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Lenherr-Taube N, Furman M, Assor E, Thummel K, Levine MA, Sochett E. Rifampin monotherapy for children with idiopathic infantile hypercalcemia. J Steroid Biochem Mol Biol 2023; 231:106301. [PMID: 36990163 PMCID: PMC10441173 DOI: 10.1016/j.jsbmb.2023.106301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Revised: 03/09/2023] [Accepted: 03/26/2023] [Indexed: 03/29/2023]
Abstract
Idiopathic Infantile Hypercalcemia (IIH) is characterized by hypercalcemia and hypercalciuria owing to PTH-independent increases in circulating concentrations of 1,25(OH)2D. At least 3 forms of IHH can be distinguished genetically and mechanistically: infantile hypercalcemia-1 (Hypercalcemia, Infantile, 1; HCINF1) due to CYP24A1 mutations results in decreased inactivation of 1,25(OH)2D; HCINF2 due to SLC34A1 mutations results in excessive 1,25(OH)2D production; and HCINF3 in which a variety of gene variants of uncertain significance (VUS) have been identified and where the mechanism for increased 1,25 (OH)2D is unclear. Conventional management with dietary calcium and vitamin D restriction has only limited success. Induction of the P450 enzyme CYP3A4 by rifampin can provide an alternate pathway for inactivation of 1,25(OH)2D that is useful in HCINF1 and may be effective in other forms of IIH. We sought to assess the efficacy of rifampin to decrease levels of serum 1,25(OH)2D and calcium, and urinary calcium concentrations in subjects with HCINF3, and to compare the response to a control subject with HCINF1. Four subjects with HCINF3 and the control subject with HCINF1 completed the study using rifampin 5 mg/kg/day and 10 mg/kg/day each for 2 months separated by a 2-month washout period. Patients had age-appropriate intake of dietary calcium plus 200 IU vitamin D/day. Primary outcome was efficacy of rifampin to lower serum concentrations of 1,25(OH)2D. The secondary outcomes included the reduction of serum calcium, urinary calcium excretion (as random urine calcium: creatinine (ca:cr) ratio) and serum 1,25(OH)2D/PTH ratio. Rifampin was well tolerated and induced CYP3A4 at both doses in all subjects. The control subject with HCINF1 showed significant response to both rifampin doses with decreases in the serum concentration of 1,25(OH)2D and the 1,25(OH)2D/PTH ratio while the serum and urine ca:cr levels were unchanged. The four patients with HCINF3 showed reductions in 1,25(OH)2D and urinary ca:cr after 10 mg/kg/d, but hypercalcemia did not improve and there were variable responses in 1,25(OH)2D/PTH ratios. These results support further longer-term studies to clarify the usefulness of rifampin as a medical therapy for IIH.
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Affiliation(s)
- Nina Lenherr-Taube
- Department of Pediatrics, Division of Endocrinology, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada; Department of Pediatrics, Division of Endocrinology, University Children's Hospital Zurich, Zurich, Switzerland.
| | - Michelle Furman
- Department of Pediatrics, Division of Endocrinology, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
| | - Esther Assor
- Department of Pediatrics, Division of Endocrinology, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
| | - Kenneth Thummel
- Department of Pharmaceutics, University of Washington, Seattle, WA, United States
| | - Michael A Levine
- Division of Endocrinology and Diabetes, The Children's Hospital of Philadelphia and Department of Pediatrics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, United States
| | - Etienne Sochett
- Department of Pediatrics, Division of Endocrinology, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
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St-Arnaud R, Arabian A, Kavame D, Kaufmann M, Jones G. Vitamin D and Diseases of Mineral Homeostasis: A Cyp24a1 R396W Humanized Preclinical Model of Infantile Hypercalcemia Type 1. Nutrients 2022; 14:nu14153221. [PMID: 35956396 PMCID: PMC9370611 DOI: 10.3390/nu14153221] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Revised: 08/03/2022] [Accepted: 08/04/2022] [Indexed: 11/17/2022] Open
Abstract
Infantile hypercalcemia type 1 (HCINF1), previously known as idiopathic infantile hypercalcemia, is caused by mutations in the 25-hydroxyvitamin D 24-hydroxylase gene, CYP24A1. The R396W loss-of-function mutation in CYP24A1 is the second most frequent mutated allele observed in affected HCINF1 patients. We have introduced the site-specific R396W mutation within the murine Cyp24a1 gene in knock-in mice to generate a humanized model of HCINF1. On the C57Bl6 inbred background, homozygous mutant mice exhibited high perinatal lethality with 17% survival past weaning. This was corrected by crossbreeding to the CD1 outbred background. Mutant animals had hypercalcemia in the first week of life, developed nephrolithiasis, and had a very high 25(OH)D3 to 24,25(OH)2D3 ratio which is a diagnostic hallmark of the HCINF1 condition. Expression of the mutant Cyp24a1 allele was highly elevated while Cyp27b1 expression was abrogated. Impaired bone fracture healing was detected in CD1-R396w/w mutant animals. The augmented lethality of the C57Bl6-R396W strain suggests an influence of distinct genetic backgrounds. Our data point to the utility of unique knock-in mice to probe the physiological ramifications of CYP24A1 variants in isolation from other biological and environmental factors.
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Affiliation(s)
- René St-Arnaud
- Research Centre, Shriners Hospital for Children-Canada, Montreal, QC H4A 0A9, Canada
- Department of Human Genetics, Faculty of Medicine and Health Sciences, McGill University, Montreal, QC H3A 0C7, Canada
- Department of Surgery, Faculty of Medicine and Health Sciences, McGill University, Montreal, QC H3G 1A4, Canada
- Department of Medicine, Faculty of Medicine and Health Sciences, McGill University, Montreal, QC H3A 1A1, Canada
- Correspondence: ; Tel.: +1-514-282-7155; Fax: +1-514-842-5581
| | - Alice Arabian
- Research Centre, Shriners Hospital for Children-Canada, Montreal, QC H4A 0A9, Canada
| | - Dila Kavame
- Research Centre, Shriners Hospital for Children-Canada, Montreal, QC H4A 0A9, Canada
- Department of Human Genetics, Faculty of Medicine and Health Sciences, McGill University, Montreal, QC H3A 0C7, Canada
| | - Martin Kaufmann
- Department of Biomedical and Molecular Sciences, Queen’s University, Kingston, ON K7L 3N6, Canada
- Department of Surgery, Queen’s University, Kingston, ON K7L 3N6, Canada
| | - Glenville Jones
- Department of Biomedical and Molecular Sciences, Queen’s University, Kingston, ON K7L 3N6, Canada
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Gorvin CM. Genetic causes of neonatal and infantile hypercalcaemia. Pediatr Nephrol 2022; 37:289-301. [PMID: 33990852 PMCID: PMC8816529 DOI: 10.1007/s00467-021-05082-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Revised: 03/25/2021] [Accepted: 04/06/2021] [Indexed: 12/02/2022]
Abstract
The causes of hypercalcaemia in the neonate and infant are varied, and often distinct from those in older children and adults. Hypercalcaemia presents clinically with a range of symptoms including failure to thrive, poor feeding, constipation, polyuria, irritability, lethargy, seizures and hypotonia. When hypercalcaemia is suspected, an accurate diagnosis will require an evaluation of potential causes (e.g. family history) and assessment for physical features (such as dysmorphology, or subcutaneous fat deposits), as well as biochemical measurements, including total and ionised serum calcium, serum phosphate, creatinine and albumin, intact parathyroid hormone (PTH), vitamin D metabolites and urinary calcium, phosphate and creatinine. The causes of neonatal hypercalcaemia can be classified into high or low PTH disorders. Disorders associated with high serum PTH include neonatal severe hyperparathyroidism, familial hypocalciuric hypercalcaemia and Jansen's metaphyseal chondrodysplasia. Conditions associated with low serum PTH include idiopathic infantile hypercalcaemia, Williams-Beuren syndrome and inborn errors of metabolism, including hypophosphatasia. Maternal hypocalcaemia and dietary factors and several rare endocrine disorders can also influence neonatal serum calcium levels. This review will focus on the common causes of hypercalcaemia in neonates and young infants, considering maternal, dietary, and genetic causes of calcium dysregulation. The clinical presentation and treatment of patients with these disorders will be discussed.
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Affiliation(s)
- Caroline M. Gorvin
- Institute of Metabolism and Systems Research and Centre for Endocrinology, Diabetes and Metabolism, University of Birmingham, Birmingham, B15 2TT UK ,Centre of Membrane Proteins and Receptors (COMPARE), Universities of Birmingham and Nottingham, Birmingham, B15 2TT UK
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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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Lenherr-Taube N, Furman M, Assor E, Elia Y, Collins C, Thummel K, Levine MA, Sochett E. Mild Idiopathic Infantile Hypercalcemia-Part 2: A Longitudinal Observational Study. J Clin Endocrinol Metab 2021; 106:2938-2948. [PMID: 34139759 PMCID: PMC8475233 DOI: 10.1210/clinem/dgab432] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Indexed: 11/19/2022]
Abstract
CONTEXT Idiopathic infantile hypercalcemia (IIH) is an uncommon disorder with variable clinical features. The natural history and response to dietary calcium and vitamin D restriction in IIH remains unclear. OBJECTIVE The aim of this study is to describe the clinical and biochemical response to dietary calcium and vitamin D restriction in a genetically characterized cohort of mild IIH. METHODS This is a longitudinal, observational cohort study of 20 children with mild IIH monitored for a median of 21months. Biochemical measures, dietary assessment, and yearly renal ultrasound results, since the time of diagnosis, were obtained and assessed prospectively every 4 to 6 months. RESULTS Median age at initial diagnosis was 4.5 months. Median levels of serum calcium (2.82 mmol/L) and 1,25 (OH)2D (192 pmol/L) were elevated, whereas serum PTH was reduced (10 ng/L). Urinary calcium:creatinine ratio was elevated for some, but not all individuals (median 1.49 mmol/mmol). All patients who were managed with a low-calcium diet showed an improvement in serum and urinary calcium measures, but the serum concentration of 1,25 dihydroxyvitamin D (1,25(OH)2D) and 1,25(OH)2D/PTH ratio remained elevated. In 2 of the 11 subjects, renal calcification worsened. There were no differences in response between individuals with CYP24A1 or SLC34A1/A3 variants. CONCLUSION The clinical presentation of mild IIH is variable, and dietary calcium and vitamin D restriction does not consistently normalize elevated 1,25(OH)2D concentrations or prevent worsening of renal calcification in all cases. Therapeutic options should target the defect in vitamin D metabolism.
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Affiliation(s)
- Nina Lenherr-Taube
- Department of Pediatrics, Division of Endocrinology, Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
| | - Michelle Furman
- Department of Pediatrics, Division of Endocrinology, Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
| | - Esther Assor
- Department of Pediatrics, Division of Endocrinology, Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
| | - Yesmino Elia
- Department of Pediatrics, Division of Endocrinology, Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
| | - Carol Collins
- Department of Pharmaceutics, University of Washington, Seattle, WA, USA
| | - Kenneth Thummel
- Department of Pharmaceutics, University of Washington, Seattle, WA, USA
| | - Michael A Levine
- Division of Endocrinology and Diabetes, The Children’s Hospital of Philadelphia and Department of Pediatrics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Etienne Sochett
- Department of Pediatrics, Division of Endocrinology, Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
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Janiec A, Halat-Wolska P, Obrycki Ł, Ciara E, Wójcik M, Płudowski P, Wierzbicka A, Kowalska E, Książyk JB, Kułaga Z, Pronicka E, Litwin M. Long-term outcome of the survivors of infantile hypercalcaemia with CYP24A1 and SLC34A1 mutations. Nephrol Dial Transplant 2021; 36:1484-1492. [PMID: 33099630 PMCID: PMC8311581 DOI: 10.1093/ndt/gfaa178] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2020] [Accepted: 05/25/2020] [Indexed: 11/12/2022] Open
Abstract
Background Infantile hypercalcaemia (IH) is a vitamin D3 metabolism disorder. The molecular basis for IH is biallelic mutations in the CYP24A1 or SLC34A1 gene. These changes lead to catabolism disorders (CYP24A1 mutations) or excessive generation of 1,25-dihydroxyvitamin D3 [1,25(OH)2D3] (SLC34A1 mutations). The incidence rate of IH in children and the risk level for developing end-stage renal disease (ESRD) are still unknown. The aim of this study was to analyse the long-term outcome of adolescents and young adults who suffered from IH in infancy. Design Forty-two children (23 girls; average age 10.7 ± 6.3 years) and 26 adults (14 women; average age 24.2 ± 4.4 years) with a personal history of hypercalcaemia with elevated 1,25(OH)2D3 levels were included in the analysis. In all patients, a genetic analysis of possible IH mutations was conducted, as well as laboratory tests and renal ultrasonography. Results IH was confirmed in 20 studied patients (10 females). CYP24A1 mutations were found in 16 patients (8 females) and SLC34A1 in 4 patients (2 females). The long-term outcome was assessed in 18 patients with an average age of 23.8 years (age range 2–34). The average glomerular filtration rate (GFR) was 72 mL/min/1.73 m2 (range 15–105). Two patients with a CYP24A1 mutation developed ESRD and underwent renal transplantation. A GFR <90 mL/min/1.73 m2 was found in 14 patients (77%), whereas a GFR <60 mL/min/1.73 m2 was seen in 5 patients (28%), including 2 adults after renal transplantation. Three of 18 patients still had serum calcium levels >2.6 mmol/L. A renal ultrasound revealed nephrocalcinosis in 16 of 18 (88%) patients, however, mild hypercalciuria was detected in only one subject. Conclusions Subjects who suffered from IH have a greater risk of progressive chronic kidney disease and nephrocalcinosis. This indicates that all survivors of IH should be closely monitored, with early implementation of preventive measures, e.g. inhibition of active metabolites of vitamin D3 synthesis.
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Affiliation(s)
- Agnieszka Janiec
- Department of Paediatrics, Nutrition and Metabolic Diseases, Children's Memorial Health Institute, Warsaw, Poland
| | - Paulina Halat-Wolska
- Department of Medical Genetics, Children's Memorial Health Institute, Warsaw, Poland
| | - Łukasz Obrycki
- Department of Nephrology, Kidney Transplantation and Arterial Hypertension, Children's Memorial Health Institute, Warsaw, Poland
| | - Elżbieta Ciara
- Department of Medical Genetics, Children's Memorial Health Institute, Warsaw, Poland
| | - Marek Wójcik
- Department of Biochemistry, Radioimmunology and Experimental Medicine, Children's Memorial Health Institute, Warsaw, Poland
| | - Paweł Płudowski
- Department of Biochemistry, Radioimmunology and Experimental Medicine, Children's Memorial Health Institute, Warsaw, Poland
| | - Aldona Wierzbicka
- Department of Biochemistry, Radioimmunology and Experimental Medicine, Children's Memorial Health Institute, Warsaw, Poland
| | - Ewa Kowalska
- Department of Biochemistry, Radioimmunology and Experimental Medicine, Children's Memorial Health Institute, Warsaw, Poland
| | - Janusz B Książyk
- Department of Paediatrics, Nutrition and Metabolic Diseases, Children's Memorial Health Institute, Warsaw, Poland
| | - Zbigniew Kułaga
- Department of Public Health, Children's Memorial Health Institute, Warsaw, Poland
| | - Ewa Pronicka
- Department of Paediatrics, Nutrition and Metabolic Diseases, Children's Memorial Health Institute, Warsaw, Poland.,Department of Medical Genetics, Children's Memorial Health Institute, Warsaw, Poland
| | - Mieczysław Litwin
- Department of Nephrology, Kidney Transplantation and Arterial Hypertension, Children's Memorial Health Institute, Warsaw, Poland
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Kowalska E, Rola R, Wójcik M, Łaszcz N, Płudowski P, Wierzbicka A, Janiec A, Książyk J, Halat P, Ciara E, Obrycki Ł, Pronicka E, Litwin M. Analysis of vitamin D 3 metabolites in survivors of infantile idiopathic hypercalcemia caused by CYP24A1 mutation or SLC34A1 mutation. J Steroid Biochem Mol Biol 2021; 208:105824. [PMID: 33516786 DOI: 10.1016/j.jsbmb.2021.105824] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/28/2020] [Revised: 12/06/2020] [Accepted: 01/14/2021] [Indexed: 12/24/2022]
Abstract
UNLABELLED Infantile hypercalcemia (IH), is a rare disorder caused by CYP24A1 or SLC34A1 variants which lead to disturbed catabolism of 25(OH)D3 and 125(OH)2D3 or increased generation of 125(OH)2D3. AIM OF STUDY To assess the status of 2425(OH)2D3 and other markers of vitamin D in IH survivors, in whom variants of CYP24A1 or SLC34A1 gene were found and to compare these unique biochemical features with those obtained from subjects who were diagnosed in the first year of life with hypercalcemia, elevated 25(OH)D3 and low PTH but in whom neither CYP24A1 nor SLC34A1 variant was found. PATIENTS AND METHODS 16 IH survivors in whom CYP24A1 (n = 13) or SLC34A1 (n = 3) variants were found and 41 subjects in whom hypercalcemia was diagnosed in the first year of life but in whom CYP24A1 or SLC34A1 variants were not found were included in the study. 25(OH)D3, 3-epi-25(OH)D3, 25(OH)D2, 2425(OH)2D3 were assessed by liquid chromatography coupled with tandem mass spectrometry. 125(OH)2D3 concentrations were assessed by chemiluminescence. RESULTS Subjects with CYP24A1 variants, despite normal 25(OH)D3 levels, had higher 25(OH)D3/2425(OH)2D3 ratio values (487; 265-1073 ng/mL) when compared to subjects with SLC34A1 variants (16; 16-23 ng/mL) and with subjects in whom CYP24A1 or SLC34A1 were not found (56; 9-56 ng/mL) (p = 0.00003). Separation of interfering metabolite further increased differences between subjects with and without CYP24A1 mutation. CONCLUSIONS Survivors of IH with CYP24A1 variant, despite being normocalcemic, still presented extremely high 25(OH)D3/2425(OH)2D3 ratio values. Separation of interfering compound further increased differences between subjects with CYP24A1 mutation and without this mutation.
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Affiliation(s)
- Ewa Kowalska
- Department of Biochemistry, Radioimmunology and Experimental Medicine, The Children's Memorial Health Institute, Warsaw, Poland
| | - Rafał Rola
- Department of Biochemistry, Radioimmunology and Experimental Medicine, The Children's Memorial Health Institute, Warsaw, Poland
| | - Marek Wójcik
- Department of Biochemistry, Radioimmunology and Experimental Medicine, The Children's Memorial Health Institute, Warsaw, Poland
| | - Natalia Łaszcz
- Department of Biochemistry, Radioimmunology and Experimental Medicine, The Children's Memorial Health Institute, Warsaw, Poland
| | - Paweł Płudowski
- Department of Biochemistry, Radioimmunology and Experimental Medicine, The Children's Memorial Health Institute, Warsaw, Poland
| | - Aldona Wierzbicka
- Department of Biochemistry, Radioimmunology and Experimental Medicine, The Children's Memorial Health Institute, Warsaw, Poland
| | - Agnieszka Janiec
- Department of Pediatrics and Nutrition, The Children's Memorial Health Institute, Warsaw, Poland
| | - Janusz Książyk
- Department of Pediatrics and Nutrition, The Children's Memorial Health Institute, Warsaw, Poland
| | - Paulina Halat
- Department of Medical Genetics, The Children's Memorial Health Institute, Warsaw, Poland
| | - Elżbieta Ciara
- Department of Medical Genetics, The Children's Memorial Health Institute, Warsaw, Poland
| | - Łukasz Obrycki
- Department of Nephrology and Arterial Hypertension, The Children's Memorial Health Institute, Warsaw, Poland
| | - Ewa Pronicka
- Department of Medical Genetics, The Children's Memorial Health Institute, Warsaw, Poland
| | - Mieczysław Litwin
- Department of Nephrology and Arterial Hypertension, The Children's Memorial Health Institute, Warsaw, Poland.
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Wójcik M, Jaworski M, Pludowski P. 25(OH)D Concentration in Neonates, Infants, and Toddlers From Poland-Evaluation of Trends During Years 1981-2011. Front Endocrinol (Lausanne) 2018; 9:656. [PMID: 30467494 PMCID: PMC6235911 DOI: 10.3389/fendo.2018.00656] [Citation(s) in RCA: 3] [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: 04/18/2018] [Accepted: 10/19/2018] [Indexed: 11/13/2022] Open
Abstract
Introduction: The numerous evidence showing spectrum of vitamin D effects on human health resulted in both updates of vitamin D supplementation guidelines for general population and concerns on potential risk of hypercalcaemia. The aim of this study was to analyse trends in serum 25-hydroxyvitamin D concentration (25(OH)D) change over the 30 years of operation of a single pediatric diagnostic unit. Materials and methods: Calcium-phosphate metabolism markers and 25(OH)D concentrations were analyzed in a group that consisted of newborns and infants commissioned for diagnostics due to suspected calcium-phosphate metabolic disturbances (n = 3,163; mean age 8.0 ± 3.0 months). Results: 25(OH)D < 10 ng/ml was noted in 4.5% of patients (n = 163), 10-20 ng/ml in 14.7% (n = 465), 20-30 ng/ml in 23.9% (n = 756) and 30-50 ng/ml in 35.9% (n = 1,136). The mean 25(OH)D concentration in analyzed group was 37.5 ± 24.5 ng/ml. In patients with 25(OH)D concentration < 10 ng/ml a normal calcaemia (2.25-2.65 mmol/l) was noted in 83.4% cases (n = 136). Eighty one patients had 25(OH)D concentrations above 100 ng/ml with co-existing calcaemia in range of 2.6-4.38 mmol/l (mean Ca = 2.69 mmol/l). Hypocalcaemia (Ca < 2.25 mmol/l) was observed in 0.54%, (n = 17). 13.8% patients revealed calcium levels >2.65 mmol/l (n = 435). In general, the mean calcium-phosphate markers values were within the reference range for age. The highest mean 25(OH)D concentration of 51.8 ng/ml ± 38.8 was noted in years 1981-1999 (n = 305). The lowest mean 25(OH)D value was observed in years 2010-2011 (29.0 ng/ml ± 13.6; n = 412). The trend of decreasing 25(OH)D concentration during analyzed time period was significant (r = -0.29, p < 0.0001). Conclusions: Eighty percentage of children aged 0-36 months had 25(OH)D concentration >20 ng/ml, however, during 3 decades a mean 25(OH)D concentrations trended significantly to decrease. A direct relationship between low 25(OH)D concentration and hypocalcaemia was not observed nor between high 25(OH)D concentration and hypercalcemia.
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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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Pronicka E, Ciara E, Halat P, Janiec A, Wójcik M, Rowińska E, Rokicki D, Płudowski P, Wojciechowska E, Wierzbicka A, Książyk JB, Jacoszek A, Konrad M, Schlingmann KP, Litwin M. Biallelic mutations in CYP24A1 or SLC34A1 as a cause of infantile idiopathic hypercalcemia (IIH) with vitamin D hypersensitivity: molecular study of 11 historical IIH cases. J Appl Genet 2017; 58:349-353. [PMID: 28470390 PMCID: PMC5509812 DOI: 10.1007/s13353-017-0397-2] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Revised: 03/19/2017] [Accepted: 04/17/2017] [Indexed: 11/08/2022]
Abstract
Idiopathic infantile hypercalcemia (IIH) is a mineral metabolism disorder characterized by severe hypercalcemia, failure to thrive, vomiting, dehydration, and nephrocalcinosis. The periodical increase in incidence of IIH, which occurred in the twentieth century in the United Kingdom, Poland, and West Germany, turned out to be a side effect of rickets over-prophylaxis. It was recently discovered that the condition is linked to two genes, CYP24A1 and SLC34A1. The aim of the study was to search for pathogenic variants of the genes in adult persons who were shortlisted in infancy as IIH caused by “hypersensitivity to vit. D”. All persons were found to carry mutations in CYP24A1 or SLC34A1, nine and two persons respectively. The changes were biallelic, with one exception. Incidence of IIH in Polish population estimated on the basis of allele frequency of recurrent p.R396W CYP24A1 variant, is 1:32,465 births. It indicates that at least a thousand homozygotes and compound heterozygotes with risk of IIH live in the country. Differences in mechanism of developing hypercalcemia indicate that its prevention may vary in both IIH defects. Theoretically, vit. D restriction is a first indication for CYP24A1 defect (which disturbs 1,25(OH)2D degradation) and phosphate supplementation for SLC34A1 defect (which impairs renal phosphate transport). In conclusion, we suggest that molecular testing for CYP24A1 and SLC34A1 mutations should be performed in each case of idiopathic hypercalcemia/hypercalciuria, both in children and adults, to determine the proper way for acute treatment and complications prevention.
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Affiliation(s)
- Ewa Pronicka
- Department of Pediatrics, Nutrition and Metabolic Diseases, The Children's Memorial Health Institute, Aleja Dzieci Polskich 20, 04-730, Warsaw, Poland. .,Department of Medical Genetics, The Children's Memorial Health Institute, Warsaw, Poland.
| | - Elżbieta Ciara
- Department of Medical Genetics, The Children's Memorial Health Institute, Warsaw, Poland
| | - Paulina Halat
- Department of Medical Genetics, The Children's Memorial Health Institute, Warsaw, Poland
| | - Agnieszka Janiec
- Department of Pediatrics, Nutrition and Metabolic Diseases, The Children's Memorial Health Institute, Aleja Dzieci Polskich 20, 04-730, Warsaw, Poland
| | - Marek Wójcik
- Department of Biochemistry, Radioimmunology and Experimental Medicine, The Children's Memorial Health Institute, Warsaw, Poland
| | - Elżbieta Rowińska
- Department of Pediatrics, Nutrition and Metabolic Diseases, The Children's Memorial Health Institute, Aleja Dzieci Polskich 20, 04-730, Warsaw, Poland
| | - Dariusz Rokicki
- Department of Pediatrics, Nutrition and Metabolic Diseases, The Children's Memorial Health Institute, Aleja Dzieci Polskich 20, 04-730, Warsaw, Poland
| | - Paweł Płudowski
- Department of Biochemistry, Radioimmunology and Experimental Medicine, The Children's Memorial Health Institute, Warsaw, Poland
| | - Ewa Wojciechowska
- Department of Nephrology, The Children's Memorial Health Institute, Warsaw, Poland
| | - Aldona Wierzbicka
- Department of Biochemistry, Radioimmunology and Experimental Medicine, The Children's Memorial Health Institute, Warsaw, Poland
| | - Janusz B Książyk
- Department of Pediatrics, Nutrition and Metabolic Diseases, The Children's Memorial Health Institute, Aleja Dzieci Polskich 20, 04-730, Warsaw, Poland
| | - Agnieszka Jacoszek
- Department of Medical Genetics, Warsaw Medical University, Warsaw, Poland.,Postgraduate School of Molecular Medicine, Warsaw, Poland
| | | | | | - Mieczysław Litwin
- Department of Nephrology, The Children's Memorial Health Institute, Warsaw, Poland
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11
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Fencl F, Bláhová K, Schlingmann KP, Konrad M, Seeman T. Severe hypercalcemic crisis in an infant with idiopathic infantile hypercalcemia caused by mutation in CYP24A1 gene. Eur J Pediatr 2013; 172:45-9. [PMID: 23001465 DOI: 10.1007/s00431-012-1818-1] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/20/2012] [Revised: 08/21/2012] [Accepted: 08/26/2012] [Indexed: 01/08/2023]
Abstract
UNLABELLED We report on a male infant presenting at 4 months of age with failure to thrive, dehydration, hypotonia, lethargy, and vomiting. Laboratory and imaging tests revealed severe hypercalcemia (5.8 mmol/l), suppressed parathyroid hormone (0.41 pmol/l), hypercalciuria (8.0 mmol/mmol creatinine), elevated 25-hydroxyvitamin D3 (over 600 nmol/l), and nephrocalcinosis. These symptoms are characteristic of idiopathic infantile hypercalcemia (IIH, MIM 143880). Conservative therapy (parenteral rehydration, diuretics, corticosteroids, bisphosphonates, and vitamin D prophylaxis withdrawal) was not able to improve the symptoms and laboratory values, and acute hemodiafiltration was necessary to normalize hypercalcemia. Clinical symptoms resolved rapidly after normalization of serum calcium levels. Molecular genetic testing revealed a homozygous mutation (R396W) in the CYP24A1 gene (MIM 126065) encoding 25-hydroxyvitamin D3 24-hydroxylase, which is the key enzyme responsible for 1,25-dihydroxyvitamin D3 degradation. The CYP24A1 gene mutation leads to the increased sensitivity of the patients to even prophylactic doses of vitamin D and to the development of severe symptomatic hypercalcemia in patients with IIH. CONCLUSION Our patient is only the thirteenth patient with IIH caused by mutation in the CYP24A1 gene and the first one needing acute hemodiafiltration for severe symptomatic hypercalcemic crisis. In all patients with suspected IIH the DNA analysis for CYP24A1 gene mutations should be performed regardless of the type of vitamin D supplementation and serum levels of vitamin D.
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Affiliation(s)
- Filip Fencl
- Department of Paediatrics, 2nd Faculty of Medicine, Charles University in Prague, Prague, Czech Republic.
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12
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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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13
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Schlingmann KP, Kaufmann M, Weber S, Irwin A, Goos C, John U, Misselwitz J, Klaus G, Kuwertz-Bröking E, Fehrenbach H, Wingen AM, Güran T, Hoenderop JG, Bindels RJ, Prosser DE, Jones G, Konrad M. Mutations in CYP24A1 and idiopathic infantile hypercalcemia. N Engl J Med 2011; 365:410-21. [PMID: 21675912 DOI: 10.1056/nejmoa1103864] [Citation(s) in RCA: 386] [Impact Index Per Article: 29.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
BACKGROUND Vitamin D supplementation for the prevention of rickets is one of the oldest and most effective prophylactic measures in medicine, having virtually eradicated rickets in North America. Given the potentially toxic effects of vitamin D, the recommendations for the optimal dose are still debated, in part owing to the increased incidence of idiopathic infantile hypercalcemia in Britain in the 1950s during a period of high vitamin D supplementation in fortified milk products. We investigated the molecular basis of idiopathic infantile hypercalcemia, which is characterized by severe hypercalcemia, failure to thrive, vomiting, dehydration, and nephrocalcinosis. METHODS We used a candidate-gene approach in a cohort of familial cases of typical idiopathic infantile hypercalcemia with suspected autosomal recessive inheritance. Identified mutations in the vitamin D-metabolizing enzyme CYP24A1 were evaluated with the use of a mammalian expression system. RESULTS Sequence analysis of CYP24A1, which encodes 25-hydroxyvitamin D 24-hydroxylase, the key enzyme of 1,25-dihydroxyvitamin D(3) degradation, revealed recessive mutations in six affected children. In addition, CYP24A1 mutations were identified in a second cohort of infants in whom severe hypercalcemia had developed after bolus prophylaxis with vitamin D. Functional characterization revealed a complete loss of function in all CYP24A1 mutations. CONCLUSIONS The presence of CYP24A1 mutations explains the increased sensitivity to vitamin D in patients with idiopathic infantile hypercalcemia and is a genetic risk factor for the development of symptomatic hypercalcemia that may be triggered by vitamin D prophylaxis in otherwise apparently healthy infants.
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14
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Koltin D, Rachmiel M, Wong BYL, Cole DEC, Harvey E, Sochett E. Mild infantile hypercalcemia: diagnostic tests and outcomes. J Pediatr 2011; 159:215-21.e1. [PMID: 21414629 DOI: 10.1016/j.jpeds.2011.01.035] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/07/2010] [Revised: 11/29/2010] [Accepted: 01/14/2011] [Indexed: 12/15/2022]
Abstract
OBJECTIVE To assess outcome in a cohort of patients with infantile hypercalcemia followed over 3 years. STUDY DESIGN Patients (n = 32) presenting to the calcium clinic between July 2002 and September 2008 were studied. In addition to tests of calcium phosphate metabolism, serum insulin-like growth factor-1, calcitonin, urine citrate, and calcium-sensing receptor gene analysis were obtained. RESULTS Mean age at presentation was 6.0 ± 6.3 months. Mean calcium level was 11.4 ± 0.7 mg/dL (2.84 ± 0.17 mmol/L). A recognized cause was found in 14% and a probable cause in 14% of the cohort. Those with nephrocalcinosis (n = 11) had significantly lower mean weight SDS and higher mean calcium levels. The biochemical profile of those in whom no cause could be determined included nonsuppressed parathyroid hormone with either normal or increased 1,25(OH)(2)D. Hypercalcemia resolved in 20 patients. However, in approximately a third, there was persistence in hypercalcemia, hypercalciuria, or nephrocalcinosis. CONCLUSIONS The addition of 1,25(OH)(2)D and calcium-sensing receptor mutation analysis to a panel of investigations may improve diagnostic yield. Clinical outcome is overall good, however, one-third need ongoing follow-up.
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Affiliation(s)
- Dror Koltin
- Division of Endocrinology, The Hospital for Sick Children, Toronto, Ontario, Canada
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15
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Schwalfenberg GK, Genuis SJ, Hiltz MN. Addressing vitamin D deficiency in Canada: a public health innovation whose time has come. Public Health 2010; 124:350-9. [PMID: 20413135 DOI: 10.1016/j.puhe.2010.03.003] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2009] [Revised: 01/20/2010] [Accepted: 03/03/2010] [Indexed: 01/04/2023]
Abstract
There is disturbing evidence of widespread vitamin D deficiency in many population groups, particularly within nations at high latitude. Numerous recent studies in the scientific literature associate vitamin D deficiency with a colossal increase in morbidity and mortality. Since Canada is at higher latitude, this review assesses the vitamin D status within the Canadian population. This review was prepared by assessing available medical and scientific literature from Medline, as well as by reviewing several books and conference proceedings. A standard 25(OH)D level of 75-80nmol/l or more was used to indicate vitamin D sufficiency. Between 70% and 97% of Canadians demonstrate vitamin D insufficiency. Furthermore, studies assessing 25(OH)D levels of vitamin D at 25-40nmol/l reveal that many Canadians have profoundly deficient levels. Repletion of vitamin D3 with 2000IU/day for those not receiving judicious sun exposure and those with no contra-indications would likely achieve normalized levels in more than 93% of patients, without risk of toxicity. Explicit directives regarding vitamin D assessment and management are urgently required.
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Affiliation(s)
- G K Schwalfenberg
- Faculty of Medicine, University of Alberta, 301, 9509-156 Street, Edmonton, Alberta T5P 4J5, Canada.
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16
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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: 9] [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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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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