1
|
Rothenbuhler A, Schnabel D, Högler W, Linglart A. Diagnosis, treatment-monitoring and follow-up of children and adolescents with X-linked hypophosphatemia (XLH). Metabolism 2020; 103S:153892. [PMID: 30928313 DOI: 10.1016/j.metabol.2019.03.009] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Revised: 03/22/2019] [Accepted: 03/25/2019] [Indexed: 11/19/2022]
Abstract
Early diagnosis, optimal therapeutic management and regular follow up of children with X-linked hypophosphatemia (XLH) determine their long term outcomes and future quality of life. Biochemical screening of potentially affected newborns in familial cases and improving physician's knowledge on clinical signs, symptoms and biochemical characteristics of XLH for de novo cases should lead to earlier diagnosis and treatment initiation. The follow-up of children with XLH includes clinical, biochemical and radiological monitoring of treatment (efficacy and complications) and screening for XLH-related dental, neurosurgical, rheumatological, cardiovascular, renal and ENT complications. In 2018, the European Union approved the use of burosumab, a humanized monoclonal anti-FGF23 antibody, as an alternative therapy to conventional therapy (active vitamin D analogues and phosphate supplements) in growing children with XLH and insufficiently controlled disease. Diagnostic criteria of XLH and the principles of disease management with conventional treatment or with burosumab are reviewed in this paper.
Collapse
Affiliation(s)
- Anya Rothenbuhler
- APHP, Endocrinology and Diabetology for Children, Bicêtre Paris Sud Hospital, Le Kremlin-Bicêtre, France; APHP, Reference Center for Rare Disorders of Calcium and Phosphate Metabolism, filière OSCAR, Paris, France; APHP, Platform of Expertise for Rare Disorders Paris-Sud, Bicêtre Paris Sud Hospital, Le Kremlin-Bicêtre, France.
| | - Dirk Schnabel
- Center for Chronic Sick Children, Pediatric Endocrinology, Charité, University Medicine Berlin, Germany
| | - Wolfgang Högler
- Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, United Kingdom; Department of Pediatrics and Adolescent Medicine, Johannes Kepler University Linz, Linz, Austria
| | - Agnès Linglart
- APHP, Endocrinology and Diabetology for Children, Bicêtre Paris Sud Hospital, Le Kremlin-Bicêtre, France; APHP, Reference Center for Rare Disorders of Calcium and Phosphate Metabolism, filière OSCAR, Paris, France; APHP, Platform of Expertise for Rare Disorders Paris-Sud, Bicêtre Paris Sud Hospital, Le Kremlin-Bicêtre, France
| |
Collapse
|
2
|
Linglart A, Biosse-Duplan M, Briot K, Chaussain C, Esterle L, Guillaume-Czitrom S, Kamenicky P, Nevoux J, Prié D, Rothenbuhler A, Wicart P, Harvengt P. Therapeutic management of hypophosphatemic rickets from infancy to adulthood. Endocr Connect 2014; 3:R13-30. [PMID: 24550322 PMCID: PMC3959730 DOI: 10.1530/ec-13-0103] [Citation(s) in RCA: 207] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
In children, hypophosphatemic rickets (HR) is revealed by delayed walking, waddling gait, leg bowing, enlarged cartilages, bone pain, craniostenosis, spontaneous dental abscesses, and growth failure. If undiagnosed during childhood, patients with hypophosphatemia present with bone and/or joint pain, fractures, mineralization defects such as osteomalacia, entesopathy, severe dental anomalies, hearing loss, and fatigue. Healing rickets is the initial endpoint of treatment in children. Therapy aims at counteracting consequences of FGF23 excess, i.e. oral phosphorus supplementation with multiple daily intakes to compensate for renal phosphate wasting and active vitamin D analogs (alfacalcidol or calcitriol) to counter the 1,25-diOH-vitamin D deficiency. Corrective surgeries for residual leg bowing at the end of growth are occasionally performed. In absence of consensus regarding indications of the treatment in adults, it is generally accepted that medical treatment should be reinitiated (or maintained) in symptomatic patients to reduce pain, which may be due to bone microfractures and/or osteomalacia. In addition to the conventional treatment, optimal care of symptomatic patients requires pharmacological and non-pharmacological management of pain and joint stiffness, through appropriated rehabilitation. Much attention should be given to the dental and periodontal manifestations of HR. Besides vitamin D analogs and phosphate supplements that improve tooth mineralization, rigorous oral hygiene, active endodontic treatment of root abscesses and preventive protection of teeth surfaces are recommended. Current outcomes of this therapy are still not optimal, and therapies targeting the pathophysiology of the disease, i.e. FGF23 excess, are desirable. In this review, medical, dental, surgical, and contributions of various expertises to the treatment of HR are described, with an effort to highlight the importance of coordinated care.
Collapse
Affiliation(s)
- Agnès Linglart
- Service d'Endocrinologie et Diabétologie de l'EnfantHôpital Bicêtre, APHP78 rue du Général Leclerc , Le Kremlin Bicêtre, 94270France
- Université Paris 11 faculté de Médecine, Hôpital Bicêtre70 rue du général Leclerc, Le Kremlin-Bicêtre, 94270France
- Centre de Référence des Maladies Rares du Métabolisme du Calcium et du PhosphoreLe Kremlin-BicêtreFrance
- Correspondence should be addressed to A Linglart
| | - Martin Biosse-Duplan
- Centre de Référence des Maladies Rares du Métabolisme du Calcium et du PhosphoreLe Kremlin-BicêtreFrance
- Service d'Odontologie-Maladies Rares Hôpital Bretonneau 2 rue Carpeaux Paris, 75018France
- Université Paris Descartes 12 Rue de l'École de MédecineParis, 75006France
| | - Karine Briot
- Université Paris Descartes 12 Rue de l'École de MédecineParis, 75006France
- Service Rhumatologie B Hôpital Cochin, APHP27, rue du Faubourg Saint-Jacques, Paris, 75014France
| | - Catherine Chaussain
- Centre de Référence des Maladies Rares du Métabolisme du Calcium et du PhosphoreLe Kremlin-BicêtreFrance
- Service d'Odontologie-Maladies Rares Hôpital Bretonneau 2 rue Carpeaux Paris, 75018France
- Université Paris Descartes 12 Rue de l'École de MédecineParis, 75006France
| | - Laure Esterle
- Service d'Endocrinologie et Diabétologie de l'EnfantHôpital Bicêtre, APHP78 rue du Général Leclerc , Le Kremlin Bicêtre, 94270France
- Centre de Référence des Maladies Rares du Métabolisme du Calcium et du PhosphoreLe Kremlin-BicêtreFrance
| | - Séverine Guillaume-Czitrom
- Service de Pédiatrie générale – Consultation de rhumatologieHôpital Bicêtre, APHP78 rue du Général Leclerc , Le Kremlin Bicêtre, 94270France
- Centre de Référence des Maladies Rares des Maladies Auto-Inflammatoires Rares de l'EnfantLe Kremlin BicêtreFrance
| | - Peter Kamenicky
- Service d'Endocrinologie et des Maladies de la ReproductionHôpital Bicêtre, APHP78 rue du Général Leclerc , Le Kremlin Bicêtre, 94270France
- Université Paris 11 faculté de Médecine, Hôpital Bicêtre70 rue du général Leclerc, Le Kremlin-Bicêtre, 94270France
- Centre de Référence des Maladies Rares du Métabolisme du Calcium et du PhosphoreLe Kremlin-BicêtreFrance
| | - Jerome Nevoux
- Service d'ORL et chirurgie cervico-maxillo-facialeHôpital Bicêtre, APHP78 rue du Général Leclerc , Le Kremlin Bicêtre, 94270France
- Université Paris 11 faculté de Médecine, Hôpital Bicêtre70 rue du général Leclerc, Le Kremlin-Bicêtre, 94270France
| | - Dominique Prié
- Université Paris Descartes 12 Rue de l'École de MédecineParis, 75006France
- Service d'explorations fonctionnelles rénales, Hôpital Necker-Enfants Malades149 rue de Sèvres, Paris, 75015France
| | - Anya Rothenbuhler
- Service d'Endocrinologie et Diabétologie de l'EnfantHôpital Bicêtre, APHP78 rue du Général Leclerc , Le Kremlin Bicêtre, 94270France
- Centre de Référence des Maladies Rares du Métabolisme du Calcium et du PhosphoreLe Kremlin-BicêtreFrance
| | - Philippe Wicart
- Centre de Référence des Maladies Rares du Métabolisme du Calcium et du PhosphoreLe Kremlin-BicêtreFrance
- Université Paris Descartes 12 Rue de l'École de MédecineParis, 75006France
- Service de Chirurgie infantile orthopédiqueHôpital Necker-Enfants Malades149 rue de Sèvres, Paris, 75015 France
| | - Pol Harvengt
- Association de patients RVRH-XLH20 rue Merlin de Thionville, Suresnes , 92150France
| |
Collapse
|
3
|
Huang X, Jiang Y, Xia W. FGF23 and Phosphate Wasting Disorders. Bone Res 2013; 1:120-32. [PMID: 26273497 DOI: 10.4248/br201302002] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2013] [Accepted: 04/25/2013] [Indexed: 11/10/2022] Open
Abstract
A decade ago, only two hormones, parathyroid hormone and 1,25(OH)2D, were widely recognized to directly affect phosphate homeostasis. Since the discovery of fibroblast growth factor 23 (FGF23) in 2000 (1), our understanding of the mechanisms of phosphate homeostasis and of bone mineralization has grown exponentially. FGF23 is the link between intestine, bone, and kidney together in phosphate regulation. However, we still do not know the complex mechanism of phosphate homeostasis and bone mineralization. The physiological role of FGF23 is to regulate serum phosphate. Secreted mainly by osteocytes and osteoblasts in the skeleton (2,3), it modulates kidney handling of phosphate reabsorption and calcitriol production. Genetic and acquired abnormalities in FGF23 structure and metabolism cause conditions of either hyper-FGF23 or hypo-FGF23. Hyper-FGF23 is related to hypophosphatemia, while hypo-FGF23 is related to hyperphosphatemia. Both hyper-FGF23 and hypo-FGF23 are detrimental to humans. In this review, we will discuss the pathophysiology of FGF23 and hyper-FGF23 related renal phosphate wasting disorders (4).
Collapse
Affiliation(s)
- Xianglan Huang
- Department of Endocrinology, Key Laboratory of Endocrinology, Ministry of Health, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences , Shuaifuyuan No. 1, Wangfujing, Dongcheng District, Beijing 100730, China
| | - Yan Jiang
- Department of Endocrinology, Key Laboratory of Endocrinology, Ministry of Health, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences , Shuaifuyuan No. 1, Wangfujing, Dongcheng District, Beijing 100730, China
| | - Weibo Xia
- Department of Endocrinology, Key Laboratory of Endocrinology, Ministry of Health, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences , Shuaifuyuan No. 1, Wangfujing, Dongcheng District, Beijing 100730, China
| |
Collapse
|
4
|
Chesney RW. American Pediatric Society's 2011 John Howland Award Acceptance Lecture: lessons from models of disease. Pediatr Res 2011; 70:543-6. [PMID: 21979561 DOI: 10.1203/pdr.0b013e31823218bc] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Russell W Chesney
- The Department of Pediatrics, Le Bonheur Children's Hospital, The University of Tennessee Health Science Center, Memphis, Tennessee 38103, USA.
| |
Collapse
|
5
|
Gattineni J, Baum M. Regulation of phosphate transport by fibroblast growth factor 23 (FGF23): implications for disorders of phosphate metabolism. Pediatr Nephrol 2010; 25:591-601. [PMID: 19669798 PMCID: PMC3151467 DOI: 10.1007/s00467-009-1273-z] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/04/2009] [Revised: 06/16/2009] [Accepted: 06/17/2009] [Indexed: 01/08/2023]
Abstract
There are a number of hypophosphatemic disorders due to renal phosphate wasting that cannot be explained by elevated levels of parathyroid hormone. The circulating factors responsible for the phosphaturia have been designated as phosphatonins. Studies of patients with tumor-induced osteomalacia and other genetic diseases of phosphate metabolism have resulted in the identification of a number of hormones that regulate phosphate homeostasis, including matrix extracellular phosphoglycoprotein (MEPE), secreted frizzled-related protein 4 (sFRP-4), dentin matrix protein 1 (DMP1), fibroblast growth factor 7 (FGF7), fibroblast growth factor 23 (FGF23), and Klotho. Our understanding of the actions of these hypophosphatemic peptides has been enhanced by studies in mice either overexpressing or not expressing these hormones. This review focuses on FGF23 since its regulation is disordered in diseases that affect children, such as X-linked hypophosphatemia, autosomal dominant and recessive hypophosphatemic rickets as well as chronic kidney disease. Recent studies have shown that FGF23 is unique among the FGFs in its requirement for Klotho for receptor activation. Here, we also discuss new potentially clinically important data pointing to the receptor(s) that mediate the binding and action of FGF23 and Klotho.
Collapse
Affiliation(s)
- Jyothsna Gattineni
- Department of Pediatrics, University of Texas Southwestern Medical Center at Dallas, 5323 Harry Hines Blvd, Dallas 75390-9063 TX, USA
| | - Michel Baum
- Department of Pediatrics, University of Texas Southwestern Medical Center at Dallas, 5323 Harry Hines Blvd, Dallas 75390-9063 TX, USA. Department of Internal Medicine, University of Texas Southwestern Medical Center at Dallas, Dallas 75235-9063 TX, USA
| |
Collapse
|
6
|
|
7
|
|
8
|
Bastepe M, Jüppner H. Inherited hypophosphatemic disorders in children and the evolving mechanisms of phosphate regulation. Rev Endocr Metab Disord 2008; 9:171-80. [PMID: 18365315 DOI: 10.1007/s11154-008-9075-3] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2008] [Accepted: 02/19/2008] [Indexed: 12/16/2022]
Abstract
Phosphorous is essential for multiple cellular functions and constitutes an important mineral in bone. Hypophosphatemia in children leads to rickets resulting in abnormal growth and often skeletal deformities. Among various causes of low serum phosphorous are inherited disorders associated with increased urinary excretion of phosphate, including autosomal dominant hypophosphatemic rickets (ADHR), X-linked hypophosphatemia (XLH), autosomal recessive hypophosphatemia (ARHP), and hereditary hypophosphatemic rickets with hypercalciuria (HHRH). Recent genetic analyses and subsequent biochemical and animal studies have revealed several novel molecules that appear to play key roles in the regulation of renal phosphate handling. These include a protein with abundant expression in bone, fibroblast growth factor 23 (FGF23), which has proven to be a circulating hormone that inhibits tubular reabsorption of phosphate in the kidney. Two other bone-specific proteins, PHEX and dentin matrix protein 1 (DMP1), appear to be necessary for limiting the expression of fibroblast growth factor 23, thereby allowing sufficient renal conservation of phosphate. This review focuses on the clinical, biochemical, and genetic features of inherited hypophosphatemic disorders, and presents the current understanding of hormonal and molecular mechanisms that govern phosphorous homeostasis.
Collapse
Affiliation(s)
- Murat Bastepe
- Endocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA
| | | |
Collapse
|
9
|
Kozlowski K, Posen S. Malignant hypophosphathaemic bone disease. Eur J Radiol 2001; 37:134-8. [PMID: 11223481 DOI: 10.1016/s0720-048x(00)00247-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
A case of crippling osteoporosis with muscular weakness, hypophosphatemia, hyperparathyroidism, defective skeletal calcification and cartilage destruction is reported. The patient, a male was observed from the age of 2 1/2 until his death at the age of 33 years. This bone/cartilage disease failed to respond to phosphate supplementation, parathyroidectomy and calcitriol. We believe this may represent a hitherto undescribed entity.
Collapse
Affiliation(s)
- K Kozlowski
- Department of Radiology, Royal Alexandra Hospital for Children, Sydney, Australia
| | | |
Collapse
|
10
|
Mactier H, Goel KM. Normal linear growth in hypophosphataemic bone disease. Scott Med J 1996; 41:150-1. [PMID: 8912987 DOI: 10.1177/003693309604100507] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
A case of hypophosphataemic bone diseases is described. Despite prescribed phosphate (PO4) supplement and 1.25 dihydroxycholecalciferol therapy, serum PO4 levels have remained low with associated diminished theoretical renal threshold for phosphate (TmPO/GFR) over a seven and a half year follow up period. Linear growth, however, has been normal.
Collapse
Affiliation(s)
- H Mactier
- Royal Hospital for Sick Children, Yorkhill NHS Trust, Glasgow
| | | |
Collapse
|
11
|
Slyper AH, Shaker JL, Thometz JG, McCormick K. Osteomalacia with hypophosphatemia and hypercalciuria: a possible new variant of osteomalacia. J Pediatr 1995; 127:105-9. [PMID: 7608793 DOI: 10.1016/s0022-3476(95)70267-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
A 12-year-old girl had a severe genu valgum deformity and osteomalacia with hypophosphatemia, hypercalciuria, and modestly elevated levels of 1,25-dihydroxyvitamin D3 and intact parathyroid hormone. This patient seems to have a different type of hypophosphatemic osteomalacia from that previously described.
Collapse
Affiliation(s)
- A H Slyper
- Department of Pediatrics, Medical College of Wisconsin, Milwaukee 53201-1997, USA
| | | | | | | |
Collapse
|
12
|
Thakker RV, Farmery MR, Sakati NA, Milner RD. Genetic linkage studies of X-linked hypophosphataemic rickets in a Saudi Arabian family. Clin Endocrinol (Oxf) 1992; 37:338-43. [PMID: 1483289 DOI: 10.1111/j.1365-2265.1992.tb02335.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
UNLABELLED OBJECTIVE, PATIENTS AND DESIGN: X-linked hypophosphataemic rickets (HYP) is the most common inherited form of rickets and the gene causing this disorder has been localized to Xp22.3-p21.3 by linkage studies of affected families of Northern European origin. In addition, the locus order Xpter-(DXS207-DXS43,DXS197)-HYP-DXS41-X cen has been established and the flanking markers are useful for the presymptomatic diagnosis of HYP. However, a recent study indicates locus heterogeneity and this may hinder the use of the flanking markers for presymptomatic diagnosis in additional families and in particular those from different populations. We have therefore investigated one Saudi-Arabian family (13 affected and six unaffected members) with hypophosphataemic rickets for linkage to these and other X-linked markers. A total of 17 cloned human X chromosome sequences identifying restriction fragment length polymorphisms were used to localize the mutant gene causing this disorder in the Saudi Arabian family. RESULTS Nine (four from Xp and five from Xq) of the 17 X-linked DNA probes proved informative and linkage was established between HYP and the DSX41 locus, peak LOD score = 4.22 (recombination fraction, theta = 0.00). A positive peak LOD score of 2.32 (theta = 0.05) was also obtained between HYP and the DXS207 locus. Thus, the HYP gene in this Saudi Arabian family is linked to two of the four flanking markers which demonstrated linkage in families of Northern European origin. CONCLUSION We conclude that the X-linked hypophosphataemic rickets gene in a Saudi Arabian family is located in the Xp22.3-p21.3, a region where this gene has previously been mapped by linkage studies of families of Northern European origin. Our studies have not demonstrated locus heterogeneity, so the flanking markers for HYP previously established in the families of Northern-European origin will be useful in the genetic counselling and presymptomatic diagnosis of this disorder in the Saudi Arabian family.
Collapse
Affiliation(s)
- R V Thakker
- Division of Molecular Medicine, MRC Clinical Research Centre, Harrow, UK
| | | | | | | |
Collapse
|
13
|
Scriver CR, Tenenhouse HS. Conserved loci on the X chromosome confer phosphate homeostasis in mice and humans. Genet Res (Camb) 1990; 56:141-52. [PMID: 2177024 DOI: 10.1017/s0016672300035229] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Several genes expressed in kidney and other tissues determine phosphate homeostasis in extracellular fluid. The major form of inherited hypophosphatemia in humans involves an X-linked locus (HPDR, Xp22.31-p21.3). It has two murine homologues (Hyp and Gy) which map to closely-linked but separate loci (crossover value 0.4%-0.8%). Both murine mutations impair Na(+)-phosphate cotransport in renal brush border membrane; an associated renal disorder of 1,25-dihydroxyvitamin D3 (1,25(OH)2D) metabolism has been characterized in Hyp mice. Whereas experiments with cultured Hyp renal epithelium indicate that the gene is expressed in kidney, studies showing the development of the mutant renal phenotype in normal mice parabiosed to Hyp mice implicate a circulating factor; these findings can be reconciled if the humoral factor is of renal origin. The gene dose effect of HPDR, Hyp and Gy on serum phosphorus values is consistently deviant and heterozygotes resemble affected hemizygotes. The deviant effect is also seen on renal phosphate transport; all mutant females (Hyp/Hyp and Hyp/+) have similar phenotypes. On the other hand, there is a normal gene dose effect of HPDR in mineralized tissue; tooth PRATIO (pulp area/tooth area) values for heterozygotes are distributed between those for affected males and normals. The tooth data imply that the X chromosome locus is expressed in both renal and non-renal cells. The polypeptide product of the X chromosome gene(s) is still unknown.
Collapse
Affiliation(s)
- C R Scriver
- DeBelle Laboratory for Biochemical Genetics, McGill University-Montreal Children's Hospital Research Institute
| | | |
Collapse
|
14
|
Shields ED, Scriver CR, Reade T, Fujiwara TM, Morgan K, Ciampi A, Schwartz S. X-linked hypophosphatemia: the mutant gene is expressed in teeth as well as in kidney. Am J Hum Genet 1990; 46:434-42. [PMID: 2155529 PMCID: PMC1683613] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Mutation at a locus (HPDR) on the X chromosome (McKusick 30780 [HPDR1]; 30781 [HPDR2]) causes impaired renal phosphate transport, hypophosphatemia, and an associated impairment in the process of mineralization in bone and teeth (X-linked hypophosphatemia [XLH]). We measured the dental pulp profile area (PRATIO [= pulp area/tooth area]) and serum phosphorus (Pi) values in uniformly treated XLH patients (six males, 81 teeth, 1,457 Pi values; 11 females, 129 teeth, 1,439 Pi values). Serum Pi values, reflecting the metabolic environment of tooth development, were obtained by repeated measurement between 1 mo and 26 years of age during treatment. PRATIO values calculated from standardized Rinn radiographs were used as outcome measurements of tooth development in XLH patients and in age-matched controls (12 males, 100 teeth; 27 females, 275 teeth). Age-dependent serum Pi values were not different in the treated XLH males and females. In teeth forming primary dentin there was no gene dosage effect on PRATIO values apparent in subjects below 15 years of age. However, in teeth forming secondary dentin a gene dosage was found in the subjects aged 15 to 25 years: XLH male teeth (n = 65) mean +/- SD = 0.163 +/- 0.046; XLH female teeth (n = 75) mean +/- SD = 0.137 +/- 0.039; control teeth (n = 209) mean +/- SD = 0.116 +/- 0.023; (higher PRATIO values mean less development or mineralization of secondary dentin); differences in these PRATIO values (males vs. female and XLH vs. control) were significant by mixed-model analysis of variance.(ABSTRACT TRUNCATED AT 250 WORDS)
Collapse
Affiliation(s)
- E D Shields
- Craniofacial Genetics, Faculty of Dentistry, McGill University, Montreal Children's Hospital, Quebec, Canada
| | | | | | | | | | | | | |
Collapse
|
15
|
Affiliation(s)
- M Levi
- Department of Internal Medicine, University of Texas, Southwestern Medical Center, Dallas
| |
Collapse
|
16
|
Brodehl J, Krause A, Hoyer PF. Assessment of maximal tubular phosphate reabsorption: comparison of direct measurement with the nomogram of Bijvoet. Pediatr Nephrol 1988; 2:183-9. [PMID: 3153009 DOI: 10.1007/bf00862587] [Citation(s) in RCA: 65] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
It is well established that plasma phosphate (Pp) is largely determined by the renal phosphate threshold, which is best described by the maximal rate of tubular phosphate reabsorption divided by the glomerular filtration rate (Tmp/GFR). For its clinical assessment either direct phosphate loading with simultaneous measurement of GFR is performed, or the nomogram described by Walton and Bijvoet is used. In order to test the validity of the two methods, we compared in 20 infants and 31 children the fasting values of phosphate reabsorption [endogenous phosphate reabsorption/inulin clearance (Tp/Cin) and Tp] with those obtained after phosphate loading [maximal phosphate reabsorption (Tmp) and Tmp/Cin], and both with those derived from the nomogram. In addition the fasting Tp/Cin of 50 infants and 143 children could be compared with the nomogram. The results demonstrate that the directly measured Tp/Cin was the same as the directly measured Tmp/Cin and that the measured Tmp/Cin was correctly estimated by the nomogram. However, the comparison of fasting Tp/Cin with nomogram-derived values showed a systematic error, by which the latter values were higher than those measured. The discrepancy was due to the splay of the phosphate titration curve, which was found by Bijvoet when the ratio of phosphate clearance (Cp) corrected for GFR (Cp/GFR) fell below 0.2. The incorporation of this splay in the nomogram could not be confirmed by data measured in our children. It is concluded that fasting Tp is already "maximal" and that, therefore, no phosphate loading is necessary to estimate Tmp. Furthermore, there is no evidence of a major splay, which makes the nomogram incompatible below a Cp/GFR ratio of 0.2.(ABSTRACT TRUNCATED AT 250 WORDS)
Collapse
Affiliation(s)
- J Brodehl
- Department of Paediatric Nephrology and Metabolic Diseases, Children's Hospital, Medical School Hannover, Federal Republic of Germany
| | | | | |
Collapse
|
17
|
Thakker RV, O'Riordan JL. Inherited forms of rickets and osteomalacia. BAILLIERE'S CLINICAL ENDOCRINOLOGY AND METABOLISM 1988; 2:157-91. [PMID: 2900631 DOI: 10.1016/s0950-351x(88)80012-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
|
18
|
Rico H, Gomez-Castresana F, Hernandez ER, Matute JA, Torrubiano J, Nunez-Torrón M. Adult hypophosphatemic osteomalacia: report of two cases. Clin Rheumatol 1985; 4:325-34. [PMID: 3840730 DOI: 10.1007/bf02031617] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Two cases of late hypophosphatemic osteomalacia are described: a male aged 30 who had the disease since he was 22 and a woman of 23 who had the disease since she was 14. Both presented with myopathy and bone pain, and showed hypophosphatemia, hyperglycinuria, reduced tubular phosphate reabsorption (TPR), increased hydroxyprolinuria and normal iPTH and iCT values. Radiologically the male had no Looser's zones and the woman did. Bone biopsy confirmed hypophosphatemic osteomalacia. Both cases were treated with vitamin D and oral phosphate and no improvement was observed. When treatment with 25(OH)D3 was initiated, no improvement was seen and afterwards this was combined with treatment using 1.25(OH)2D3 and from this time on a clinical improvement of the myopathy became evident in both patients. In the woman, healing of the bone lesions occurred at the same time as that of the myopathy, whereas in the male the bone lesions became worse. Healing of the myopathy was only obtained when treatment with 1.25(OH)2D3 was begun. Both patients had reduced values of 2.3 erythrocytic DPG and low level of serum phosphorus when the myopathy was cured, which suggests a lack of effect of 2.3 DPG or serum phosphorus as a cause of the myopathy. Although this had been attributed to a deficiency in the function of 25(OH)D3, the response to 1.25(OH)2D3 and due to the effects of this metabolite on calcium transport in muscle, suggests that the myopathy which occurs in late hypophosphatemic osteomalacia is a result of deficiency or resistance to the muscular effect of this metabolite. We cannot explain the lack of bone healing in the man and further therapeutic studies are required.
Collapse
|
19
|
|
20
|
Tieder M, Modai D, Samuel R, Arie R, Halabe A, Bab I, Gabizon D, Liberman UA. Hereditary hypophosphatemic rickets with hypercalciuria. N Engl J Med 1985; 312:611-7. [PMID: 2983203 DOI: 10.1056/nejm198503073121003] [Citation(s) in RCA: 160] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
We studied a new hereditary syndrome of hypophosphatemic rickets and hypercalciuria in six affected members of one kindred. In all patients, the manifestations of disease began in early childhood. The characteristic features are rickets, short stature, increased renal phosphate clearance (the ratio between the maximal tubular reabsorption rate for phosphorus and the glomerular filtration rate [TmP/GFR] is 2 to 4 S.D. below the age-related mean), hypercalciuria (8.6 mg of urinary calcium per kilogram of body weight per 24 hours vs. the upper normal value of 4.0), normal serum calcium levels, increased gastrointestinal absorption of calcium and phosphorus, an elevated serum concentration of 1,25-dihydroxyvitamin D (390 +/- 99 pg per milliliter vs. the upper normal value of 110), and suppressed parathyroid function (an immunoreactive parathyroid hormone level of 0.33 +/- 0.1 ng per milliliter and a cyclic AMP level of 1.39 +/- 0.12 nmol per deciliter of glomerular filtrate vs. the lower normal values of 0.3 and 1.5, respectively). Long-term phosphate supplementation as the sole therapy resulted in reversal of all clinical and biochemical abnormalities except the decreased TmP/GFR. We propose that the pivotal defect in this syndrome is a renal phosphate leak resulting in hypophosphatemia with an appropriate elevation of 1,25-dihydroxyvitamin D levels, which causes increased calcium absorption, parathyroid suppression, and hypercalciuria. This syndrome may represent one end of a spectrum of hereditary absorptive hypercalciuria. Our observations support the importance of phosphate as a mediator in controlling 1,25-dihydroxyvitamin D production in human beings.
Collapse
|
21
|
Carlsen NL, Krasilnikoff PA, Eiken M. Premature cranial synostosis in X-linked hypophosphatemic rickets: possible precipitation by 1-alpha-OH-cholecalciferol intoxication. ACTA PAEDIATRICA SCANDINAVICA 1984; 73:149-54. [PMID: 6538374 DOI: 10.1111/j.1651-2227.1984.tb09917.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
A child suffering from X-linked hypophosphatemic rickets developed vitamin D intoxication under treatment with 1-alpha-OH-cholecalciferol (1(OH)D3) and phosphorus. Beside the usual findings in this condition he showed precocious synostosis of the skull with signs of raised intracranial pressure. In view of earlier reports of coincidence of craniostenosis and X-linked hypophosphatemic rickets, we conclude that the possibility exists that intoxication with 1(OH)D3 has been the precipitating factor. In addition we found hypersensitivity to 1(OH)D3 2 months after cessation of treatment, and normal levels of calcitriol (1,25(OH)2D3) at the same time.
Collapse
|