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Wechsung K, Schnabel D, Wiegand S. Longitudinal analysis of vitamin D levels considering sunshine duration and suggestion for a standardised approach for vitamin D supplementation in children and adolescents with obesity. BMC Pediatr 2024; 24:337. [PMID: 38750418 PMCID: PMC11094954 DOI: 10.1186/s12887-024-04823-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/14/2023] [Accepted: 05/09/2024] [Indexed: 05/19/2024] Open
Abstract
BACKGROUND Children with obesity have low 25 hydroxy-vitamin D (25-OH-D3) levels compared to lean children. Recommendations on when to start vitamin D supplementation differ largely between countries. Longitudinal data on 25-OH-D3 levels to guide treatment decisions are scarce since they are largely influenced by solar radiation and are difficult to compare. METHODS We carried out a retrospective analysis of multiple 25-OH-D3 and parathyroid hormone (PTH) measurements in a cohort of 543 patients without vitamin D supplementation. All measurements were taken at the local paediatric obesity clinic as documented in the German-Austrian-Swiss APV (Prospective Documentation of Overweight Children and Adolescents) registry from 2009 to 2019. Serial 25-OH-D3 and PTH levels were adjusted for sunshine duration over the last 30 days to account for seasonal variation, as well as for sex and body mass index (BMI). We further performed an exploratory analysis of the association of sunshine duration, sex, BMI SDS (standard deviation score), abnormal lipid levels or dysglycemia with the 25-OH-D3 trend. RESULTS 229 obese patients (mean BMI SDS: 2,58 (± 0,56), 53% females, mean age: 12 (± 3) years, range: 2-21 years) with two, 115 with three and 96 with four repeated 25-OH-D3 measurements were identified. Mean adjusted 25-OH-D3 (48.2 nmol/l) and PTH (34.9 ng/l) levels remained stable over 120 weeks. 5% of the patients had an elevated PTH > 65 ng/l. High total cholesterol ≥ 200 mg/dl and high triglycerides ≥ 130 mg/dl were associated with higher 25-OH-D3 levels. CONCLUSION We propose a simple method to include sunshine duration in the analysis of 25-OH-D3 levels to minimise the bias of seasonal variation. Based on our data we established the pragmatic strategy of limiting vitamin D supplementation to patients with biochemical signs of mineralisation disorders such as elevated PTH and alkaline phosphatase (AP). In children with normal PTH and AP we recommend adjustment of calcium intake and increase of outdoor activity instead.
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Affiliation(s)
- Katja Wechsung
- Department for Pediatric Endocrinology and Diabetology, Center for Chronically Sick Children, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health, Augustenburger Platz 1, 13353, Berlin, Germany.
| | - Dirk Schnabel
- Department for Pediatric Endocrinology and Diabetology, Center for Chronically Sick Children, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health, Augustenburger Platz 1, 13353, Berlin, Germany
| | - Susanna Wiegand
- Department for Pediatric Endocrinology and Diabetology, Center for Chronically Sick Children, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health, Augustenburger Platz 1, 13353, Berlin, Germany
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2
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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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Pott V, Tietze H, Kanzelmeyer N, von der Born J, Baumann U, Mindermann C, Suhlrie A, Drube J, Melk A, Das AM, Schnabel D, Haffner D, Leifheit-Nestler M. LMS-Based Pediatric Reference Values for Parameters of Phosphate Homeostasis in the HARP Cohort. J Clin Endocrinol Metab 2024; 109:668-679. [PMID: 37850343 DOI: 10.1210/clinem/dgad597] [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: 08/17/2023] [Revised: 10/04/2023] [Accepted: 10/05/2023] [Indexed: 10/19/2023]
Abstract
CONTEXT The assessment of phosphate homeostasis in children is challenging due to the marked changes in laboratory parameters during growth and development, and the lack of adequate reference values. OBJECTIVE To develop Lambda-Mu-Sigma (LMS)-based continuous pediatric reference percentiles for 7 key laboratory parameters of phosphate homeostasis. METHODS This cross-sectional, single-center study, the HAnnover Reference values for Pediatrics (HARP) study, included 455 children aged 0.1-18 years (254 boys) from outpatient hospital clinics and a secondary school program. Main outcome measures were LMS-based continuous reference percentiles for serum phosphate, plasma intact fibroblast growth factor 23 (iFGF23), and its cofactor soluble Klotho (sKlotho), tubular maximum phosphate reabsorption per glomerular filtration rate (TmP/GFR), fractional tubular reabsorption of phosphate (TRP), and urinary calcium/creatinine (Ca/Crea) and phosphate/creatinine (Pi/Crea) ratios. RESULTS LMS-based percentiles and z-scores were established for 7 key laboratory parameters of phosphate homeostasis, which were all found to be age-dependent. Serum phosphate, TmP/GFR, and sKlotho associated with sex. Serum phosphate, TmP/GFR, and urinary Ca/Crea and Pi/Crea levels were highest in infancy and declined until age 18 years, while phosphate and TmP/GFR values reached adult levels earlier in girls compared to boys. iFGF23 concentrations are highest in infancy and fall to a stable plateau by 4 years of age, while sKlotho peaks during adolescence. CONCLUSION This is the first report of LMS-based continuous pediatric reference percentiles for key laboratory parameters of phosphate homeostasis that allow calculation of standardized patient z-scores to facilitate test result interpretation in children and adolescents.
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Affiliation(s)
- Veronika Pott
- Department of Pediatric Kidney, Liver and Metabolic Diseases, Pediatric Research Center, Hannover Medical School, 30625 Hannover, Germany
| | - Helene Tietze
- Department of Pediatric Kidney, Liver and Metabolic Diseases, Pediatric Research Center, Hannover Medical School, 30625 Hannover, Germany
| | - Nele Kanzelmeyer
- Department of Pediatric Kidney, Liver and Metabolic Diseases, Pediatric Research Center, Hannover Medical School, 30625 Hannover, Germany
| | - Jeannine von der Born
- Department of Pediatric Kidney, Liver and Metabolic Diseases, Pediatric Research Center, Hannover Medical School, 30625 Hannover, Germany
| | - Ulrich Baumann
- Department of Pediatric Pneumology, Allergy and Neonatology, Hannover Medical School, 30625 Hannover, Germany
| | - Charlotte Mindermann
- Department of Pediatric Kidney, Liver and Metabolic Diseases, Pediatric Research Center, Hannover Medical School, 30625 Hannover, Germany
| | - Adriana Suhlrie
- Department of Pediatric Kidney, Liver and Metabolic Diseases, Pediatric Research Center, Hannover Medical School, 30625 Hannover, Germany
| | - Jens Drube
- Department of Pediatric Kidney, Liver and Metabolic Diseases, Pediatric Research Center, Hannover Medical School, 30625 Hannover, Germany
| | - Anette Melk
- Department of Pediatric Kidney, Liver and Metabolic Diseases, Pediatric Research Center, Hannover Medical School, 30625 Hannover, Germany
| | - Anibh M Das
- Department of Pediatric Kidney, Liver and Metabolic Diseases, Pediatric Research Center, Hannover Medical School, 30625 Hannover, Germany
| | - Dirk Schnabel
- Center for Chronically Sick Children, Pediatric Endocrinology, University Medicine, Charité Berlin, 13353 Berlin, Germany
| | - Dieter Haffner
- Department of Pediatric Kidney, Liver and Metabolic Diseases, Pediatric Research Center, Hannover Medical School, 30625 Hannover, Germany
| | - Maren Leifheit-Nestler
- Department of Pediatric Kidney, Liver and Metabolic Diseases, Pediatric Research Center, Hannover Medical School, 30625 Hannover, Germany
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4
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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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5
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Raimann A, Misof BM, Fratzl P, Fratzl-Zelman N. Bone Material Properties in Bone Diseases Affecting Children. Curr Osteoporos Rep 2023; 21:787-805. [PMID: 37897675 DOI: 10.1007/s11914-023-00822-6] [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] [Accepted: 09/12/2023] [Indexed: 10/30/2023]
Abstract
PURPOSE OF REVIEW Metabolic and genetic bone disorders affect not only bone mass but often also the bone material, including degree of mineralization, matrix organization, and lacunar porosity. The quality of juvenile bone is moreover highly influenced by skeletal growth. This review aims to provide a compact summary of the present knowledge on the complex interplay between bone modeling and remodeling during skeletal growth and to alert the reader to the complexity of bone tissue characteristics in children with bone disorders. RECENT FINDINGS We describe cellular events together with the characteristics of the different tissues and organic matrix organization (cartilage, woven and lamellar bone) occurring during linear growth. Subsequently, we present typical alterations thereof in disorders leading to over-mineralized bone matrix compared to those associated with low or normal mineral content based on bone biopsy studies. Growth spurts or growth retardation might amplify or mask disease-related alterations in bone material, which makes the interpretation of bone tissue findings in children complex and challenging.
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Affiliation(s)
- 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
| | - Barbara M Misof
- Vienna Bone and Growth Center, Vienna, Austria
- Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of OEGK and AUVA Trauma Center Meidling, 1st Medical Department, Hanusch Hospital, Vienna, Austria
| | - Peter Fratzl
- Max Planck Institute of Colloids and Interfaces, Department of Biomaterials, Research Campus Golm, Potsdam, Germany
| | - Nadja Fratzl-Zelman
- Vienna Bone and Growth Center, Vienna, Austria.
- Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of OEGK and AUVA Trauma Center Meidling, 1st Medical Department, Hanusch Hospital, Vienna, Austria.
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6
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Müller S, Kluck R, Jagodzinski C, Brügelmann M, Hohenfellner K, Büscher A, Kemper MJ, Fröde K, Oh J, Billing H, Thumfart J, Weber LT, Acham-Roschitz B, Arbeiter K, Tönshoff B, Hagenberg M, Pavičić L, Haffner D, Zivicnjak M. Chest configuration in children and adolescents with infantile nephropathic cystinosis compared with other chronic kidney disease entities and its clinical determinants. Pediatr Nephrol 2023; 38:3989-3999. [PMID: 37415042 PMCID: PMC10584709 DOI: 10.1007/s00467-023-06058-x] [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: 03/13/2023] [Revised: 06/09/2023] [Accepted: 06/13/2023] [Indexed: 07/08/2023]
Abstract
BACKGROUND Infantile nephropathic cystinosis (INC) is a systemic lysosomal storage disease causing intracellular cystine accumulation, resulting in renal Fanconi syndrome, progressive kidney disease (CKD), rickets, malnutrition, and myopathy. An INC-specific disproportionately diminished trunk length compared to leg length poses questions regarding the functionality of the trunk. METHODS Thus, we prospectively investigated thoracic dimensions and proportions, as well as their clinical determinants in 44 pediatric patients with INC with CKD stages 1-5 and 97 age-matched patients with CKD of other etiology between the ages of 2-17 years. A total of 92 and 221 annual measurements of patients with INC and CKD, respectively, were performed, and associations between anthropometric and clinical parameters were assessed using linear mixed-effects models. RESULTS Patients with INC exhibited altered chest dimensions that were distinct from CKD controls, characterized by markedly increased chest depth to height and chest depth to chest width ratio z-scores (> 1.0), while those of patients with CKD were only mildly affected (z-score within ± 1.0). Ratio z-scores differed significantly between both patient groups from 2-6 years of age onward. The degree of chest disproportion in INC patients was significantly associated with both the degree of CKD and tubular dysfunction (e.g., low serum phosphate and bicarbonate) across three different age groups (2-6, 7-12, and 13-17 years). CONCLUSION Our data show an INC-specific alteration in thoracic shape from early childhood onward, which is distinct from CKD of other etiologies, suggesting early childhood subclinical changes of the musculoskeletal unit of the thoracic cage, which are associated with kidney function. A higher resolution version of the Graphical abstract is available as Supplementary information.
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Affiliation(s)
- Sophia Müller
- Department of Pediatric Kidney, Liver and Metabolic Diseases, Hannover Medical School, Children's Hospital, Carl-Neuberg-Str. 1, 30625, Hannover, Germany
| | - Rika Kluck
- Department of Pediatric Kidney, Liver and Metabolic Diseases, Hannover Medical School, Children's Hospital, Carl-Neuberg-Str. 1, 30625, Hannover, Germany
| | - Celina Jagodzinski
- Department of Pediatric Kidney, Liver and Metabolic Diseases, Hannover Medical School, Children's Hospital, Carl-Neuberg-Str. 1, 30625, Hannover, Germany
| | - Malina Brügelmann
- Department of Pediatric Kidney, Liver and Metabolic Diseases, Hannover Medical School, Children's Hospital, Carl-Neuberg-Str. 1, 30625, Hannover, Germany
| | | | - Anja Büscher
- Department of Pediatrics II, University Hospital Essen, Essen, Germany
| | | | - Kerstin Fröde
- Department of Pediatric Kidney, Liver and Metabolic Diseases, Hannover Medical School, Children's Hospital, Carl-Neuberg-Str. 1, 30625, Hannover, Germany
| | - Jun Oh
- Division of Pediatric Nephrology, University Children's Hospital Hamburg, Hamburg, Germany
| | - Heiko Billing
- Clinic for Pediatric and Adolescent Medicine, RHK Clinic Ludwigsburg, Ludwigsburg, Germany
| | - Julia Thumfart
- Department of Pediatric Gastroenterology, Nephrology and Metabolic Diseases, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Lutz T Weber
- Pediatric Nephrology, Children's and Adolescents' Hospital, University of Cologne, Faculty of Medicine and University Hospital, Cologne, Germany
| | | | - Klaus Arbeiter
- Division of Pediatric Nephrology and Gastroenterology, Medical University Vienna, Vienna, Austria
| | - Burkhard Tönshoff
- Department of Pediatrics I, University Children's Hospital Heidelberg, Heidelberg, Germany
| | - Martina Hagenberg
- Children's Hospital St. Elisabeth and St. Barbara, Halle (Saale), Germany
| | | | - Dieter Haffner
- Department of Pediatric Kidney, Liver and Metabolic Diseases, Hannover Medical School, Children's Hospital, Carl-Neuberg-Str. 1, 30625, Hannover, Germany
| | - Miroslav Zivicnjak
- Department of Pediatric Kidney, Liver and Metabolic Diseases, Hannover Medical School, Children's Hospital, Carl-Neuberg-Str. 1, 30625, Hannover, Germany.
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7
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García-Nieto VM, González-Rodríguez JD, Cabrera-Sevilla JE, Martín-Fernández de Basoa MC, Luis-Yanes MI. Reflections on TRP and TP/GFR in the definition of renal phosphate loss: conceptual review. Pediatr Nephrol 2023; 38:3845-3848. [PMID: 37052691 DOI: 10.1007/s00467-023-05941-x] [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: 12/12/2022] [Revised: 03/05/2023] [Accepted: 03/08/2023] [Indexed: 04/14/2023]
Abstract
BACKGROUND Fractional tubular reabsorption of phosphate (TRP) has been used for over 60 years to establish the existence of renal phosphate loss. It is a parameter of corrected volume per decilitre of glomerular filtration rate (GFR). Later, a mass parameter per dl GFR called TP/GFR (tubular PO4 reabsorption per dl GFR) was devised which some authors have sought to substitute for TRP. The aim of the present work is to attempt to demonstrate that TRP and TP/GFR are similar parameters and, in certain aspects, TRP is more effective for diagnosis. METHODS Data were gathered on the metabolism of phosphate corresponding to a group of healthy children without hypophosphatemia (n = 47), a group of patients with idiopathic hypercalciuria (n = 27), and ten patients diagnosed with X-linked hypophosphatemia (XLH). The TRP, the TP/GFR, and the percent tubular reabsorption of phosphate were calculated. RESULTS All the patients with XLH presented TRP values lower than 95 ml/dl GFR and of TP/GFR equal to or lower than 2.8 mg/dl GFR. In the total sample, a direct correlation was observed between TRP and TP/GFR (r = 0.65; p = 0.01). The TRP and the percent tubular reabsorption of phosphate values were the same in the three groups (r = 1; p = 0.01). CONCLUSIONS TRP and TP/GFR are similar parameters. TRP is more effective than TP/GFR given that in renal hypophosphatemia it is always below 95% and above 95% in reduced phosphatemia and normal kidney proximal tubular function. There is no solid reason for using TP/GFR rather than TRP. A higher resolution version of the Graphical abstract is available as Supplementary information.
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Affiliation(s)
- Víctor Manuel García-Nieto
- Pediatric Nephrology Unit, Hospital Universitario Nuestra Señora de Candelaria, Santa Cruz de Tenerife, Canary Islands, Spain.
| | | | | | | | - María Isabel Luis-Yanes
- Pediatric Nephrology Unit, Hospital Universitario Nuestra Señora de Candelaria, Santa Cruz de Tenerife, Canary Islands, Spain
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8
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Darraj H, Hakami KM, Maghrabi R, Bakri N, Alhazmi MH, Names AA, Akkur A, Sayegh M, Alhazmi A, Khubrani SM, Gohal G, Alomar AH, Alhazmi AH. Nutritional Rickets Among Children: A Retrospective Study from Saudi Arabia. Pediatric Health Med Ther 2023; 14:301-308. [PMID: 37849986 PMCID: PMC10577373 DOI: 10.2147/phmt.s425459] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2023] [Accepted: 10/04/2023] [Indexed: 10/19/2023] Open
Abstract
Background Nutritional rickets remains a significant concern in certain countries, with increasing prevalence attributed to factors such as limited sunlight exposure and undernourishment. This study aimed to identify the factors associated with rickets due to nutritional deficiency in children from Jazan Province, southwestern Saudi Arabia. Methods A retrospective cross-sectional study was conducted using descriptive data from medical records at a tertiary hospital in Jazan Province. Records of patients diagnosed with rickets between January 2010 and December 2020 were analyzed. Symptomatic rickets cases from pediatric clinics were included, and diagnoses were based on biochemical and clinical tests. Risk factors were assessed using patient medical records. Data were analyzed using percentages, mean, and standard deviation. Results The study included 84 patients with rickets (53 females and 31 males), primarily between 11-18 years old. The mean body mass index (BMI) of the participants was 21.21. The most common risk factor was nutritional deficiencies, including vitamin D deficiency or calcium deficiency, with 75 patients reporting a family history of vitamin D deficiency. The children had limited sunlight exposure and low levels of calcium and vitamin D. Malnutrition was identified as the highest risk factor for rickets in the study population. Conclusion Nutritional rickets appears to be prevalent in the Jazan Province, emphasizing the need for government organizations to address this preventable disease. Adequate sun exposure and recommended dietary vitamin D intake are crucial to prevent rickets, as this study detected inadequate levels of calcium and vitamin D in children. National studies are required to further identify risk factors and develop appropriate strategies.
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Affiliation(s)
- Hussam Darraj
- Faculty of Medicine, Jazan University, Jazan, 45142, Saudi Arabia
| | - Khalid M Hakami
- Faculty of Medicine, Jazan University, Jazan, 45142, Saudi Arabia
| | - Rawan Maghrabi
- Faculty of Medicine, Jazan University, Jazan, 45142, Saudi Arabia
| | - Nawaf Bakri
- Faculty of Medicine, Jazan University, Jazan, 45142, Saudi Arabia
| | | | - Abdellh A Names
- Faculty of Medicine, Jazan University, Jazan, 45142, Saudi Arabia
| | - Ahmed Akkur
- Faculty of Medicine, Jazan University, Jazan, 45142, Saudi Arabia
| | - Maram Sayegh
- Faculty of Medicine, Jazan University, Jazan, 45142, Saudi Arabia
| | - Asma Alhazmi
- Faculty of Medicine, Jazan University, Jazan, 45142, Saudi Arabia
| | - Saad M Khubrani
- Faculty of Medicine, Jazan University, Jazan, 45142, Saudi Arabia
| | - Gassem Gohal
- Faculty of Medicine, Jazan University, Jazan, 45142, Saudi Arabia
| | - Amro H Alomar
- King Fahad Central Hospital, Ministry of Health, Jazan, 85534, Saudi Arabia
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9
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Ewert A, Rehberg M, Schlingmann KP, Hiort O, John-Kroegel U, Metzing O, Wühl E, Schaefer F, Kemper MJ, Derichs U, Richter-Unruh A, Patzer L, Albers N, Dunstheimer D, Haberland H, Heger S, Schröder C, Jorch N, Schmid E, Staude H, Weitz M, Freiberg C, Leifheit-Nestler M, Zivicnjak M, Schnabel D, Haffner D. Effects of Burosumab Treatment on Mineral Metabolism in Children and Adolescents With X-linked Hypophosphatemia. J Clin Endocrinol Metab 2023; 108:e998-e1006. [PMID: 37097907 DOI: 10.1210/clinem/dgad223] [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: 11/25/2022] [Revised: 04/05/2023] [Accepted: 04/13/2023] [Indexed: 04/26/2023]
Abstract
CONTEXT Burosumab has been approved for the treatment of children and adults with X-linked hypophosphatemia (XLH). Real-world data and evidence for its efficacy in adolescents are lacking. OBJECTIVE To assess the effects of 12 months of burosumab treatment on mineral metabolism in children (aged <12 years) and adolescents (aged 12-18 years) with XLH. DESIGN Prospective national registry. SETTING Hospital clinics. PATIENTS A total of 93 patients with XLH (65 children, 28 adolescents). MAIN OUTCOME MEASURES Z scores for serum phosphate, alkaline phosphatase (ALP), and renal tubular reabsorption of phosphate per glomerular filtration rate (TmP/GFR) at 12 months. RESULTS At baseline, patients showed hypophosphatemia (-4.4 SD), reduced TmP/GFR (-6.5 SD), and elevated ALP (2.7 SD, each P < .001 vs healthy children) irrespective of age, suggesting active rickets despite prior therapy with oral phosphate and active vitamin D in 88% of patients. Burosumab treatment resulted in comparable increases in serum phosphate and TmP/GFR in children and adolescents with XLH and a steady decline in serum ALP (each P < .001 vs baseline). At 12 months, serum phosphate, TmP/GFR, and ALP levels were within the age-related normal range in approximately 42%, 27%, and 80% of patients in both groups, respectively, with a lower, weight-based final burosumab dose in adolescents compared with children (0.72 vs 1.06 mg/kg, P < .01). CONCLUSIONS In this real-world setting, 12 months of burosumab treatment was equally effective in normalizing serum ALP in adolescents and children, despite persistent mild hypophosphatemia in one-half of patients, suggesting that complete normalization of serum phosphate is not mandatory for substantial improvement of rickets in these patients. Adolescents appear to require lower weight-based burosumab dosage than children.
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Affiliation(s)
- Annika Ewert
- Department of Pediatric Kidney, Liver and Metabolic Diseases, Hannover Medical School, Hannover 30625, Germany
| | - Mirko Rehberg
- Department of Pediatrics, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne 50937, Germany
| | - Karl Peter Schlingmann
- Department of General Pediatrics, Pediatric Nephrology, University Children's Hospital, Münster 48149, Germany
| | - Olaf Hiort
- Division of Pediatric Endocrinology and Diabetes, Department of Pediatrics and Adolescent Medicine, University of Lübeck, Lübeck 23562, Germany
| | | | | | - Elke Wühl
- Division of Pediatric Nephrology, Center for Pediatric and Adolescent Medicine, University Hospital Heidelberg, Heidelberg 69120, Germany
| | - Franz Schaefer
- Division of Pediatric Nephrology, Center for Pediatric and Adolescent Medicine, University Hospital Heidelberg, Heidelberg 69120, Germany
| | - Markus J Kemper
- Asklepios Children's Hospital Hamburg-Heidberg, Hamburg-Heidberg 22417, Germany
| | - Ute Derichs
- University Children's Hospital, Mainz 55131, Germany
| | | | - Ludwig Patzer
- St. Elisabeth and St. Barbara Children's Hospital, Halle/Saale 06110, Germany
| | - Norbert Albers
- Christliches Kinderhospital Osnabrück, Osnabrück 49074, Germany
| | | | - Holger Haberland
- Children's Hospital, Sana Klinikum Lichtenberg, Berlin Lichtenberg 10365, Germany
| | - Sabine Heger
- Kinderkrankenhaus auf der Bult, Hannover 30173, Germany
| | - Carmen Schröder
- University Children's Hospital Greifswald, Greifswald 17475, Germany
| | - Norbert Jorch
- University Children's Hospital, Evangelisches Klinikum Bethel, Bielefeld 33617, Germany
| | - Elmar Schmid
- Clinic for Pediatric Nephrology Hirschaid, Hirschaid 96114, Germany
| | - Hagen Staude
- University Children's Hospital Rostock, Rostock 18057, Germany
| | - Marcus Weitz
- Department of General Pediatrics and Hematology/Oncology, University Children's Hospital, University Hospital Tübingen, Tübingen 72076, Germany
| | - Clemens Freiberg
- Department of Pediatrics and Adolescent Medicine, University Medical Center Göttingen, Göttingen 37075, Germany
| | - Maren Leifheit-Nestler
- Department of Pediatric Kidney, Liver and Metabolic Diseases, Hannover Medical School, Hannover 30625, Germany
| | - Miroslav Zivicnjak
- Department of Pediatric Kidney, Liver and Metabolic Diseases, Hannover Medical School, Hannover 30625, Germany
| | - Dirk Schnabel
- Center for Chronically Sick Children, Pediatric Endocrinology, University Medicine, Charité, Berlin 13353, Germany
| | - Dieter Haffner
- Department of Pediatric Kidney, Liver and Metabolic Diseases, Hannover Medical School, Hannover 30625, Germany
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10
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Abseyi SN, Şıklar Z. Approach to Rickets: Is It Calciopenic or Phosphopenic? Turk Arch Pediatr 2023; 58:458-466. [PMID: 37427438 PMCID: PMC10543743 DOI: 10.5152/turkarchpediatr.2023.23050] [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: 03/03/2023] [Accepted: 04/04/2023] [Indexed: 07/11/2023]
Abstract
Rickets is a childhood disorder of decreased mineralization of bone tissue. It is either calciopenic or phosphopenic, according to the deficient mineral. Calcium, phosphate, and vitamin D metabolism should be known to understand the pathophysiology of rickets. A deficiency of calcium or vitamin D can be caused by several conditions. These conditions lead to defective osteoid mineralization, impaired chondrocyte differentiation, and apoptosis in the growth plate, resulting in clinical and radiological findings of rickets. Rickets developing as a result of vitamin D deficiency is the most frequently encountered form. Vitamin D-dependent rickets classification is made according to genetic abnormalities of enzymes that are involved in vitamin D metabolism. Phosphopenic rickets is divided mainly into 2 categories that are FGF23 related or not. A systemic approach that includes a detailed history, physical examination, and laboratory evaluation is required when performing a diagnostic evaluation. Vitamin D and calcium supplementation should be used to treat nutritional rickets. To prevent rickets and its morbidities, vitamin D prophylaxis in the newborn period is suggested. High dose of vitamin D3, 1.25(OH)2D, and calcium are treatment choices in vitamin D-dependent rickets according to its subgroup. If conventional treatment consisting of phosphate and calcitriol is ineffective in the treatment of phosphopenic rickets, Burosumab is the new treatment option.
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Affiliation(s)
- Sema Nilay Abseyi
- Department of Pediatric Endocrinology, Ankara University Faculty of Medicine, Ankara, Turkey
| | - Zeynep Şıklar
- Department of Pediatric Endocrinology, Ankara University Faculty of Medicine, Ankara, Turkey
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11
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Joshi M, Uday S. Vitamin D Deficiency in Chronic Childhood Disorders: Importance of Screening and Prevention. Nutrients 2023; 15:2805. [PMID: 37375708 DOI: 10.3390/nu15122805] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Revised: 06/09/2023] [Accepted: 06/13/2023] [Indexed: 06/29/2023] Open
Abstract
Vitamin D plays a vital role in regulating calcium and phosphate metabolism and maintaining bone health. A state of prolonged or profound vitamin D deficiency (VDD) can result in rickets in children and osteomalacia in children and adults. Recent studies have demonstrated the pleiotropic action of vitamin D and identified its effects on multiple biological processes in addition to bone health. VDD is more prevalent in chronic childhood conditions such as long-standing systemic illnesses affecting the renal, liver, gastrointestinal, skin, neurologic and musculoskeletal systems. VDD superimposed on the underlying disease process and treatments that can adversely affect bone turnover can all add to the disease burden in these groups of children. The current review outlines the causes and mechanisms underlying poor bone health in certain groups of children and young people with chronic diseases with an emphasis on the proactive screening and treatment of VDD.
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Affiliation(s)
- Madhura Joshi
- Birmingham Women's and Children's Hospital, Steelhouse Lane, Birmingham B4 6NH, UK
| | - Suma Uday
- Birmingham Women's and Children's Hospital, Steelhouse Lane, Birmingham B4 6NH, UK
- Institute of Metabolism and Systems Research, University of Birmingham, Edgbaston B15 2TT, UK
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12
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Gnoli M, Brizola E, Tremosini M, Di Cecco A, Sangiorgi L. Vitamin D and Bone fragility in Individuals with Osteogenesis Imperfecta: A Scoping Review. Int J Mol Sci 2023; 24:ijms24119416. [PMID: 37298368 DOI: 10.3390/ijms24119416] [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: 04/26/2023] [Revised: 05/21/2023] [Accepted: 05/25/2023] [Indexed: 06/12/2023] Open
Abstract
Vitamin D affects several body functions, and thus general health, due to its pleiotropic activity. It plays a key role in bone metabolism, and its deficiency impacts bone development, leading to bone fragility. In osteogenesis imperfecta (OI), a group of hereditary connective tissue disorders characterized by bone fragility, additional factors, such as vitamin D deficiency, can affect the expression of the phenotype and aggravate the disorder. The aim of this scoping review was to assess the incidence of vitamin D deficit in OI patients and the association between vitamin D status and supplementation in individuals affected by OI. We searched the PubMed Central and Embase databases and included studies published between January/2000 and October/2022 evaluating vitamin D measurement and status (normal, insufficiency, deficiency) and supplementation for OI. A total of 263 articles were identified, of which 45 were screened by title and abstract, and 10 were included after a full-text review. The review showed that low levels of vitamin D was a frequent finding in OI patients. Vitamin D supplementation was mainly indicated along with drug therapy and calcium intake. Even if widely used in clinical practice, vitamin D supplementation for OI individuals still needs a better characterization and harmonized frame for its use in the clinical setting, as well as further studies focusing on its effect on bone fragility.
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Affiliation(s)
- Maria Gnoli
- Department of Rare Skeletal Disorders, IRCCS Istituto Ortopedico Rizzoli, 40100 Bologna, Italy
| | - Evelise Brizola
- Department of Rare Skeletal Disorders, IRCCS Istituto Ortopedico Rizzoli, 40100 Bologna, Italy
| | - Morena Tremosini
- Department of Rare Skeletal Disorders, IRCCS Istituto Ortopedico Rizzoli, 40100 Bologna, Italy
| | - Alessia Di Cecco
- Department of Rare Skeletal Disorders, IRCCS Istituto Ortopedico Rizzoli, 40100 Bologna, Italy
| | - Luca Sangiorgi
- Department of Rare Skeletal Disorders, IRCCS Istituto Ortopedico Rizzoli, 40100 Bologna, Italy
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13
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Pons-Belda OD, Alonso-Álvarez MA, González-Rodríguez JD, Mantecón-Fernández L, Santos-Rodríguez F. Mineral Metabolism in Children: Interrelation between Vitamin D and FGF23. Int J Mol Sci 2023; 24:ijms24076661. [PMID: 37047636 PMCID: PMC10094813 DOI: 10.3390/ijms24076661] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Revised: 03/29/2023] [Accepted: 04/01/2023] [Indexed: 04/05/2023] Open
Abstract
Fibroblast growth factor 23 (FGF23) was identified at the turn of the century as the long-sought circulating phosphatonin in human pathology. Since then, several clinical and experimental studies have investigated the metabolism of FGF23 and revealed its relevant pathogenic role in various diseases. Most of these studies have been performed in adult individuals. However, the mineral metabolism of the child is, to a large extent, different from that of the adult because, in addition to bone remodeling, the child undergoes a specific process of endochondral ossification responsible for adequate mineralization of long bones’ metaphysis and growth in height. Vitamin D metabolism is known to be deeply involved in these processes. FGF23 might have an influence on bones’ growth as well as on the high and age-dependent serum phosphate concentrations found in infancy and childhood. However, the interaction between FGF23 and vitamin D in children is largely unknown. Thus, this review focuses on the following aspects of FGF23 metabolism in the pediatric age: circulating concentrations’ reference values, as well as those of other major variables involved in mineral homeostasis, and the relationship with vitamin D metabolism in the neonatal period, in vitamin D deficiency, in chronic kidney disease (CKD) and in hypophosphatemic disorders.
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Affiliation(s)
| | | | | | | | - Fernando Santos-Rodríguez
- Hospital Universitario Central de Asturias, 33011 Oviedo, Spain
- Department of Medicine, Faculty of Medicine, University of Oviedo, 33003 Oviedo, Spain
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14
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Makris K, Mousa C, Cavalier E. Alkaline Phosphatases: Biochemistry, Functions, and Measurement. Calcif Tissue Int 2023; 112:233-242. [PMID: 36571614 DOI: 10.1007/s00223-022-01048-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Accepted: 12/01/2022] [Indexed: 12/27/2022]
Abstract
Alkaline phosphatases (ALPs) are a group of isoenzymes, situated on the external layer of the cell membrane; they catalyze the hydrolysis of organic phosphate esters present in the extracellular space. Zinc and magnesium are significant co-factors for the biological activity of these enzymes. Although ALPs are available in various body tissues and have distinct physiochemical properties, they are true isoenzymes since they catalyze a similar reaction. In the liver, ALP is cytosolic and present in the canalicular membrane of the hepatocytes. ALPs are available in placenta, ileal mucosa, kidney, bone, and liver. However, most of the ALPs in serum (over 80%) are delivered from liver and bone and in more modest quantities from the intestines. Despite the fact that alkaline phosphatases are found in numerous tissues all through the body, their exact physiological function remains largely unknown.
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Affiliation(s)
- Konstantinos Makris
- Clinical Biochemistry Department, KAT General Hospital, Kifissia, Athens, Greece
- Laboratory for the Research of Musculoskeletal System "Th. Garofalidis", School of Medicine, National and Kapodistrian, University of Athens, Athens, Greece
| | - Chagigia Mousa
- 6th Orthopedic Department, KAT General Hospital, Kifissia, Athens, Greece
| | - Etienne Cavalier
- Department of Clinical Chemistry, CIRM, University of Liege, CHU de Liège, CHU Sart-Tilman, B-4000, Liège, Belgium.
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15
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Muscle and Bone Impairment in Infantile Nephropathic Cystinosis: New Concepts. Cells 2022; 11:cells11010170. [PMID: 35011732 PMCID: PMC8749987 DOI: 10.3390/cells11010170] [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: 11/11/2021] [Revised: 12/28/2021] [Accepted: 01/01/2022] [Indexed: 11/17/2022] Open
Abstract
Cystinosis Metabolic Bone Disease (CMBD) has emerged during the last decade as a well-recognized, long-term complication in patients suffering from infantile nephropathic cystinosis (INC), resulting in significant morbidity and impaired quality of life in teenagers and adults with INC. Its underlying pathophysiology is complex and multifactorial, associating complementary, albeit distinct entities, in addition to ordinary mineral and bone disorders observed in other types of chronic kidney disease. Amongst these long-term consequences are renal Fanconi syndrome, hypophosphatemic rickets, malnutrition, hormonal abnormalities, muscular impairment, and intrinsic cellular bone defects in bone cells, due to CTNS mutations. Recent research data in the field have demonstrated abnormal mineral regulation, intrinsic bone defects, cysteamine toxicity, muscle wasting and, likely interleukin-1-driven inflammation in the setting of CMBD. Here we summarize these new pathophysiological deregulations and discuss the crucial interplay between bone and muscle in INC. In future, vitamin D and/or biotherapies targeting the IL1β pathway may improve muscle wasting and subsequently CMBD, but this remains to be proven.
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16
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Haffner D, Leifheit-Nestler M, Grund A, Schnabel D. Rickets guidance: part II-management. Pediatr Nephrol 2022; 37:2289-2302. [PMID: 35352187 PMCID: PMC9395459 DOI: 10.1007/s00467-022-05505-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 02/08/2022] [Accepted: 02/09/2022] [Indexed: 11/28/2022]
Abstract
Here, we discuss the management of different forms of rickets, including new therapeutic approaches based on recent guidelines. Management includes close monitoring of growth, the degree of leg bowing, bone pain, serum phosphate, calcium, alkaline phosphatase as a surrogate marker of osteoblast activity and thus degree of rickets, parathyroid hormone, 25-hydroxyvitamin D3, and calciuria. An adequate calcium intake and normal 25-hydroxyvitamin D3 levels should be assured in all patients. Children with calcipenic rickets require the supplementation or pharmacological treatment with native or active vitamin D depending on the underlying pathophysiology. Treatment of phosphopenic rickets depends on the underlying pathophysiology. Fibroblast-growth factor 23 (FGF23)-associated hypophosphatemic rickets was historically treated with frequent doses of oral phosphate salts in combination with active vitamin D, whereas tumor-induced osteomalacia (TIO) should primarily undergo tumor resection, if possible. Burosumab, a fully humanized FGF23-antibody, was recently approved for treatment of X-linked hypophosphatemia (XLH) and TIO and shown to be superior for treatment of XLH compared to conventional treatment. Forms of hypophosphatemic rickets independent of FGF23 due to genetic defects of renal tubular phosphate reabsorption are treated with oral phosphate only, since they are associated with excessive 1,25-dihydroxyvitamin D production. Finally, forms of hypophosphatemic rickets caused by Fanconi syndrome, such as nephropathic cystinosis and Dent disease require disease-specific treatment in addition to phosphate supplements and active vitamin D. Adjustment of medication should be done with consideration of treatment-associated side effects, including diarrhea, gastrointestinal discomfort, hypercalciuria, secondary hyperparathyroidism, and development of nephrocalcinosis or nephrolithiasis.
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Affiliation(s)
- Dieter Haffner
- Department of Pediatric Kidney, Liver and Metabolic Diseases, Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany. .,Pediatric Research Center, Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany.
| | - Maren Leifheit-Nestler
- Department of Pediatric Kidney, Liver and Metabolic Diseases, Hannover Medical School, Carl-Neuberg-Str. 1, 30625 Hannover, Germany ,Pediatric Research Center, Hannover Medical School, Carl-Neuberg-Str. 1, 30625 Hannover, Germany
| | - Andrea Grund
- Department of Pediatric Kidney, Liver and Metabolic Diseases, Hannover Medical School, Carl-Neuberg-Str. 1, 30625 Hannover, Germany ,Pediatric Research Center, Hannover Medical School, Carl-Neuberg-Str. 1, 30625 Hannover, Germany
| | - Dirk Schnabel
- Center for Chronically Sick Children, Pediatric Endocrinology, Charitè, University Medicine, Berlin, Germany
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