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Abstract
Vitamin D metabolism represents a well-integrated, hormonally regulated endocrine unit interlinking calcium and phosphate metabolism. Pathophysiologic processes disturbing vitamin D metabolism comprise classic defects of vitamin D activation and action presenting as different forms of vitamin D-dependent rickets as well as disorders with increased vitamin D activity. The latter may result in hypercalcemia, hypercalciuria, and renal calcifications. Acquired and hereditary disorders causing hypervitaminosis D are discussed, including vitamin D intoxication, granulomatous disease, and idiopathic infantile hypercalcemia that may be caused by either a defective vitamin D degradation or by a primary defect in phosphate conservation.
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Affiliation(s)
- Karl Peter Schlingmann
- Department of General Pediatrics, University Children's Hospital, Albert-Schweitzer-Campus 1, Münster 48149, Germany.
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Mirea AM, Pop RM, Căinap SS, Trifa AP. Presymptomatic diagnosis of CYP24A1-related infantile idiopathic hypercalcemia: A case report. Eur J Med Genet 2020; 63:104100. [PMID: 33186763 DOI: 10.1016/j.ejmg.2020.104100] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Revised: 10/27/2020] [Accepted: 11/04/2020] [Indexed: 11/29/2022]
Abstract
Vitamin D plays an important role in calcium homeostasis and bone mineralization. Inefficient inactivation of vitamin D leads to a condition called idiopathic infantile hypercalcemia (IIH). In the last decade mutations in CYP24A1, the gene responsible for vitamin D inactivation, were described as the main molecular cause of IIH. In this study, we present a family with two daughters diagnosed with IIH due to two different mutations in CYP24A1 gene. Based on next-generation sequencing (NGS), the elder daughter was diagnosed as carrying the mutations CYP24A1: c.1186C > T; (p.Arg396Trp) and c.428_430del; (p.Glu143del). Within this context, we were able to presymptomatically diagnose her newborn sister using Sanger sequencing technique. Screening for CYP24A1 mutations in families with IIH history helps preventing disease manifestations in newborn siblings. Thus, NGS combined with Sanger sequencing validation opens up the perspective of preventive medicine with great impact on IIH management, where stopping vitamin D administration is enough to prevent disease manifestation, in most cases.
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Affiliation(s)
- Andreea-Manuela Mirea
- Department of Medical Genetics, "Iuliu Hatieganu" University of Medicine and Pharmacy, Cluj-Napoca, Romania
| | - Raluca M Pop
- Department of Pharmacology, "Iuliu Hatieganu" University of Medicine and Pharmacy, Cluj-Napoca, Romania
| | - Simona Sorana Căinap
- 2(nd) Pediatric Clinic, Mother and Child Department, University of Medicine and Pharmacy Iuliu Haţieganu Cluj-Napoca, Emergency Clinical Hospital for Children, Cluj-Napoca, Romania
| | - Adrian P Trifa
- Department of Medical Genetics, "Iuliu Hatieganu" University of Medicine and Pharmacy, Cluj-Napoca, Romania; Department of Genetics, "Ion Chiricuta" Cancer Institute, Cluj-Napoca, Romania.
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Schlingmann KP, Cassar W, Konrad M. Juvenile onset IIH and CYP24A1 mutations. Bone Rep 2018; 9:42-46. [PMID: 30591926 PMCID: PMC6303532 DOI: 10.1016/j.bonr.2018.06.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Revised: 06/13/2018] [Accepted: 06/16/2018] [Indexed: 12/23/2022] Open
Abstract
The term Idiopathic infantile hypercalcemia (IIH) was first introduced almost 70 years ago when symptomatic hypercalcemia developed in children after receiving high doses of vitamin D for the prevention of rickets. The underlying pathophysiology remained unknown until recessive mutations in CYP24A1 encoding Vitamin D3-24-hydroxylase were discovered. The defect in vitamin D degradation leads to an accumulation of active 1,25(OH)2D3 with subsequent hypercalcemia. Enhanced renal calcium excretions lead to hypercalciuria and nephrocalcinosis. Meanwhile, the phenotypic spectrum associated with CYP24A1 mutations has significantly broadened. Patients may present at all age groups with symptoms originating from increased serum calcium levels as well as from increased urinary calcium excretions, i.e. kidney stones. Possible long term sequelae comprise chronic renal failure as well as cardiovascular disease. Here, we present a family with two affected siblings with differing clinical presentation as an example for the phenotypic variability of CYP24A1 defects. CYP24A1 mutations result in increased vitamin D sensitivity. Associated phenotypes range from infantile hypercalcemia to kidney stone disease. Potential long-term sequelae include chronic renal failure. Future research needs to focus on potential treatments to limit vitamin D activation.
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Affiliation(s)
- Karl P Schlingmann
- Department of General Pediatrics, University Children's Hospital, Münster, Germany
| | | | - Martin Konrad
- Department of General Pediatrics, University Children's Hospital, Münster, Germany
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Jones G, Kottler ML, Schlingmann KP. Genetic Diseases of Vitamin D Metabolizing Enzymes. Endocrinol Metab Clin North Am 2017; 46:1095-1117. [PMID: 29080636 DOI: 10.1016/j.ecl.2017.07.011] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Vitamin D metabolism involves 3 highly specific cytochrome P450 (CYP) enzymes (25-hydroxylase, 1α-hydroxylase, and 24-hydroxylase) involved in the activation of vitamin D3 to the hormonal form, 1,25-(OH)2D3, and the inactivation of 1,25-(OH)2D3 to biliary excretory products. Mutations of the activating enzymes CYP2R1 and CYP27B1 cause lack of normal 1,25-(OH)2D3 synthesis and result in rickets whereas mutations of the inactivating enzyme CYP24A1 cause build-up of excess 1,25-(OH)2D3 and result in hypercalcemia, nephrolithiasis, and nephrocalcinosis. This article reviews the literature for 3 clinical conditions. Symptoms, diagnosis, treatment, and management of vitamin D-dependent rickets and idiopathic infantile hypercalcemia are discussed.
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Affiliation(s)
- Glenville Jones
- Department of Biomedical and Molecular Sciences, Queen's University, Room 650, Botterell Hall, Kingston, ON K7L 3N6, Canada.
| | - Marie Laure Kottler
- Department of Genetics, University de Basse-Normandie, National Reference Center for Rare Diseases of Calcium and Phosphorus Metabolism, Caen University Hospital, Avenue de la Côte de Nacre, 14033 Caen, France; Team 7450 BIOTARGEN, Caen-Normandy University, Esplanade de la Paix, 14032 Caen, France
| | - Karl Peter Schlingmann
- Department of General Pediatrics, University Children's Hospital, Waldeyerstr. 22, D-48149 Muenster, Germany
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Ertl DA, Raimann A, Csaicsich D, Patsch JM, Laccone F, Haeusler G. A Pediatric Patient with a CYP24A1 Mutation: Four Years of Clinical, Biochemical, and Imaging Follow-Up. Horm Res Paediatr 2017; 87:196-204. [PMID: 27798933 DOI: 10.1159/000450947] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Accepted: 09/20/2016] [Indexed: 01/21/2023] Open
Abstract
BACKGROUND A female infant was admitted to hospital due to failure to thrive. She presented hypercalcemia (4.09 mmol/L, normal range: 2.2-2.65 mmol/L), high 25-hydroxyvitamin D (283 nmol/L, normal range: 75-250 nmol/L), 1,25-dihydroxyvitamin D in the upper normal range, and low parathyroid hormone. Vitamin D intoxication was suspected. The patient had received routine rickets prophylaxis. METHODS Williams-Beuren syndrome was genetically excluded. Sequencing of CYP24A1 showed 2 mutations: c.443T>C and c.1186C>T. RESULTS The patient's clinical status improved after intravenous rehydration, cessation of supplementation, and on a low-calcium diet. 25-Hydroxyvitamin D concentrations normalized within days, while 1,25-dihydroxyvitamin D remained in the upper normal range. We also investigated our patient's bone health. CONCLUSION The patient was hospitalized initially on suspicion of vitamin D intoxication but proved to be a case of compound heterozygosity. Data on the long-term clinical and biochemical evolution of patients with idiopathic infantile hypercalcemia are sparse. Our follow-up showed seasonal variations of vitamin D and calcium parameters, with no influence on kidney function or bone health for the investigated period.
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Affiliation(s)
- Diana-Alexandra Ertl
- University Clinic for Pediatrics and Adolescent Medicine, Medical University of Vienna, Vienna, Austria
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Dauber A, Nguyen TT, Sochett E, Cole DEC, Horst R, Abrams SA, Carpenter TO, Hirschhorn JN. Genetic defect in CYP24A1, the vitamin D 24-hydroxylase gene, in a patient with severe infantile hypercalcemia. J Clin Endocrinol Metab 2012; 97:E268-74. [PMID: 22112808 PMCID: PMC3275367 DOI: 10.1210/jc.2011-1972] [Citation(s) in RCA: 93] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
CONTEXT Idiopathic infantile hypercalcemia (IIH) is a disorder the genetic etiology and physiological basis of which are not well understood. OBJECTIVE The objective of the study was to describe the underlying physiology and genetic cause of hypercalcemia in an infant with severe IIH and to extend these genetic findings into an additional cohort of children with IIH. DESIGN This was an inpatient study of a single patient with consanguineous parents at an academic medical center with follow-up in a specialty clinic cohort. PATIENTS The patient population was one patient with severe IIH for gene discovery and physiological testing and 27 patients with idiopathic infantile hypercalcemia in the replication cohort. INTERVENTIONS Interventions included a calcium isotopic absorption study as well as homozygosity mapping and whole-exome sequencing in a single patient followed up by gene sequencing in replication cohort. MAIN OUTCOME MEASURE Fractional absorption of calcium and genetic variants causing hypercalcemia were measured. RESULTS Intestinal calcium absorption was extremely elevated (∼90%). A rare homozygous deletion in the CYP24A1 gene was found, leading to the loss of a single highly conserved amino acid. In vivo functional studies confirmed decreased 24-hydroxylase activity because the subject had undetectable levels of 24,25-dihydroxyvitamin D. No coding variants in CYP24A1 were found in the 27 additional patients with IIH. CONCLUSIONS Our study confirms that CYP24A1 plays a causal role in some but not all cases of IIH via markedly increased intestinal absorption of calcium, suggesting that genetic diagnosis could be helpful in a subset of IIH patients. This case demonstrates the power of an unbiased, genome-wide approach accompanied by informative physiological studies to provide new insights into human biology.
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Affiliation(s)
- Andrew Dauber
- Division of Endocrinology, Children's Hospital Boston, Clinical Investigator Training Program, Boston, Massachusetts 02115, USA.
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Hollis BW, Johnson D, Hulsey TC, Ebeling M, Wagner CL. Vitamin D supplementation during pregnancy: double-blind, randomized clinical trial of safety and effectiveness. J Bone Miner Res 2011; 26:2341-57. [PMID: 21706518 PMCID: PMC3183324 DOI: 10.1002/jbmr.463] [Citation(s) in RCA: 518] [Impact Index Per Article: 39.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The need, safety, and effectiveness of vitamin D supplementation during pregnancy remain controversial. In this randomized, controlled trial, women with a singleton pregnancy at 12 to 16 weeks' gestation received 400, 2000, or 4000 IU of vitamin D(3) per day until delivery. The primary outcome was maternal/neonatal circulating 25-hydroxyvitamin D [25(OH)D] concentration at delivery, with secondary outcomes of a 25(OH)D concentration of 80 nmol/L or greater achieved and the 25(OH)D concentration required to achieve maximal 1,25-dihydroxyvitamin D(3) [1,25(OH)(2)D(3)] production. Of the 494 women enrolled, 350 women continued until delivery: Mean 25(OH)D concentrations by group at delivery and 1 month before delivery were significantly different (p < 0.0001), and the percent who achieved sufficiency was significantly different by group, greatest in 4000-IU group (p < 0.0001). The relative risk (RR) for achieving a concentration of 80 nmol/L or greater within 1 month of delivery was significantly different between the 2000- and the 400-IU groups (RR = 1.52, 95% CI 1.24-1.86), the 4000- and the 400-IU groups (RR = 1.60, 95% CI 1.32-1.95) but not between the 4000- and. 2000-IU groups (RR = 1.06, 95% CI 0.93-1.19). Circulating 25(OH)D had a direct influence on circulating 1,25(OH)(2)D(3) concentrations throughout pregnancy (p < 0.0001), with maximal production of 1,25(OH)(2)D(3) in all strata in the 4000-IU group. There were no differences between groups on any safety measure. Not a single adverse event was attributed to vitamin D supplementation or circulating 25(OH)D levels. It is concluded that vitamin D supplementation of 4000 IU/d for pregnant women is safe and most effective in achieving sufficiency in all women and their neonates regardless of race, whereas the current estimated average requirement is comparatively ineffective at achieving adequate circulating 25(OH)D concentrations, especially in African Americans.
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Affiliation(s)
- Bruce W Hollis
- Division of Neonatology and Department of Obstetrics and Gynecology, Medical University of South Carolina, Charleston, SC 29425, USA.
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Kenny J, Lees MM, Drury S, Barnicoat A, Van't Hoff W, Palmer R, Morrogh D, Waters JJ, Lench NJ, Bockenhauer D. Sotos syndrome, infantile hypercalcemia, and nephrocalcinosis: a contiguous gene syndrome. Pediatr Nephrol 2011; 26:1331-4. [PMID: 21597970 DOI: 10.1007/s00467-011-1884-z] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/06/2011] [Revised: 03/14/2011] [Accepted: 03/16/2011] [Indexed: 11/29/2022]
Abstract
Sotos syndrome is characterized by overgrowth, a typical facial appearance, and learning difficulties. It is caused by heterozygous mutations, including deletions, of NSD1 located at chromosome 5q35. Here we report two unrelated cases of Sotos syndrome associated with nephrocalcinosis. One patient also had idiopathic infantile hypercalcemia. Genetic investigations revealed heterozygous deletions at 5q35 in both patients, encompassing NSD1 and SLC34A1 (NaPi2a). Mutations in SLC34A1 have previously been associated with hypercalciuria/nephrolithiasis. Our cases suggest a contiguous gene deletion syndrome including NSD1 and SLC34A1 and provide a potential genetic basis for idiopathic infantile hypercalcemia.
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Affiliation(s)
- Joanna Kenny
- North East Thames Regional Genetics Service, Great Ormond Street Hospital for Children NHS Trust, London, WC1N 3JH, UK
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Infantile hypercalcemia and hypercalciuria: new insights into a vitamin D-dependent mechanism and response to ketoconazole treatment. J Pediatr 2010; 157:296-302. [PMID: 20394945 DOI: 10.1016/j.jpeds.2010.02.025] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/27/2009] [Revised: 01/05/2010] [Accepted: 02/18/2010] [Indexed: 11/24/2022]
Abstract
OBJECTIVE To analyze vitamin D metabolism and response to ketoconazole, an imidazole derivative that inhibits the vitamin D-1-hydroxylase, in infants with idiopathic hypercalcemia, and hypercalciuria. STUDY DESIGN Twenty infants (4 days-17 months) with hypercalcemia, severe hypercalciuria, and low parathyroid hormone level, (10 had nephrocalcinosis), including 10 treated with ketoconazole (3-9 mg/kg/day), were followed to the age of 2 to 51 months. Vitamin D receptor expression (VDR), 24-hydroxylase activity, and functional gene polymorphisms of vitamin D metabolism regulators VDR(rs4516035), 1-hydroxylase(rs10877012), 24-hydroxylase(rs2248359), FGF23(rs7955866), Klotho(rs9536314, rs564481, rs648202), were evaluated. RESULTS Serum calcium levels, which occurred faster in the ketoconazole group (0.7 +/- 0.2 versus 2.4 +/- 0.6 months; P = .0076), and urinary calcium excretion (2.5 +/- 0.5 versus 4.2 +/- 1.7 months) normalized in all patients. Serum 1,25-(OH)2D levels were high normal and positively correlated to 25-(OH)D levels. Serum 24,25-(OH)2D levels were low normal, and skin fibroblasts from 1 patient showed defective up-regulation of the 24-hydroxylase by 1,25-(OH)2D despite normal VDR binding ability. An abnormally low prevalence of haplotype CC/CC for H589H/A749A in Klotho gene was found in patients and family members. CONCLUSIONS Ketoconazole is a potentially useful and safe agent for treatment of infantile hypercalcemia. Abnormal vitamin D metabolism is suggested as the mechanism, possibly involving defective up-regulation of the 24-hydroxylase by 1,25-(OH)2D3, and the klotho-FGF23 axis.
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Lameris ALL, Huybers S, Burke JR, Monnens LA, Bindels RJM, Hoenderop JGJ. Involvement of claudin 3 and claudin 4 in idiopathic infantile hypercalcaemia: a novel hypothesis? Nephrol Dial Transplant 2010; 25:3504-9. [PMID: 20466674 DOI: 10.1093/ndt/gfq221] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Idiopathic infantile hypercalcaemia (IIH) is a rare disease that generally resolves spontaneously between the age of 1 and 3 years. Similar symptoms may occur in patients suffering from Williams-Beuren syndrome (WBS), which is caused by a microdeletion on chromosome 7. Two of the genes, named CLDN3 and CLDN4, located within this region are members of the claudin family that has been shown to be involved in paracellular calcium (Ca(2+)) absorption. Based on the hemizygous loss of CLDN3 and CLDN4 in WBS and the function of these genes in paracellular Ca(2+) transport, we hypothesized that mutations in CLDN3 or CLDN4 could also be involved in IIH. METHODS Biochemical characteristics, including calciotropic hormone levels, were obtained from three typical IIH patients. CLDN3 and CLDN4 sequences were also analysed in these patients. The major intestinal Ca(2+) transporter TRPV6 was also screened for the presence of mutations, since hypercalcaemia in IIH and WBS has been shown to result from intestinal hyperabsorption. All three patients were also analysed for the presence of deletions or duplications using a single-nucleotide polymorphism (SNP) array for genomic DNA. RESULTS The serum Ca(2+) levels of patients were 2.9, 3.3 and 3.8 mmol/L (normal <2.7 mmol/L). Levels of 25-hydroxyvitamin D(3) and 1,25-dihydroxyvitamin D(3) were normal, parathyroid hormone (PTH) and PTH-related peptide (PTHrP) levels were appropriately low. Sequencing of coding regions and intron-exon boundaries did not reveal mutations in CLDN3, CLDN4 and TRPV6. Identified SNPs were not correlated with the disease phenotype. A SNP array did not reveal genomic deletions or duplications. CONCLUSIONS Biochemical analysis did not reveal inappropriate levels of calciotropic hormones in IIH patients in this study. Furthermore, based on the lack of mutations in CLDN3, CLDN4 and TRPV6, we conclude that IIH is neither caused by mutations in these candidate genes nor by deletions or duplications in the genome of these patients.
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Affiliation(s)
- Anke L L Lameris
- Department of Physiology, Radboud University Nijmegen Medical Centre, The Netherlands
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11
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Abstract
The current recommended dietary requirement for vitamin D intake (200 IU/d) during pregnancy and lactation is based on little, if any, scientific evidence, and as a result is clinically irrelevant with respect to maintaining nutritional vitamin D status during these demanding human conditions. Current research has shown that the actual dietary requirement during pregnancy and lactation may actually be as high as 6000 IU/d. Current data on which these new recommendations could be based are presented.
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Huang J, Coman D, McTaggart SJ, Burke JR. Long-term follow-up of patients with idiopathic infantile hypercalcaemia. Pediatr Nephrol 2006; 21:1676-80. [PMID: 16932902 DOI: 10.1007/s00467-006-0217-0] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/10/2005] [Revised: 04/24/2006] [Accepted: 04/26/2006] [Indexed: 11/24/2022]
Abstract
Idiopathic infantile hypercalcaemia (IIH) is a rare disorder of unknown etiology that presents with hypercalcaemia in a child's first year of life. There is only a limited number of published reports of the natural history of this condition, and the long-term prognosis is largely unknown. The presentation, treatment and long-term follow-up of 11 children with IIH treated at our institution since 1993 are described. Hypercalcaemia resolved in the majority of children by the time they were 3 years of age, but nephrocalcinosis and persistent hypercalciuria were common, and, in some cases, urinary calcium excretion increased after initially becoming normal. This study suggests that clinical and biochemical abnormalities may persist for longer than previously reported and implies the need for ongoing surveillance of patients with IIH.
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Affiliation(s)
- Jianping Huang
- Queensland Child and Adolescent Renal Service, Royal Children's Hospital and Mater Children's Hospitals, Brisbane, Queensland, Australia
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Cagle AP, Waguespack SG, Buckingham BA, Shankar RR, Dimeglio LA. Severe infantile hypercalcemia associated with Williams syndrome successfully treated with intravenously administered pamidronate. Pediatrics 2004; 114:1091-5. [PMID: 15466114 DOI: 10.1542/peds.2003-1146-l] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Infantile hypercalcemia occurs in approximately 15% of children with Williams syndrome (WS) and is typically not clinically severe. We report on 3 children with WS (confirmed with fluorescent in situ hybridization probes) who presented with severe symptomatic hypercalcemia. The first patient's severe hypercalcemia resolved with traditional therapies, whereas the subsequent 2 patients were treated with intravenously administered pamidronate after traditional measures proved only partially successful. Besides asymptomatic mild hypocalcemia, there were no complications resulting from pamidronate administration. We conclude that WS-associated hypercalcemia can be quite severe and symptomatic and that it can be successfully and safely treated with intravenously administered bisphosphonate in some cases.
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Affiliation(s)
- Andrew P Cagle
- Department of Pediatrics, Section of Pediatric Endocrinology and Diabetology, Indiana University School of Medicine, Indianapolis, Indiana, USA
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Abstract
Disturbances in mineral homeostasis are common in the neonatal period, especially in premature infants and infants who are hospitalised in an intensive care unit. In many cases these disturbances are thought to be exaggerated responses to the normal physiological transition from the intrauterine environment to neonatal independence. By contrast, some disturbances in calcium homeostasis are the result of genetic defects, which in many instances can now be identified at the molecular level. In other cases hypocalcaemia or hypercalcaemia may result from pathological intrauterine conditions, birth trauma or stress, or fetal immaturity. Diagnosis and management of hypocalcaemia and hypercalcaemia in the neonate and infant requires specific knowledge of perinatal mineral physiology and the unique clinical and biochemical features of newborn mineral metabolism. In this chapter we will provide a brief overview of calcium metabolism with an emphasis on the neonatal transition, followed by discussion of the common causes of hypercalcaemia and hypocalcaemia.
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Affiliation(s)
- Stephanie C Hsu
- Department of Pediatrics, The John Hopkins University, Baltimore, MD 21287, USA
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