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Takashi Y, Kawanami D, Fukumoto S. Recent advances in fibroblast growth factor 23-related hypophosphatemic disorders. Curr Opin Endocrinol Diabetes Obes 2024:01266029-990000000-00093. [PMID: 38687287 DOI: 10.1097/med.0000000000000866] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 05/02/2024]
Abstract
PURPOSE OF REVIEW Fibroblast growth factor 23 (FGF23) is a hormone to reduce blood phosphate concentration. Excessive actions of FGF23 induce FGF23-related hypophosphatemic disorders, such as X-linked hypophosphatemic rickets (XLH) and tumor-induced osteomalacia (TIO). We will summarize recent advances in the diagnosis and treatment of FGF23-related hypophosphatemic disorders. RECENT FINDINGS The measurement of blood FGF23 is useful to make a diagnosis of FGF23-related hypophosphatemic disorders. It was reported that many patients with FGF23-related hypophosphatemic disorders, especially TIO, were misdiagnosed, therefore, it is necessary to enhance the awareness of these diseases. A novel method to inhibit excessive actions of FGF23 by a human monoclonal antibody for FGF23, burosumab, has been approved in several countries. In more long-term observation than clinical trials, burosumab has also been shown to improve biochemical abnormalities and symptoms of rickets/osteomalacia. Following these advances, several registries and consensus recommendations on FGF23-related hypophosphatemic disorders, especially XLH, have been established in each country or region. SUMMARY Further long-term effects of burosumab and the precise mechanism of FGF23 overproduction in patients with FGF23-related hypophosphatemic disorders need to be clarified in the future studies.
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Affiliation(s)
- Yuichi Takashi
- Department of Endocrinology and Diabetes, Fukuoka University School of Medicine
| | - Daiji Kawanami
- Department of Endocrinology and Diabetes, Fukuoka University School of Medicine
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Vaisbich MH, de Cillo ACP, Silva BCC, DÁlva CB, de Carvalho ÉH, de Almeida JMCM, Marques LLM, Ribeiro M, da Silva MBM, de Medeiros PFV, Mendes PH. Real-world data of Brazilian adults with X-linked hypophosphatemia (XLH) treated with burosumab and comparison with other worldwide cohorts. Mol Genet Genomic Med 2024; 12:e2387. [PMID: 38337160 PMCID: PMC10858313 DOI: 10.1002/mgg3.2387] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Revised: 12/23/2023] [Accepted: 01/17/2024] [Indexed: 02/12/2024] Open
Abstract
BACKGROUND Disease-related variants in PHEX cause XLH by an increase of fibroblast growth factor 23 (FGF23) circulating levels, resulting in hypophosphatemia and 1,25(OH)2 vitamin D deficiency. XLH manifests in early life with rickets and persists in adulthood with osseous and extraosseous manifestations. Conventional therapy (oral phosphate and calcitriol) improves some symptoms, but evidence show that it is not completely effective, and it can lead to nephrocalcinosis (NC) and hyperparathyroidism (HPT). Burosumab (anti-FGF23 antibody) has shown to be effective and safety in the clinical trials. METHODS The current real-world collaborative study evaluated genetic, clinical and laboratory data of XLH Brazilian adult patients treated with burosumab. RESULTS Nineteen unrelated patients were studied. Patients reported pain, limb deformities and claudication, before burosumab initiation. 78% of them were previously treated with conventional therapy. The severity of the disease was moderate to severe (15 patients with score >5). At the baseline, 3 patients presented NC (16.7%) and 12 HPT (63%). After 16 ± 8.4 months under burosumab, we observed a significant: increase in stature (p = 0.02), in serum phosphate from 1.90 ± 0.43 to 2.67 ± 0.52 mg/dL (p = 0.02); in TmP/GFR from 1.30 ± 0.46 to 2.27 ± 0.64 mg/dL (p = 0.0001), in 1,25 (OH)2 D from 50.5 ± 23.3 to 71.1 ± 19.1 pg/mL (p = 0.03), and a decrease in iPTH from 86.8 ± 37.4 pg/mL to 66.5 ± 31.1 (p = 0.002). Nineteen variants were found (10 novel). HPT tended to develop in patients with truncated PHEX variants (p = 0.06). CONCLUSIONS This study confirms the efficacy and safety of burosumab on XLH adult patients observed in clinical trials. Additionally, we observed a decrease in iPTH levels in patients with moderate to severe HPT at the baseline.
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Affiliation(s)
| | | | - Bárbara Campolina C. Silva
- Hospital Felício Rocho, Osteometabolism Unit of Santa Casa de Belo HorizonteProfessor of Medicine at University Center of Belo Horizonte – UNIBHBelo HorizonteBrazil
| | | | - Érico Higino de Carvalho
- Instituto de Medicina Integrada Professor Fernado Figueira, recifeFederal University of PernambucoRecifeBrazil
| | | | | | - Marcia Ribeiro
- Genetic Unit of Federal University of Rio de JaneiroRio de JaneiroBrazil
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Ariceta G, Beck-Nielsen SS, Boot AM, Brandi ML, Briot K, de Lucas Collantes C, Emma F, Giannini S, Haffner D, Keen R, Levtchenko E, Mӓkitie O, Mughal MZ, Nilsson O, Schnabel D, Tripto-Shkolnik L, Liu J, Williams A, Wood S, Zillikens MC. The International X-Linked Hypophosphatemia (XLH) Registry: first interim analysis of baseline demographic, genetic and clinical data. Orphanet J Rare Dis 2023; 18:304. [PMID: 37752558 PMCID: PMC10523658 DOI: 10.1186/s13023-023-02882-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Accepted: 08/24/2023] [Indexed: 09/28/2023] Open
Abstract
BACKGROUND X-linked hypophosphatemia (XLH) is a rare, hereditary, progressive, renal phosphate-wasting disorder characterized by a pathological increase in FGF23 concentration and activity. Due to its rarity, diagnosis may be delayed, which can adversely affect outcomes. As a chronic disease resulting in progressive accumulation of musculoskeletal manifestations, it is important to understand the natural history of XLH over the patient's lifetime and the impact of drug treatments and other interventions. This multicentre, international patient registry (International XLH Registry) was established to address the paucity of these data. Here we present the findings of the first interim analysis of the registry. RESULTS The International XLH Registry was initiated in August 2017 and includes participants of all ages diagnosed with XLH, regardless of their treatment and management. At the database lock for this first interim analysis (29 March 2021), 579 participants had entered the registry before 30 November 2020 and are included in the analysis (360 children [62.2%], 217 adults [37.5%] and 2 whose ages were not recorded [0.3%]; 64.2% were female). Family history data were available for 319/345 (92.5%) children and 145/187 (77.5%) adults; 62.1% had biological parents affected by XLH. Genetic testing data were available for 341 (94.7%) children and 203 (93.5%) adults; 370/546 (67.8%) had genetic test results; 331/370 (89.5%) had a confirmed PHEX mutation. A notably longer time to diagnosis was observed in adults ≥ 50 years of age (mean [median] duration 9.4 [2.0] years) versus all adults (3.7 [0.1] years) and children (1.0 [0.2] years). Participants presented with normal weight, shorter length or height and elevated body mass index (approximately - 2 and + 2 Z-scores, respectively) versus the general population. Clinical histories were collected for 349 participants (239 children and 110 adults). General data trends for prevalence of bone, dental, renal and joint conditions in all participants were aligned with expectations for a typical population of people with XLH. CONCLUSION The data collected within the International XLH Registry, the largest XLH registry to date, provide substantial information to address the paucity of natural history data, starting with demographic, family history, genetic testing, diagnosis, auxology and baseline data on clinical presentation.
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Affiliation(s)
- Gema Ariceta
- Department of Pediatric Nephrology, Hospital Vall d'Hebron, Universitat Autonoma Barcelona, Barcelona, Spain.
| | - Signe Sparre Beck-Nielsen
- Centre for Rare Diseases, Aarhus University Hospital, Åarhus, Denmark
- Department of Clinical Medicine, Aarhus University, Åarhus, Denmark
| | - Annemieke M Boot
- Department of Pediatrics, Division of Endocrinology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | | | - Karine Briot
- Hôpital Cochin, Service de Rhumatologie, Centre de Référence des Maladies Rares du Métabolisme du Calcium et du Phosphate Filière OSCAR, AP-HP, Paris, France
| | | | - Francesco Emma
- Division of Nephrology, Bambino Gesù Children's Hospital - IRCCS, Rome, Italy
| | - Sandro Giannini
- Department of Medicine, Clinica Medica 1, University of Padova, Padua, Italy
| | - Dieter Haffner
- Department of Pediatric Kidney, Liver and Metabolic Diseases, Hannover Medical School, Hannover, Germany
| | - Richard Keen
- Royal National Orthopaedic Hospital, Stanmore, UK
| | - Elena Levtchenko
- Department of Pediatric Nephrology and Development and Regeneration, University Hospitals Leuven, University of Leuven, Leuven, Belgium
| | - Outi Mӓkitie
- Children's Hospital, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - M Zulf Mughal
- Department of Paediatric Endocrinology, Royal Manchester Children's Hospital, Manchester University Hospital's NHS Trust, Manchester, UK
| | - Ola Nilsson
- Division of Pediatric Endocrinology and Center for Molecular Medicine, Department of Women's and Children's Health, Karolinska Institutet and University Hospital, Stockholm, Sweden
- School of Medical Sciences and Department of Pediatrics, Örebro University and University Hospital, Örebro, Sweden
| | - Dirk Schnabel
- Center for Chronically Sick Children, Pediatric Endocrinology, Charité, University Medicine Berlin, Berlin, Germany
| | - Liana Tripto-Shkolnik
- Division of Endocrinology, Diabetes and Metabolism, Chaim Sheba Medical Center, Tel Hashomer, Israel
- Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | | | | | - Sue Wood
- Kyowa Kirin International, Marlow, UK
| | - M Carola Zillikens
- Bone Center, Department of Internal Medicine, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
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Ito N. Adult Presentation of X-Linked Hypophosphatemia. Endocrines 2022; 3:375-390. [DOI: 10.3390/endocrines3030030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [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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