurology, Respirology, Endocrinology and Metabolism, Department of Internal Medicine, Faculty of Medicine, University of Miyazaki, Miyazaki, Japan
| | - Hideki Yamaguchi
- Division of Neurology, Respirology, Endocrinology and Metabolism, Department of Internal Medicine, Faculty of Medicine, University of Miyazaki, Miyazaki, Japan
| | - Yo Niida
- Division of Genomic Medicine, Department of Advanced Medicine, Medical Research Institute, Kanazawa Medical University, Ishikawa, Japan
| | - Masamitsu Nakazato
- Division of Neurology, Respirology, Endocrinology and Metabolism, Department of Internal Medicine, Faculty of Medicine, University of Miyazaki, Miyazaki, Japan
| | - Masaomi Nangaku
- Division of Nephrology and Endocrinology, The University of Tokyo Hospital, Tokyo, Japan
| | - Noriko Makita
- Division of Nephrology and Endocrinology, The University of Tokyo Hospital, Tokyo, Japan
- Osteoporosis center, The University of Tokyo Hospital, Tokyo, Japan
| | - Toshinari Takamura
- Department of Endocrinology and Metabolism, Kanazawa University Graduate School of Medical Sciences, Ishikawa, Japan
| | - Taku Saito
- Osteoporosis center, The University of Tokyo Hospital, Tokyo, Japan
- Department of Orthopedic Surgery, The University of Tokyo Hospital, Tokyo, Japan
| | | | - Nobuaki Ito
- Division of Nephrology and Endocrinology, The University of Tokyo Hospital, Tokyo, Japan
- Osteoporosis center, The University of Tokyo Hospital, Tokyo, Japan
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