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Chaturvedi D, Mehasi TE, Benbrahim A, ElDeeb L, Deeb A. Lessons learned from the real-world diagnosis and management of hereditary hypophosphatemic rickets. Bone Rep 2024; 21:101753. [PMID: 39011543 PMCID: PMC11247149 DOI: 10.1016/j.bonr.2024.101753] [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: 02/27/2024] [Accepted: 03/20/2024] [Indexed: 07/17/2024] Open
Abstract
Hypophosphatemic rickets, which is often hereditary, is still under- or misdiagnosed in both children and adults, denying these individuals access to optimal management and genetic counseling. There have been recent calls to compile real-world data and share best practice on these rare conditions to guide clinical decision-making. Here we present eight clinical vignettes of patients with hypophosphatemic rickets encountered in our tertiary pediatric endocrinology practice. We describe the clinical features, genetics, and management of four cases of X-linked hypophosphatemia (PHEX mutations), one each of autosomal recessive hypophosphatemic rickets (DMP1 mutation) and autosomal recessive vitamin D-dependent rickets type 1A (CYP27B1 mutation), and two cases of distal renal tubular acidosis with FOXI1 mutation-associated hypophosphatemic rickets. Our cases prompt consideration of the (i) frequent misdiagnosis of hypophosphatemic rickets in clinical practice and the importance of comprehensive genetic testing; (ii) variable expressivity of the causative mutations; and (iii) a lack of responsiveness and/or compliance to conventional therapy and the value of burosumab in modern management, provided access is equitable. These cases highlight common real-world themes and challenges to managing patients presenting with these diverse conditions, especially the burden of disease hidden by misdiagnosis. In sharing these cases, we hope to raise awareness of these conditions, promote best practice in genetic diagnosis and management, and further advocate for reimbursement equity for the best available therapies.
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Affiliation(s)
- Deepti Chaturvedi
- Paediatric Endocrine Division, Sheikh Shakhbout Medical City, Abu Dhabi, United Arab Emirates
| | - Taif EmadEldin Mehasi
- Paediatric Endocrine Division, Sheikh Shakhbout Medical City, Abu Dhabi, United Arab Emirates
| | - Assia Benbrahim
- Paediatric Endocrine Division, Sheikh Shakhbout Medical City, Abu Dhabi, United Arab Emirates
| | - Lubna ElDeeb
- Clinical Trial Unit, Sheikh Shakhbout Medical City, Abu Dhabi, United Arab Emirates
| | - Asma Deeb
- Paediatric Endocrine Division, Sheikh Shakhbout Medical City, Abu Dhabi, United Arab Emirates
- Faculty of Health and Science, Khalifa University, Abu Dhabi, UAE
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2
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Dodamani MH, Kumar SC, Bhattacharjee S, Barnabas R, Kumar S, Ranjan Lila A, Samad Memon S, Karlekar M, A Patil V, R Bandgar T. Efficacy and safety of burosumab compared with conventional therapy in patients with X-linked hypophosphatemia: A systematic review. ARCHIVES OF ENDOCRINOLOGY AND METABOLISM 2024; 68:e230242. [PMID: 38788147 PMCID: PMC11156178 DOI: 10.20945/2359-4292-2023-0242] [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: 06/17/2023] [Accepted: 11/29/2023] [Indexed: 05/26/2024]
Abstract
Burosumab, a monoclonal antibody directed against the fibroblast growth factor 23 (FGF23), has been approved for the treatment of X-linked hypophosphatemia (XLH). We conducted a systematic review to compare the efficacy and safety of burosumab versus conventional therapy (phosphorus and calcitriol) on XLH treatment. After a comprehensive literature search on MEDLINE/PubMed and Embase, we found nine studies for inclusion in the analysis. Risk of bias was assessed, and a random-effects model was used to determine the effect size. Clinical, biochemical, and radiological parameters of disease severity before and after treatment were analyzed and expressed in standardized mean difference (SMD). Burosumab resulted in normalization of phosphate homeostasis with an increase in renal tubular phosphate reabsorption and significant resolution of skeletal lesions (change in Thacher's total rickets severity score SMD: -1.46, 95% confidence interval [CI]: -1.76 to -1.17, p < 0.001, improvement in deformities, and decline in serum alkaline phosphatase levels [SMD: 130.68, 95% CI: 125.26-136.1, p < 0.001)]. Conventional therapy led to similar improvements in all these parameters but to a lower degree. In adults, burosumab normalized phosphorus levels (SMD: 1.23, 95% CI: 0.98-1.47, p < 0.001) with resultant clinical improvement. Burosumab treatment was well tolerated, with only mild treatment-related adverse effects. The present review indicates a potential role for burosumab in improving rickets, deformities, and growth in children with XLH. Given its superior efficacy and safety profile, burosumab could be an effective therapeutic option in children. We suggest further studies comparing burosumab versus conventional therapy in children and adults with XLH.
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Affiliation(s)
| | | | - Samiksha Bhattacharjee
- Department of Clinical Pharmacology, Post-graduate Institute of Medical Education and Research, Chandigarh, India
| | - Rohit Barnabas
- Department of Endocrinology, Seth G.S. Medical College & KEM Hospital, Mumbai, Maharashtra, India
| | - Sandeep Kumar
- Department of Endocrinology, Seth G.S. Medical College & KEM Hospital, Mumbai, Maharashtra, India
| | - Anurag Ranjan Lila
- Department of Endocrinology, Seth G.S. Medical College & KEM Hospital, Mumbai, Maharashtra, India
| | - Saba Samad Memon
- Department of Endocrinology, Seth G.S. Medical College & KEM Hospital, Mumbai, Maharashtra, India
| | - Manjiri Karlekar
- Department of Endocrinology, Seth G.S. Medical College & KEM Hospital, Mumbai, Maharashtra, India
| | - Virendra A Patil
- Department of Endocrinology, Seth G.S. Medical College & KEM Hospital, Mumbai, Maharashtra, India
| | - Tushar R Bandgar
- Department of Endocrinology, Seth G.S. Medical College & KEM Hospital, Mumbai, Maharashtra, India,
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3
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Baroncelli GI, Comberiati P, Aversa T, Baronio F, Cassio A, Chiarito M, Cosci o di Coscio M, De Sanctis L, Di Iorgi N, Faienza MF, Fintini D, Franceschi R, Kalapurackal M, Longhi S, Mariani M, Pitea M, Secco A, Tessaris D, Vierucci F, Wasniewska M, Weber G, Mora S. Diagnosis, treatment, and management of rickets: a position statement from the Bone and Mineral Metabolism Group of the Italian Society of Pediatric Endocrinology and Diabetology. Front Endocrinol (Lausanne) 2024; 15:1383681. [PMID: 38706696 PMCID: PMC11066174 DOI: 10.3389/fendo.2024.1383681] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/07/2024] [Accepted: 04/03/2024] [Indexed: 05/07/2024] Open
Abstract
Rickets results from impaired mineralization of growing bone due to alterations in calcium and phosphate homeostasis. Clinical signs of rickets are related to the age of the patient, the duration of the disease, and the underlying disorder. The most common signs of rickets are swelling of the wrists, knees or ankles, bowing of the legs (knock-knees, outward bowing, or both) and inability to walk. However, clinical features alone cannot differentiate between the various forms of rickets. Rickets includes a heterogeneous group of acquired and inherited diseases. Nutritional rickets is due to a deficiency of vitamin D, dietary calcium or phosphate. Mutations in genes responsible for vitamin D metabolism or function, the production or breakdown of fibroblast growth factor 23, renal phosphate regulation, or bone mineralization can lead to the hereditary form of rickets. This position paper reviews the relevant literature and presents the expertise of the Bone and Mineral Metabolism Group of the Italian Society of Pediatric Endocrinology and Diabetology (SIEDP). The aim of this document is to provide practical guidance to specialists and healthcare professionals on the main criteria for diagnosis, treatment, and management of patients with rickets. The various forms of rickets are discussed, and detailed references for the discussion of each form are provided. Algorithms to guide the diagnostic approach and recommendations to manage patients with rare forms of hereditary rickets are proposed.
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Affiliation(s)
- Giampiero I. Baroncelli
- Pediatric and Adolescent Endocrinology, Division of Pediatrics, Department of Obstetrics, Gynecology and Pediatrics, University Hospital, Pisa, Italy
| | - Pasquale Comberiati
- Pediatric and Adolescent Endocrinology, Division of Pediatrics, Department of Obstetrics, Gynecology and Pediatrics, University Hospital, Pisa, Italy
- Department of Clinical and Experimental Medicine, Section of Paediatrics, University of Pisa, Pisa, Italy
| | - Tommaso Aversa
- Department of Human Pathology of Adulthood and Childhood, University of Messina, Messina, Italy
- Pediatric Unit, University Hospital “G. Martino”, Messina, Italy
| | - Federico Baronio
- Pediatric Unit, IRCCS Azienda Ospedaliero-Universitaria di Bologna, Bologna, Italy
| | - Alessandra Cassio
- Pediatric Unit, IRCCS Azienda Ospedaliero-Universitaria di Bologna, Bologna, Italy
- Department of Medical and Surgical Sciences, University of Bologna, Bologna, Italy
| | - Mariangela Chiarito
- Pediatric Unit, Department of Precision and Regenerative Medicine and Ionian Area, University “A. Moro” of Bari, Bari, Italy
| | - Mirna Cosci o di Coscio
- Pediatric and Adolescent Endocrinology, Division of Pediatrics, Department of Obstetrics, Gynecology and Pediatrics, University Hospital, Pisa, Italy
| | - Luisa De Sanctis
- Division of Pediatric Endocrinology, Department of Public Health and Pediatrics, University of Turin, Regina Margherita Children’s Hospital, Turin, Italy
| | - Natascia Di Iorgi
- Department of Pediatrics, IRCCS Istituto Giannina Gaslini, Genova, Italy
- Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genova, Genova, Italy
| | - Maria Felicia Faienza
- Pediatric Unit, Department of Precision and Regenerative Medicine and Ionian Area, University “A. Moro” of Bari, Bari, Italy
| | - Danilo Fintini
- Endocrinology and Diabetology Unit, Bambino Gesù Children Hospital, IRCCS, Rome, Italy
| | - Roberto Franceschi
- Department of Pediatrics, Santa Chiara Hospital of Trento, APSS, Trento, Italy
| | - Mila Kalapurackal
- Department of Pediatrics, Hospital of Bolzano (SABES-ASDAA), Teaching Hospital of Paracelsus Medical University (PMU), Bolzano, Italy
| | - Silvia Longhi
- Department of Pediatrics, Hospital of Bolzano (SABES-ASDAA), Teaching Hospital of Paracelsus Medical University (PMU), Bolzano, Italy
| | - Michela Mariani
- Endocrinology and Diabetology Unit, Bambino Gesù Children Hospital, IRCCS, Rome, Italy
| | - Marco Pitea
- Pediatric Endocrinology Unit, Department of Pediatrics, IRCCS Ospedale San Raffaele, Milan, Italy
| | - Andrea Secco
- Pediatric and Pediatric Emergency Unit, Children Hospital, Azienda Ospedaliera SS Antonio e Biagio e C. Arrigo, Alessandria, Italy
| | - Daniele Tessaris
- Division of Pediatric Endocrinology, Department of Public Health and Pediatrics, University of Turin, Regina Margherita Children’s Hospital, Turin, Italy
| | | | - Malgorzata Wasniewska
- Department of Human Pathology of Adulthood and Childhood, University of Messina, Messina, Italy
| | - Giovanna Weber
- Pediatric Endocrinology Unit, Department of Pediatrics, IRCCS Ospedale San Raffaele, Milan, Italy
| | - Stefano Mora
- Laboratory of Pediatric Endocrinology, Department of Pediatrics, IRCCS Ospedale San Raffaele, Milan, Italy
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4
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Bosman A, Appelman-Dijkstra NM, Boot AM, de Borst MH, van de Ven AC, de Jongh RT, Bökenkamp A, van den Bergh JP, van der Eerden BCJ, Zillikens MC. Disease Manifestations and Complications in Dutch X-Linked Hypophosphatemia Patients. Calcif Tissue Int 2024; 114:255-266. [PMID: 38226986 PMCID: PMC10901935 DOI: 10.1007/s00223-023-01172-2] [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] [Received: 09/12/2023] [Accepted: 11/27/2023] [Indexed: 01/17/2024]
Abstract
X-linked hypophosphatemia (XLH) is the most common monogenetic cause of chronic hypophosphatemia, characterized by rickets and osteomalacia. Disease manifestations and treatment of XLH patients in the Netherlands are currently unknown. Characteristics of XLH patients participating in the Dutch observational registry for genetic hypophosphatemia and acquired renal phosphate wasting were analyzed. Eighty XLH patients, including 29 children, were included. Genetic testing, performed in 78.8% of patients, showed a PHEX mutation in 96.8%. Median (range) Z-score for height was - 2.5 (- 5.5; 1.0) in adults and - 1.4 (- 3.7; 1.0) in children. Many patients were overweight or obese: 64.3% of adults and 37.0% of children. All children received XLH-related medication e.g., active vitamin D, phosphate supplementation or burosumab, while 8 adults used no medication. Lower age at start of XLH-related treatment was associated with higher height at inclusion. Hearing loss was reported in 6.9% of children and 31.4% of adults. Knee deformities were observed in 75.0% of all patients and osteoarthritis in 51.0% of adult patients. Nephrocalcinosis was observed in 62.1% of children and 33.3% of adults. Earlier start of XLH-related treatment was associated with higher risk of nephrocalcinosis and detection at younger age. Hyperparathyroidism longer than six months was reported in 37.9% of children and 35.3% of adults. This nationwide study confirms the high prevalence of adiposity, hearing loss, bone deformities, osteoarthritis, nephrocalcinosis and hyperparathyroidism in Dutch XLH patients. Early start of XLH-related treatment appears to be beneficial for longitudinal growth but may increase development of nephrocalcinosis.
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Affiliation(s)
- A Bosman
- Department of Internal Medicine, Erasmus MC, University Medical Center Rotterdam, PO Box 2040, 3000, CA, Rotterdam, The Netherlands
| | - N M Appelman-Dijkstra
- Department of Internal Medicine, Leiden University Medical Center, Leiden, The Netherlands
| | - A M Boot
- Department of Pediatrics, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - M H de Borst
- Department of Internal Medicine, University Medical Center Groningen, Groningen, The Netherlands
| | - A C van de Ven
- Department of Internal Medicine, Radboud University Medical Center, Nijmegen, The Netherlands
| | - R T de Jongh
- Department of Internal Medicine, Amsterdam University Medical Center, Vrije Universiteit, Amsterdam, The Netherlands
| | - A Bökenkamp
- Department of Pediatric Nephrology, Amsterdam University Medical Center, Emma Children's Hospital, Amsterdam, The Netherlands
| | - J P van den Bergh
- Department of Internal Medicine, VieCuri Medical Center, Venlo, The Netherlands
| | - B C J van der Eerden
- Department of Internal Medicine, Erasmus MC, University Medical Center Rotterdam, PO Box 2040, 3000, CA, Rotterdam, The Netherlands
| | - M C Zillikens
- Department of Internal Medicine, Erasmus MC, University Medical Center Rotterdam, PO Box 2040, 3000, CA, Rotterdam, The Netherlands.
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5
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Goyal A, Tandon N. Burosumab: Current status and future prospects. Best Pract Res Clin Endocrinol Metab 2024; 38:101826. [PMID: 37858479 DOI: 10.1016/j.beem.2023.101826] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/21/2023]
Abstract
Hypophosphatemic rickets/osteomalacia caused by FGF23 excess is conventionally treated with multiple doses of inorganic phosphate salts and active vitamin D analogs. However, conventional therapy targets the consequences of elevated FGF23 and not the elevated FGF23 itself and is associated with poor adherence and long-term complications such as nephrocalcinosis and secondary/tertiary hyperparathyroidism. Burosumab is a fully human IgG1 monoclonal antibody that binds to and neutralises FGF-23, thereby leading to improvement in phosphate homeostasis and healing of rickets and osteomalacia. Data from phase 2 and 3 trials report overall safety and efficacy and Burosumab is now FDA approved for treatment of XLH and TIO in children and adults. Cost and absence of long-term data are major issues with Burosumab which should be addressed in near future. At present, experts recommend Burosumab use in patients with severe disease or those with mild-moderate disease and a failed response to a trial of conventional therapy.
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Affiliation(s)
- Alpesh Goyal
- Department of Endocrinology and Metabolism, All India Institute of Medical Sciences, Convergence Block, Room no 7002, Seventh Floor, New Delhi 110029, India.
| | - Nikhil Tandon
- Department of Endocrinology and Metabolism, All India Institute of Medical Sciences, Convergence Block, Room no 7002, Seventh Floor, New Delhi 110029, India.
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6
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Park E, Kang HG. X-linked hypophosphatemic rickets: from diagnosis to management. Clin Exp Pediatr 2024; 67:17-25. [PMID: 37321578 PMCID: PMC10764665 DOI: 10.3345/cep.2022.01459] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/18/2022] [Revised: 02/02/2023] [Accepted: 03/28/2023] [Indexed: 06/17/2023] Open
Abstract
X-linked hypophosphatemia (XLH), the most common cause of hypophosphatemic rickets, affects one in every 20,000 people. Although conventional therapy for XLH was introduced approximately 4 decades ago, the temporary replacement of oral phosphate salts and activated vitamin D cannot completely control chronic hypophosphatemia, leaving patients with incomplete healing and residual skeletal deformity as well as at risk of endocrine abnormalities and adverse drug reactions. However, understanding the pathophysiology has led to the development of a targeted therapy, burosumab, a fibroblast growth factor-23 inhibitor that was recently approved in Korea for the treatment of XLH. This review provides insight into the diagnosis, evaluation, treatment, and recommended follow-up for a typical case of XLH and reviews its pathophysiology.
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Affiliation(s)
- Eujin Park
- Department of Pediatrics, Korea University Guro Hospital, Korea University College of Medicine, Seoul, Korea
| | - Hee Gyung Kang
- Department of Pediatrics, Seoul National University College of Medicine, Seoul, Korea
- Departments of Pediatrics, Seoul National University Children’s Hospital, Seoul, Korea
- Kidney Research Institute, Medical Research Center, Seoul National University College of Medicine, Seoul, Korea
- Wide River Institute of Immunology, Seoul National University, Hongcheon, Korea
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7
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Levy-Shraga Y, Levi S, Regev R, Gal S, Brener A, Lebenthal Y, Gillis D, Strich D, Zung A, Cleper R, Borovitz Y, Bello R, Tenenbaum A, Zadik Z, Davidovits M, Zeitlin L, Tiosano D. Linear growth of children with X-linked hypophosphatemia treated with burosumab: a real-life observational study. Eur J Pediatr 2023; 182:5191-5202. [PMID: 37707589 DOI: 10.1007/s00431-023-05190-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/16/2023] [Revised: 08/30/2023] [Accepted: 09/02/2023] [Indexed: 09/15/2023]
Abstract
To assess the long-term efficacy of burosumab for pediatric patients with X-linked hypophosphatemia, focusing on linear growth. This multi-center retrospective study included 35 pediatric patients who began treatment with burosumab between January 2018 and January 2021. We collected clinical data, anthropometric measurements, laboratory results, and Rickets Severity Score (RSS), from 2 years prior to treatment initiation and up to 4 years after. Burosumab was initiated at a mean age of 7.5 ± 4.4 years (range 0.6-15.9), with a mean initial dose of 0.8 ± 0.3 mg/kg, which was subsequently increased to 1.1 ± 0.4 mg/kg. The patients were followed for 2.9 ± 1.4 years (range 1-4) after initiating burosumab. Serum phosphorus levels increased from 2.7 ± 0.8 mg/dl at burosumab initiation to 3.4 ± 0.6 mg/dl after 3 months and remained stable (p < 0.001). Total reabsorption of phosphorus increased from 82.0 ± 6.8 to 90.1 ± 5.3% after 12 months of treatment (p = 0.041). The RSS improved from 1.7 ± 1.0 at burosumab initiation to 0.5 ± 0.6 and 0.3 ± 0.6 after 12 and 24 months, respectively (p < 0.001). Both height z-score and weight z-score improved from burosumab initiation to the end of the study: from - 2.07 ± 1.05 to - 1.72 ± 1.04 (p < 0.001) and from - 0.51 ± 1.12 to - 0.11 ± 1.29 (p < 0.001), respectively. Eight children received growth hormone combined with burosumab treatment. Height z-score improved among those who received growth hormone (from - 2.33 ± 1.12 to - 1.94 ± 1.24, p = 0.042) and among those who did not (from - 2.01 ± 1.01 to - 1.66 ± 1.01, p = 0.001). CONCLUSION Burosumab treatment in a real-life setting improved phosphate homeostasis and rickets severity and enhanced linear growth. WHAT IS KNOWN • Compared to conventional therapy, burosumab treatment has been shown to increase serum phosphate levels and reduce the severity of rickets. • The effect of burosumab on growth is still being study. WHAT IS NEW • Height z-score improved between the start of burosumab treatment and the end of the study (-2.07 ± 1.05 vs. -1.72 ± 1.04, p < 0.001). • Eight children received burosumab combined with growth hormone treatment without side effects during the concomitant treatments.
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Affiliation(s)
- Yael Levy-Shraga
- Pediatric Endocrinology Unit, The Edmond and Lily Safra Children's Hospital, Chaim Sheba Medical Center, Tel Hashomer, 52621, Israel.
- The Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
| | - Shelly Levi
- The Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
- Institute of Pediatric Nephrology, Schneider Children's Medical Center, Petah Tikva, Israel
| | - Ravit Regev
- The Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
- Pediatric Endocrinology and Diabetes Unit, Dana-Dwek Children's Hospital, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel
| | - Shoshana Gal
- Division of Pediatric Endocrinology, Ruth Rappaport Children's Hospital, Rambam Medical Center, Haifa, Israel
- Bruce Rappaport Faculty of Medicine, Technion, Haifa, Israel
| | - Avivit Brener
- The Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
- Pediatric Endocrinology and Diabetes Unit, Dana-Dwek Children's Hospital, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel
| | - Yael Lebenthal
- The Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
- Pediatric Endocrinology and Diabetes Unit, Dana-Dwek Children's Hospital, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel
| | - David Gillis
- Pediatric Endocrinology Unit, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
- Faculty of Medicine, Hebrew University of Jerusalem, Hadassah Medical School, Jerusalem, Israel
| | - David Strich
- Faculty of Medicine, Hebrew University of Jerusalem, Hadassah Medical School, Jerusalem, Israel
- Department of Pediatrics, Shaare Zedek Medical Center, Jerusalem, Israel
| | - Amnon Zung
- Faculty of Medicine, Hebrew University of Jerusalem, Hadassah Medical School, Jerusalem, Israel
- Pediatrics Department, Kaplan Medical Center, Rehovot, Israel
| | - Roxana Cleper
- The Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
- Pediatric Nephrology Unit, Dana-Dwek Children's Hospital, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel
| | - Yael Borovitz
- The Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
- Institute of Pediatric Nephrology, Schneider Children's Medical Center, Petah Tikva, Israel
| | - Rachel Bello
- The Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
- The Shafer Institute for Endocrinology and Diabetes, Schneider Children's Medical Center, Petah Tikva, Israel
| | - Ariel Tenenbaum
- The Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
- The Shafer Institute for Endocrinology and Diabetes, Schneider Children's Medical Center, Petah Tikva, Israel
| | - Zvi Zadik
- Faculty of Medicine, Hebrew University of Jerusalem, Hadassah Medical School, Jerusalem, Israel
- Pediatrics Department, Kaplan Medical Center, Rehovot, Israel
| | - Miriam Davidovits
- The Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
- Institute of Pediatric Nephrology, Schneider Children's Medical Center, Petah Tikva, Israel
| | - Leonid Zeitlin
- The Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
- Pediatric Orthopedic Department, Dana-Dwek Children's Hospital, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel
| | - Dov Tiosano
- Division of Pediatric Endocrinology, Ruth Rappaport Children's Hospital, Rambam Medical Center, Haifa, Israel
- Bruce Rappaport Faculty of Medicine, Technion, Haifa, Israel
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8
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Seefried L, Alzahrani A, Arango Sancho P, Bacchetta J, Crowley R, Emma F, Gibbins J, Grandone A, Javaid MK, Mindler G, Raimann A, Rothenbuhler A, Tucker I, Zeitlin L, Linglart A. XLH Matters 2022: Insights and recommendations to improve outcomes for people living with X-linked hypophosphataemia (XLH). Orphanet J Rare Dis 2023; 18:333. [PMID: 37885021 PMCID: PMC10604503 DOI: 10.1186/s13023-023-02883-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2023] Open
Affiliation(s)
- Lothar Seefried
- Orthopedic Institute, König-Ludwig Haus, University of Würzburg, Würzburg, Germany
| | - Ali Alzahrani
- King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - Pedro Arango Sancho
- Department of Pediatric Nephrology, Hospital Sant Joan de Déu, Barcelona, Spain
- Department of Onco-Nephrology, Pediatric Cancer Center, Barcelona, Spain
| | - Justine Bacchetta
- Pediatric Nephrology, Reference Center for Rare Diseases of Calcium and Phosphate, Filières OSCAR et ORKID, INSERM1033, Hospices Civils de Lyon, Lyon, France
| | - Rachel Crowley
- St Vincent's University Hospital and Rare Disease Clinical Trial Network, University College Dublin, Dublin, Ireland
| | - Francesco Emma
- Division of Nephrology, Children's Hospital Bambino Gesù-IRCCS, Rome, Italy
| | | | - Anna Grandone
- Department of Woman, Child, General and Specialized Surgery, University of Campania L. Vanvitelli, Naples, Italy
| | - Muhammad Kassim Javaid
- Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, University of Oxford, Oxford, UK
| | - Gabriel Mindler
- Department of Pediatric Orthopaedics, Orthopaedic Hospital Speising, Vienna, Austria
- Vienna Bone and Growth Center, Vienna, Austria
| | | | - Anya Rothenbuhler
- APHP, Endocrinology and Diabetology for Children, Bicêtre Paris Saclay Hospital, Le Kremlin-Bicêtre, France
- APHP, Reference Center for Rare Disorders of Calcium and Phosphate Metabolism, Filière OSCAR, Paris, France
- APHP, Platform of Expertise for Rare Disorders Paris Saclay, Bicêtre Paris Saclay Hospital, Le Kremlin-Bicêtre, France
| | - Ian Tucker
- Bristol Royal Hospital for Children, University Hospitals Bristol and Weston NHS Foundation Trust, Bristol, UK
| | - Leonid Zeitlin
- Pediatric Bone Clinic, Orthopedic Department, Dana-Dwek Children's Hospital, Tel-Aviv Medical Center, Tel Aviv-Yafo, Israel
| | - Agnès Linglart
- APHP, Endocrinology and Diabetology for Children, Bicêtre Paris Saclay Hospital, Le Kremlin-Bicêtre, France.
- APHP, Reference Center for Rare Disorders of Calcium and Phosphate Metabolism, Filière OSCAR, Paris, France.
- APHP, Platform of Expertise for Rare Disorders Paris Saclay, Bicêtre Paris Saclay Hospital, Le Kremlin-Bicêtre, France.
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Boros E, Ertl DA, Berkenou J, Audrain C, Lecoq AL, Kamenicky P, Briot K, Amouroux C, Zhukouskaya V, Gueorguieva I, Mignot B, Girerd B, Porquet Bordes V, Salles JP, Edouard T, Coutant R, Bacchetta J, Linglart A, Rothenbuhler A. Adult height improved over decades in patients with X-linked hypophosphatemia: a cohort study. Eur J Endocrinol 2023; 189:469-475. [PMID: 37831782 DOI: 10.1093/ejendo/lvad144] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Revised: 07/28/2023] [Accepted: 09/07/2023] [Indexed: 10/15/2023]
Abstract
OBJECTIVES The aim of this study is to analyze height after cessation of growth (final height [FH]) and its evolution over the last decades in X-linked hypophosphatemia (XLH) patients in France, as the data on natural history of FH in XLH are lacking. DESIGN We performed a retrospective observational study in a large cohort of French XLH patients with available data on FH measurements. MATERIALS AND METHODS We divided patients into 3 groups according to their birth year: group 1 born between 1950 and 1974, group 2 born between 1975 and 2000, and group 3 born between 2001 and 2006, respectively, and compared their FHs. RESULTS A total of 398 patients were included. Mean FHs were the following: for group 1, -2.31 ± 1.11 standard deviation score (SDS) (n = 127), 156.3 ± 9.7 cm in men and 148.6 ± 6.5 cm in women; for group 2, -1.63 ± 1.13 SDS (n = 193), 161.6 ± 8.5 cm in men and 153.1 ± 7.2 cm in women; and for group 3, -1.34 ± 0.87 SDS (n = 78), 165.1 ± 5.5 cm in men and 154.7 ± 6 cm in women. We report a significant increase in mean FH SDS over 3 generations of patients, for both men and women (P < .001). Final height SDS in male (-2.08 ± 1.18) was lower than in female (-1.70 ± 1.12) (P = .002). CONCLUSION The FH of XLH patients in France increased significantly over the last decades. Even though men's FHs improved more than women's, men with XLH remain shorter reflecting a more severe disease phenotype. While the results are promising, most patients with XLH remain short leaving room for improvement.
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Affiliation(s)
- Emese Boros
- Pediatric Endocrinology Unit, Hôpital Universitaire de Bruxelles (HUB), Hôpital Universitaire des Enfants Reine Fabiola (HUDERF), Université Libre de Bruxelles, Brussels 1020, Belgium
| | - Diana-Alexandra Ertl
- AP-HP, Department of Endocrinology and Diabetes for Children, Department of Adolescent Medicine, Bicetre Paris-Saclay University Hospital, 78 Rue du General Leclerc, Le Kremlin-Bicêtre 94270, France
- AP-HP, Reference Center for Rare Disorders of the Calcium and Phosphate Metabolism, Filiere OSCAR and Platform of Expertise for Rare Diseases Paris-Saclay, Bicetre Paris-Saclay Hospital, 78 Rue du General Leclerc, Le Kremlin-Bicêtre 94270, France
| | - Jugurtha Berkenou
- AP-HP, Department of Endocrinology and Diabetes for Children, Department of Adolescent Medicine, Bicetre Paris-Saclay University Hospital, 78 Rue du General Leclerc, Le Kremlin-Bicêtre 94270, France
- AP-HP, Reference Center for Rare Disorders of the Calcium and Phosphate Metabolism, Filiere OSCAR and Platform of Expertise for Rare Diseases Paris-Saclay, Bicetre Paris-Saclay Hospital, 78 Rue du General Leclerc, Le Kremlin-Bicêtre 94270, France
| | - Christelle Audrain
- AP-HP, Department of Endocrinology and Diabetes for Children, Department of Adolescent Medicine, Bicetre Paris-Saclay University Hospital, 78 Rue du General Leclerc, Le Kremlin-Bicêtre 94270, France
- AP-HP, Reference Center for Rare Disorders of the Calcium and Phosphate Metabolism, Filiere OSCAR and Platform of Expertise for Rare Diseases Paris-Saclay, Bicetre Paris-Saclay Hospital, 78 Rue du General Leclerc, Le Kremlin-Bicêtre 94270, France
| | - Anne Lise Lecoq
- AP-HP, Centre de Recherche Clinique Paris Saclay, Hôpital Bicêtre, Le Kremlin-Bicêtre 94270, France
- Assistance Publique-Hôpitaux de Paris (AP-HP), Hôpital de Bicêtre, Service d'Endocrinologie et des Maladies de la Reproduction, Centre de Référence des Maladies Rares du Métabolisme du Calcium et du Phosphate, Filière OSCAR, 78 rue du Général Leclerc, Le Kremlin-Bicêtre 94270, France
| | - Peter Kamenicky
- Assistance Publique-Hôpitaux de Paris (AP-HP), Hôpital de Bicêtre, Service d'Endocrinologie et des Maladies de la Reproduction, Centre de Référence des Maladies Rares du Métabolisme du Calcium et du Phosphate, Filière OSCAR, 78 rue du Général Leclerc, Le Kremlin-Bicêtre 94270, France
- Physiologie et Physiopathologie Endocriniennes, Université Paris-Saclay, Inserm, Le Kremlin-Bicêtre 94276, France
| | - Karine Briot
- Rheumatology Department, Université Paris-Cité, Cochin Hospital, Paris 75014, France
| | - Cyril Amouroux
- Service de Néphrologie et Endocrinologie Pédiatriques, CHU de Montpellier, Montpellier 34090, France
- Faculté de Médecine, Université de Montpellier, Montpellier 34090, France
- Centres Maladies Rares Métabolisme du Calcium et du Phosphore et Maladies Osseuses Constitutionnelles, Filière de Santé Maladies Rares OSCAR, 34090 Montpellier, France
| | - Volha Zhukouskaya
- AP-HP, Department of Endocrinology, Hôpital Cochin, Paris 75014, France
- Institut des Maladies Musculo-squelettiques, Laboratory Orofacial Pathologies, Imaging and Biotherapies URP2496 and FHU-DDS-Net, Dental School, and Plateforme d'Imagerie du Vivant (PIV), Université Paris Cité, Montrouge 92129, France
- Centre de Référence des Maladies Rares du Métabolisme du Calcium et du Phosphate, Plateforme d'Expertise Maladies Rares Paris Saclay, Filière OSCAR, EndoRare and BOND ERN, Hôpital de Bicêtre, Le Kremlin-Bicêtre 94270, France
| | - Iva Gueorguieva
- Pediatric Endocrine Unit, CHU Lille, Université Lille, Lille 59800, France
| | - Brigitte Mignot
- Service de Médecine Pédiatrique, CHRU J Minjoz, 3 Boulevard Fleming, Besançon 25030, France
| | - Barbara Girerd
- AP-HP, Department of Endocrinology and Diabetes for Children, Department of Adolescent Medicine, Bicetre Paris-Saclay University Hospital, 78 Rue du General Leclerc, Le Kremlin-Bicêtre 94270, France
- AP-HP, Reference Center for Rare Disorders of the Calcium and Phosphate Metabolism, Filiere OSCAR and Platform of Expertise for Rare Diseases Paris-Saclay, Bicetre Paris-Saclay Hospital, 78 Rue du General Leclerc, Le Kremlin-Bicêtre 94270, France
| | - Valerie Porquet Bordes
- Endocrine, Bone Diseases and Genetics Unit, Reference Centre for Rare Diseases of Calcium and Phosphate Metabolism, Competence Centre for Bone Diseases, ERN BOND, OSCAR Network, Children's Hospital, Toulouse University Hospital, Toulouse 31059, France
| | - Jean Pierre Salles
- Unité d'Endocrinologie, Maladies Osseuses, Hôpital des Enfants, Centre de Référence des Maladies Rares du Calcium et du Phosphate, ENR BOND, Hôpital des Enfants, CHU de Toulouse, TSA 70034, Toulouse 31059, France
- INFINITY CENTER, INSERM CNRS UMR 1291, Université de Toulouse, Paul Sabatier Toulouse III, Hôpital Purpan, Toulouse 31024, France
| | - Thomas Edouard
- Endocrine, Bone Diseases and Genetics Unit, Toulouse University Hospital, Toulouse 31059, France
| | - Régis Coutant
- Unité d' Endocrinologie Diabetologie Pédiatrique and Centre des Maladies Rares de la Réceptivité Hormonale, CHU-Angers, Angers 49055, France
| | - Justine Bacchetta
- Centre de Référence des Maladies Rénales Rares, Centre de Référence des Maladies Rares du Calcium et du Phosphore, Filières Santé Maladies Rares OSCAR et ORKID, Filières Santé ERKNet et BOND, INSERM1033, Université de Lyon, Lyon 69372, France
| | - Agnès Linglart
- AP-HP, Department of Endocrinology and Diabetes for Children, Department of Adolescent Medicine, Bicetre Paris-Saclay University Hospital, 78 Rue du General Leclerc, Le Kremlin-Bicêtre 94270, France
- AP-HP, Reference Center for Rare Disorders of the Calcium and Phosphate Metabolism, Filiere OSCAR and Platform of Expertise for Rare Diseases Paris-Saclay, Bicetre Paris-Saclay Hospital, 78 Rue du General Leclerc, Le Kremlin-Bicêtre 94270, France
- Physiologie et Physiopathologie Endocriniennes, Université Paris-Saclay, Inserm, Le Kremlin-Bicêtre 94276, France
| | - Anya Rothenbuhler
- AP-HP, Department of Endocrinology and Diabetes for Children, Department of Adolescent Medicine, Bicetre Paris-Saclay University Hospital, 78 Rue du General Leclerc, Le Kremlin-Bicêtre 94270, France
- AP-HP, Reference Center for Rare Disorders of the Calcium and Phosphate Metabolism, Filiere OSCAR and Platform of Expertise for Rare Diseases Paris-Saclay, Bicetre Paris-Saclay Hospital, 78 Rue du General Leclerc, Le Kremlin-Bicêtre 94270, France
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10
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Abdullah SJ, Mahwi TO, Mohamad Salih Saeed A, Abdulateef DS, Rahman HS, Ahmed SF, Abdulqader SA. X-Linked Familial Hypophosphatemia: A Case Report of 27-Year Old Male and Review of Literature. Horm Metab Res 2023; 55:653-664. [PMID: 37813097 PMCID: PMC10562047 DOI: 10.1055/a-2159-8429] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Accepted: 08/15/2023] [Indexed: 10/11/2023]
Abstract
X-linked hypophosphatemia (XLH) associated with short stature during childhood are mostly referred to the hospital and diagnosed as vitamin D deficiency rickets and received vitamin D before adulthood. A case is presented with clinical features of hypophosphatemia from childhood who did not seek medical care for diagnosis and treatment, nor did his mother or two brothers, who have short statures, bone pain, and fractures. The patient was assessed for sociodemographic, hematological, and biochemical parameters together with a genetic assessment. A DEXA scan and X-ray were done to determine the abnormalities and deformities of joints and bones despite clinical examination by an expert physician. All imaging, laboratory parameters, and the genetic study confirmed the diagnosis of XLH. A detailed follow-up of his condition was performed after the use of phosphate tablets and other treatments. X-linked hypophosphatemia needs a good assessment, care, and follow up through a complementary medical team including several specialties. Phosphate tablets in adulthood significantly affects clinical and physical improvement and prevention of further skeletal abnormality and burden on daily activity. The patients should be maintained with an adequate dose of phosphate for better patient compliance. More awareness is needed in society and for health professionals when conducting medical checkups during the presence of stress fractures, frequent dental and gum problems, rickets, short stature, or abnormality in the skeleton or walking to think of secondary causes such as hypophosphatemia. Further investigations including a visit to a specialist is imperative to check for the primary cause of these disturbances.
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Affiliation(s)
| | - Taha Othman Mahwi
- Medicine, University of Sulaimani College of Medicine, Sulaymaniyah,
Kurdistan region, Iraq
| | | | - Darya Saeed Abdulateef
- Medical Education, University of Sulaimani College of Medicine,
Sulaymaniyah, Kurdistan region, Iraq
| | - Heshu Sulaiman Rahman
- Physiology, University of Sulaimani College of Medicine, Sulaymaniyah,
Kurdistan region, Iraq
| | - Shaho Fatah Ahmed
- Endocrine Unit, Internal Medicine, Shar Hospital, Sulaymaniyah,
Kurdistan region, Iraq
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11
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Seefried L, Duplan MB, Briot K, Collins MT, Evans R, Florenzano P, Hawkins N, Javaid MK, Lachmann R, Ward LM. Anticipated effects of burosumab treatment on long-term clinical sequelae in XLH: expert perspectives. Front Endocrinol (Lausanne) 2023; 14:1211426. [PMID: 37547321 PMCID: PMC10400326 DOI: 10.3389/fendo.2023.1211426] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Accepted: 06/27/2023] [Indexed: 08/08/2023] Open
Abstract
X-linked hypophosphatemia (XLH) is a rare, progressive, genetic disease with multisystem impact that typically begins to manifest in early childhood. Two treatment options exist: oral phosphate in combination with active vitamin D ("conventional therapy") and a fully human monoclonal anti-FGF23 antibody, burosumab. The clinical benefit of conventional therapy in adults is limited, and poor tolerance and complications are common. Burosumab was first approved as a treatment for XLH in 2018 and its disease-modifying benefits in clinical trials in children suggest burosumab treatment could also alter the disease course in adults. Without long-term clinical data on multiple XLH-related sequelae available, the results of an elicitation exercise are reported, in which eight global experts in XLH posited how long-term treatment with burosumab is anticipated to impact the life course of clinical sequelae in adults with XLH. Based on their clinical experiences, the available evidence and their disease understanding, the experts agreed that some long-term benefits of using burosumab are likely in adults with XLH even if they have a misaligned skeleton from childhood. Burosumab treatment is anticipated to reduce the incidence of fractures and halt the progression of clinical sequelae associated with conventional therapy. While the trajectories for established dental abscesses are not expected to improve with burosumab treatment, dental abscess development may be prevented. Starting treatment with burosumab in childhood to increase the likelihood of an aligned skeleton and continuation into and throughout adulthood to maintain euphosphatemia may optimize patient outcomes, although future real-world investigation is required to support this hypothesis.
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Affiliation(s)
- Lothar Seefried
- Orthopedic Department, University of Würzburg, Würzburg, Germany
| | - Martin Biosse Duplan
- Service de Médecine Bucco-Dentaire, Hôpital Bretonneau, AP-HP, Paris, France
- UFR d’Odontologie, Université de Paris, Paris, France
- Institut Imagine, INSERM, Paris, France
| | - Karine Briot
- Department of Rheumatology, Hôpital Cochin, Université de Paris-Cité, Paris, France
| | - Michael T. Collins
- Skeletal Disorders and Mineral Homeostasis Section, National Institutes of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD, United States
| | - Rachel Evans
- Health Economics, Visible Analytics, Oxford, United Kingdom
| | - Pablo Florenzano
- Department of Endocrinology, Pontificia Universidad Católica de Chile, Santiago, Chile
- Department of Endocrinology, Centro Traslacional en Endocrinologia (CETREN-UC), Santiago, Chile
| | - Neil Hawkins
- Health Economics, Visible Analytics, Oxford, United Kingdom
| | - Muhammad Kassim Javaid
- Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, University of Oxford, Oxford, United Kingdom
| | - Robin Lachmann
- Charles Dent Metabolic Unit, National Hospital for Neurology and Neurosurgery, London, United Kingdom
| | - Leanne M. Ward
- Children’s Hospital of Eastern Ontario, University of Ottawa, Ottawa, ON, Canada
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12
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Abstract
Nutritional rickets, caused by vitamin D and/or calcium deficiency is by far the most common cause of rickets. In resource-limited settings, it is therefore not uncommon to treat rickets with vitamin D and calcium. If rickets fails to heal and/or if there is a family history of rickets, then refractory rickets should be considered as a differential diagnosis. Chronic low serum phosphate is the pathological hallmark of all forms of rickets as its low concentration in extracellular space leads to the failure of apoptosis of hypertrophic chondrocytes leading to defective mineralisation of the growth plate. Parathyroid hormone (PTH) and fibroblast growth factor 23 (FGF23) control serum phosphate concentration by facilitating the excretion of phosphate in the urine through their action on the proximal renal tubules. An increase in PTH, as seen in nutritional rickets and genetic disorders of vitamin D-dependent rickets (VDDRs), leads to chronic low serum phosphate, causing rickets. Genetic conditions leading to an increase in FGF23 concentration cause chronic low serum phosphate concentration and rickets. Genetic conditions and syndromes associated with proximal renal tubulopathies can also lead to chronic low serum phosphate concentration by excess phosphate leak in urine, causing rickets.In this review, authors discuss an approach to the differential diagnosis and management of refractory rickets.
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Affiliation(s)
- Amish Chinoy
- Department of Paediatric Endocrinology, Royal Manchester Children's Hospital, Manchester, M13 9WL, UK
- Faculty of Biology Medicine and Health, University of Manchester, Manchester, M13 9PL, UK
| | - Raja Padidela
- Department of Paediatric Endocrinology, Royal Manchester Children's Hospital, Manchester, M13 9WL, UK.
- Faculty of Biology Medicine and Health, University of Manchester, Manchester, M13 9PL, UK.
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13
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Kubota T, Namba N, Tanaka H, Muroya K, Imanishi Y, Takeuchi Y, Kanematsu M, Sun W, Seino Y, Ozono K. Self-Administration of Burosumab in Children and Adults with X-Linked Hypophosphataemia in Two Open-Label, Single-Arm Clinical Studies. Adv Ther 2023; 40:1530-1545. [PMID: 36719566 PMCID: PMC9887240 DOI: 10.1007/s12325-022-02412-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Accepted: 12/15/2022] [Indexed: 02/01/2023]
Abstract
INTRODUCTION X-linked hypophosphataemia (XLH) is a rare, genetic renal phosphate-wasting disease, resulting from excess fibroblast growth factor 23 (FGF23) activity, which has a progressive and profound impact on patients throughout life. The monoclonal anti-FGF23 antibody, burosumab, is a subcutaneous injection indicated for the treatment of XLH in children and adults. Originally, burosumab was approved to be administered by a healthcare professional (HCP), but the option of self-administration would enable patient independence and easier access to treatment. Two open-label, single-arm clinical trials, conducted in Japan and Korea, have assessed the safety and efficacy of self-administration of burosumab in both children and adults with XLH. METHODS In KRN23-003 (n = 15 children aged 1-12 years) and KRN23-004 (n = 5 children aged 3-13 years, n = 4 adults aged 21-65 years), children initially received 0.8 mg/kg of burosumab every 2 weeks and adults initially received 1.0 mg/kg of burosumab every 4 weeks. Self-administration was permitted from Week 4, and patients or carers were provided with training to inject correctly. RESULTS In both trials, burosumab had an acceptable safety profile with mainly mild-to-moderate adverse events. Following self-administration, no patients reported serious treatment-emergent adverse events ≥ grade 3, injection-site reactions or hypersensitivity reactions related to burosumab. Serum phosphate and active vitamin D levels increased from baseline in children and adults. CONCLUSIONS These results indicated that the efficacy and safety of burosumab when administered either by a carer or patient are similar to that when administered by an HCP and show that self-administration is a viable option for patients with XLH. TRIAL REGISTRATION NUMBERS NCT03233126 and NCT04308096.
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Affiliation(s)
- Takuo Kubota
- Department of Paediatrics, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Noriyuki Namba
- Division of Paediatrics and Perinatology, Tottori University Faculty of Medicine, Tottori, Japan
| | - Hiroyuki Tanaka
- Department of Paediatrics, Okayama Saiseikai General Hospital, Okayama, Japan
| | - Koji Muroya
- Department of Endocrinology and Metabolism, Kanagawa Children's Medical Centre, Kanagawa, Japan
| | - Yasuo Imanishi
- Department of Metabolism, Endocrinology and Molecular Medicine, Osaka Metropolitan University Graduate School of Medicine, Osaka, Japan
| | - Yasuhiro Takeuchi
- Endocrine Centre, Toranomon Hospital, Tokyo, Japan
- Okinaka Memorial Institute for Medical Research, Tokyo, Japan
| | - Masanori Kanematsu
- Kyowa Kirin Co., Ltd., Oteomachi Financial City Grand Cube, 1-9-2 Otemachi, Chiyoda-ku, Tokyo, Japan.
| | - Wei Sun
- Kyowa Kirin, Inc., 212 Carnegie Centre, Princeton, NJ, 08540, USA
| | - Yoshiki Seino
- Department of Paediatrics, Osaka Hospital, Japan Community Healthcare Organisation, Osaka, Japan
| | - Keiichi Ozono
- Department of Paediatrics, Osaka University Graduate School of Medicine, Osaka, Japan
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14
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Insights into the Molecular and Hormonal Regulation of Complications of X-Linked Hypophosphatemia. ENDOCRINES 2023. [DOI: 10.3390/endocrines4010014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/06/2023] Open
Abstract
X-linked hypophosphatemia (XLH) is characterized by mutations in the PHEX gene, leading to elevated serum levels of FGF23, decreased production of 1,25 dihydroxyvitamin D3 (1,25D), and hypophosphatemia. Those affected with XLH manifest impaired growth and skeletal and dentoalveolar mineralization as well as increased mineralization of the tendon–bone attachment site (enthesopathy), all of which lead to decreased quality of life. Many molecular and murine studies have detailed the role of mineral ions and hormones in regulating complications of XLH, including how they modulate growth and growth plate maturation, bone mineralization and structure, osteocyte-mediated mineral matrix resorption and canalicular organization, and enthesopathy development. While these studies have provided insight into the molecular underpinnings of these skeletal processes, current therapies available for XLH do not fully prevent or treat these complications. Therefore, further investigations are needed to determine the molecular pathophysiology underlying the complications of XLH.
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15
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Presentation and Diagnosis of Pediatric X-Linked Hypophosphatemia. ENDOCRINES 2023. [DOI: 10.3390/endocrines4010012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/24/2023] Open
Abstract
X-linked hypophosphatemia (XLH) is a rare type of hereditary hypophosphatemic rickets. Patients with XLH have various symptoms that lower their QOL as defined by HAQ, RAPID3, SF36-PCS, and SF36-MCS in adult patients and SF-10 and PDCOI in pediatric patients. Early diagnosis and treatment are needed to reduce the burden, but the condition is often diagnosed late in childhood. The present review aims to summarize the symptoms, radiological and biological characteristics, and long-term prognosis of pediatric XLH. Typical symptoms of XLH are lower leg deformities (age six months or later), growth impairment (first year of life or later), and delayed gross motor development with progressive lower limb deformities (second year of life or later). Other symptoms include dental abscess, bone pain, hearing impairment, and Chiari type 1 malformation. Critical, radiological findings of rickets are metaphyseal widening, cupping, and fraying, which tend to occur in the load-bearing bones. The Rickets Severity Score, validated for XLH, is useful for assessing the severity of rickets. The biochemical features of XLH include elevated FGF23, hypophosphatemia, low 1,25(OH)2D, and elevated urine phosphate. Renal phosphate wasting can be assessed using the tubular maximum reabsorption of phosphate per glomerular filtration rate (TmP/GFR), which yields low values in patients with XLH. XLH should be diagnosed early because the multisystem symptoms often worsen over time. The present review aims to help physicians diagnose XLH at an early stage.
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Dental manifestations and treatment of hypophosphatemic rickets: A case report and review of literature. BDJ Open 2023; 9:2. [PMID: 36717535 PMCID: PMC9886973 DOI: 10.1038/s41405-023-00129-9] [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: 10/31/2022] [Revised: 12/29/2022] [Accepted: 01/02/2023] [Indexed: 01/31/2023] Open
Abstract
BACKGROUND The treatment and management of patients suffering from hypophosphatemic rickets (HR) remain a major challenge for dental practitioners and affected patients. OBJECTIVES To report a case of HR presenting with specific dental findings and to review the dental manifestations and treatment of HR patients. METHODS Case: A 32-year-old male presented with multiple dental abscesses and short stature. A thorough history was taken followed by clinical oral examination, and relevant radiological investigation was done. Literature research: In 2020, electronic literature searches were carried out in PubMed and complemented by a careful assessment of the reference lists of the identified relevant papers. Articles and reports fulfilled the inclusion criteria: indexed reviews, case series and case reports in English and restricted to human studies were considered. RESULTS The intraoral examination revealed multiple dental abscesses and general periodontal disease; the radiographic examination showed poorly defined lamina dura, large pulp chambers and periapical lesions. Based on the contents of the 43 articles identified in the search, the current knowledge of dental manifestations, treatment and management of HR was summarized. CONCLUSIONS As HR is a multisystem disease, multidisciplinary care is needed. By summarizing current evidences, we proposed an evidence-based dental management and provided recommendations on diagnosis and treatment of the disease. It is of profound clinical significance to acquire knowledge of the dental manifestations and provide optimal treatment options for patients.
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17
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Larsson A, Regnstrand T, Skott P, Mäkitie O, Björnsdottir S, Garming-Legert K. Dental health of patients with X-linked hypophosphatemia: A controlled study. FRONTIERS IN ORAL HEALTH 2023; 4:1087761. [PMID: 37026091 PMCID: PMC10070686 DOI: 10.3389/froh.2023.1087761] [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: 11/02/2022] [Accepted: 02/28/2023] [Indexed: 04/08/2023] Open
Abstract
Objective The present study compared the dental health of patients with X-linked hypophosphatemia (XLH) with healthy age- and gender-matched controls to increase our knowledge of the impact of XLH on oral health. Materials and methods Twenty-two adult patients with XLH in the Stockholm region of Sweden were referred to the Department of Orofacial Medicine at Karolinska Institutet for an extended clinical and radiological examination. Pre-existing radiologic examinations of 44 healthy age- and gender-matched controls were retrieved from the Department of Oral Radiology, at Karolinska Institutet. Results The 22 patients with XLH (15 females, median age 38 years, range 20-71; 7 males, median age 49 years, range 24-67) had a significantly higher number of root-filled teeth compared to healthy controls (p = .001). In the XLH group, females had significantly better oral health than males, especially concerning endodontic and cariological status (p's = .01 and .02, respectively). Periodontal status differed non-significantly between the XLH and control groups. Conclusion Patients with XLH had a significantly lower oral health status compared to a healthy population especially concerning endodontic conditions. Male patients with XLH had a higher risk of poor oral health compared to female patients with XLH.
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Affiliation(s)
- Amila Larsson
- Department of Dental Medicine, Karolinska Institutet, Huddinge, Sweden
- Public Dental Health Service Stockholm AB, Stockholm, Sweden
- Correspondence: Amila Larsson
| | - Tobias Regnstrand
- Department of Dental Medicine, Karolinska Institutet, Huddinge, Sweden
| | - Pia Skott
- Department of Dental Medicine, Karolinska Institutet, Huddinge, Sweden
- Public Dental Health Service Stockholm AB, Stockholm, Sweden
| | - Outi Mäkitie
- Department of Pediatric Research, Children's Hospital, Pediatric Research Center, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
- Department of Clinical Genetics, Clinical Genetics, Karolinska University Hospital, Stockholm, Sweden
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
| | - Sigridur Björnsdottir
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
- Department of Endocrinology, Metabolism and Diabetes, Karolinska University Hospital, Stockholm, Sweden
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18
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André J, Zhukouskaya VV, Lambert AS, Salles JP, Mignot B, Bardet C, Chaussain C, Rothenbuhler A, Linglart A. Growth hormone treatment improves final height in children with X-linked hypophosphatemia. Orphanet J Rare Dis 2022; 17:444. [PMID: 36544157 PMCID: PMC9768884 DOI: 10.1186/s13023-022-02590-5] [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: 06/04/2022] [Accepted: 12/07/2022] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND/AIM Despite optimal conventional treatment (oral phosphate supplements and active vitamin D analogs), about 40-50% of children with well-controlled X-linked hypophosphatemia (XLH) show linear growth failure, making them less likely to achieve an acceptable final height. Here, we studied the hypothesis that rhGH treatment improves final height in children with XLH and growth failure. METHODS Two cohorts of children with XLH were included in this retrospective longitudinal analysis: (1) a cohort treated with rhGH for short stature (n = 34) and (2) a cohort not treated with rhGH (n = 29). The mean duration of rhGH treatment was 4.4 ± 2.9 years. We collected the auxological parameters at various time points during follow-up until final height. RESULTS In rhGH-treated children, 2 years of rhGH therapy was associated with a significant increase in height from - 2.4 ± 0.9 to - 1.5 ± 0.7 SDS (p < 0.001). Their mean height at rhGH discontinuation was - 1.2 ± 0.9 SDS and at final height was - 1.3 ± 0.9 SDS corresponding to 165.5 ± 6.4 cm in boys and 155.5 ± 6.3 cm in girls. Notably, the two groups had similar final heights; i.e., the final height in children not treated with rhGH being - 1.2 ± 1.1 SDS (165.4 ± 6.8 cm in boys and 153.7 ± 7.8 cm in girls), p = 0.7. CONCLUSION Treatment with rhGH permits to improve final height in children with XLH and growth failure, despite optimal conventional treatment. We propose therefore that rhGH therapy could be considered as an option for short stature in the context of XLH.
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Affiliation(s)
- Julia André
- grid.413784.d0000 0001 2181 7253AP-HP, Endocrinology and Diabetes for Children, Reference Center for Rare Diseases of Calcium and Phosphate Metabolism, DMU SEA, OSCAR Filière, EndoRare and BOND ERN, Bicêtre Paris Saclay Hospital, 78 Rue du Général Leclerc, 94270 Le Kremlin Bicêtre, France
| | - Volha V. Zhukouskaya
- grid.413784.d0000 0001 2181 7253AP-HP, Endocrinology and Diabetes for Children, Reference Center for Rare Diseases of Calcium and Phosphate Metabolism, DMU SEA, OSCAR Filière, EndoRare and BOND ERN, Bicêtre Paris Saclay Hospital, 78 Rue du Général Leclerc, 94270 Le Kremlin Bicêtre, France ,grid.508487.60000 0004 7885 7602Laboratory Orofacial Pathologies, Imaging and Biotherapies URP2496 and FHU-DDS-Net, Dental School, and Plateforme d’Imagerie du Vivant (PIV), Université Paris Cité, Montrouge, France
| | - Anne-Sophie Lambert
- grid.413784.d0000 0001 2181 7253AP-HP, Endocrinology and Diabetes for Children, Reference Center for Rare Diseases of Calcium and Phosphate Metabolism, DMU SEA, OSCAR Filière, EndoRare and BOND ERN, Bicêtre Paris Saclay Hospital, 78 Rue du Général Leclerc, 94270 Le Kremlin Bicêtre, France ,grid.413784.d0000 0001 2181 7253AP-HP, Medicine for Adolescents, Bicêtre Paris Saclay Hospital, Le Kremlin Bicêtre, France
| | - Jean-Pierre Salles
- grid.508721.9Unit of Endocrinology and Bone Diseases, Children Hospital, Toulouse University Hospital, CHU de Toulouse, Université de Toulouse, ERN BOND, INSERM UMR 1291/CNRS 5051, INFINITY Center, Toulouse, France
| | - Brigitte Mignot
- grid.411158.80000 0004 0638 9213Department of Pediatrics, CHU of Besancon, Besançon, France
| | - Claire Bardet
- grid.508487.60000 0004 7885 7602Laboratory Orofacial Pathologies, Imaging and Biotherapies URP2496 and FHU-DDS-Net, Dental School, and Plateforme d’Imagerie du Vivant (PIV), Université Paris Cité, Montrouge, France
| | - Catherine Chaussain
- grid.413784.d0000 0001 2181 7253AP-HP, Endocrinology and Diabetes for Children, Reference Center for Rare Diseases of Calcium and Phosphate Metabolism, DMU SEA, OSCAR Filière, EndoRare and BOND ERN, Bicêtre Paris Saclay Hospital, 78 Rue du Général Leclerc, 94270 Le Kremlin Bicêtre, France ,grid.508487.60000 0004 7885 7602Laboratory Orofacial Pathologies, Imaging and Biotherapies URP2496 and FHU-DDS-Net, Dental School, and Plateforme d’Imagerie du Vivant (PIV), Université Paris Cité, Montrouge, France ,grid.50550.350000 0001 2175 4109AP-HP, Reference Center for Rare Disorders of the Calcium and Phosphate Metabolism, Dental Medicine Department, Bretonneau Hospital, GHN-Universite de Paris, Paris, France
| | - Anya Rothenbuhler
- grid.413784.d0000 0001 2181 7253AP-HP, Endocrinology and Diabetes for Children, Reference Center for Rare Diseases of Calcium and Phosphate Metabolism, DMU SEA, OSCAR Filière, EndoRare and BOND ERN, Bicêtre Paris Saclay Hospital, 78 Rue du Général Leclerc, 94270 Le Kremlin Bicêtre, France
| | - Agnès Linglart
- grid.413784.d0000 0001 2181 7253AP-HP, Endocrinology and Diabetes for Children, Reference Center for Rare Diseases of Calcium and Phosphate Metabolism, DMU SEA, OSCAR Filière, EndoRare and BOND ERN, Bicêtre Paris Saclay Hospital, 78 Rue du Général Leclerc, 94270 Le Kremlin Bicêtre, France ,grid.460789.40000 0004 4910 6535INSERM, Physiologie Et Physiopathologie Endocrinienne, Bicêtre Paris Saclay Hospital, Paris Saclay University, Le Kremlin Bicêtre, France
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19
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Impact of X-Linked Hypophosphatemia on Muscle Symptoms. Genes (Basel) 2022; 13:genes13122415. [PMID: 36553684 PMCID: PMC9778127 DOI: 10.3390/genes13122415] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Revised: 12/08/2022] [Accepted: 12/15/2022] [Indexed: 12/24/2022] Open
Abstract
X-linked hypophosphatemia (XLH) is the most common hereditary form of rickets and deficiency of renal tubular phosphate transport in humans. XLH is caused by the inactivation of mutations within the phosphate-regulating endopeptidase homolog X-linked (PHEX) gene and follows an X-dominant transmission. It has an estimated frequency of 1 case per 20,000, and over 300 distinct pathogenic variations have been reported that result in an excess of fibroblast growth factor 23 (FGF23) in the serum. Increased levels of FGF23 lead to renal phosphate loss, decreased serum 1,25-dihydroxyvitamin D, and increased metabolism of 1,25-dihydoxyvitamin D, resulting in hypophosphatemia. Major clinical manifestations include rickets, bone deformities, and growth retardation that develop during childhood, and osteomalacia-related fractures or pseudo-fractures, degenerative osteoarthritis, enthesopathy, dental anomalies, and hearing loss during adulthood, which can affect quality of life. In addition, fatigue is also a common symptom in patients with XLH, who experience decreased motion, muscle weakness, and pain, contributing to altered quality of life. The clinical and biomedical characteristics of XLH are extensively defined in bone tissue since skeletal deformations and mineralization defects are the most evident effects of high FGF23 and low serum phosphate levels. However, despite the muscular symptoms that XLH causes, very few reports are available on the effects of FGF23 and phosphate in muscle tissue. Given the close relationship between bones and skeletal muscles, studying the effects of FGF23 and phosphate on muscle could provide additional opportunities to understand the interactions between these two important compartments of the body. By describing the current literature on XLH and skeletal muscle dysfunctions, the purpose of this review is to highlight future areas of research that could contribute to a better understanding of XLH muscular disability and its management.
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20
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Paloian NJ, Nemeth B, Sharafinski M, Modaff P, Steiner RD. Real-world effectiveness of burosumab in children with X-linked hypophosphatemic rickets. Pediatr Nephrol 2022; 37:2667-2677. [PMID: 35211790 DOI: 10.1007/s00467-022-05484-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Revised: 01/26/2022] [Accepted: 01/27/2022] [Indexed: 11/29/2022]
Abstract
BACKGROUND X-linked hypophosphatemic rickets (XLH) is the most common cause of inherited rickets. Historically, XLH was treated with oral phosphate and calcitriol (conventional treatment). Burosumab, a fibroblast growth factor 23 (FGF-23) monoclonal antibody, was approved by the United States Food and Drug Administration (FDA) in 2018 for XLH treatment. Nevertheless, conventional treatment of XLH continues to be recommended by some specialists due to lack of published experience with burosumab in the clinical setting. We compared laboratory and radiographic changes observed following transition from conventional therapy to burosumab in pediatric XLH patients as part of routine care. METHODS This retrospective single-center study identified and retroactively studied twelve patients aged 1-18 years old with XLH previously treated with conventional therapy and transitioned to burosumab. Laboratory studies and radiographs were obtained routinely as standard of care during two treatment periods: (1) conventional therapy and (2) burosumab treatment. Laboratory values and radiologic rickets severity scores were compared between periods. RESULTS All laboratory values demonstrated improvement following 1 month of burosumab treatment, findings which were sustained over the 2-year study period. Rickets severity scores and height z-scores also improved with burosumab. There were no serious adverse events with burosumab, and adverse events overall were very infrequent and mild. One patient developed an asymptomatic mild elevation of serum phosphate while taking burosumab resulting in a temporary pause in therapy. CONCLUSIONS Safety and effectiveness of burosumab in treatment of XLH were demonstrated as burosumab yielded statistically significant improvement in laboratory and radiographic markers of rickets and height compared to conventional therapy. A higher resolution version of the Graphical abstract is available as Supplementary information.
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Affiliation(s)
- Neil J Paloian
- Department of Pediatrics, University of Wisconsin School of Medicine and Public Health, 600 Highland Ave, Madison, WI, 53792, USA.
| | - Blaise Nemeth
- Department of Orthopedics and Rehabilitation, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
| | | | - Peggy Modaff
- Department of Pediatrics, University of Wisconsin School of Medicine and Public Health, 600 Highland Ave, Madison, WI, 53792, USA
| | - Robert D Steiner
- Department of Pediatrics, University of Wisconsin School of Medicine and Public Health, 600 Highland Ave, Madison, WI, 53792, USA
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21
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Charoenngam N, Nasr A, Shirvani A, Holick MF. Hereditary Metabolic Bone Diseases: A Review of Pathogenesis, Diagnosis and Management. Genes (Basel) 2022; 13:genes13101880. [PMID: 36292765 PMCID: PMC9601711 DOI: 10.3390/genes13101880] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2022] [Revised: 10/03/2022] [Accepted: 10/13/2022] [Indexed: 11/20/2022] Open
Abstract
Hereditary metabolic bone diseases are characterized by genetic abnormalities in skeletal homeostasis and encompass one of the most diverse groups among rare diseases. In this review, we examine 25 selected hereditary metabolic bone diseases and recognized genetic variations of 78 genes that represent each of the three groups, including sclerosing bone disorders, disorders of defective bone mineralization and disorder of bone matrix and cartilage formation. We also review pathophysiology, manifestation and treatment for each disease. Advances in molecular genetics and basic sciences has led to accurate genetic diagnosis and novel effective therapeutic strategies for some diseases. For other diseases, the genetic basis and pathophysiology remain unclear. Further researches are therefore crucial to innovate ways to overcome diagnostic challenges and develop effective treatment options for these orphan diseases.
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Affiliation(s)
- Nipith Charoenngam
- Section Endocrinology, Diabetes, Nutrition and Weight Management, Department of Medicine, Boston University School of Medicine, Boston, MA 02118, USA
- Department of Medicine, Mount Auburn Hospital, Harvard Medical School, Cambridge, MA 02138, USA
- Department of Medicine, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand
| | - Aryan Nasr
- Section Endocrinology, Diabetes, Nutrition and Weight Management, Department of Medicine, Boston University School of Medicine, Boston, MA 02118, USA
| | - Arash Shirvani
- Section Endocrinology, Diabetes, Nutrition and Weight Management, Department of Medicine, Boston University School of Medicine, Boston, MA 02118, USA
| | - Michael F. Holick
- Section Endocrinology, Diabetes, Nutrition and Weight Management, Department of Medicine, Boston University School of Medicine, Boston, MA 02118, USA
- Correspondence: ; Tel.: +1-617-358-6139
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22
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Brandi ML, Ariceta G, Beck-Nielsen SS, Boot AM, Briot K, de Lucas Collantes C, Emma F, Giannini S, Haffner D, Keen R, Levtchenko E, Mӓkitie O, Nilsson O, Schnabel D, Tripto-Shkolnik L, Zillikens MC, Liu J, Tudor A, Mughal MZ. Post-authorisation safety study of burosumab use in paediatric, adolescent and adult patients with X-linked hypophosphataemia: rationale and description. Ther Adv Chronic Dis 2022; 13:20406223221117471. [PMID: 36082134 PMCID: PMC9445456 DOI: 10.1177/20406223221117471] [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: 10/08/2021] [Accepted: 07/15/2022] [Indexed: 11/16/2022] Open
Abstract
Background: X-linked hypophosphataemia (XLH) is a rare, inherited, phosphate-wasting disorder that elevates fibroblast growth factor 23 (FGF23), causing renal phosphate-wasting and impaired active vitamin D (1,25(OH)2D) synthesis. Disease characteristics include rickets, osteomalacia, odontomalacia, and short stature. Historically, treatment has been oral phosphate and 1,25(OH)2D supplements. However, these treatments do not correct the primary pathogenic mechanism or treat all symptoms and can be associated with adverse effects. Burosumab is a recombinant human immunoglobulin G1 monoclonal antibody against FGF23, approved for treating XLH in several geographical regions, including Europe and Israel. Burosumab restores normal serum phosphate levels, minimising the clinical consequences of XLH. Safety data on long-term treatment with burosumab are lacking owing to the rarity of XLH. This post-authorisation safety study (PASS) aims to evaluate the safety outcomes in patients aged >1 year. Methods: The PASS is a 10-year retrospective and prospective cohort study utilising data from the International XLH Registry (NCT03193476), which includes standard diagnostic and monitoring practice data at participating centres. The PASS aims to evaluate frequency and severity of safety outcomes, frequency and outcomes of pregnancies in female patients, and safety outcomes in patients with mild to moderate kidney disease at baseline, in children, adolescents and adults treated with burosumab for XLH. It is expected that there will be at least 400 patients who will be administered burosumab. Results: Data collection started on 24 April 2019. The expected date of the final study report is 31 December 2028, with two interim reports. Conclusion: This PASS will provide data on the long-term safety of burosumab treatment for XLH patients and describe safety outcomes for patients receiving burosumab contrasted with those patients receiving other XLH treatments, to help inform the future management of XLH patients. The PASS will be the largest real-world safety study of burosumab. Registry identification: The International XLH Registry is registered with clinicaltrials.gov as NCT03193476 (https://clinicaltrials.gov/ct2/show/NCT03193476), and the PASS is registered with the European Union electronic Register of Post-Authorisation Studies as EUPAS32190 (http://www.encepp.eu/encepp/viewResource.htm?id=32191).
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Affiliation(s)
| | - Gema Ariceta
- Department of Pediatric Nephrology, Hospital Universitario Vall d'Hebron, Universidad Autónoma de Barcelona, Barcelona, Spain
| | - Signe Sparre Beck-Nielsen
- Centre for Rare Diseases, Department of Paediatrics, Aarhus University Hospital, Aarhus, Denmark.,Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Annemieke M Boot
- Department of Pediatric Endocrinology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Karine Briot
- APHP, Department of Rheumatology, Cochin Hospital, Université de Paris, Paris, France
| | - Carmen de Lucas Collantes
- Department of Nephrology, Hospital Infantil Universitario Niño Jesús, Universidad Autónoma de Madrid, Madrid, Spain
| | - Francesco Emma
- Division of Nephrology, Bambino Gesù Children's Hospital IRCCS, Rome, Italy
| | - Sandro Giannini
- Department of Medicine, Clinica Medica 1, University of Padua, Padua, Italy
| | - Dieter Haffner
- Department of Pediatric Kidney, Liver and Metabolic Diseases, Children's Hospital, Hannover Medical School, Hannover, Germany
| | - Richard Keen
- Metabolic Unit, Royal National Orthopaedic Hospital NHS Trust, London, UK
| | - Elena Levtchenko
- Department of Pediatric Nephrology and Development and Regeneration, University Hospitals Leuven, University of Leuven, Leuven, Belgium
| | - Outi Mӓkitie
- Pediatric Endocrinology, Children's Hospital, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - Ola Nilsson
- Division of Pediatric Endocrinology, Department of Women's and Children's Health, Karolinska Institutet and University Hospital, Stockholm, Sweden.,Department of Medical Sciences and Department of Pediatrics, Örebro University and University Hospital, Örebro, Sweden
| | - Dirk Schnabel
- Center for Chronic Sick Children, Pediatric Endocrinology, Charitè, University Medicine, Berlin, Germany
| | - Liana Tripto-Shkolnik
- Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv, Israel.,Division of Endocrinology, Diabetes and Metabolism, Sheba Medical Center, Tel-Hashomer, Israel
| | - M Carola Zillikens
- Department of Internal Medicine, Erasmus MC Bone Center - Erasmus University Medical Center, Rotterdam, The Netherlands
| | | | | | - M Zulf Mughal
- Department of Paediatric Endocrinology, Royal Manchester Children's Hospital, Manchester, UK.,Faculty of Biology, Medicine & Health, University of Manchester, Manchester, UK
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23
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Complications and Treatments in Adult X-Linked Hypophosphatemia. ENDOCRINES 2022. [DOI: 10.3390/endocrines3030047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
X-linked hypophosphatemia (XLH) is a rare inherited disorder involving elevated levels of fibroblast growth factor (FGF) 23, and is caused by loss-of-function mutations in the PHEX gene. FGF23 induces renal phosphate wasting and suppresses the activation of vitamin D, resulting in defective bone mineralization and rachitic changes in the growth plate and osteomalacia. Conventional treatment with combinations of oral inorganic phosphate and active vitamin D analogs enhances bone calcification, but the efficacy of conventional treatment is insufficient for adult XLH patients to achieve an acceptable quality of life. Burosumab, a fully human monoclonal anti-FGF23 antibody, binds and inhibits FGF23, correcting hypophosphatemia and hypovitaminosis D. This review describes a typical adult with XLH and summarizes the results of clinical trials of burosumab in adults with XLH.
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24
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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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25
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Treatment of X-Linked Hypophosphatemia in Children. ENDOCRINES 2022. [DOI: 10.3390/endocrines3030042] [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
The conventional treatment for X-linked hypophosphatemia (XLH), consisting of phosphorus supplementation and a biologically active form of vitamin D (alfacalcidol or calcitriol), is used to treat rickets and leg deformities and promote growth. However, patients’ adult height often remains less than −2 SD. Moreover, adverse events, such as renal calcification and hyperparathyroidism, may occur. The main pathology in XLH is caused by excessive production of fibroblast growth factor 23 (FGF23). Several studies have demonstrated that treatment with burosumab, a blocking neutralizing antibody against FGF23, is better than conventional therapy for severe XLH and has no serious, short-term side effects. Thus, treatment with burosumab may be an option for severe XLH. The present article reviews the conventional and burosumab therapies. In addition to the fact that the long-term efficacy of antibody-based treatment has not been demonstrated, there are other, unresolved issues concerning the burosumab treatment of XLH.
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26
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Jurca CM, Iuhas O, Kozma K, Petchesi CD, Zaha DC, Bembea M, Jurca S, Paul C, Jurca AD. Effects of Burosumab Treatment on Two Siblings with X-Linked Hypophosphatemia. Case Report and Literature Review. Genes (Basel) 2022; 13:genes13081392. [PMID: 36011303 PMCID: PMC9407333 DOI: 10.3390/genes13081392] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Revised: 08/01/2022] [Accepted: 08/03/2022] [Indexed: 11/16/2022] Open
Abstract
X-linked hypophosphatemia (XLH) or vitamin D-resistant rickets (MIM#307800), is a monogenic disorder with X-linked inheritance. It is caused by mutations present in the Phosphate Regulating Endopeptidase Homolog X-Linked (PHEX) gene responsible for the degradation of the bone-derived hormone fibroblast growth factor 23 (FGF23) into inactive fragments, but the entire mechanism is currently unclear. The inactivation of the gene prevents the degradation of FGF23, causing increased levels of FGF23, which leads to decreased tubular reabsorbtion of phosphorus. Clinical aspects are growth delay, limb deformities, bone pain, osteomalacia, dental anomalies, and enthesopathy. Laboratory evaluation shows hypophosphatemia, elevated alkaline phosphatase (ALP), and normal serum calcium levels, whereas parathormone (PTH) may be normal or increased and FGF23 greatly increased. Conventional treatment consists of administration of oral phosphate and calcitriol. Treatment with Burosumab, a monoclonal antibody that binds to FGF23, reducing its activity, was approved in 2018. Methods. We describe a case of two siblings, a girl and a boy, diagnosed with XLH, monitored by the Genetic Department of the County Emergency Clinical Hospital since 2019. The clinical picture is suggestive for XLH, both siblings exhibiting short stature, lower limb curvature, bone pain, marked walking weakness, and fatigue. Radiological aspects showed marked deformity of the lower limbs: genu varum in the girl, genu varum and valgum in the boy. Laboratory investigations showed hypophosphathemia, hyperphosphaturia, elevated ALP, normal PTH, and highly increased FGF23 in both. DNA analysis performed on the two siblings revealed a nonsense mutation in exone 5 of the PHEX gene: NM_000444.6(PHEX):c.565C > T (p.Gln189Ter). Results. At the age of 13½ on 7 June 2021, the two children started treatment with Burosumab in therapeutic doses and were monitored clinically and biochemically at regular intervals according to the protocol established by the Endocrinology Commission of the Romanian Health Ministry. Conclusions. The first results of the Burosumab treatment in the two siblings are extremely encouraging and suggest a favorable long-term evolution under this treatment.
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Affiliation(s)
- Claudia Maria Jurca
- Faculty of Medicine and Pharmacy, Department of Preclinical Disciplines, 1 December Sq., University of Oradea, 410081 Oradea, Romania
- Regional Center of Medical Genetics Bihor, County Emergency Clinical Hospital Oradea, Romania, (Part of ERN THACA), 410469 Oradea, Romania
| | - Oana Iuhas
- Regional Center of Medical Genetics Bihor, County Emergency Clinical Hospital Oradea, Romania, (Part of ERN THACA), 410469 Oradea, Romania
| | - Kinga Kozma
- Faculty of Medicine and Pharmacy, Department of Preclinical Disciplines, 1 December Sq., University of Oradea, 410081 Oradea, Romania
- Regional Center of Medical Genetics Bihor, County Emergency Clinical Hospital Oradea, Romania, (Part of ERN THACA), 410469 Oradea, Romania
| | - Codruta Diana Petchesi
- Faculty of Medicine and Pharmacy, Department of Preclinical Disciplines, 1 December Sq., University of Oradea, 410081 Oradea, Romania
- Correspondence:
| | - Dana Carmen Zaha
- Faculty of Medicine and Pharmacy, Department of Preclinical Disciplines, 1 December Sq., University of Oradea, 410081 Oradea, Romania
| | - Marius Bembea
- Faculty of Medicine and Pharmacy, Department of Preclinical Disciplines, 1 December Sq., University of Oradea, 410081 Oradea, Romania
| | - Sanziana Jurca
- Faculty of Medicine and Pharmacy, Department of Preclinical Disciplines, 1 December Sq., University of Oradea, 410081 Oradea, Romania
| | - Corina Paul
- Department of Pediatrics, Victor Babes University of Medicine and Pharmacy, 300041 Timisoara, Romania
| | - Alexandru Daniel Jurca
- Faculty of Medicine and Pharmacy, Department of Preclinical Disciplines, 1 December Sq., University of Oradea, 410081 Oradea, Romania
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27
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Orthopedic Complications and Management in Children with X-Linked Hypophosphatemia. ENDOCRINES 2022. [DOI: 10.3390/endocrines3030039] [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
X-linked hypophosphatemia is an inheritable disease of renal phosphate wasting that results in clinically manifestations associated with rickets or osteomalacia. The various symptoms in the skeletal system are well recognized, such as short stature; lower limb deformities; and bone, joint, or muscle pain, and it is often difficult to control these symptoms, despite the use of medication therapy in growing children. In addition, lower limb deformities can lead to degenerative osteoarthritis and dysfunction of lower limbs at the skeletal maturity. To prevent from future manifestation of those symptoms, orthopedic surgeries are applicable to growing patients with severe skeletal deformities or without response to conventional medication. Bone deformities are treated by acute or gradual corrective osteotomies and temporally hemiepiphysiodesis using guided growth method. The clinicians should choose the right procedure based on age, symptoms and state of deformities of the patient.
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Ward LM, Glorieux FH, Whyte MP, Munns CF, Portale AA, Högler W, Simmons JH, Gottesman GS, Padidela R, Namba N, Cheong HI, Nilsson O, Mao M, Chen A, Skrinar A, Roberts MS, Imel EA. Effect of Burosumab Compared With Conventional Therapy on Younger vs Older Children With X-linked Hypophosphatemia. J Clin Endocrinol Metab 2022; 107:e3241-e3253. [PMID: 35533340 PMCID: PMC9282253 DOI: 10.1210/clinem/dgac296] [Citation(s) in RCA: 31] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Indexed: 11/19/2022]
Abstract
CONTEXT Younger age at treatment onset with conventional therapy (phosphate salts and active vitamin D; Pi/D) is associated with improved growth and skeletal outcomes in children with X-linked hypophosphatemia (XLH). The effect of age on burosumab efficacy and safety in XLH is unknown. OBJECTIVE This work aimed to explore the efficacy and safety of burosumab vs Pi/D in younger (< 5 years) and older (5-12 years) children with XLH. METHODS This post hoc analysis of a 64-week, open-label, randomized controlled study took place at 16 academic centers. Sixty-one children aged 1 to 12 years with XLH (younger, n = 26; older, n = 35) participated. Children received burosumab starting at 0.8 mg/kg every 2 weeks (younger, n = 14; older, n = 15) or continued Pi/D individually titrated per recommended guidelines (younger, n = 12; older, n = 20). The main outcome measure included the least squares means difference (LSMD) in Radiographic Global Impression of Change (RGI-C) rickets total score from baseline to week 64. RESULTS The LSMD in outcomes through 64 weeks on burosumab vs conventional therapy by age group were as follows: RGI-C rickets total score (younger, +0.90; older, +1.07), total Rickets Severity Score (younger, -0.86; older, -1.44), RGI-C lower limb deformity score (younger, +1.02; older, +0.91), recumbent length or standing height Z-score (younger, +0.20; older, +0.09), and serum alkaline phosphatase (ALP) (younger, -31.15% of upper normal limit [ULN]; older, -52.11% of ULN). On burosumab, dental abscesses were not reported in younger children but were in 53% of older children. CONCLUSION Burosumab appears to improve outcomes both in younger and older children with XLH, including rickets, lower limb deformities, growth, and ALP, compared with Pi/D.
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Affiliation(s)
- Leanne M Ward
- Correspondence: Leanne M. Ward, MD, Pediatrics, University of Ottawa, Ottawa, Ontario, Canada, Rm 250H, 401 Smyth Rd, Ottawa, Ontario, K1H 8L1, Canada.
| | - Francis H Glorieux
- Shriners Hospitals for Children, Canada, McGill University, Montreal, Quebec H4A OA9, Canada
| | - Michael P Whyte
- Shriners Hospitals for Children St Louis, St Louis, Missouri 63110,USA
| | - Craig F Munns
- Child Health Research Centre, The University of Queensland, Brisbane, Queensland 4072, Australia
- Department of Endocrinology and Diabetes, Queensland Children’s Hospital, Brisbane, Queensland 4101, Australia
| | - Anthony A Portale
- Department of Pediatrics, University of California, San Francisco, San Francisco, California 94143, USA
| | - Wolfgang Högler
- Department of Pediatrics and Adolescent Medicine, Johannes Kepler University Linz, Linz 4040, Austria
- Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, B15 2TT, UK
| | - Jill H Simmons
- Department of Pediatrics, Division of Endocrinology and Diabetes, Vanderbilt University School of Medicine, Vanderbilt University, 680-8570 Nashville, Tennessee, 63110, USA
| | - Gary S Gottesman
- Shriners Hospitals for Children St Louis, St Louis, Missouri 63110, USA
| | - Raja Padidela
- Department of Paediatric Endocrinology, Royal Manchester Children’s Hospital, Manchester M13 9WL, UK
| | - Noriyuki Namba
- Department of Pediatrics, Osaka Hospital, Japan
- Community Healthcare Organization
- Osaka University Graduate School of Medicine, Osaka 553-0003, Japan
- Division of Pediatrics and Perinatology, Tottori University Faculty of Medicine, Yonago, Japan
| | - Hae Il Cheong
- Department of Pediatrics, Seoul National University Children’s Hospital, Seoul 14068, South Korea
| | - Ola Nilsson
- Division of Pediatric Endocrinology and Center for Molecular Medicine, Karolinska Institutet, Stockholm 17177, Sweden
- School of Medical Sciences, Department of Pediatrics, Örebro University and University Hospital, Örebro S-703 62, Sweden
| | - Meng Mao
- Ultragenyx Pharmaceutical Inc, Novato, California 94949, USA
| | - Angel Chen
- Ultragenyx Pharmaceutical Inc, Novato, California 94949, USA
| | - Alison Skrinar
- Ultragenyx Pharmaceutical Inc, Novato, California 94949, USA
| | | | - Erik A Imel
- Department of Medicine and Department of Pediatrics, Indiana University School of Medicine, Indianapolis, Indianapolis 46202, USA
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Del Pino M, Viterbo GL, Arenas MA, Perez Garrido N, Ramirez P, Marino R, Belgorosky A, Fano V. Growth in height and body proportion from birth to adulthood in hereditary hypophosphatemic rickets: a retrospective cohort study. J Endocrinol Invest 2022; 45:1349-1358. [PMID: 35226335 DOI: 10.1007/s40618-022-01768-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/20/2021] [Accepted: 02/14/2022] [Indexed: 10/19/2022]
Abstract
PURPOSE Patients with hereditary hypophosphatemic rickets are short and disproportionate and very little information is available on segmental growth, but the body disproportion at adulthood leads us to think that the growth velocity of legs is slower. METHODS A total of 96 children were included and molecular testing was carried out in 42. Children who reached adult height were classified into two groups according to their compliance to conventional treatment (phosphate supplement and calcitriol). Individual growth records of height and sitting height/height were plotted using Argentine reference data in 96 children and growth curves were estimated by fitting Preece-Baines Model 1 in 19 of the children. RESULTS Molecular testing revealed sequence deleterious alterations or large deletions in 36/42 patients. During childhood, 76% of children grew below - 1.88 standard deviation score (SDS) and 97% had body disproportion. During adolescence, the mean peak height velocity for the good and poor compliance to treatment groups was 7.8 (0.6) and 5.4 (0.4) cm/year in boys and 7.0 (0.7) and 5.2 (0.8) cm/year in girls, respectively. At adulthood, the median sitting height/height ratio was 2.32 and 6.21 SDS for the good and poor compliance to treatment groups, respectively. The mean pubertal growth spurt of the trunk was -0.8 (1.4) SDS, with a short pubertal growth spurt of - 1.8 (0.4) SDS for limbs in the good compliance group. Median adult height in 13/29 males and 30/67 females was -4.56 and -3.16 SDS, respectively. CONCLUSION For all patients the growth spurt was slower, secondary to a short growth spurt of limbs, reaching a short adult height with body disproportion that was more prominent in the poor compliance group.
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Affiliation(s)
- M Del Pino
- Growth and Development, Hospital Garrahan, Combate de los Pozos 1881 (1245), Buenos Aires, Argentina.
| | - G L Viterbo
- Endocrinology, Hospital Garrahan, Buenos Aires, Argentina
| | - M A Arenas
- Growth and Development, Hospital Garrahan, Combate de los Pozos 1881 (1245), Buenos Aires, Argentina
| | - N Perez Garrido
- Endocrinology Molecular Laboratory, Hospital Garrahan, Buenos Aires, Argentina
| | - P Ramirez
- Endocrinology Molecular Laboratory, Hospital Garrahan, Buenos Aires, Argentina
| | - R Marino
- Endocrinology Molecular Laboratory, Hospital Garrahan, Buenos Aires, Argentina
| | - A Belgorosky
- Endocrinology, Hospital Garrahan, Buenos Aires, Argentina
- CONICET, Hospital Garrahan, Buenos Aires, Argentina
| | - V Fano
- Growth and Development, Hospital Garrahan, Combate de los Pozos 1881 (1245), Buenos Aires, Argentina
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30
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Jin C, Zhang C, Ni X, Zhao Z, Xu L, Wu B, Chi Y, Jiajue R, Jiang Y, Wang O, Li M, Xing X, Meng X, Xia W. The efficacy and safety of different doses of calcitriol combined with neutral phosphate in X-linked hypophosphatemia: a prospective study. Osteoporos Int 2022; 33:1385-1395. [PMID: 35088103 PMCID: PMC9106624 DOI: 10.1007/s00198-021-06221-w] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Accepted: 10/19/2021] [Indexed: 11/03/2022]
Abstract
UNLABELLED The present study was the first prospective cohort evaluated the efficacy and safety of different doses of calcitriol in XLH children. The results suggested that a dose of 40 ng/kg/day calcitriol, compared with 20 ng/kg/day, was more effective in relieving the rickets, with similar safety outcomes. Further investigations were expected to set more dose groups. INTRODUCTION Dose recommended for calcitriol in X-linked hypophosphatemia (XLH) varies in different studies. Therefore, we aimed to compare the efficacy as well as the safety of 20 ng/kg/d and 40 ng/kg/d calcitriol in Chinese XLH pediatrics population. METHODS A 2-year, randomized, open-label, prospective study recruited 68 XLH children, which were randomized to receive either 40 ng/kg/day or 20 ng/kg/day calcitriol. Efficacy endpoints were the total Thacher ricket severity score (RSS) change from baseline to month 12 and 24, the difference in serum TALP level, fasting serum phosphate level, body height Z-score, and frequency of dental abscess. Safety assessments were done using renal ultrasound nephrocalcinosis grades (0-4), fasting serum and 24 h urine calcium level, and the occurrence of hyperparathyroidism. RESULTS The decrease in the total RSS from baseline was more significant in the high-dose group at 12 (difference 0.87, p = 0.049) and 24 month (difference 1.23, p = 0.011). The serum TALP level was significantly lower in the high-dose group at 6 months. Pi level, height Z-score change, frequency of dental abscess and ratio of de novo nephrocalcinosis were comparable. A lower incidence of secondary hyperparathyroidism was seen in the high-dose group (p < 0.0001). CONCLUSION For the first time in this prospective cohort, 40 ng/kg/d calcitriol was shown to be the more effective therapy in XLH children than the 20 ng/kg/d. Moreover, 40 ng/kg/d calcitriol was not associated with increasing adverse events. TRIAL REGISTRATION ClinicalTrials.gov Identifier: NCT 03,820,518.
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Affiliation(s)
- C Jin
- Department of Endocrinology, Key Laboratory of Endocrinology, NHC, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Shuaifuyuan No. 1, Dongcheng District, Beijing, 100730, China
| | - C Zhang
- Department of Endocrinology, Key Laboratory of Endocrinology, NHC, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Shuaifuyuan No. 1, Dongcheng District, Beijing, 100730, China
| | - X Ni
- Department of Endocrinology, Key Laboratory of Endocrinology, NHC, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Shuaifuyuan No. 1, Dongcheng District, Beijing, 100730, China
| | - Z Zhao
- Department of Endocrinology, Key Laboratory of Endocrinology, NHC, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Shuaifuyuan No. 1, Dongcheng District, Beijing, 100730, China
| | - L Xu
- Department of Endocrinology, Key Laboratory of Endocrinology, NHC, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Shuaifuyuan No. 1, Dongcheng District, Beijing, 100730, China
| | - B Wu
- Department of Endocrinology, Key Laboratory of Endocrinology, NHC, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Shuaifuyuan No. 1, Dongcheng District, Beijing, 100730, China
| | - Y Chi
- Department of Endocrinology, Key Laboratory of Endocrinology, NHC, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Shuaifuyuan No. 1, Dongcheng District, Beijing, 100730, China
| | - R Jiajue
- Department of Endocrinology, Key Laboratory of Endocrinology, NHC, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Shuaifuyuan No. 1, Dongcheng District, Beijing, 100730, China
| | - Y Jiang
- Department of Endocrinology, Key Laboratory of Endocrinology, NHC, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Shuaifuyuan No. 1, Dongcheng District, Beijing, 100730, China
| | - O Wang
- Department of Endocrinology, Key Laboratory of Endocrinology, NHC, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Shuaifuyuan No. 1, Dongcheng District, Beijing, 100730, China
| | - Mei Li
- Department of Endocrinology, Key Laboratory of Endocrinology, NHC, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Shuaifuyuan No. 1, Dongcheng District, Beijing, 100730, China
| | - X Xing
- Department of Endocrinology, Key Laboratory of Endocrinology, NHC, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Shuaifuyuan No. 1, Dongcheng District, Beijing, 100730, China
| | - X Meng
- Department of Endocrinology, Key Laboratory of Endocrinology, NHC, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Shuaifuyuan No. 1, Dongcheng District, Beijing, 100730, China
| | - W Xia
- Department of Endocrinology, Key Laboratory of Endocrinology, NHC, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Shuaifuyuan No. 1, Dongcheng District, Beijing, 100730, China.
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Trombetti A, Al-Daghri N, Brandi ML, Cannata-Andía JB, Cavalier E, Chandran M, Chaussain C, Cipullo L, Cooper C, Haffner D, Harvengt P, Harvey NC, Javaid MK, Jiwa F, Kanis JA, Laslop A, Laurent MR, Linglart A, Marques A, Mindler GT, Minisola S, Yerro MCP, Rosa MM, Seefried L, Vlaskovska M, Zanchetta MB, Rizzoli R. Interdisciplinary management of FGF23-related phosphate wasting syndromes: a Consensus Statement on the evaluation, diagnosis and care of patients with X-linked hypophosphataemia. Nat Rev Endocrinol 2022; 18:366-384. [PMID: 35484227 DOI: 10.1038/s41574-022-00662-x] [Citation(s) in RCA: 38] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 03/10/2022] [Indexed: 12/17/2022]
Abstract
X-linked hypophosphataemia (XLH) is the most frequent cause of hypophosphataemia-associated rickets of genetic origin and is associated with high levels of the phosphaturic hormone fibroblast growth factor 23 (FGF23). In addition to rickets and osteomalacia, patients with XLH have a heavy disease burden with enthesopathies, osteoarthritis, pseudofractures and dental complications, all of which contribute to reduced quality of life. This Consensus Statement presents the outcomes of a working group of the European Society for Clinical and Economic Aspects of Osteoporosis, Osteoarthritis and Musculoskeletal Diseases, and provides robust clinical evidence on management in XLH, with an emphasis on patients' experiences and needs. During growth, conventional treatment with phosphate supplements and active vitamin D metabolites (such as calcitriol) improves growth, ameliorates leg deformities and dental manifestations, and reduces pain. The continuation of conventional treatment in symptom-free adults is still debated. A novel therapeutic approach is the monoclonal anti-FGF23 antibody burosumab. Although promising, further studies are required to clarify its long-term efficacy, particularly in adults. Given the diversity of symptoms and complications, an interdisciplinary approach to management is of paramount importance. The focus of treatment should be not only on the physical manifestations and challenges associated with XLH and other FGF23-mediated hypophosphataemia syndromes, but also on the major psychological and social impact of the disease.
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Affiliation(s)
- Andrea Trombetti
- Division of Bone Diseases, Department of Medicine, Geneva University Hospitals and Faculty of Medicine, Geneva, Switzerland
- Division of Geriatrics, Department of Rehabilitation and Geriatrics, Geneva University Hospitals and Faculty of Medicine, Geneva, Switzerland
| | - Nasser Al-Daghri
- Chair for Biomarkers of Chronic Diseases, Biochemistry Department, College of Science, King Saud University, Riyadh, Kingdom of Saudi Arabia
| | | | - Jorge B Cannata-Andía
- Hospital Universitario Central de Asturias (HUCA), Oviedo, Spain
- Universidad de Oviedo, Oviedo, Spain
- Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), Oviedo, Spain
- Retic REDinREN-RICORS, 2040-ISCIII, Madrid, Spain
| | - Etienne Cavalier
- Department of Clinical Chemistry, University of Liege, CHU de Liège, Liège, Belgium
| | - Manju Chandran
- Complicated Metabolic Bone Disorders Clinic, Osteoporosis and Bone Metabolism Unit, Department of Endocrinology, Singapore General Hospital, Singapore, Singapore
| | - Catherine Chaussain
- Université de Paris, Institut des maladies musculo-squelettiques, URP2496, UFR Odontologie, Montrouge, France
- AP-HP, FHU DDS-Net, Centre de Référence des Maladies Rares du Métabolisme du Calcium et du Phosphore, Service médecine bucco-dentaire, Hôpital Bretonneau, GH Paris Nord Université de Paris, Paris, France
| | - Lucia Cipullo
- Patient representative with XLH, Geneva, Switzerland
| | - Cyrus Cooper
- MRC Lifecourse Epidemiology Centre, University of Southampton, Southampton, UK
- NIHR Southampton Biomedical Research Centre, University of Southampton and University Hospital Southampton NHS Foundation Trust, Southampton, UK
- NIHR Oxford Biomedical Research Centre, University of Oxford, Oxford, UK
| | - Dieter Haffner
- Department of Paediatric Kidney, Liver and Metabolic Diseases, Hannover Medical School, Hannover, Germany
| | - Pol Harvengt
- XLH Belgium, Belgian association of patients with XLH (a member of the International XLH Alliance), Waterloo, Belgium
| | - Nicholas C Harvey
- MRC Lifecourse Epidemiology Centre, University of Southampton, Southampton, UK
- NIHR Southampton Biomedical Research Centre, University of Southampton and University Hospital Southampton NHS Foundation Trust, Southampton, UK
| | | | - Famida Jiwa
- Chair of the Committee of Patients Societies at the International Osteoporosis Foundation, Osteoporosis Canada, Toronto, Canada
| | - John A Kanis
- Mary McKillop Institute for Health Research, Australian Catholic University, Melbourne, Australia
- Centre for Metabolic Bone Diseases, University of Sheffield Medical School, Sheffield, UK
| | - Andrea Laslop
- Scientific Office, Federal Office for Safety in Health Care, Vienna, Austria
| | - Michaël R Laurent
- Centre for Metabolic Bone Diseases, University Hospitals Leuven, Leuven, Belgium
| | - Agnès Linglart
- Paris-Saclay University, INSERM U1185, Le Kremlin-Bicêtre, France
- AP-HP, endocrinology and diabetes for children, Reference centre for rare diseases of calcium and phosphate metabolism, OSCAR network, Platform of expertise for rare diseases of Paris Saclay Hospital, Bicêtre Paris Saclay Hospital, Le Kremlin-Bicêtre, France
| | - Andréa Marques
- Rheumatology Department, Centro Hospitalar Universitário de Coimbra, Coimbra, Portugal
- Health Sciences Research Unit: Nursing (UICiSA:E), Nursing School of Coimbra, Coimbra, Portugal
| | - Gabriel T Mindler
- Department of Paediatric Orthopaedics, Orthopaedic Hospital Speising, Vienna, Austria
- Vienna Bone and Growth Center, Vienna, Austria
| | - Salvatore Minisola
- Department of Clinical, Internal, Anaesthesiologic and Cardiovascular Sciences, 'Sapienza', Rome University, Rome, Italy
| | | | - Mario Miguel Rosa
- Departamento de Neurociências, Laboratório de Farmacologia Clínica E Terapêutica Faculdade de Medicina da Universidade de Lisboa, Lisbon, Portugal
| | - Lothar Seefried
- Orthopedic Department, University of Würzburg, Würzburg, Germany
| | - Mila Vlaskovska
- Medical Faculty, Department of Pharmacology, Medical University Sofia, Sofia, Bulgaria
| | - María Belén Zanchetta
- Instituto de Investigaciones Metabólicas (IDIM), Universidad del Salvador, Buenos Aires, Argentina
| | - René Rizzoli
- Division of Bone Diseases, Department of Medicine, Geneva University Hospitals and Faculty of Medicine, Geneva, Switzerland.
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Yang Y, Wang Y, Shen Y, Liu M, Dai S, Wang X, Liu H. Identification of a Novel Missense Mutation of the PHEX Gene in a Large Chinese Family with X-Linked Hypophosphataemia. Front Genet 2022; 13:792183. [PMID: 35251124 PMCID: PMC8891598 DOI: 10.3389/fgene.2022.792183] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2021] [Accepted: 01/18/2022] [Indexed: 11/13/2022] Open
Abstract
X-linked hypophosphataemia (XLH) is an X-linked dominant rare disease that refers to the most common hereditary hypophosphatemia (HH) caused by mutations in the phosphate-regulating endopeptidase homolog X-linked gene (PHEX; OMIM: * 300550). However, mutations that have already been reported cannot account for all cases of XLH. Extensive genetic analysis can thus be helpful for arriving at the diagnosis of XLH. Herein, we identified a novel heterozygous mutation of PHEX (NM_000444.5: c.1768G > A) in a large Chinese family with XLH by whole-exome sequencing (WES). In addition, the negative effect of this mutation in PHEX was confirmed by both bioinformatics analysis and in vitro experimentation. The three-dimensional protein-model analysis predicted that this mutation might impair normal zinc binding. Immunofluorescence staining, qPCR, and western blotting analysis confirmed that the mutation we detected attenuated PHEX protein expression. The heterozygous mutation of PHEX (NM_000444.5: c.1768G > A) identified in this study by genetic and functional experiments constitutes a novel genetic cause of XLH, but further study will be required to expand its use in clinical and molecular diagnoses of XLH.
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Affiliation(s)
- Yanting Yang
- Department of Obstetrics and Gynecology, West China Second University Hospital, Sichuan University, Chengdu, China
- Medical Genetics Department/Prenatal Diagnostic Center, West China Second University Hospital, Sichuan University, Chengdu, China
- Key Laboratory of Birth Defects and Related Diseases of Women and Children, Ministry of Education, Sichuan University, Chengdu, China
| | - Yuanda Wang
- State Key Laboratory of Biotherapy and Cancer Center, Sichuan University, Chengdu, China
| | - Ying Shen
- Department of Obstetrics/Gynecology, Joint Laboratory of Reproductive Medicine (SCU-CUHK), Key Laboratory of Obstetric, Gynecologic and Pediatric Diseases and Birth Defects of Ministry of Education, West China Second University Hospital, Sichuan University, Chengdu, China
| | - Mohan Liu
- State Key Laboratory of Biotherapy and Cancer Center, Sichuan University, Chengdu, China
| | - Siyu Dai
- Department of Obstetrics and Gynecology, West China Second University Hospital, Sichuan University, Chengdu, China
- Medical Genetics Department/Prenatal Diagnostic Center, West China Second University Hospital, Sichuan University, Chengdu, China
- Key Laboratory of Birth Defects and Related Diseases of Women and Children, Ministry of Education, Sichuan University, Chengdu, China
| | - Xiaodong Wang
- Department of Obstetrics and Gynecology, West China Second University Hospital, Sichuan University, Chengdu, China
- Key Laboratory of Birth Defects and Related Diseases of Women and Children, Ministry of Education, Sichuan University, Chengdu, China
- *Correspondence: Xiaodong Wang, ; Hongqian Liu,
| | - Hongqian Liu
- Department of Obstetrics and Gynecology, West China Second University Hospital, Sichuan University, Chengdu, China
- Medical Genetics Department/Prenatal Diagnostic Center, West China Second University Hospital, Sichuan University, Chengdu, China
- Key Laboratory of Birth Defects and Related Diseases of Women and Children, Ministry of Education, Sichuan University, Chengdu, China
- *Correspondence: Xiaodong Wang, ; Hongqian Liu,
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Glorieux FH, Bonewald LF, Harvey NC, van der Meulen MCH. Potential influences on optimizing long-term musculoskeletal health in children and adolescents with X-linked hypophosphatemia (XLH). Orphanet J Rare Dis 2022; 17:30. [PMID: 35101067 PMCID: PMC8802511 DOI: 10.1186/s13023-021-02156-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Accepted: 12/19/2021] [Indexed: 12/20/2022] Open
Abstract
In recent years, much progress has been made in understanding the mechanisms of bone growth and development over a lifespan, including the crosstalk between muscle and bone, to achieve optimal structure and function. While there have been significant advances in understanding how to help improve and maintain bone health in normal individuals, there is limited knowledge on whether these mechanisms apply or are compromised in pathological states. X-linked hypophosphatemia (XLH) (ORPHA:89936) is a rare, heritable, renal phosphate-wasting disorder. The resultant chronic hypophosphatemia leads to progressive deterioration in musculoskeletal function, including impaired growth, rickets, and limb deformities in children, as well as lifelong osteomalacia with reduced bone quality and impaired muscle structure and function. The clinical manifestations of the disease vary both in presentation and severity in affected individuals, and many of the consequences of childhood defects persist into adulthood, causing significant morbidity that impacts physical function and quality of life. Intervention to restore phosphate levels early in life during the critical stages of skeletal development in children with XLH could optimize growth and may prevent or reduce bone deformities in childhood. A healthier bone structure, together with improved muscle function, can lead to physical activity enhancing musculoskeletal health throughout life. In adults, continued management may help to maintain the positive effects acquired from childhood treatment, thereby slowing or halting disease progression. In this review, we summarize the opinions from members of a working group with expertise in pediatrics, epidemiology, and bone, joint and muscle biology, on potential outcomes for people with XLH, who have been optimally treated from an early age and continue treatment throughout life.
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Affiliation(s)
| | - Lynda F Bonewald
- Indiana Center for Musculoskeletal Health, Indiana University, Indianapolis, IN, USA
| | - Nicholas C Harvey
- MRC Lifecourse Epidemiology Centre, University of Southampton, Southampton, UK
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Fuente R, García-Bengoa M, Fernández-Iglesias Á, Gil-Peña H, Santos F, López JM. Cellular and Molecular Alterations Underlying Abnormal Bone Growth in X-Linked Hypophosphatemia. Int J Mol Sci 2022; 23:ijms23020934. [PMID: 35055123 PMCID: PMC8778463 DOI: 10.3390/ijms23020934] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Revised: 01/12/2022] [Accepted: 01/13/2022] [Indexed: 12/21/2022] Open
Abstract
X-linked hypophosphatemia (XLH), the most common form of hereditary hypophosphatemic rickets, is caused by inactivating mutations of the phosphate-regulating endopeptidase gene (PHEX). XLH is mainly characterized by short stature, bone deformities and rickets, while in hypophosphatemia, normal or low vitamin D levels and low renal phosphate reabsorption are the principal biochemical aspects. The cause of growth impairment in patients with XLH is not completely understood yet, thus making the study of the growth plate (GP) alterations necessary. New treatment strategies targeting FGF23 have shown promising results in normalizing the growth velocity and improving the skeletal effects of XLH patients. However, further studies are necessary to evaluate how this treatment affects the GP as well as its long-term effects and the impact on adult height.
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Affiliation(s)
- Rocío Fuente
- Division of Pediatrics, Department of Medicine, Faculty of Medicine, University of Oviedo, 33006 Oviedo, Spain; (R.F.); (M.G.-B.); (Á.F.-I.); (H.G.-P.); (F.S.)
- Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), 33011 Oviedo, Spain
- Institute of Physiology, Center for Integrative Human Physiology (ZIHP), University of Zurich, Winterthurerstrasse 190, CH-8057 Zurich, Switzerland
| | - María García-Bengoa
- Division of Pediatrics, Department of Medicine, Faculty of Medicine, University of Oviedo, 33006 Oviedo, Spain; (R.F.); (M.G.-B.); (Á.F.-I.); (H.G.-P.); (F.S.)
- Research Center for Emerging Infections and Zoonoses (RIZ), University of Veterinary Medicine Hannover, 30559 Hanover, Germany
| | - Ángela Fernández-Iglesias
- Division of Pediatrics, Department of Medicine, Faculty of Medicine, University of Oviedo, 33006 Oviedo, Spain; (R.F.); (M.G.-B.); (Á.F.-I.); (H.G.-P.); (F.S.)
- Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), 33011 Oviedo, Spain
| | - Helena Gil-Peña
- Division of Pediatrics, Department of Medicine, Faculty of Medicine, University of Oviedo, 33006 Oviedo, Spain; (R.F.); (M.G.-B.); (Á.F.-I.); (H.G.-P.); (F.S.)
- Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), 33011 Oviedo, Spain
- Department of Pediatrics, Hospital Universitario Central de Asturias (HUCA), 33011 Oviedo, Spain
| | - Fernando Santos
- Division of Pediatrics, Department of Medicine, Faculty of Medicine, University of Oviedo, 33006 Oviedo, Spain; (R.F.); (M.G.-B.); (Á.F.-I.); (H.G.-P.); (F.S.)
- Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), 33011 Oviedo, Spain
- Department of Pediatrics, Hospital Universitario Central de Asturias (HUCA), 33011 Oviedo, Spain
| | - José Manuel López
- Department of Morphology and Cellular Biology, Faculty of Medicine, University of Oviedo, 33006 Oviedo, Spain
- Correspondence:
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Aljuraibah F, Bacchetta J, Brandi ML, Florenzano P, Javaid MK, Mäkitie O, Raimann A, Rodriguez M, Siggelkow H, Tiosano D, Vervloet M, Wagner CA. An Expert Perspective on Phosphate Dysregulation With a Focus on Chronic Hypophosphatemia. J Bone Miner Res 2022; 37:12-20. [PMID: 34870347 PMCID: PMC9306528 DOI: 10.1002/jbmr.4486] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Revised: 11/18/2021] [Accepted: 11/27/2021] [Indexed: 12/11/2022]
Abstract
Because of their rarity, diseases characterized by chronic hypophosphatemia can be underrecognized and suboptimally managed, resulting in poor clinical outcomes. Moreover, serum phosphate may not be measured routinely in primary care practice. Authors participated in several working sessions to advance the understanding of phosphate homeostasis and the causes, consequences, and clinical implications of chronic hypophosphatemia. Phosphate levels are regulated from birth to adulthood. Dysregulation of phosphate homeostasis can result in hypophosphatemia, which becomes chronic if phosphate levels cannot be normalized. Chronic hypophosphatemia may be underrecognized as serum phosphate measurement is not always part of routine analysis in the primary care setting and results might be misinterpreted, for instance, due to age-specific differences not being accounted for and circadian variations. Clinical consequences of chronic hypophosphatemia involve disordered endocrine regulation, affect multiple organ systems, and vary depending on patient age and the underlying disorder. Signs and symptoms of chronic hypophosphatemic diseases that manifest during childhood or adolescence persist into adulthood if the disease is inadequately managed, resulting in an accumulation of clinical deficits and a progressive, debilitating impact on quality of life. Early identification and diagnosis of patients with chronic hypophosphatemia is crucial, and clinical management should be started as soon as possible to maximize the likelihood of improving health outcomes. Furthermore, in the absence of a universally accepted description for "chronic hypophosphatemia," a definition is proposed here that aims to raise awareness of these diseases, facilitate diagnosis, and guide optimal phosphate management strategies by improving monitoring and assessment of patient response to treatment. © 2021 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).
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Affiliation(s)
- Fahad Aljuraibah
- College of Medicine, King Saud bin Abdulaziz University for Health Sciences, Riyadh, Saudi Arabia
| | | | | | | | | | - Outimaija Mäkitie
- Children's Hospital, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | | | | | | | | | - Marc Vervloet
- Amsterdam University Medical Center, Amsterdam, The Netherlands
| | - Carsten A Wagner
- University of Zurich, Zurich.,Swiss National Center of Competence in Research NCCR Kidney.CH, Zurich
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Mughal MZ, Baroncelli GI, de Lucas-Collantes C, Linglart A, Magnolato A, Raimann A, Santos F, Schnabel D, Shaw N, Nilsson O. Burosumab for X-linked hypophosphatemia in children and adolescents: Opinion based on early experience in seven European countries. Front Endocrinol (Lausanne) 2022; 13:1034580. [PMID: 36798486 PMCID: PMC9928183 DOI: 10.3389/fendo.2022.1034580] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Accepted: 11/11/2022] [Indexed: 02/03/2023] Open
Abstract
Given the relatively recent introduction of burosumab in the management of X-linked hypophosphatemia (XLH), there is limited real-world data to guide its use in clinical practice. As a group of European physicians experienced with burosumab treatment in clinical practice, we convened with the objective of sharing these practice-based insights on the use of burosumab in children and adolescents with XLH. We attended two virtual meetings, then discussed key questions via Within3, a virtual online platform. Points of discussion related to patient selection criteria, burosumab starting dose, dose titration and treatment monitoring. Our discussions revealed that criteria for selecting children with XLH varied across Europe from all children above 1 year to only children with overt rickets despite conventional treatment being eligible. We initiated burosumab dosing according to guidance in the Summary of Product Characteristics, an international consensus statement from 2019 and local country guidelines. Dose titration was primarily guided by serum phosphate levels, with some centers also using the ratio of tubular maximum reabsorption of phosphate to glomerular filtration rate (TmP/GFR). We monitored response to burosumab treatment clinically (growth, deformities, bone pain and physical functioning), radiologically (rickets and deformities) and biochemically (serum phosphate, alkaline phosphatase, 1,25-dihydroxyvitamin D, 25-hydroxyvitamin D, urine calcium-creatinine ratio and TmP/GFR). Key suggestions made by our group were initiation of burosumab treatment in children as early as possible, from the age of 1 year, particularly in those with profound rickets, and a need for clinical studies on continuation of burosumab throughout adolescence and into adulthood.
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Affiliation(s)
- M. Zulf Mughal
- Department of Paediatric Endocrinology and Metabolic Bone Diseases, Royal Manchester Children’s Hospital, Manchester, United Kingdom
- The Faculty of Biology, Medicine, and Health, University of Manchester, Manchester, United Kingdom
- *Correspondence: M. Zulf Mughal,
| | - Giampiero I. Baroncelli
- Division of Pediatrics, Endocrine Unit, ERN-BOND Representative, Department of Obstetrics, Gynecology and Pediatrics, University-Hospital, Pisa, Italy
| | - Carmen de Lucas-Collantes
- Servicio Nefrología, Hospital Infantil Universitario Niño Jesús, Universidad Autónoma de Madrid, Madrid, Spain
| | - Agnès Linglart
- AP-HP, Endocrinology and Diabetes for Children, Reference Center for Rare Disorders of Calcium and Phosphate Metabolism, Filière OSCAR, Bicêtre Paris Saclay Hospital, Paris, France
- Platform of Expertise for Rare Disorders, INSERM, Physiologie et Physiopathologie Endocriniennes, Paris Saclay University, Paris, France
| | - Andrea Magnolato
- Department of Pediatrics, Institute for Maternal and Child Health – IRCCS “Burlo Garofolo”, Trieste, Italy
| | - Adalbert Raimann
- Department of Pediatrics and Adolescent Medicine, Division of Pediatric Pulmonology, Allergology and Endocrinology, Medical University of Vienna, Vienna, Austria
- Vienna Bone and Growth Center, Vienna, Austria
| | - Fernando Santos
- Hospital Universitario Central de Asturias (HUCA), University of Oviedo, Oviedo, Spain
| | - Dirk Schnabel
- Center for Chronic Sick Children, Pediatric Endocrinology, Charitè, University Medicine, Berlin, Germany
| | - Nick Shaw
- Department of Endocrinology and Diabetes, Birmingham Women’s and Children’s NHS Foundation Trust, Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, United Kingdom
| | - Ola Nilsson
- Division of Pediatric Endocrinology, Department of Women’s and Children’s Health , Karolinska Institutet and University Hospital, Stockholm, Sweden
- School of Medical Sciences, Department of Pediatrics, Örebro University and University Hospital, Örebro, Sweden
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Yamazaki M, Michigami T. Osteocytes and the pathogenesis of hypophosphatemic rickets. Front Endocrinol (Lausanne) 2022; 13:1005189. [PMID: 36246908 PMCID: PMC9556901 DOI: 10.3389/fendo.2022.1005189] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Accepted: 09/15/2022] [Indexed: 11/13/2022] Open
Abstract
Since phosphorus is a component of hydroxyapatite, its prolonged deprivation affects bone mineralization. Fibroblast growth factor 23 (FGF23) is essential for maintaining phosphate homeostasis and is mainly produced by osteocytes. FGF23 increases the excretion of inorganic phosphate (Pi) and decreases the production of 1,25-dihydroxyvitamin D in the kidneys. Osteocytes are cells of osteoblastic lineage that have undergone terminal differentiation and become embedded in mineralized bone matrix. Osteocytes express FGF23 and other multiple genes responsible for hereditary hypophosphatemic rickets, which include phosphate-regulating gene homologous to endopeptidase on X chromosome (PHEX), dentin matrix protein 1 (DMP1), and family with sequence similarity 20, member C (FAM20C). Since inactivating mutations in PHEX, DMP1, and FAM20C boost the production of FGF23, these molecules might be considered as local negative regulators of FGF23. Mouse studies have suggested that enhanced FGF receptor (FGFR) signaling is involved in the overproduction of FGF23 in PHEX-deficient X-linked hypophosphatemic rickets (XLH) and DMP1-deficient autosomal recessive hypophosphatemic rickets type 1. Since FGFR is involved in the transduction of signals evoked by extracellular Pi, Pi sensing in osteocytes may be abnormal in these diseases. Serum levels of sclerostin, an inhibitor Wnt/β-catenin signaling secreted by osteocytes, are increased in XLH patients, and mouse studies have suggested the potential of inhibiting sclerostin as a new therapeutic option for the disease. The elucidation of complex abnormalities in the osteocytes of FGF23-related hypophosphatemic diseases will provide a more detailed understanding of their pathogenesis and more effective treatments.
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Alikasifoglu A, Unsal Y, Gonc EN, Ozon ZA, Kandemir N, Alikasifoglu M. Long-term effect of conventional phosphate and calcitriol treatment on metabolic recovery and catch-up growth in children with PHEX mutation. J Pediatr Endocrinol Metab 2021; 34:1573-1584. [PMID: 34525271 DOI: 10.1515/jpem-2021-0387] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Accepted: 08/30/2021] [Indexed: 11/15/2022]
Abstract
OBJECTIVES Hereditary hypophosphatemic rickets (HR) is conventionally treated with phosphate and calcitriol. Exploring genotype and phenotypic spectrum of X-linked hypophosphatemic rickets (XLHR), focusing on short-term, long-term, and pubertal impact of conventional treatment was aimed. METHODS Sixteen patients from 12 unrelated families with HR were analyzed for phosphate regulating endopeptidase homolog X-linked (PHEX) mutation. Initially Sanger sequencing analysis was performed. If PHEX mutation was not detected, multiplex ligation-dependent probe amplification (MLPA) was performed. If molecular defect was detected, first-degree relatives were analyzed. Thirteen patients (81%) and five first-degree relatives with XLHR were evaluated for genotype-phenotype or gender-phenotype correlation. Clinical characteristics and response to conventional treatment were determined retrospectively. RESULTS Nine different PHEX mutations were identified; four splice-site, three point mutations, and two single exon deletions. Four were novel mutations. Despite conventional treatment, median adult height was lower than median height on admission (-3.8 and -2.3 SDS, respectively), metabolic and radiographic recovery were not achieved, adherence was low (30%). Although mean adult height was better in compliant patients than noncompliants (-2.6 vs. -3.7 SDS, respectively), they were still short. Correlation between phenotype and genotype or gender could not be shown. Median phosphate decreased significantly throughout puberty (p=0.014). Median pubertal height was lower than prepubertal height (-4.4 vs. -3.6 SDS; respectively), pubertal growth spurt was not observed. Among five patients with a follow-up longer than five years, three had nephrocalcinosis (60%), two had hyperparathyroidism (40%), 4/6 (33%) required correction osteotomy. CONCLUSIONS Conventional treatment appears to have limited effect on metabolic, clinical and radiographic recovery in XLHR. Metabolic control and growth worsened during puberty. Although, long-term adverse effects are yet to be seen, introduction of burosumab as first-line treatment may be an alternative after infancy.
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Affiliation(s)
- Ayfer Alikasifoglu
- Division of Pediatric Endocrinology, Department of Pediatrics, Hacettepe University Faculty of Medicine, Ankara, Turkey
| | - Yagmur Unsal
- Division of Pediatric Endocrinology, Department of Pediatrics, Hacettepe University Faculty of Medicine, Ankara, Turkey
| | - Elmas Nazli Gonc
- Division of Pediatric Endocrinology, Department of Pediatrics, Hacettepe University Faculty of Medicine, Ankara, Turkey
| | - Zeynep Alev Ozon
- Division of Pediatric Endocrinology, Department of Pediatrics, Hacettepe University Faculty of Medicine, Ankara, Turkey
| | - Nurgun Kandemir
- Division of Pediatric Endocrinology, Department of Pediatrics, Hacettepe University Faculty of Medicine, Ankara, Turkey
| | - Mehmet Alikasifoglu
- Division of Medical Genetics, Department of Medical Genetics, Hacettepe University Faculty of Medicine, Ankara, Turkey
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Uday S, Shaw NJ, Mughal MZ, Randell T, Högler W, Santos R, Padidela R. Monitoring response to conventional treatment in children with XLH: Value of ALP and Rickets Severity Score (RSS) in a real world setting. Bone 2021; 151:116025. [PMID: 34052463 DOI: 10.1016/j.bone.2021.116025] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/05/2020] [Revised: 04/22/2021] [Accepted: 05/25/2021] [Indexed: 11/30/2022]
Abstract
INTRODUCTION X-linked hypophosphataemia (XLH) is conventionally managed with oral phosphate and active vitamin D analogues. OBJECTIVES To evaluate long term treatment response by assessing biochemical disease activity [serum alkaline phosphatase (ALP)], radiological rickets severity score (RSS), growth and morbidity in patients with XLH on conventional therapy and assess the correlation between serum ALP and RSS. METHODS XLH patients from 3 UK tertiary centres with ≥3 radiographs one year apart were included. Data was collected retrospectively. The RSS was assessed from routine hand and knee radiographs and ALP z scores were calculated using age-specific reference data. RESULTS Thirty-eight (male = 12) patients met the inclusion criteria. The mean ± SD knee, wrist and total RSS at baseline (median age 1.2 years) were 2.0 ± 1.2, 1.9 ± 1.2 and 3.6 ± 1.3 respectively; and at the most recent clinic visit (median age 9.0 years, range 3.3-18.9) were 1.6 ± 1.0, 1.0 ± 1.0 and 2.5 ± 1.5 respectively. The mean ± SD serum ALP z scores at baseline and the most recent visit were 4.2 ± 2.3 and 4.0 ± 3.3. Median height SDS at baseline and most recent visit were -1.2 and -2.1 (p = 0.05). Dental abscess, craniosynostosis, limb deformity requiring orthopaedic intervention and nephrocalcinosis were present in 31.5%, 7.9%, 31.6% and 42.1% of the cohort respectively. There was no statistically significant (p > 0.05) correlation between ALP z scores and knee (r = 0.07) or total (r = 0.12) RSS. CONCLUSIONS Conventional therapy was not effective in significantly improving biochemical and radiological features of disease. The lack of association between serum ALP and rickets severity on radiographs limits the value of ALP as the sole indicator of rickets activity in patients receiving conventional therapy.
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Affiliation(s)
- S Uday
- IMSR, University of Birmingham, Birmingham, UK; Birmingham Women's and Children's Hospital, Birmingham, UK.
| | - N J Shaw
- IMSR, University of Birmingham, Birmingham, UK; Birmingham Women's and Children's Hospital, Birmingham, UK
| | - M Z Mughal
- Royal Manchester Children's Hospital, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | - T Randell
- Nottingham Children's Hospital, Nottingham, UK
| | - W Högler
- IMSR, University of Birmingham, Birmingham, UK; Johannes Kepler University, Linz, Austria
| | - R Santos
- Evelina London Children's Hospital, London, UK
| | - R Padidela
- Royal Manchester Children's Hospital, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
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Metwalley K, Farghaly H. Hormone resistance in children: what primary care physicians need to know. ACTA BIO-MEDICA : ATENEI PARMENSIS 2021; 92:e2021255. [PMID: 34487068 PMCID: PMC8477115 DOI: 10.23750/abm.v92i4.11613] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Accepted: 05/28/2021] [Indexed: 01/13/2023]
Abstract
Hormone resistance is defined as a reduced or absence of target tissues responsiveness to a hormone, where the presentation is related to either a relative lack or excess of hormones. Various disorders of hormone resistance were encountered including, Laron syndrome, nephrogenic diabetes insipidus, thyroid hormone resistance syndrome, pseudohypoparathyroidism, insulin resistance, familial glucocorticoid deficiency, pseudohypoaldosteronism, X linked hypophosphatemic rickets and androgen insensitivity syndrome. The article gives a summary that presents, in concentrated form, what the primary care physicians need to know about recognition, clinical presentation, diagnosis, and management of various hormone resistance in children.
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Affiliation(s)
- Kotb Metwalley
- Department of Pediatrics, Faculty of Medicine, Assiut University, Assiut, Egypt..
| | - Hekma Farghaly
- Department of Pediatrics, Faculty of Medicine, Assiut University, Assiut, Egypt..
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Jiménez M, Ivanovic-Zuvic D, Loureiro C, Carvajal CA, Cavada G, Schneider P, Gallardo E, García C, Gonzalez G, Contreras O, Collins MT, Florenzano P. Clinical and molecular characterization of Chilean patients with X-linked hypophosphatemia. Osteoporos Int 2021; 32:1825-1836. [PMID: 33666701 DOI: 10.1007/s00198-021-05875-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Accepted: 02/02/2021] [Indexed: 11/30/2022]
Abstract
UNLABELLED We report the most comprehensive clinical and molecular characterization of XLH patients performed in Chile. We show high prevalence of musculoskeletal burden and pain, associated with significantly impaired physical capacity and quality of life, with many relevant complications presenting more frequently than previously reported in cohorts from developed countries. INTRODUCTION Our current understanding of the clinical presentation and natural history of X-linked hypophosphatemia (XLH) comes mainly from cohorts from developed countries, with limited data on the clinical and genetic abnormalities of XLH patients in South America. OBJECTIVE To describe the clinical, biochemical, and molecular presentation of patients with XLH in Chile. METHODS Patients with XLH referred by endocrinologist throughout Chile were included. Demographic data and clinical presentation were obtained from a clinical interview. Surveys were applied for quality of life (QoL), pain, and functionality. FGF23 was measured by ELISA, and genetic testing was performed. Imaging studies were conducted to assess skeletal and renal involvement. RESULTS We included 26 patients, aged 2-64 years, from 17 unrelated Chilean families. All pediatric patients but only 40% of adults were receiving conventional therapy, while 65% of all patients had elevated alkaline phosphatase. All patients had mutations in PHEX, including 5 novel variants. Radiographic skeletal events (RSE) and enthesopathies in adults were frequent (34% and 85%, respectively). The duration of treatment was associated with fewer RSE (p < 0.05). Most adults reported pain and impaired QoL, and 50% had impaired physical capacity. The number of enthesopathies was associated with worse pain and stiffness scores (p < 0.05). CONCLUSION Chilean patients with XLH have a high prevalence of musculoskeletal burden associated with pain and impaired physical capacity and QoL, especially in adults who were generally undertreated. These data identify a significant unmet need, inform our understanding of the current status of patients, and can guide care for XLH patients in similarly socioeconomically defined countries.
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Affiliation(s)
- M Jiménez
- Endocrinology Department, School of Medicine, Pontificia Universidad Católica de Chile, Av. Diagonal Paraguay 362, Cuarto Piso, Santiago, Chile
| | - D Ivanovic-Zuvic
- Internal Medicine Department, School of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - C Loureiro
- Department of Pediatric Endocrinology, School of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - C A Carvajal
- Endocrinology Department, School of Medicine, Pontificia Universidad Católica de Chile, Av. Diagonal Paraguay 362, Cuarto Piso, Santiago, Chile
- Center for Translational Research in Endocrinology, CETREN-UC, School of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - G Cavada
- Biostatistics division, School of Public Health, Universidad de Chile, Santiago, Chile
- School of Medicine, Universidad Finnis Terrae, Santiago, Chile
| | - P Schneider
- Department of Pediatric Endocrinology, School of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - E Gallardo
- Radiology Department, School of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - C García
- Radiology Department, School of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - G Gonzalez
- Endocrinology Department, School of Medicine, Pontificia Universidad Católica de Chile, Av. Diagonal Paraguay 362, Cuarto Piso, Santiago, Chile
- Center for Translational Research in Endocrinology, CETREN-UC, School of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - O Contreras
- Radiology Department, School of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - M T Collins
- Skeletal Disorders and Mineral Homeostasis Section, National Institutes of Dental and Craniofacial Research, National Institutes of Health (NIH), Bethesda, MD, USA
| | - P Florenzano
- Endocrinology Department, School of Medicine, Pontificia Universidad Católica de Chile, Av. Diagonal Paraguay 362, Cuarto Piso, Santiago, Chile.
- Center for Translational Research in Endocrinology, CETREN-UC, School of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile.
- Skeletal Disorders and Mineral Homeostasis Section, National Institutes of Dental and Craniofacial Research, National Institutes of Health (NIH), Bethesda, MD, USA.
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Harada D, Ueyama K, Oriyama K, Ishiura Y, Kashiwagi H, Yamada H, Seino Y. Switching from conventional therapy to burosumab injection has the potential to prevent nephrocalcinosis in patients with X-linked hypophosphatemic rickets. J Pediatr Endocrinol Metab 2021; 34:791-798. [PMID: 33837680 DOI: 10.1515/jpem-2020-0734] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Accepted: 03/08/2021] [Indexed: 12/18/2022]
Abstract
OBJECTIVES X-linked hypophosphatemic rickets (XLH) is a congenital fibroblast growth factor (FGF)23-related metabolic bone disease that is treated with active vitamin D and phosphate as conventional therapies. Complications of these therapies include nephrocalcinosis (NC) caused by excessive urine calcium and phosphate concentrations. Recently, an anti-FGF23 antibody, burosumab, was developed and reported to be effective in poorly-controlled or severe XLH patients. This study aimed to reveal the impact of switching treatments in relatively well-controlled XLH children with the Rickets Severity Scale less than 2.0. METHODS The effects of the two treatments in eight relatively well-controlled XLH children with a mean age of 10.4 ± 1.9 years were compared retrospectively for the same treatment duration (31 ± 11 months) before and after the baseline. RESULTS Actual doses of alfacalcidol and phosphate as conventional therapy were 150.9 ± 43.9 ng/kg and 27.5 ± 6.3 mg/kg per day, respectively. Renal echography revealed spotty NC in 8/8 patients, but no aggravation of NC was detected by switching treatments. Switching treatments increased TmP/GFR (p=0.002) and %TRP (p<0.001), and improved the high urine calcium/creatinine ratio to the normal range (p<0.001) although both treatments controlled disease markers equally. Additionally, low intact parathyroid hormone during conventional therapy was increased within the normal range by switching treatments. CONCLUSIONS Our results suggest that a high dose of alfacalcidol was needed to control the disease, but it caused hypercalciuria and NC. We concluded that switching treatments in relatively well-controlled XLH children improved renal phosphate reabsorption and decreased urine calcium extraction, and may have the potential to prevent NC.
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Affiliation(s)
- Daisuke Harada
- Department of Pediatrics, Osaka Hospital, Japan Community Healthcare Organization (JCHO), Osaka, Japan
| | - Kaoru Ueyama
- Department of Pediatrics, Osaka Hospital, Japan Community Healthcare Organization (JCHO), Osaka, Japan
| | - Kyoko Oriyama
- Department of Pediatrics, Osaka Hospital, Japan Community Healthcare Organization (JCHO), Osaka, Japan
| | - Yoshihito Ishiura
- Department of Pediatrics, Osaka Hospital, Japan Community Healthcare Organization (JCHO), Osaka, Japan
| | - Hiroko Kashiwagi
- Department of Pediatrics, Osaka Hospital, Japan Community Healthcare Organization (JCHO), Osaka, Japan
| | - Hiroyuki Yamada
- Department of Pediatrics, Osaka Hospital, Japan Community Healthcare Organization (JCHO), Osaka, Japan
| | - Yoshiki Seino
- Department of Pediatrics, Osaka Hospital, Japan Community Healthcare Organization (JCHO), Osaka, Japan
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Bacchetta J, Rothenbuhler A, Gueorguieva I, Kamenicky P, Salles JP, Briot K, Linglart A. X-linked hypophosphatemia and burosumab: Practical clinical points from the French experience. Joint Bone Spine 2021; 88:105208. [PMID: 34102329 DOI: 10.1016/j.jbspin.2021.105208] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Accepted: 04/14/2021] [Indexed: 10/21/2022]
Abstract
Hereditary hypophosphatemia with increased FGF23 levels are rare inherited metabolic diseases characterized by low serum phosphate because of impaired renal tubular phosphate reabsorption. The most common form is X-linked hypophosphatemia (XLH), secondary to a mutation in the PHEX gene. In children, XLH is often manifested by rickets, delayed development of gait, lower limb deformities, growth retardation, craniosynostosis, and spontaneous dental abscesses. In adults, patients present diffuse musculoskeletal pain (bone and joints), early osteoarthritis, entesopathies, pseudo-fractures, muscular weakness, and severe dental damage. Conventional medical management is based on the combined administration of oral phosphate supplementation with active vitamin D analogs. Treatment with the recently approved anti-FGF23 burosumab is an alternative, especially in severe forms. Burosumab restores phosphate reabsorption in the proximal tubule and stimulates the endogenous synthesis of calcitriol. In Europe, burosumab has been approved for the treatment of XLH with radiographic evidence of bone disease in pediatric patients from one year of age and in adults. This manuscript will discuss the specific management of burosumab in children and adolescents in daily practice.
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Affiliation(s)
- Justine Bacchetta
- Reference Center for Rare Renal Diseases, Department of Pediatric Nephrology, Rheumatology and Dermatology, Nephrogones, Filière ORKiD, HFME, Lyon University Hospital, Lyon, France; Reference Center for Rare Diseases of Calcium and Phosphate Metabolism, Filière OSCAR, HFME, Lyon University Hospital, Lyon, France
| | - Anya Rothenbuhler
- AP-HP, Reference Center for Rare Diseases of Calcium and Phosphate Metabolism, and Filière OSCAR, Paris, France; AP-HP, Endocrinology and Diabetes for Children, Bicêtre Paris-Sud Hospital, Le Kremlin-Bicêtre, France
| | - Iva Gueorguieva
- Pediatric Department, Endocrinology Unit, Children's Center, Lille University Hospital, Jeanne-de-Flandre Hospital, Lille, France
| | - Peter Kamenicky
- AP-HP, Reference Center for Rare Diseases of Calcium and Phosphate Metabolism, and Filière OSCAR, Paris, France; AP-HP, Department of Endocrinology and Reproductive Diseases, Bicêtre Paris-Sud Hospital, Paris, France
| | - Jean-Pierre Salles
- Unit of Endocrinology, Bone Diseases, Genetics and Gynecology, Children's Hospital, Toulouse University Hospital, 31059 Toulouse cedex 09, France; Toulouse-Purpan Pathophysiology Center, CPTP, INSERM UMR 1043, Paul-Sabatier University, Toulouse, France
| | - Karine Briot
- AP-HP, Reference Center for Rare Diseases of Calcium and Phosphate Metabolism, and Filière OSCAR, Paris, France; AP-HP, Department of Rheumatology, Cochin Hospital, Paris, France
| | - Agnès Linglart
- AP-HP, Reference Center for Rare Diseases of Calcium and Phosphate Metabolism, and Filière OSCAR, Paris, France; AP-HP, Endocrinology and Diabetes for Children, Bicêtre Paris-Sud Hospital, Le Kremlin-Bicêtre, France.
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Lin X, Li S, Zhang Z, Yue H. Clinical and Genetic Characteristics of 153 Chinese Patients With X-Linked Hypophosphatemia. Front Cell Dev Biol 2021; 9:617738. [PMID: 34141703 PMCID: PMC8204109 DOI: 10.3389/fcell.2021.617738] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Accepted: 04/16/2021] [Indexed: 11/27/2022] Open
Abstract
X-linked hypophosphatemia (XLH) is caused by inactivating mutations in the phosphate-regulating endopeptidase homolog, X-linked (PHEX) gene, resulting in an excess of circulating intact fibroblast growth factor-23 (iFGF-23) and a waste of renal phosphate. In the present study, we retrospectively reviewed the clinical and molecular features of 153 Chinese patients, representing 87 familial and 66 sporadic cases with XLH. A total of 153 patients with XLH presented with signs or symptoms at a median age of 18.0 months (range, 9.0 months–26.0 years). Lower-limb deformity was the most frequent clinical manifestation, accounting for 79.1% (121/153). Biochemical screening showed increased serum levels of iFGF23 in patients with XLH, with a wide variation ranging from 14.39 to 730.70 pg/ml. Median values of serum iFGF23 in pediatric and adult patients were 94.87 pg/ml (interquartile range: 74.27–151.86 pg/ml) and 72.82 pg/ml (interquartile range: 39.42–136.00 pg/ml), respectively. Although no difference in circulating iFGF23 levels between these two groups was observed (P = 0.062), the proportion of patients with high levels of circulating iFGF23 (>42.2 pg/ml) was greater in the pediatric group than in the adult group (P = 0.026). Eighty-eight different mutations in 153 patients were identified, with 27 (30.7%) being novel. iFGF23 levels and severity of the disease did not correlate significantly with truncating and non-truncating mutations or N-terminal and C-terminal PHEX mutations. This study provides a comprehensive description of the clinical profiles, circulating levels of iFGF23 and gene mutation features of patients with XLH, further enriching the genotypic spectrum of the diseases. The findings show no evident correlation of circulating iFGF23 levels with the age or disease severity in patients with XLH.
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Affiliation(s)
- Xiaoyun Lin
- Shanghai Clinical Research Center of Bone Diseases, Department of Osteoporosis and Bone Diseases, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiao Tong University, Shanghai, China
| | - Shanshan Li
- Shanghai Clinical Research Center of Bone Diseases, Department of Osteoporosis and Bone Diseases, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiao Tong University, Shanghai, China
| | - Zhenlin Zhang
- Shanghai Clinical Research Center of Bone Diseases, Department of Osteoporosis and Bone Diseases, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiao Tong University, Shanghai, China
| | - Hua Yue
- Shanghai Clinical Research Center of Bone Diseases, Department of Osteoporosis and Bone Diseases, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiao Tong University, Shanghai, China
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Abstract
PURPOSE OF REVIEW X-Linked hypophosphatemia (XLH) is the most common genetic cause of rickets. This review describes advances in the management of XLH using burosumab which was FDA approved for treating children with XLH in 2018. RECENT FINDINGS Elevated FGF23 in XLH leads to systemic hypophosphatemia and several musculoskeletal manifestations, including rachitic bone deformities, impaired growth, dental abscesses, insufficiency fractures, osteoarthritis, and enthesopathy, with lifelong consequences for physical function and quality of life. Burosumab treatment has demonstrated clinical improvement of rickets and growth in children, including during a randomized controlled trial compared with conventional therapy. Burosumab also improved pseudofracture healing in adults. Burosumab led to greater improvement in rickets and growth than conventional therapy. However, many questions remain regarding the impact of burosumab on several outcomes, including final height, nephrocalcinosis, dental disease, enthesopathy, and surgical interventions.
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Affiliation(s)
- Erik A Imel
- Department of Medicine, Indiana University School of Medicine, 1120 West Michigan Street, CL 365, Indianapolis, IN, 46202-5111, USA.
- Department of Pediatrics, Indiana University School of Medicine, 1120 West Michigan Street, CL 365, Indianapolis, IN, 46202-5111, USA.
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Gómez CJB, Gil-Peña H, Álvarez FAO, Rodríguez FS. Outcome of primary tubular tubulopathies diagnosed in pediatric age. Nefrologia 2021; 41:182-190. [PMID: 36165379 DOI: 10.1016/j.nefroe.2020.07.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Accepted: 07/25/2020] [Indexed: 06/16/2023] Open
Abstract
BACKGROUND AND OBJECTIVE Primary tubulopathies are rare and usually present at pediatric age. Recent advances in genetic diagnosis and treatment have changed its natural history. This study provides the clinical spectrum of a series of primary tubulopathies diagnosed in a Pediatric Nephrology Unit and to offer long-term follow-up data regarding growth, estimated glomerular filtration (eGFR) and intercurrent complications. PATIENTS AND METHODS Observational study in 53 patients with primary tubulopathies and identified genetic defect: Gitelman syndrome (36%), distal renal tubular acidosis (15%), cystinuria (11%), X-linked hypophosphatemic rickets (7%), Dent-syndrome Lowe (7%), cystinosis (6%), and 1-2 cases of other tubulopathies. Demographic, analytical and clinical data were collected at diagnosis, during evolution and at the time of the study. RESULTS The age (median and interquartile range) at diagnosis was 5.08 years (1.33-8.50). The most frequent presentation manifestations were metabolic decompensations associated with intercurrent processes (40%) and short stature (38%). Height (mean ± SD) was -1.39 ± 1.49 at diagnosis and 1.07 ± 1.54 after a follow-up of 18.92 (6.25-24.33) years. Sixteen (32%) developed an eGFR <90 ml/min/1.73 m2. Three patients required replacement renal replacement. Eleven patients had metabolic decompensations that required hospitalization, 9 renal colic and/or kidney stones and 10 mental problems. Six of 8 patients with distal renal tubular acidosis developed sensorineural deafness. CONCLUSIONS Primary tubulopathies are a heterogeneous group of diseases that cause growth impairment, largely reversible with treatment, risk of eGFR reduction and significant extrarenal complications derived or associated.
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Affiliation(s)
| | - Helena Gil-Peña
- Hospital Universitario Central de Asturias, Oviedo, Asturias, Spain.
| | | | - Fernando Santos Rodríguez
- Hospital Universitario Central de Asturias, Oviedo, Asturias, Spain; Universidad de Oviedo, Oviedo, Asturias, Spain.
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Baroncelli GI, Zampollo E, Manca M, Toschi B, Bertelloni S, Michelucci A, Isola A, Bulleri A, Peroni D, Giuca MR. Pulp chamber features, prevalence of abscesses, disease severity, and PHEX mutation in X-linked hypophosphatemic rickets. J Bone Miner Metab 2021; 39:212-223. [PMID: 32772199 DOI: 10.1007/s00774-020-01136-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Accepted: 07/27/2020] [Indexed: 02/07/2023]
Abstract
INTRODUCTION Rickets, growth failure, and recurrent periapical abscesses with fistulae are main signs in patients with X-linked hypophosphatemic rickets (XLH). Prevalence of abscesses, pulp chamber features, biochemical findings, disease severity, and PHEX gene mutation were examined. MATERIALS AND METHODS Pulp chambers size, shape, and morphology were assessed by orthopantomography in XLH patients (n = 24, age 5.8 ± 1.6 years) and in sex and age-matched healthy controls (n = 23, age 6.2 ± 1.4 years). XLH patients received conventional treatment (3.5 ± 1.9 years). Pulp chamber features were assessed in teeth of primary dentition and in the permanent left mandibular first molar and compared with those of controls. Rickets severity score was assessed at wrist, knee, and ankle. RESULTS The mean pulp chamber area/tooth area ratio, mean pulp chamber height/pulp chamber width ratio, and prominence of pulp horns into the tooth crown in primary and secondary molars were significantly higher in patients than in controls and in patients suffered abscesses than in patients without abscesses. Sixteen patients (67%) had a history of abscesses; incisors were affected more than canines and molars. Severity of rickets and mean serum parathyroid hormone (PTH) levels were significantly higher, and mean serum 1,25-dihydroxyvitamin D [1,25(OH)2D] levels significantly lower in patients suffered abscesses than in patients without abscesses. PHEX gene mutations were not correlated with dental phenotype and disease severity. CONCLUSION Enlarged pulp chambers with altered shape and morphology affected the majority of XLH patients predisposing to recurrent periapical abscesses with fistulae. Dental phenotype was associated with severity of rickets, high serum PTH, and low serum 1,25(OH)2D levels.
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Affiliation(s)
- Giampiero I Baroncelli
- Division of Pediatrics, Endocrine Unit, Department of Obstetrics, Gynecology and Pediatrics, University-Hospital, Via Roma 67, 56126, Pisa, Italy.
| | - Elisa Zampollo
- Division of Dentistry and Oral Surgery, Department of Surgical Specialties, University-Hospital, Pisa, Italy
| | - Mario Manca
- Unit of Orthopedics, Usl Northwest-Tuscany, Versilia Hospital, Camaiore, Italy
| | - Benedetta Toschi
- Division of Medical Genetics, Department of Medical and Oncological Area, University-Hospital, Pisa, Italy
| | - Silvano Bertelloni
- Division of Pediatrics, Endocrine Unit, Department of Obstetrics, Gynecology and Pediatrics, University-Hospital, Via Roma 67, 56126, Pisa, Italy
| | - Angela Michelucci
- Unit of Molecular Genetics, Department of Laboratory Medicine, University-Hospital, Pisa, Italy
| | - Alessandro Isola
- Unit of Orthopedics, Usl Northwest-Tuscany, Versilia Hospital, Camaiore, Italy
| | - Alessandra Bulleri
- Unit of Radiodiagnostic, Department of Diagnostic Imaging, University-Hospital, Pisa, Italy
| | - Diego Peroni
- Division of Pediatrics, Endocrine Unit, Department of Obstetrics, Gynecology and Pediatrics, University-Hospital, Via Roma 67, 56126, Pisa, Italy
| | - Maria Rita Giuca
- Division of Dentistry and Oral Surgery, Department of Surgical Specialties, University-Hospital, Pisa, Italy
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Barratt KR, Sawyer RK, Atkins GJ, St-Arnaud R, Anderson PH. Vitamin D supplementation improves bone mineralisation independent of dietary phosphate in male X-linked hypophosphatemic (Hyp) mice. Bone 2021; 143:115767. [PMID: 33232838 DOI: 10.1016/j.bone.2020.115767] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Revised: 11/16/2020] [Accepted: 11/19/2020] [Indexed: 12/21/2022]
Abstract
The disorder of X-linked hypophosphatemia (XLH), results in the supressed renal production of active 1α,25-dihydroxyvitamin D (1,25(OH)2D) due to elevated fibroblast growth factor-23 (FGF23) levels. While adequate 25(OH)D levels are generally associated with improved mineralisation of the skeleton independent of circulating 1,25(OH)2D levels, it is unclear whether raising 25(OH)D to sufficiently high levels through dietary vitamin D3 administration contributes to improving bone mineralisation in the murine homolog for XLH, Hyp mice. Three-week-old male Hyp mice were fed one of four diets containing either 1000 IU (C) or 20,000 IU (D) vitamin D3/kg diet with either 0.35% phosphate or 1.25% phosphate (P) until 12 weeks of age (n = 12/group). When compared to C-fed mice, D-fed mice significantly elevated serum 25(OH)D levels to 72.8 ± 4.9 nmol/L (2-fold, p < 0.001) and increased both cortical bone mineral density (15%, p < 0.01), and vertebral trabecular BV/TV% (80%, p < 0.001), despite persistent hypophosphatemia and normocalcemia. The increase in bone volume was associated with improved Tb.Th (12%, p < 0.01) and Tb.N (63%, p < 0.001). Unlike with D-diet, P-fed mice resulted in increased femoral (15%, p < 0.001) and vertebral (12%, p < 0.001) length, and a 34% increase in vertebral trabecular BV/TV% when compared to control fed animals (p < 0.001). However, the addition of the high P diet to the high D diet did not result in additive effects on bone mineralisation when compared to the effects of D diet alone, despite serum 25(OH)D levels elevated to 118.8 ± 8.6 nmol/L. In D-fed mice, the increase in bone mineral density and volume was associated with reduced osteoid volume, reduced ObS/BS, and a trend for reduced serum PTH levels, suggesting reduced bone turnover in these animals. Thus, elevating serum 25(OH)D levels independently improves bone mineralisation in Hyp mice without causing hypercalcemia, suggesting that further studies are required in XLH patients to establish the role of increasing 25(OH)D levels in improving bone mineralisation.
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Affiliation(s)
- Kate R Barratt
- University of South Australia, Clinical and Health Sciences, Health and Biomedical Innovation, Adelaide, SA 5000, Australia.
| | - Rebecca K Sawyer
- University of South Australia, Clinical and Health Sciences, Health and Biomedical Innovation, Adelaide, SA 5000, Australia.
| | - Gerald J Atkins
- Centre for Orthopaedic & Trauma Research, The University of Adelaide, Adelaide, SA 5000, Australia.
| | - Rene St-Arnaud
- Shriners Hospitals for Children - Canada and McGill University, Montreal, QC H4A 0A9, Canada.
| | - Paul H Anderson
- University of South Australia, Clinical and Health Sciences, Health and Biomedical Innovation, Adelaide, SA 5000, Australia.
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Diagnosis and management of X-linked hypophosphatemia in children and adolescent in the Gulf Cooperation Council countries. Arch Osteoporos 2021; 16:52. [PMID: 33660084 PMCID: PMC7929956 DOI: 10.1007/s11657-021-00879-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Accepted: 01/04/2021] [Indexed: 02/03/2023]
Abstract
INTRODUCTION X-linked hypophosphatemia (XLH) is a rare inherited cause of hypophosphatemic rickets and osteomalacia. It is caused by mutations in the phosphate-regulating endopeptidase homolog, X-linked (PHEX). This results in increased plasma fibroblast growth factor-23 (FGF23), which leads to loss of renal sodium-phosphate co-transporter expression leading to chronic renal phosphate excretion. It also leads to low serum 1,25-dihydroxyvitamin D (1,25(OH)2D), resulting in impaired intestinal phosphate absorption. Chronic hypophosphatemia in XLH leads to impaired endochondral mineralization of the growth plates of long bones with bony deformities. XLH in children and adolescents also causes impaired growth, myopathy, bone pain, and dental abscesses. XLH is the most frequent inherited cause of phosphopenic rickets/osteomalacia. Hypophosphatemia is also found in calcipenic rickets/osteomalacia as a result of secondary hyperparathyroidism. Thus, chronic hypophosphatemia is a common etiologic factor in all types of rickets. RESULTS There is considerable overlap between symptoms and signs of phosphopenic and calcipenic rickets/osteomalacia. Wrong diagnosis leads to inappropriate treatment of rickets/osteomalacia. Nutritional rickets and osteomalacia are common in the Gulf Cooperation Council countries which include Saudi Arabia, United Arab Emirates, Kuwait, Qatar, Bahrain, and Oman. Due to high levels of consanguinity in the region, genetic causes of phosphopenic and calcipenic rickets/osteomalacia are also common. CONCLUSION This guideline was developed to provide an approach to the diagnosis of XLH, especially where there is no family history of the disease, and that other related conditions are not mistaken for XLH. We also guide the medical management of XLH with conventional treatment and with burosumab, a recombinant human IgG1 monoclonal antibody to FGF23.
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50
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Laurent MR, De Schepper J, Trouet D, Godefroid N, Boros E, Heinrichs C, Bravenboer B, Velkeniers B, Lammens J, Harvengt P, Cavalier E, Kaux JF, Lombet J, De Waele K, Verroken C, van Hoeck K, Mortier GR, Levtchenko E, Vande Walle J. Consensus Recommendations for the Diagnosis and Management of X-Linked Hypophosphatemia in Belgium. Front Endocrinol (Lausanne) 2021; 12:641543. [PMID: 33815294 PMCID: PMC8018577 DOI: 10.3389/fendo.2021.641543] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Accepted: 02/19/2021] [Indexed: 12/11/2022] Open
Abstract
X-linked hypophosphatemia (XLH) is the most common genetic form of hypophosphatemic rickets and osteomalacia. In this disease, mutations in the PHEX gene lead to elevated levels of the hormone fibroblast growth factor 23 (FGF23), resulting in renal phosphate wasting and impaired skeletal and dental mineralization. Recently, international guidelines for the diagnosis and treatment of this condition have been published. However, more specific recommendations are needed to provide guidance at the national level, considering resource availability and health economic aspects. A national multidisciplinary group of Belgian experts convened to discuss translation of international best available evidence into locally feasible consensus recommendations. Patients with XLH may present to a wide array of primary, secondary and tertiary care physicians, among whom awareness of the disease should be raised. XLH has a very broad differential-diagnosis for which clinical features, biochemical and genetic testing in centers of expertise are recommended. Optimal care requires a multidisciplinary approach, guided by an expert in metabolic bone diseases and involving (according to the individual patient's needs) pediatric and adult medical specialties and paramedical caregivers, including but not limited to general practitioners, dentists, radiologists and orthopedic surgeons. In children with severe or refractory symptoms, FGF23 inhibition using burosumab may provide superior outcomes compared to conventional medical therapy with phosphate supplements and active vitamin D analogues. Burosumab has also demonstrated promising results in adults on certain clinical outcomes such as pseudofractures. In summary, this work outlines recommendations for clinicians and policymakers, with a vision for improving the diagnostic and therapeutic landscape for XLH patients in Belgium.
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Affiliation(s)
- Michaël R. Laurent
- Centre for Metabolic Bone Diseases, University Hospitals Leuven, Leuven, Belgium
- *Correspondence: Michaël R. Laurent,
| | - Jean De Schepper
- Division of Pediatric Endocrinology, KidZ Health Castle, University Hospital Brussels, Vrije Universiteit Brussel (VUB), Brussels, Belgium
- Department of Pediatric Endocrinology, University Hospital Ghent, Ghent, Belgium
| | - Dominique Trouet
- Department of Pediatric Nephrology, Antwerp University Hospital, Antwerp, Belgium
- Laboratory of Experimental Medicine and Pediatrics, University of Antwerp, Antwerp, Belgium
| | - Nathalie Godefroid
- Pediatric Nephrology, Cliniques Universitaires St. Luc (UCL), Brussels, Belgium
| | - Emese Boros
- Paediatric Endocrinology Unit, Hôpital Universitaire des Enfants Reine Fabiola, Université Libre de Bruxelles, Brussels, Belgium
| | - Claudine Heinrichs
- Paediatric Endocrinology Unit, Hôpital Universitaire des Enfants Reine Fabiola, Université Libre de Bruxelles, Brussels, Belgium
| | - Bert Bravenboer
- Department of Endocrinology, University Hospital Brussels, Vrije Universiteit Brussel (VUB), Brussels, Belgium
| | - Brigitte Velkeniers
- Department of Endocrinology, University Hospital Brussels, Vrije Universiteit Brussel (VUB), Brussels, Belgium
| | - Johan Lammens
- Department of Orthopaedic Surgery and Department of Development and Regeneration, Prometheus LRD Division of Skeletal Tissue Engineering, KU Leuven - University Hospitals Leuven, Leuven, Belgium
| | - Pol Harvengt
- XLH Belgium, Belgian X-Linked Hypophosphatemic Rickets (XLH) Patient Association, Waterloo, Belgium
| | - Etienne Cavalier
- Department of Clinical Chemistry, University Hospital Center of Liège, University of Liège, Liège, Belgium
| | - Jean-François Kaux
- Physical Medicine, Rehabilitation and Sports Traumatology, University and University Hospital of Liège, Liège, Belgium
| | - Jacques Lombet
- Division of Nephrology, Department of Pediatrics, University Hospital Center of Liège, Liège, Belgium
| | - Kathleen De Waele
- Department of Pediatric Endocrinology, University Hospital Ghent, Ghent, Belgium
| | - Charlotte Verroken
- Unit for Osteoporosis and Metabolic Bone Diseases, Department of Endocrinology and Metabolism, Ghent University Hospital, Ghent, Belgium
| | - Koenraad van Hoeck
- Department of Pediatric Nephrology, Antwerp University Hospital, Antwerp, Belgium
- Laboratory of Experimental Medicine and Pediatrics, University of Antwerp, Antwerp, Belgium
| | - Geert R. Mortier
- Department of Medical Genetics, Antwerp University Hospital and University of Antwerp, Antwerp, Belgium
| | - Elena Levtchenko
- Department of Pediatrics/Pediatric Nephrology, University Hospitals Leuven, Leuven, Belgium
| | - Johan Vande Walle
- Department of Pediatric Nephrology, University Hospital Ghent, Ghent, Belgium
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