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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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Khosravi M, Walsh SB. The long-term complications of the inherited tubulopathies: an adult perspective. Pediatr Nephrol 2015; 30:385-95. [PMID: 24566812 DOI: 10.1007/s00467-014-2779-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/15/2013] [Revised: 01/23/2014] [Accepted: 01/27/2014] [Indexed: 11/25/2022]
Abstract
The inherited tubulopathies are lifelong disorders and their clinical features and complications may present quite different challenges in adulthood from those in childhood. In this review we outline the pathophysiology and documented complications (including the late and unusual) of the monogenic tubulopathies from the perspective of the adult nephrologist.
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Affiliation(s)
- Maryam Khosravi
- UCL Centre for Nephrology, Royal Free Hospital, University College London, London, UK
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A translocation causing increased alpha-klotho level results in hypophosphatemic rickets and hyperparathyroidism. Proc Natl Acad Sci U S A 2008; 105:3455-60. [PMID: 18308935 DOI: 10.1073/pnas.0712361105] [Citation(s) in RCA: 190] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Phosphate homeostasis is central to diverse physiologic processes including energy homeostasis, formation of lipid bilayers, and bone formation. Reduced phosphate levels due to excessive renal loss cause hypophosphatemic rickets, a disease characterized by prominent bone defects; conversely, hyperphosphatemia, a major complication of renal failure, is accompanied by parathyroid hyperplasia, hyperparathyroidism, and osteodystrophy. Here, we define a syndrome featuring both hypophosphatemic rickets and hyperparathyroidism due to parathyroid hyperplasia as well as other skeletal abnormalities. We show that this disease is due to a de novo translocation with a breakpoint adjacent to alpha-Klotho, which encodes a beta-glucuronidase, and is implicated in aging and regulation of FGF signaling. Plasma alpha-Klotho levels and beta-glucuronidase activity are markedly increased in the affected patient; unexpectedly, the circulating FGF23 level is also markedly elevated. These findings suggest that the elevated alpha-Klotho level mimics aspects of the normal response to hyperphosphatemia and implicate alpha-Klotho in the selective regulation of phosphate levels and in the regulation of parathyroid mass and function; they also have implications for the pathogenesis and treatment of renal osteodystrophy in patients with kidney failure.
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Hoshino C, Satoh N, Sugawara S, Kuriyama C, Kikuchi A, Ohta M. Sporadic adult-onset hypophosphatemic osteomalacia caused by excessive action of fibroblast growth factor 23. Intern Med 2008; 47:453-7. [PMID: 18310982 DOI: 10.2169/internalmedicine.47.0665] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
A 50-year-old man without family history of metabolic bone disease was referred to our hospital with a 5-year history of progressively worsening spinal and bilateral diffuse leg pain and proximal muscle weakness. Two years before admission, he was diagnosed as ankylosing spondylitis by a rheumatologist and was maintained on low-dose prednisone therapy without benefit. He developed progressive spinal and thoracic deformities, resulting in a 10 cm loss in height in the preceding 2 years. On physical examination, marked thoracic kyphosis and pectus carinatum was noted. Plain radiograph revealed pseudofracture in the right femoral neck. Laboratory findings showed a normal level of serum calcium, elevated level of serum alkaline phosphatase and inappropriately increased urinary phosphate excretion despite extreme hypophosphatemia. He was diagnosed as adult-onset hypophosphatemic osteomalacia caused by renal phosphate wasting. Serum fibroblast growth factor 23 was the upper limit of normal despite extreme hypophosphatemia and no neoplastic lesion potentially inducing hypophosphatemic osteomalacia could be identified in a thorough search including imaging studies of his entire body. Oral administration of phosphate and activated vitamin D together with dipyridamole relieved the persistent pain and weakness, and he became fully ambulatory.
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Affiliation(s)
- Chisho Hoshino
- Department of General Internal Medicine, Ohta-Nishinouchi Hospital, Koriyama.
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Abstract
Hereditary hypophosphatemic rickets groups together X-linked hypophosphatemic rickets (XLH), autosomal dominant hypophosphatemic rickets (ADHR) and hereditary hypophosphatemic rickets with hypercalciuria (HHRH, autosomal recessive). Clinical and biological characteristics and treatment depend on specific etiology. Mutations causing hereditary hypophosphatemic rickets involve PHEX located on Xp11.22 for XLH and FGF-23 located on 12p13 for ADHR. The gene involved in HHRH remains unknown: candidates may encode proteins that modulate phosphate transporter expression or activity. Others forms of rickets must be ruled out: acquired hypophosphatemia due to oncogenic osteomalacia, X-linked recessive hypophosphatemic rickets or Dent's disease, and hereditary 1, 25-dihydroxyvitamin D-resistant rickets with a defect either in the 1-alpha-hydroxylase gene (pseudo-vitamin D deficiency rickets, PDDR) or in the vitamin D receptor (hereditary vitamin D-resistant rickets, HVDRR).
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Affiliation(s)
- F-L Vélayoudom-Céphise
- Service d'endocrinologie et métabolisme, Clinique Marc Linquette, CHRU de Lille (59). flvelayoudom@ tiscali.fr
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Buranakarl C, Kitjtawonrat A, Pondeenana S, Sunyasujaree B, Kanchanapangka S, Chaiyabutr N, Bovee KC. Comparison of dipyridamole and fosinopril on renal progression in nephrectomized rats. Nephrology (Carlton) 2003; 8:80-91. [PMID: 15012738 DOI: 10.1046/j.1440-1797.2003.00141.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
There is evidence to suggest that antiplatelet aggregation and inhibition of angiotensin converting enzyme will attenuate the progression of renal disease. In the present study, dipyridamole (DPM; 30 mg/kg per day, p.o.) or fosinopril (FOS; 20 mg/kg per day, p.o.) was given to rats for 5 weeks starting immediately after renal mass reduction (right uninephrectomy and ligation of approximately two-thirds of the blood supply to the left kidney). Renal mass reduction caused increased mean arterial blood pressure, reduced effective renal plasma flow (ERPF) and glomerular filtration rate (GFR), azotemia and proteinuria. Neither proteinuria nor hypertension was affected by DPM, although renal function improved markedly. Rats receiving FOS showed normalization of blood pressure with a significant increase in both ERPF and GFR, along with a lower degree of proteinuria. A histological examination of the remnant kidney detected the presence of vasodilation with a lower degree of podocyte swelling in both treatment groups, with a remarkable effect in the FOS group. These data indicate that both FOS and DPM attenuate the progression of glomerular disease associated with renal mass reduction in rats. However, FOS was more beneficial than DPM because it reduced proteinuria and lowered blood pressure.
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Affiliation(s)
- Chollada Buranakarl
- Department of Physiology, Faculty of Veterinary Science, Chulalongkorn University, Bangkok, Thailand.
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