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Zhu Z, Bo-Ran Ho B, Chen A, Amrhein J, Apetrei A, Carpenter TO, Lazaretti-Castro M, Colazo JM, McCrystal Dahir K, Geßner M, Gurevich E, Heier CA, Simmons JH, Hunley TE, Hoppe B, Jacobsen C, Kouri A, Ma N, Majumdar S, Molin A, Nokoff N, Ott SM, Peña HG, Santos F, Tebben P, Topor LS, Deng Y, Bergwitz C. An update on clinical presentation and responses to therapy of patients with hereditary hypophosphatemic rickets with hypercalciuria (HHRH). Kidney Int 2024; 105:1058-1076. [PMID: 38364990 PMCID: PMC11106756 DOI: 10.1016/j.kint.2024.01.031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Revised: 12/23/2023] [Accepted: 01/08/2024] [Indexed: 02/18/2024]
Abstract
Pathogenic variants in solute carrier family 34, member 3 (SLC34A3), the gene encoding the sodium-dependent phosphate cotransporter 2c (NPT2c), cause hereditary hypophosphatemic rickets with hypercalciuria (HHRH). Here, we report a pooled analysis of clinical and laboratory records of 304 individuals from 145 kindreds, including 20 previously unreported HHRH kindreds, in which two novel SLC34A3 pathogenic variants were identified. Compound heterozygous/homozygous carriers show above 90% penetrance for kidney and bone phenotypes. The biochemical phenotype for heterozygous carriers is intermediate with decreased serum phosphate, tubular reabsorption of phosphate (TRP (%)), fibroblast growth factor 23, and intact parathyroid hormone, but increased serum 1,25-dihydroxy vitamin D, and urine calcium excretion causing idiopathic hypercalciuria in 38%, with bone phenotypes still observed in 23% of patients. Oral phosphate supplementation is the current standard of care, which typically normalizes serum phosphate. However, although in more than half of individuals this therapy achieves correction of hypophosphatemia it fails to resolve the other outcomes. The American College of Medical Genetics and Genomics score correlated with functional analysis of frequent SLC34A3 pathogenic variants in vitro and baseline disease severity. The number of mutant alleles and baseline TRP (%) were identified as predictors for kidney and bone phenotypes, baseline TRP (%) furthermore predicted response to therapy. Certain SLC34A3/NPT2c pathogenic variants can be identified with partial responses to therapy, whereas with some overlap, others present only with kidney phenotypes and a third group present only with bone phenotypes. Thus, our report highlights important novel clinical aspects of HHRH and heterozygous carriers, raises awareness to this rare group of disorders and can be a foundation for future studies urgently needed to guide therapy of HHRH.
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Affiliation(s)
- Zewu Zhu
- Department of Internal Medicine, Section of Endocrinology, Yale University School of Medicine, New Haven, Connecticut, USA; Department of Urology, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Bryan Bo-Ran Ho
- Department of Internal Medicine, Section of Endocrinology, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Alyssa Chen
- Department of Internal Medicine, Section of Endocrinology, Yale University School of Medicine, New Haven, Connecticut, USA; Department of Otolaryngology, Harvard Medical School, Boston, Massachusetts, USA
| | - James Amrhein
- Pediatric Endocrinology and Diabetes, School of Medicine Greenville Campus, University of South Carolina, Greenville, South Carolina, USA
| | - Andreea Apetrei
- Caen University Hospital, Department of Genetics, UR7450 Biotargen, Reference Center for Rare Diseases of Calcium and Phosphate Metabolism, OSCAR Network, Caen, France
| | - Thomas Oliver Carpenter
- Department of Internal Medicine, Section of Endocrinology, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Marise Lazaretti-Castro
- Division of Endocrinology, Escola Paulista de Medicina-Universidade Federal de Sao Paulo (EPM-UNIFESP), Sao Paulo, Brazil
| | - Juan Manuel Colazo
- Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee, USA
| | - Kathryn McCrystal Dahir
- Division of Endocrinology, Program for Metabolic Bone Disorders, Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Michaela Geßner
- Pediatric Nephrology, Children's and Adolescents' Hospital, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
| | - Evgenia Gurevich
- Schneider Children's Medical Center of Israel, Pediatric Nephrology Institute, Petach Tikva, Israel; Faculty of Health Sciences, Ben Gurion University of the Negev, Beer Sheva, Israel
| | | | - Jill Hickman Simmons
- Department of Pediatrics, Division of Endocrinology and Diabetes, Vanderbilt University School of Medicine, Vanderbilt University, Nashville, Tennessee, USA
| | - Tracy Earl Hunley
- Division of Pediatric Nephrology, Vanderbilt University Medical Center, Monroe Carell Jr Children's Hospital at Vanderbilt, Nashville, Tennessee, USA
| | - Bernd Hoppe
- Division of Pediatric Nephrology, Department of Pediatrics, University of Bonn, Bonn, Germany
| | - Christina Jacobsen
- Division of Endocrinology, Harvard Medical School, Boston, Massachusetts, USA
| | - Anne Kouri
- Pediatric Nephrology, University of Minnesota, Minneapolis, Minnesota, USA
| | - Nina Ma
- Section of Pediatric Endocrinology, Children's Hospital Colorado, Aurora, Colorado, USA; Department of Pediatrics, University of Colorado School of Medicine, Aurora, Colorado, USA
| | - Sachin Majumdar
- Department of Internal Medicine, Section of Endocrinology, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Arnaud Molin
- Caen University Hospital, Department of Genetics, UR7450 Biotargen, Reference Center for Rare Diseases of Calcium and Phosphate Metabolism, OSCAR Network, Caen, France
| | - Natalie Nokoff
- Department of Pediatrics, Section of Endocrinology, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Susan M Ott
- Department of Medicine, University of Washington, Seattle, Washington, USA
| | - Helena Gil Peña
- Department of Pediatrics, Hospital Universitario Central de Asturias (HUCA), Oviedo, Spain
| | - Fernando Santos
- Department of Pediatrics, Hospital Universitario Central de Asturias (HUCA), Oviedo, Spain
| | - Peter Tebben
- Division of Endocrinology, Diabetes, Metabolism, and Nutrition, Mayo Clinic, Rochester, Minnesota, USA; Division of Pediatric Endocrinology, Mayo Clinic, Rochester, Minnesota, USA
| | - Lisa Swartz Topor
- Division of Pediatric Endocrinology, Hasbro Children's Hospital, Warren Alpert Medical School of Brown University, Providence, Rhode Island, USA
| | - Yanhong Deng
- Yale School of Public Health, New Haven, Connecticut, USA
| | - Clemens Bergwitz
- Department of Internal Medicine, Section of Endocrinology, Yale University School of Medicine, New Haven, Connecticut, USA.
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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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Mohan S, Sheehan M, Tebben P, Wermers R. Efficacy of Oral Cinacalcet in Non-PTH Nonmalignant Hypercalcemia from Excess 1,25-Dihydroxyvitamin D. JCEM CASE REPORTS 2024; 2:luae022. [PMID: 38476635 PMCID: PMC10928506 DOI: 10.1210/jcemcr/luae022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Indexed: 03/14/2024]
Abstract
Elevated 1,25-dihydroxyvitamin D (1,25(OH)2D) is a rare cause of non-parathyroid hormone (PTH)-mediated hypercalcemia seen in granulomatous disease, malignancy (most often lymphoma), or genetic mutations. Therapeutic options are limited. We report the case of a 67-year-old White man with nonmalignant, nongranulomatous, 1,25(OH)2D-mediated hypercalcemia treated successfully with cinacalcet. At presentation, he had hypercalcemia, hypercalciuria with recurrent nephrolithiasis, low PTH, elevated 1,25(OH)2D, and normal 25-hydroxyvitamin D. The 1,25(OH)2D levels were inappropriate in the setting of hypercalcemia with low PTH. Evaluations for sarcoidosis, tuberculosis, and malignancy were negative. Genetic testing showed biallelic variants in the CYP24A1 gene. Cinacalcet was trialed and showed normalization of calcium levels. On cinacalcet, biochemical indices showed a slight increase in 1,25(OH)2D and 24-hour urine calcium and mild decrease in PTH. He briefly experienced symptomatic hypocalcemia that resolved after reducing cinacalcet dose. Due to limited symptomatic benefit, he opted to stop cinacalcet. Additional follow-up showed intermittently elevated serum calcium levels after stopping cinacalcet, most recently 10.3 mg/dL. Cinacalcet may be a therapeutic option in nonmalignant, 1,25(OH)2D-mediated hypercalcemia. Further study is necessary to confirm efficacy, understand risks and benefits, and elucidate mechanism(s) of action.
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Affiliation(s)
- Sneha Mohan
- Division of Endocrinology, Diabetes, Metabolism, and Nutrition and Department of Medicine, Mayo College of Medicine, Mayo Clinic, Rochester, MN 55905, USA
| | - Michael Sheehan
- Division of Endocrinology, Marshfield Clinic Health System, Weston Center, Weston, WI 54476, USA
| | - Peter Tebben
- Division of Endocrinology, Diabetes, Metabolism, and Nutrition and Department of Medicine, Mayo College of Medicine, Mayo Clinic, Rochester, MN 55905, USA
- Division of Pediatric Endocrinology and Department of Pediatric and Adolescent Medicine, Mayo College of Medicine, Mayo Clinic, Rochester, MN 55905, USA
| | - Robert Wermers
- Division of Endocrinology, Diabetes, Metabolism, and Nutrition and Department of Medicine, Mayo College of Medicine, Mayo Clinic, Rochester, MN 55905, USA
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Dodamani MH, Memon SS, Karlekar M, Lila AR, Khan M, Sarathi V, Arya S, Jamale T, Thakare S, Patil VA, Shah NS, Bergwitz C, Bandgar TR. Hereditary Hypophosphatemic Rickets with Hypercalciuria Presenting with Enthesopathy, Renal Cysts, and High Serum c-Terminal FGF23: Single-Center Experience and Systematic Review. Calcif Tissue Int 2024; 114:137-146. [PMID: 37981601 DOI: 10.1007/s00223-023-01156-2] [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: 08/01/2023] [Accepted: 10/10/2023] [Indexed: 11/21/2023]
Abstract
Hereditary hypophosphatemic rickets with hypercalciuria (HHRH) is a rare disorder of phosphate homeostasis. We describe a single-center experience of genetically proven HHRH families and perform systematic review phenotype-genotype correlation in reported biallelic probands and their monoallelic relatives. Detailed clinical, biochemical, radiological, and genetic data were retrieved from our center and a systematic review of Pub-Med and Embase databases for patients and relatives who were genetically proven. Total of nine subjects (probands:5) carrying biallelic SLC34A3 mutations (novel:2) from our center had a spectrum from rickets/osteomalacia to normal BMD, with hypophosphatemia and hypercalciuria in all. We describe the first case of genetically proven HHRH with enthesopathy. Elevated FGF23 in another patient with hypophosphatemia, iron deficiency anemia, and noncirrhotic periportal fibrosis led to initial misdiagnosis as tumoral osteomalacia. On systematic review of 58 probands (with biallelic SLC34A3 mutations; 35 males), early-onset HHRH and renal calcification were present in ~ 70% and late-onset HHRH in 10%. c.575C > T p.(Ser192Leu) variant occurred in 53% of probands without skeletal involvement. Among 110 relatives harboring monoallelic SLC34A3 mutation at median age 38 years, renal calcification, hypophosphatemia, high 1,25(OH)2D, and hypercalciuria were observed in ~30%, 22.3%, 40%, and 38.8%, respectively. Renal calcifications correlated with age but were similar across truncating and non-truncating variants. Although most relatives were asymptomatic for bone involvement, 6/12(50%) had low bone mineral density. We describe the first monocentric HHRH case series from India with varied phenotypes. In a systematic review, frequent renal calcifications and low BMD in relatives with monoallelic variants (HHRH trait) merit identification.
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Affiliation(s)
- Manjunath Havalappa Dodamani
- Department of Endocrinology, Seth G.S Medical College & KEM Hospital, OPD, Parel, Mumbai, Maharashtra, 400012, India
| | - Saba Samad Memon
- Department of Endocrinology, Seth G.S Medical College & KEM Hospital, OPD, Parel, Mumbai, Maharashtra, 400012, India.
| | - Manjiri Karlekar
- Department of Endocrinology, Seth G.S Medical College & KEM Hospital, OPD, Parel, Mumbai, Maharashtra, 400012, India
| | - Anurag Ranjan Lila
- Department of Endocrinology, Seth G.S Medical College & KEM Hospital, OPD, Parel, Mumbai, Maharashtra, 400012, India
| | - Mustafa Khan
- Department of Endocrinology, Brown University, 375 Wampanoag Trail, Providence, RI, 02913, USA
- Section Endocrinology and Metabolism, Yale University School of Medicine, Anlyan Center, Office S117, Lab S110, 1 Gilbert Street, New Haven, CT, 06519, USA
| | - Vijaya Sarathi
- Department of Endocrinology, Vydehi Institute of Medical Sciences and Research Centre, Bengaluru, Karnataka, India
| | - Sneha Arya
- Department of Endocrinology, Seth G.S Medical College & KEM Hospital, OPD, Parel, Mumbai, Maharashtra, 400012, India
| | - Tukaram Jamale
- Department of Nephrology, Seth G.S Medical College & KEM Hospital, Mumbai, Maharashtra, India
| | - Sayali Thakare
- Department of Nephrology, Seth G.S Medical College & KEM Hospital, Mumbai, Maharashtra, India
| | - Virendra A Patil
- Department of Endocrinology, Seth G.S Medical College & KEM Hospital, OPD, Parel, Mumbai, Maharashtra, 400012, India
| | - Nalini S Shah
- Department of Endocrinology, Seth G.S Medical College & KEM Hospital, OPD, Parel, Mumbai, Maharashtra, 400012, India
| | - Clemens Bergwitz
- Section Endocrinology and Metabolism, Yale University School of Medicine, Anlyan Center, Office S117, Lab S110, 1 Gilbert Street, New Haven, CT, 06519, USA
| | - Tushar R Bandgar
- Department of Endocrinology, Seth G.S Medical College & KEM Hospital, OPD, Parel, Mumbai, Maharashtra, 400012, India
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Choo KS, Yew J, Tan EJH, Puar THK. Case Report: Hypercalcemia as a manifestation of acute adrenal crisis precipitated by fluconazole use, and a review of the literature. Front Endocrinol (Lausanne) 2023; 14:1168797. [PMID: 37274338 PMCID: PMC10232950 DOI: 10.3389/fendo.2023.1168797] [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: 02/18/2023] [Accepted: 05/04/2023] [Indexed: 06/06/2023] Open
Abstract
Acute adrenal crisis classically presents with vomiting, altered sensorium, and hypotension. We describe a unique case manifesting with severe hypercalcemia. Addisonian crisis was unusually precipitated by fluconazole use. We reviewed other reported cases and discuss the possible mechanisms of hypercalcemia in adrenal insufficiency. This 67-year-old man presented with fever, cough, and vomiting for 1 week and with anorexia and confusion for 3 weeks. He was hypotensive and clinically dehydrated. Investigations revealed left-sided lung consolidation, acute renal failure, and severe non-parathyroid hormone (PTH)-mediated hypercalcemia (calcium, 3.55mol/L; PTH, 0.81pmol/L). Initial impression was pneumonia complicated by septic shock and hypercalcemia secondary to possible malignancy. He received mechanical ventilation; treatment with intravenous fluids, inotropes, and hydrocortisone for septic shock; and continuous renal replacement therapy with low-calcium dialysate. Although hypercalcemia resolved and he was weaned off inotropes, dialysis, and hydrocortisone, his confusion persisted. When hypercalcemia recurred on day 19 of admission, early morning cortisol was <8 nmol/L, with low ACTH level (3.2 ng/L). Other pituitary hormones were normal. Hypercalcemia resolved 3 days after reinstating stress doses of hydrocortisone, and his mentation normalized. On further questioning, he recently received fluconazole for a forearm abscess. He previously consumed traditional medications but stopped several years ago, which may have contained glucocorticoids. He was discharged on oral hydrocortisone. Cortisol levels improved gradually, and glucocorticoid replacement was ceased after 8 years, without any recurrence of hypercalcemia or Addisonian crisis. Both hypercalcemia and adrenal insufficiency may present with similar non-specific symptoms. It is important to consider adrenal insufficiency in hypercalcemia of unclear etiology.
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Affiliation(s)
- Kuan Swen Choo
- Department of Endocrinology, Changi General Hospital, Singapore, Singapore
| | - Jielin Yew
- Department of Endocrinology, Changi General Hospital, Singapore, Singapore
| | - Eberta Jun Hui Tan
- Raffles Diabetes and Endocrine Centre, Raffles Medical Group, Singapore, Singapore
| | - Troy Hai Kiat Puar
- Department of Endocrinology, Changi General Hospital, Singapore, Singapore
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Brazier F, Courbebaisse M, David A, Bergerat D, Leroy C, Lindner M, Maruani G, Saint Jacques C, Letavernier E, Hureaux M, Vargas-Poussou R, Prié D. Relationship between clinical phenotype and in vitro analysis of 13 NPT2c/SCL34A3 mutants. Sci Rep 2023; 13:85. [PMID: 36596813 PMCID: PMC9810644 DOI: 10.1038/s41598-022-25995-5] [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: 05/06/2022] [Accepted: 12/07/2022] [Indexed: 01/04/2023] Open
Abstract
Biallelic pathogenic variants in the SLC34A3 gene, encoding for the NPT2c cotransporter, cause Hereditary Hypophosphatemic Rickets with Hypercalciuria (HHRH). However, the associated phenotype is highly variable. In addition, mice deleted for Slc34a3 exhibit a different phenotype compared to humans, without urinary phosphate leakage. The mechanisms by which SLC34A3 variants disrupt phosphate/calcium metabolism are un-completely understood. In this study we explored these mechanisms in vitro using SLC34A3 variants identified in patients with urinary phosphate leakage. We analyzed the consequences of these variants on NPT2c function and the link with the phenotype of the patients. We studied 20 patients with recurrent nephrolithiasis and low serum phosphate concentration harboring variants in the SLC34A3 gene. Half of the patients carried homozygous or composite heterozygous variants. Three patients had in addition variants in SLC34A1 and SLC9A3R1 genes. All these patients benefited from a precise analysis of their phenotype. We generated 13 of these mutants by site-directed mutagenesis. Then we carried out transient transfections of these mutants in HEK cells and measured their phosphate uptake capacity under different conditions. Among the 20 patients included, 3 had not only mutations in NPT2c but also in NPT2a or NHERF1 genes. Phosphate uptake was decreased in 8 NPT2c mutants studied and normal for 5. Four variants were initially categorized as variants of uncertain significance. Expression of the corresponding mutants showed that one did not modify phosphate transport, two reduced it moderately and one abolished it. Co-transfection of the NPT2c mutants with the wild-type plasmid of NPT2c or NPT2a did not reveal dominant negative effect of the mutants on NPT2c-mediated phosphate transport. A detailed analysis of patient phenotypes did not find a link between the severity of the disorder and the level of phosphate transport impairment. NPT2c mutations classified as ACMG3 identified in patients with renal phosphate leak should be characterized by in vitro study to check if they alter NPT2c-mediated phosphate transport since phosphate uptake capacity may not be affected. In addition, research for mutations in NHERF1 and NPT2a genes should always be associated to NPT2c sequencing.
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Affiliation(s)
- François Brazier
- Université de Paris Cité, Faculté de Médecine, INSERM U1151, Paris, France.,Département de Physiologie, hôpital Necker Assistance Publique Hôpitaux de Paris, Paris, France
| | - Marie Courbebaisse
- Université de Paris Cité, Faculté de Médecine, INSERM U1151, Paris, France.,Service de Physiologie, hôpital européen Georges Pompidou, Assistance Publique Hôpitaux de Paris, Paris, France
| | - Amandine David
- Université de Paris Cité, Faculté de Médecine, INSERM U1151, Paris, France
| | - David Bergerat
- Université de Paris Cité, Faculté de Médecine, INSERM U1151, Paris, France
| | - Christine Leroy
- Université de Paris Cité, Faculté de Médecine, INSERM U1151, Paris, France
| | - Marta Lindner
- Université de Paris Cité, Faculté de Médecine, INSERM U1151, Paris, France
| | - Gérard Maruani
- Département de Physiologie, hôpital Necker Assistance Publique Hôpitaux de Paris, Paris, France.,Service de Physiologie, hôpital européen Georges Pompidou, Assistance Publique Hôpitaux de Paris, Paris, France
| | - Camille Saint Jacques
- Service d'Explorations fonctionnelles multidisciplinaires, hôpital Tenon, Assistance Publique Hôpitaux de Paris, Paris, France.,Université Paris Sorbonne, Paris, France
| | - Emmanuel Letavernier
- Service d'Explorations fonctionnelles multidisciplinaires, hôpital Tenon, Assistance Publique Hôpitaux de Paris, Paris, France.,Université Paris Sorbonne, Paris, France
| | - Marguerite Hureaux
- Service de Génétique, hôpital européen Georges Pompidou, Assistance Publique Hôpitaux de Paris, 75015, Paris, France.,Université de Paris Cité, Faculté de médecine, INSERM U970, Paris, France
| | - Rosa Vargas-Poussou
- Service de Génétique, hôpital européen Georges Pompidou, Assistance Publique Hôpitaux de Paris, 75015, Paris, France
| | - Dominique Prié
- Université de Paris Cité, Faculté de Médecine, INSERM U1151, Paris, France. .,Département de Physiologie, hôpital Necker Assistance Publique Hôpitaux de Paris, Paris, France.
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7
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AlSubaihin A, Harrington J. Hereditary Rickets: A Quick Guide for the Pediatrician. Curr Pediatr Rev 2022; 19:CPR-EPUB-128008. [PMID: 36475338 DOI: 10.2174/1573396319666221205123402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Revised: 09/10/2022] [Accepted: 11/01/2022] [Indexed: 12/12/2022]
Abstract
With the increased discovery of genes implicated in vitamin D metabolism and the regulation of calcium and phosphate homeostasis, a growing number of genetic forms of rickets are now recognized. These are categorized into calciopenic and phosphopenic rickets. Calciopenic forms of hereditary rickets are caused by genetic mutations that alter the enzymatic activity in the vitamin D activation pathway or impair the vitamin D receptor action. Hereditary forms of phosphopenic rickets, on the other hand, are caused by genetic mutations that lead to increased expression of FGF23 hormone or that impair the absorptive capacity of phosphate at the proximal renal tubule. Due to the clinical overlap between acquired and genetic forms of rickets, identifying children with hereditary rickets can be challenging. A clear understanding of the molecular basis of hereditary forms of rickets and their associated biochemical patterns allow the health care provider to assign the correct diagnosis, avoid non-effective interventions and shorten the duration of the diagnostic journey in these children. In this mini-review, known forms of hereditary rickets listed on the Online Mendelian Inheritance in Man database are discussed. Further, a clinical approach to identify and diagnose children with hereditary forms of rickets is suggested.
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Affiliation(s)
- Abdulmajeed AlSubaihin
- Department of Pediatrics, College of Medicine, King Saud University, Riyadh, Saudi Arabia
- King Saud University Medical City, Riyadh, Saudi Arabia
| | - Jennifer Harrington
- Division of Endocrinology, Women's and Children's Health Network, North Adelaide, Australia
- Faculty of Health and Medical Sciences, University of Adelaide, Adelaide, Australia
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Bertholet-Thomas A, Portefaix A, Flammier S, Dhelens C, Subtil F, Dubourg L, Laudy V, Le Bouar M, Boussaha I, Ndiaye M, Molin A, Lemoine S, Bacchetta J. Fluconazole in hypercalciuric patients with increased 1,25(OH) 2D levels: the prospective, randomized, placebo-controlled, double-blind FLUCOLITH trial. Trials 2022; 23:499. [PMID: 35710560 PMCID: PMC9204961 DOI: 10.1186/s13063-022-06302-z] [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: 10/21/2021] [Accepted: 04/13/2022] [Indexed: 11/23/2022] Open
Abstract
Background Hypercalciuria is one of the most frequent metabolic disorders associated with nephrolithiasis and/or nephrocalcinosis possibly leading to chronic kidney disease (CKD) and bone complications in adults. Orphan diseases with different underlying primary pathophysiology share inappropriately increased 1,25(OH)2D levels and hypercalciuria, e.g., hypersensitivity to vitamin D and renal phosphate wasting. Their management is challenging, typically based on hyperhydration and dietary advice. The antifungal azoles are known to inhibit the 1α-hydroxylase and therefore decrease 1,25(OH)2D levels; they are commonly used, with well described pharmacokinetic and tolerability data. Fluconazole has been successfully reported to reduce calciuria in patients with CYP24A1 or SLC34A3 mutations, with no safety warnings. Thus, based on these case reports, we hypothesize that fluconazole is effective to decrease and normalize calciuria in patients with hypercalciuria and increased 1,25(OH)2D levels. Methods The FLUCOLITH trial is a prospective, interventional, randomized in parallel groups (1:1), placebo-controlled, double-blind trial. A total of 60 patients (10–60 years) with nephrolithiasis and/or nephrocalcinosis history, hypercalciuria (> 0.1 mmol/kg/day), increased 1,25(OH)2D levels (> 150 pmol/L), and 25-OH-D levels >20 nmol/L will be included. Inclusions will be performed only from mid-September to the beginning of February to avoid bias due to sunlight-induced vitamin D synthesis. The primary endpoint will be the proportion of patients with normalization of 24-h calciuria between baseline and 16 weeks, or with a relative decrease of at least 30% of 24-h calciuria in patients who still display at W16 a 24-h hypercalciuria. Discussion The current challenge is to propose an efficient treatment to patients with hypercalciuria and increased 1,25(OH)2D levels in order to prevent later complications and notably CKD that can ultimately lead to end-stage renal disease. Based on improvement of knowledge in phosphate/calcium metabolism, pathophysiology and genetics, the “off-label” use of fluconazole was recently reported to be useful in hypercalciuric patients with increased 1,25(OH)2D levels. Thus, the FLUCOLITH study is a unique opportunity to develop a new indication of a well-known and not expensive drug in orphan renal diseases, the ultimate objective being the secondary prevention of CKD worsening in these patients. Trial registration ClinicalTrials.gov NCT04495608. Registered on July 23, 2020. Supplementary Information The online version contains supplementary material available at 10.1186/s13063-022-06302-z.
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Affiliation(s)
- Aurélia Bertholet-Thomas
- Centre de Référence des Maladies Rénales Rares, filières maladies rares ORKID and ERK-Net, Service de Néphrologie, Rhumatologie et Dermatologie Pédiatriques, Hôpital Femme Mère Enfant, Boulevard Pinel, 69677, Bron, Cedex, France.,Centre de Référence des Maladies Rares du Calcium et du Phosphate, filière maladies rares OSCAR, Hôpital Femme Mère Enfant, Bron, France.,INSERM 1033, Prévention des Maladies Osseuses, Lyon, France
| | - Aurélie Portefaix
- Centre d'Investigation Clinique, Hôpital Cardiovasculaire Louis Pradel, Inserm 1407, 69500, Bron, France
| | - Sacha Flammier
- Centre de Référence des Maladies Rénales Rares, filières maladies rares ORKID and ERK-Net, Service de Néphrologie, Rhumatologie et Dermatologie Pédiatriques, Hôpital Femme Mère Enfant, Boulevard Pinel, 69677, Bron, Cedex, France.,Centre de Référence des Maladies Rares du Calcium et du Phosphate, filière maladies rares OSCAR, Hôpital Femme Mère Enfant, Bron, France
| | - Carole Dhelens
- Pharmacie, FRIPHARM, Hôpital Edouard Herriot, Lyon, France
| | - Fabien Subtil
- Service de Biostatistique, Hospices Civils de Lyon, Lyon, France.,Université de Lyon, Université Lyon 1, CNRS, Laboratoire de Biométrie et Biologie Évolutive UMR 5558, Villeurbanne, France
| | - Laurence Dubourg
- Néphrologie, Dialyse, Hypertension Artérielle et Exploration Fonctionnelle Rénale, Hôpital Edouard Herriot, Lyon, France.,Faculté de Médecine Lyon Est, Université Lyon 1, Lyon, France
| | - Valérie Laudy
- Centre d'Investigation Clinique, Hôpital Cardiovasculaire Louis Pradel, Inserm 1407, 69500, Bron, France
| | - Myrtille Le Bouar
- Centre d'Investigation Clinique, Hôpital Cardiovasculaire Louis Pradel, Inserm 1407, 69500, Bron, France
| | - Inesse Boussaha
- Centre d'Investigation Clinique, Hôpital Cardiovasculaire Louis Pradel, Inserm 1407, 69500, Bron, France
| | - Marietou Ndiaye
- Centre d'Investigation Clinique, Hôpital Cardiovasculaire Louis Pradel, Inserm 1407, 69500, Bron, France
| | - Arnaud Molin
- Service de Génétique, CHU de Caen, Caen, France.,Centre de Référence des Maladies Rares du Calcium et du Phosphate, filière maladies rares OSCAR Caen, Caen, France
| | - Sandrine Lemoine
- Centre de Référence des Maladies Rénales Rares, filières maladies rares ORKID and ERK-Net, Service de Néphrologie, Rhumatologie et Dermatologie Pédiatriques, Hôpital Femme Mère Enfant, Boulevard Pinel, 69677, Bron, Cedex, France.,Centre de Référence des Maladies Rares du Calcium et du Phosphate, filière maladies rares OSCAR, Hôpital Femme Mère Enfant, Bron, France.,Néphrologie, Dialyse, Hypertension Artérielle et Exploration Fonctionnelle Rénale, Hôpital Edouard Herriot, Lyon, France.,Faculté de Médecine Lyon Est, Université Lyon 1, Lyon, France
| | - Justine Bacchetta
- Centre de Référence des Maladies Rénales Rares, filières maladies rares ORKID and ERK-Net, Service de Néphrologie, Rhumatologie et Dermatologie Pédiatriques, Hôpital Femme Mère Enfant, Boulevard Pinel, 69677, Bron, Cedex, France. .,Centre de Référence des Maladies Rares du Calcium et du Phosphate, filière maladies rares OSCAR, Hôpital Femme Mère Enfant, Bron, France. .,INSERM 1033, Prévention des Maladies Osseuses, Lyon, France. .,Faculté de Médecine Lyon Est, Université Lyon 1, Lyon, France.
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Filler G, Schott C, Salerno FR, Ens A, McIntyre CW, Díaz González de Ferris ME, Stein R. Growth hormone therapy in HHRH. Bone Rep 2022; 16:101591. [PMID: 35663378 PMCID: PMC9156862 DOI: 10.1016/j.bonr.2022.101591] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/27/2022] [Revised: 05/08/2022] [Accepted: 05/16/2022] [Indexed: 01/20/2023] Open
Abstract
Background Hereditary Hypophosphatemic Rickets with Hypercalciuria (HHRH) (SLC34A3 gene, OMIM 241530) is an autosomal recessive disorder that results in a loss of function of the sodium-phosphate NPT2c channel at the proximal tubule. Phosphate supplementation rarely improves serum phosphate, hypercalciuria, nephrocalcinosis, 1,25(OH)2 vitamin D (1,25(OH)2D) levels or short stature. Methods We describe 23Na MRI and the successful use of recombinant human growth hormone (rhGH) and Fluconazole to improve growth (possibly confounded by puberty) and hypercalciuria in a now 12-year-old male with HHRH (novel homozygous SLC34A3 mutation, c.835_846 + 10del.T). Results The patient had chronic bone pain, hypophosphatemia (0.65 mmol/L[reference interval 1.1-1.9]), pathological fractures and medullary nephrocalcinosis/hypercalciuria (urinary calcium/creatinine ratio 1.66 mol/mmol[<0.6]). TmP/GFR was 0.65 mmol/L[0.97-1.64]; 1,25(OH)2D was >480 pmol/L[60-208]. Rickets Severity Score was 4. Treatment with 65 mg/kg/day of sodium phosphate and potassium citrate 10 mmol TID failed to correct the abnormalities.Adding rhGH at 0.35 mg/kg/week to the phosphate therapy, improved bone pain, height z-score from -2.09 to -1.42 over 6 months, without a sustained effect on TmP/GFR. Fluconazole was titrated to 100 mg once daily, resulting for the first time in a reduction of the 1,25(OH)2D to 462 and 426 pmol/L; serum phosphate 0.87 mmol/L, and calcium/creatinine ratio of 0.73.23Na MRI showed normal skin (z-score + 0.68) and triceps surae muscle (z-score + 1.5) Na+ levels; despite a defect in a sodium transporter, hence providing a rationale for a low sodium diet to improve hypercalciuria. Conclusions The addition of rhGH, Fluconazole and salt restriction to phosphate/potassium supplementation improved the conventional therapy. Larger studies are needed to confirm our findings.
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Affiliation(s)
- Guido Filler
- Departments of Pediatrics, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Canada
- Medicine, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Canada
- Pathology & Laboratory Medicine, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Canada
- Lilibeth Caberto Kidney Clinical Research Unit, London, Ontario, Canada
| | - Clara Schott
- Medical Sciences, University of Western Ontario, Canada
| | - Fabio Rosario Salerno
- Biophysics, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Canada
- Lilibeth Caberto Kidney Clinical Research Unit, London, Ontario, Canada
| | - Andrea Ens
- Departments of Pediatrics, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Canada
| | - Christopher William McIntyre
- Departments of Pediatrics, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Canada
- Medicine, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Canada
- Biophysics, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Canada
- Lilibeth Caberto Kidney Clinical Research Unit, London, Ontario, Canada
| | | | - Robert Stein
- Departments of Pediatrics, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Canada
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How the diagnosis and the management of genetic renal phosphate leak impact the life of kidney stone formers? Urolithiasis 2022; 50:319-331. [DOI: 10.1007/s00240-022-01316-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Accepted: 02/08/2022] [Indexed: 10/19/2022]
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Rousseau-Nepton I, Jones G, Schlingmann K, Kaufmann M, Zuijdwijk CS, Khatchadourian K, Gupta IR, Pacaud D, Pinsk MN, Mokashi A, Nour MA, Alexander RT, Rodd CJ. CYP24A1 and SLC34A1 Pathogenic Variants Are Uncommon in a Canadian Cohort of Children with Hypercalcemia or Hypercalciuria. Horm Res Paediatr 2022; 94:124-132. [PMID: 34320495 DOI: 10.1159/000517548] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Accepted: 06/01/2021] [Indexed: 11/19/2022] Open
Abstract
OBJECTIVES Biallelic pathogenic variants in CYPA24A1 and SLC34A1 are causes of idiopathic infantile hypercalcemia. Pathogenic variants in both may also give rise to hypercalciuria with nephrocalcinosis or nephrolithiasis without previous hypercalcemia (renal group). Our objective was to examine the frequency of CYP24A1 or SLC34A1 variants in children with early hypercalcemia or late-onset hypercalciuria. METHOD Forty-one children from 7 centers across Canada were recruited. Local investigations were undertaken. The serum was evaluated by liquid chromatography tandem-mass spectrometry for the ratio of 25-hydroxyvitamin D3 to 24,25-dihydroxyvitamin D3, (25-OH-D3:24,25-(OH)2D3), an elevation pathognomonic for the loss of function of the CYP24A1 enzyme. Mutational analyses were undertaken. Family cascade screening was performed if pathogenic variants were detected in probands. RESULTS Twenty-nine children had early-onset hypercalcemia; none had elevated 25-OH-D3:24,25-(OH)2D3 or variants. Interestingly, 2 of 12 in the renal group had elevated 25-OH-D3:24,25-(OH)2D3 and presented as preadolescents. In case 1, cascade testing revealed a sibling and parent with asymptomatic pathogenic variants in CYP24A1. Four CYP24A1 pathogenic variants were identified in these 2 probands: 3 have been described in European populations, and 1 is a rare variant in exon 7 (c931delC) that is likely pathogenic. No SLC34A1 pathogenic variants were detected. CONCLUSION In Canada, pathogenic variants in CYP24A1 appear to manifest with late-onset hypercalciuria and its sequelae. The 25-OH-D3:24,25-(OH)2D3 ratio is an excellent tool for screening for biallelic pathogenic variants in CYP24A1. We confirm that cascade testing is important for these variants.
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Affiliation(s)
| | - Glenville Jones
- Department of Biomedical & Molecular Sciences, Queen's University, Kingston, Ontario, Canada
| | - Karlpiet Schlingmann
- Department of General Pediatrics, University Children's Hospital, University of Münster, Münster, Germany
| | - Martin Kaufmann
- Department of Biomedical & Molecular Sciences, Queen's University, Kingston, Ontario, Canada
| | | | | | - Indra R Gupta
- Department of Pediatrics, McGill University, Montreal, Québec, Canada
| | - Danièle Pacaud
- Department of Pediatrics, University of Calgary, Calgary, Alberta, Canada
| | - Maury N Pinsk
- Department of Pediatrics and Child Health, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Arati Mokashi
- Department of Pediatrics, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Munier A Nour
- Department of Pediatrics, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - R Todd Alexander
- Department of Pediatrics, University of Alberta, Edmonton, Alberta, Canada
| | - Celia J Rodd
- Department of Pediatrics and Child Health, University of Manitoba, Winnipeg, Manitoba, Canada
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Dubourg LD, Aurelle M, Chardon L, Flammier S, Lemoine S, Bacchetta J. TmP/GFR reference values from childhood to adulthood in the era of IDMS-standardized creatinine values. Nephrol Dial Transplant 2021; 37:2150-2156. [PMID: 34850142 DOI: 10.1093/ndt/gfab331] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND The assessment of phosphate homeostasis in clinical practice relies on circulating phosphate levels but also on phosphate tubular reabsorption, ideally assessed using the Tubular maximum Phosphate Reabsorption per Glomerular Filtration Rate (TmP/GFR). TmP/GFR reference values were established before the onset of IDMS-standardized creatinine assays, and thus need to be updated. Our objective is to provide reference values for TmP/GFR from childhood to adulthood, using the gold-standard of GFR assessment and IDMS-standardized creatinine values. METHODS We retrospectively analyzed all the inulin and iohexol clearances (mGFR) performed in children and in adults screened for a living-donation in our unit since the beginning of IDMS-creatinine assays. TmP/GFR was calculated on a fasting sample, using the conventional formula without correction for TRP in subjects below 19 years of age. RESULTS A total of 2051 subjects (1711 children, 340 adults), aged from 1.9 to 73.4 years with normal GFR, normal phosphate and normal calcium levels, was included for TmP/GFR analysis. As expected, there was a progressive decrease along puberty in both genders of plasma phosphate and TmP/GFR, the decrease occurring earlier in girls. After the age of 19, there was a stabilization of plasma phosphate and TmP/GFR levels until the age of 55, phosphate levels and TmP/GFR being slightly lower in men than in women. CONCLUSION We present the largest cohort describing TmP/GFR reference values in the era of IDMS-standardized creatinine assays. We believe that these data will help physicians to better diagnose and manage patients with abnormal phosphate metabolism in daily clinical routine.
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Affiliation(s)
- Laurence Derain Dubourg
- Service d'Exploration Fonctionnelle Rénale, Département de Néphrologie, Hôpital Edouard Herriot, Lyon, France.,Centre de Référence des Maladies Rénales Rares, filière maladies rares ORKID and ERKNet, Hospices Civils de Lyon, Bron, France.,Faculté de Médecine Lyon Est, Université de Lyon, Lyon, France
| | - Manon Aurelle
- Centre de Référence des Maladies Rénales Rares, filière maladies rares ORKID and ERKNet, Hospices Civils de Lyon, Bron, France.,Faculté de Médecine Lyon Est, Université de Lyon, Lyon, France
| | - Laurence Chardon
- Service de Biochimie, Groupement Hospitalier Est, Hospices Civils de Lyon, Bron, France
| | - Sacha Flammier
- Centre de Référence des Maladies Rénales Rares, filière maladies rares ORKID and ERKNet, Hospices Civils de Lyon, Bron, France.,Centre de Référence des Maladies Rares du Calcium et du Phosphore, filière maladies rares OSCAR, Hospices Civils de Lyon, Bron, France
| | - Sandrine Lemoine
- Service d'Exploration Fonctionnelle Rénale, Département de Néphrologie, Hôpital Edouard Herriot, Lyon, France.,Centre de Référence des Maladies Rénales Rares, filière maladies rares ORKID and ERKNet, Hospices Civils de Lyon, Bron, France.,Faculté de Médecine Lyon Est, Université de Lyon, Lyon, France.,Centre de Référence des Maladies Rares du Calcium et du Phosphore, filière maladies rares OSCAR, Hospices Civils de Lyon, Bron, France
| | - Justine Bacchetta
- Centre de Référence des Maladies Rénales Rares, filière maladies rares ORKID and ERKNet, Hospices Civils de Lyon, Bron, France.,Faculté de Médecine Lyon Est, Université de Lyon, Lyon, France.,Centre de Référence des Maladies Rares du Calcium et du Phosphore, filière maladies rares OSCAR, Hospices Civils de Lyon, Bron, France.,INSERM 1033 Research Unit, Prévention des Maladies Osseuses, Lyon, France
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The interest of oral calcium loads test in the diagnosis and management of pediatric nephrolithiasis with hypercalciuria: Experience from a tertiary pediatric centre. J Pediatr Urol 2020; 16:489.e1-489.e9. [PMID: 32593617 DOI: 10.1016/j.jpurol.2020.05.160] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Revised: 04/30/2020] [Accepted: 05/22/2020] [Indexed: 11/20/2022]
Abstract
INTRODUCTION The use of calcium load has been forgotten in pediatrics until recently whereas it is of utmost importance to have a practical approach to guide management of hypercalciuric nephrolithiasis. OBJECTIVE The purpose of this study was to evaluate the practical interest of oral calcium loads to improve the overall management of nephrolithiasis in children. METHODS We retrospectively studied all pediatric patients having undergone an oral calcium load in our pediatric nephrology unit between September 2015 and April 2017. RESULTS A total of 16 patients were included, at a median age of 12.0 (5.5-17.5) years. The indications of oral calcium load were: presence of an active urolithiasis without any obvious explanation after ruling out the "classical" biological abnormalities, or presence of hypercalciuria with stones composed of weddellite or carbapatite crystals. Among the 16 patients, 6 (38%) patients displayed absorptive hypercalciuria, 2 (12%) renal leak, 3 (19%) "unclassified" inadapted PTH, and 5 (31%) a normal calcium load test. The result of oral calcium load modified the clinical management in 14 (88%) patients, mainly based on the type of hypercalciuria. It allowed us to individualize nutritional advice: in patients with absorptive hypercalciuria, we proposed calcium intake within the lower normal range for age with dairy products not enriched with vitamin D, with the advice to avoid salt and calcium loads during evenings. Conversely, in patients with resorptive hypercalciuria, we proposed normal calcium intake for age. Showing the results of the calcium load is meaningful to patients and parents, and can be considered as an "educational" tool. DISCUSSION To the best of our knowledge, this study is the first to evaluate the interest of calcium load in children with nephrolithiasis in an era of routine PTH and 1-25-D assessment. Here, we demonstrate the feasibility and safety of oral calcium load in children, its interest to understand the underlying mechanisms of hypercalciuria, and its major interest as an "educational tool" for patients to explain them the underlying mechanisms and thus guide the therapeutic management using an individualized dietary approach. This study did not include many patients, but to the best of our knowledge, this is the first study evaluating and validating the feasibility of a safe and non-expensive diagnosis tool in pediatric hypercalciuria. CONCLUSION Oral calcium load is helpful to guide therapeutic adaptation in pediatrics using an individualized dietary approach.
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