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Florance JA, Schollum JBW, Pomeranc A, Endre ZH, Walker RJ. Autosomal dominant hypercalciuric hypocalcaemia: the calcium-sensing receptor in renal calcium homeostasis and the impact of renal transplantation. Intern Med J 2024; 54:852-860. [PMID: 38665051 DOI: 10.1111/imj.16403] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2024] [Accepted: 03/28/2024] [Indexed: 06/18/2024]
Abstract
Calcium-sensing receptors (CaSRs) are G protein-coupled receptors that help maintain Ca2+ concentrations, modulating calciotropic hormone release (parathyroid hormone (PTH), calcitonin and 1,25-dihydroxyvitamin D) by direct actions in the kidneys, gastrointestinal tract and bone. Variability in population calcium levels has been attributed to single nucleotide polymorphisms in CaSR genes, and several conditions affecting calcium and phosphate homeostasis have been attributed to gain- or loss-of-function mutations. An example is autosomal dominant hypercalciuric hypocalcaemia, because of a missense mutation at codon 128 of chromosome 3, as reported in our specific case and her family. As a consequence of treating symptomatic hypocalcaemia as a child, this female subject slowly developed progressive end-stage kidney failure because of nephrocalcinosis and nephrolithiasis. After kidney transplantation, she remains asymptomatic, with decreased vitamin D and elemental calcium requirements, stable fluid and electrolyte homeostasis during intercurrent illnesses and has normalised urinary calcium and phosphate excretion, reducing the likelihood of hypercalciuria-induced graft impairment. We review the actions of the CaSR, its role in regulating renal Ca2+ homeostasis along with the impact of a proven gain-of-function mutation in the CaSR gene resulting in autosomal dominant hypercalciuric hypocalcaemia before and after kidney transplantation.
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Affiliation(s)
- James A Florance
- Department of Nephrology, Dunedin Hospital, Dunedin, Otago, New Zealand
| | - John B W Schollum
- Department of Nephrology, Dunedin Hospital, Dunedin, Otago, New Zealand
| | - Abigail Pomeranc
- Department of Nephrology, Dunedin Hospital, Dunedin, Otago, New Zealand
| | - Zoltan H Endre
- Department of Nephrology, Prince of Wales Clinical School, UNSW Medicine, Sydney, New South Wales, Australia
| | - Robert J Walker
- Department of Nephrology, Dunedin Hospital, Dunedin, Otago, New Zealand
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Walker E, Hayes W, Bockenhauer D. Inherited non-FGF23-mediated phosphaturic disorders: A kidney-centric review. Best Pract Res Clin Endocrinol Metab 2024; 38:101843. [PMID: 38042745 DOI: 10.1016/j.beem.2023.101843] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/04/2023]
Abstract
Phosphate is freely filtered by the glomerulus and reabsorbed exclusively in the proximal tubule by two key transporters, NaPiIIA and NaPiIIC, encoded by SLC34A1 and SLC34A3, respectively. Regulation of these transporters occurs primarily through the hormone FGF23 and, to a lesser degree, PTH. Consequently, inherited non-FGF23 mediated phosphaturic disorders are due to generalised proximal tubular dysfunction, loss-of-function variants in SLC34A1 or SLC34A3 or excess PTH signalling. The corresponding disorders are Renal Fanconi Syndrome, Infantile Hypercalcaemia type 2, Hereditary Hypophosphataemic Rickets with Hypercalciuria and Familial Hyperparathyroidism. Several inherited forms of Fanconi renotubular syndrome (FRTS) have also been described with the underlying genes encoding for GATM, EHHADH, HNF4A and NDUFAF6. Here, we will review their pathophysiology, clinical manifestations and the implications for treatment from a kidney-centric perspective, focussing on those disorders caused by dysfunction of renal phosphate transporters. Moreover, we will highlight specific genetic aspects, as the availability of large population genetic databases has raised doubts about some of the originally proposed gene-disease associations concerning phosphate transporters or their associated proteins.
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Affiliation(s)
- Emma Walker
- Nephrology Unit, Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK
| | - Wesley Hayes
- Nephrology Unit, Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK
| | - Detlef Bockenhauer
- Nephrology Unit, Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK; Department of Renal Medicine, University College London, London, UK.
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Alshanafey S, Maqbol S, AlAmeer A, Ahmad F, Al-Ashwal A. Surgical management of neonatal severe hyperparathyroidism. Ann Saudi Med 2023; 43:352-356. [PMID: 37916585 PMCID: PMC11182428 DOI: 10.5144/0256-4947.2023.01.11.1200] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/16/2023] [Accepted: 08/15/2023] [Indexed: 11/03/2023] Open
Abstract
BACKGROUND Neonatal severe hyperparathyroidism (NSHPT) is a rare disease that can be lethal. Most patients require parathyroidectomy. OBJECTIVE Report experience in managing this severe disease. DESIGN Retrospective chart review of case series. SETTING Tertiary health care center. PATIENTS AND METHODS We reviewed data on patients managed for NSHPT from June 2001 to January 2023. Demographic, clinical, and follow-up data were collected, and descriptive data were generated. MAIN OUTCOME MEASURES Pre- and postoperative levels of parathyroid hormone (PTH) and serum calcium, and effect of autotransplantation. SAMPLE SIZE 19. RESULTS The 13 males and 6 females had a a mean age of 46 days at referral. The mean preoperative parathyroid hormone (PTH) and serum calcium levels were 996 ng/L and 4.54 mmol/L, respectively. Twelve patients underwent ultrasonography preoperatively. Of these, six had prominent glands, while no glands were seen in the other six. A Sestamibi scan was done for 15 patients, of which nine showed negative results and six showed positive results, with three glands observed in the neck and three in the sublingual area. Nineteen patients underwent renal ultrasonography, with nine showing nephrocalcinosis. The mean age at surgery was 5.2 months. Total parathyroidectomy (four glands) was performed in 17 patients, and 15 underwent concurrent auto-transplantation. One patient had three glands removed, in addition to auto-transplantation. Another underwent single gland excision as a redo-surgery after previous surgery elsewhere. The mean postoperative follow-up duration was 6 years. The mean postoperative PTH and calcium levels were 25 ng/L and 1.64 mmol/L, respectively. Ultimately, all the patients were required to initiate calcium and vitamin D supplements, except for two patients who had undergone auto-transplantation. Molecular genetic screening of the calcium-sensing receptor gene reported likely pathogenic/pathogenic mutations in 16 of 19 patients (13 were homozygous, two were heterozygous, one was negative, and data was unavailable for the remaining three patients). CONCLUSIONS Surgical treatment of NSHPT is effective. Preoperative radiological localization studies did not impact the treatment plan. Auto-transplantation proved ineffective in maintaining independence from medical supplements. LIMITATIONS The retrospective nature of the study may imply inaccuracybut since the data are gathered from electronic medical records, we believe it is highly accurate. The small sample size limits generalizability.
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Affiliation(s)
- Saud Alshanafey
- From the Department of Surgery, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia
| | - Sabreen Maqbol
- From the Academic and Training Affairs, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia
| | - Ali AlAmeer
- From the Academic and Training Affairs, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia
| | - Faiqa Ahmad
- From the Clinical Genomics, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia
| | - Abdullah Al-Ashwal
- From the Department of Pediatrics, King Faisal specialist Hospital and Research Centre, Riyadh, Saudi Arabia
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Joshi M, Uday S. Vitamin D Deficiency in Chronic Childhood Disorders: Importance of Screening and Prevention. Nutrients 2023; 15:2805. [PMID: 37375708 DOI: 10.3390/nu15122805] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Revised: 06/09/2023] [Accepted: 06/13/2023] [Indexed: 06/29/2023] Open
Abstract
Vitamin D plays a vital role in regulating calcium and phosphate metabolism and maintaining bone health. A state of prolonged or profound vitamin D deficiency (VDD) can result in rickets in children and osteomalacia in children and adults. Recent studies have demonstrated the pleiotropic action of vitamin D and identified its effects on multiple biological processes in addition to bone health. VDD is more prevalent in chronic childhood conditions such as long-standing systemic illnesses affecting the renal, liver, gastrointestinal, skin, neurologic and musculoskeletal systems. VDD superimposed on the underlying disease process and treatments that can adversely affect bone turnover can all add to the disease burden in these groups of children. The current review outlines the causes and mechanisms underlying poor bone health in certain groups of children and young people with chronic diseases with an emphasis on the proactive screening and treatment of VDD.
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Affiliation(s)
- Madhura Joshi
- Birmingham Women's and Children's Hospital, Steelhouse Lane, Birmingham B4 6NH, UK
| | - Suma Uday
- Birmingham Women's and Children's Hospital, Steelhouse Lane, Birmingham B4 6NH, UK
- Institute of Metabolism and Systems Research, University of Birmingham, Edgbaston B15 2TT, UK
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Brennan SC, Mun HC, Delbridge L, Kuchel PW, Conigrave AD. Temperature sensing by the calcium-sensing receptor. Front Physiol 2023; 14:1117352. [PMID: 36818436 PMCID: PMC9931745 DOI: 10.3389/fphys.2023.1117352] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Accepted: 01/16/2023] [Indexed: 02/05/2023] Open
Abstract
Whether GPCRs support the sensing of temperature as well as other chemical and physical modalities is not well understood. Introduction: Extracellular Ca2+ concentration (Ca2+ o) modulates core body temperature and the firing rates of temperature-sensitive CNS neurons, and hypocalcemia provokes childhood seizures. However, it is not known whether these phenomena are mediated by Ca2+ o-sensing GPCRs, including the calcium-sensing receptor (CaSR). In favor of the hypothesis, CaSRs are expressed in hypothalamic regions that support core temperature regulation, and autosomal dominant hypocalcemia, due to CaSR activating mutations, is associated with childhood seizures. Methods: Herein, we tested whether CaSR-dependent signaling is temperature sensitive using an established model system, CaSR-expressing HEK-293 cells. Results: We found that the frequency of Ca2+ o-induced Ca2+ i oscillations but not the integrated response was linearly dependent on temperature in a pathophysiologically relevant range. Chimeric receptor analysis showed that the receptor's C-terminus is required for temperature-dependent modulation and experiments with the PKC inhibitor GF109203X and CaSR mutants T888A and T888M, which eliminate a key phosphorylation site, demonstrated the importance of repetitive phosphorylation and dephosphorylation. Discussion and Conclusion: CaSRs mediate temperature-sensing and the mechanism, dependent upon repetitive phosphorylation and dephosphorylation, suggests that GPCRs more generally contribute to temperature-sensing.
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Affiliation(s)
- Sarah C. Brennan
- School of Life and Environmental Sciences, Faculty of Science, The University of Sydney, Sydney, NSW, Australia,Charles Perkins Centre, University of Sydney, Sydney, NSW, Australia
| | - Hee-chang Mun
- Charles Perkins Centre, University of Sydney, Sydney, NSW, Australia
| | - Leigh Delbridge
- Department of Surgery, Mater Hospital, North Sydney, NSW, Australia
| | - Philip W. Kuchel
- School of Life and Environmental Sciences, Faculty of Science, The University of Sydney, Sydney, NSW, Australia
| | - Arthur D. Conigrave
- School of Life and Environmental Sciences, Faculty of Science, The University of Sydney, Sydney, NSW, Australia,Charles Perkins Centre, University of Sydney, Sydney, NSW, Australia,*Correspondence: Arthur D. Conigrave,
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Sviridonova MA. [Syndrome of hypocalсiuric hypercalcemia. Is it rare? Two clinical cases in an outpatient clinic]. PROBLEMY ENDOKRINOLOGII 2022; 68:24-31. [PMID: 36337015 DOI: 10.14341/probl13125] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Revised: 06/17/2022] [Accepted: 06/17/2022] [Indexed: 11/09/2022]
Abstract
Hypocalciuric hypercalcemia syndrome (familial hypocalciuric hypercalcemia, FHH) is an inherited condition based on dysfunction of the calcium receptor or its associated partner proteins. Recent evidence suggests that the prevalence of this condition may be comparable to that of primary hyperparathyroidism. Clinical manifestations of FHH are usually absent; however the classic symptoms of hypercalcemia may be present in some cases. Timely differential diagnosis of FHH avoids unnecessary and expensive instrumental examination, as well as ineffective treatment. The clinical cases presented in this publication demonstrate the unjustified difficulties in this issue and the necessity to raise the awareness of physicians about the familial hypocalciuric hypercalcemia.
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Drosataki E, Maragkou S, Dermitzaki K, Stavrakaki I, Lygerou D, Latsoudis H, Pleros C, Petrakis I, Zaganas I, Stylianou K. Dent-2 disease with a Bartter-like phenotype caused by the Asp631Glu mutation in the OCRL gene. BMC Nephrol 2022; 23:182. [PMID: 35549682 PMCID: PMC9097321 DOI: 10.1186/s12882-022-02812-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Accepted: 05/04/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Dent disease is an X-linked disorder characterized by low molecular weight proteinuria (LMWP), hypercalciuria, nephrolithiasis and chronic kidney disease (CKD). It is caused by mutations in the chloride voltage-gated channel 5 (CLCN5) gene (Dent disease-1), or in the OCRL gene (Dent disease-2). It is associated with chronic metabolic acidosis; however metabolic alkalosis has rarely been reported. CASE PRESENTATION We present a family with Dent-2 disease and a Bartter-like phenotype. The main clinical problems observed in the proband included a) primary phosphaturia leading to osteomalacia and stunted growth; b) elevated serum calcitriol levels, leading to hypercalcemia, hypercalciuria, nephrolithiasis and nephrocalcinosis; c) severe salt wasting causing hypotension, hyperaldosteronism, hypokalemia and metabolic alkalosis; d) partial nephrogenic diabetes insipidus attributed to hypercalcemia, hypokalemia and nephrocalcinosis; e) albuminuria, LMWP. Phosphorous repletion resulted in abrupt cessation of hypercalciuria and significant improvement of hypophosphatemia, physical stamina and bone histology. Years later, he presented progressive CKD with nephrotic range proteinuria attributed to focal segmental glomerulosclerosis (FSGS). Targeted genetic analysis for several phosphaturic diseases was unsuccessful. Whole Exome Sequencing (WES) revealed a c.1893C > A variant (Asp631Glu) in the OCRL gene which was co-segregated with the disease in male family members. CONCLUSIONS We present the clinical characteristics of the Asp631Glu mutation in the OCRL gene, presenting as Dent-2 disease with Bartter-like features. Phosphorous repletion resulted in significant improvement of all clinical features except for progressive CKD. Angiotensin blockade improved proteinuria and stabilized kidney function for several years.
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Affiliation(s)
- Eleni Drosataki
- Nephrology Department, Heraklion University Hospital, Voutes, 71500, Heraklion, Crete, Greece
| | - Sevasti Maragkou
- Nephrology Department, Heraklion University Hospital, Voutes, 71500, Heraklion, Crete, Greece
| | - Kleio Dermitzaki
- Nephrology Department, Heraklion University Hospital, Voutes, 71500, Heraklion, Crete, Greece
| | - Ioanna Stavrakaki
- Nephrology Department, Heraklion University Hospital, Voutes, 71500, Heraklion, Crete, Greece
| | - Dimitra Lygerou
- Nephrology Department, Heraklion University Hospital, Voutes, 71500, Heraklion, Crete, Greece
| | - Helen Latsoudis
- Foundation for Research and Technology - Hellas, Heraklion, Crete, Greece
| | - Christos Pleros
- Nephrology Department, Heraklion University Hospital, Voutes, 71500, Heraklion, Crete, Greece
| | - Ioannis Petrakis
- Department of Nephrology, Saarland University Medical Center, Homburg, Germany
| | - Ioannis Zaganas
- Neurogenetics Laboratory Medical School, University of Crete, Heraklion, Greece
| | - Kostas Stylianou
- Nephrology Department, Heraklion University Hospital, Voutes, 71500, Heraklion, Crete, Greece.
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Kakkar V, Pandit K, Yadav M, Saha A. Recurrent hypocalcemic tetany presenting to the emergency room: Answers. Pediatr Nephrol 2022; 37:581-584. [PMID: 34796387 DOI: 10.1007/s00467-021-05283-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Accepted: 08/12/2021] [Indexed: 11/29/2022]
Affiliation(s)
- Vanshika Kakkar
- Division of Pediatric Nephrology, Lady Hardinge Medical College and Associated Kalawati Saran Children Hospital, Room no 102, New Delhi, 110001, India
| | - Kaveri Pandit
- Division of Pediatric Nephrology, Lady Hardinge Medical College and Associated Kalawati Saran Children Hospital, Room no 102, New Delhi, 110001, India
| | - Menka Yadav
- Division of Pediatric Nephrology, Lady Hardinge Medical College and Associated Kalawati Saran Children Hospital, Room no 102, New Delhi, 110001, India
| | - Abhijeet Saha
- Division of Pediatric Nephrology, Lady Hardinge Medical College and Associated Kalawati Saran Children Hospital, Room no 102, New Delhi, 110001, India.
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Palmieri S, Grassi G, Guarnieri V, Chiodini I, Arosio M, Eller-Vainicher C. Case Report: Unusual Presentations of Loss-of-Function Mutations of the Calcium-Sensing Receptor. Front Med (Lausanne) 2022; 8:809067. [PMID: 35141253 PMCID: PMC8818680 DOI: 10.3389/fmed.2021.809067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Accepted: 12/21/2021] [Indexed: 11/13/2022] Open
Abstract
BackgroundIn recent years, heterozygous loss-of-function mutations of the Calcium Sensing Receptor gene (CaSR) were implicated in different hypercalcemic syndromes besides familial hypocalciuric hypercalcemia (FHH), including neonatal severe primary hyperparathyroidism (NSHPT) and primary hyperparathyroidism (PHPT).Cases presentationHere we describe two unusual presentations of heterozygous inactivating CaSR mutations. Case 1: a case of NSHPT due to a de novo, p.(ArgR185Gln) CaSR mutation and successfully treated with cinacalcet monotherapy for 8 years until definitive surgical resolution. Case 2: a 37 years-old woman with PHPT complicated with hypercalcemia and nephrocalcinosis with a novel heterozygous p.(Pro393Arg) CaSR mutation and cured with parathyroidectomy.ConclusionsThese cases reinforce the fact that the clinical spectrum of inactivating mutations of the CaSR has widened and, although carrying a mutation suggestive of FHH, some patients may have different clinical phenotypes and complications requiring individualized therapies.
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Affiliation(s)
- Serena Palmieri
- Unit of Endocrinology, Fondazione Istituto di Ricovero e Cura a Carattere Scientifico Ca' Granda—Ospedale Maggiore Policlinico, Milan, Italy
- *Correspondence: Serena Palmieri
| | - Giorgia Grassi
- Unit of Endocrinology, Fondazione Istituto di Ricovero e Cura a Carattere Scientifico Ca' Granda—Ospedale Maggiore Policlinico, Milan, Italy
| | - Vito Guarnieri
- Division of Medical Genetics, Fondazione IRCCS Ospedale Casa Sollievo della Sofferenza, San Giovanni Rotondo (FG), Milan, Italy
| | - Iacopo Chiodini
- Department of Endocrine and Metabolic Diseases, IRCCS, Istituto Auxologico Italiano, Milan, Italy
- Departments of Medical Biotechnology and Translational Medicine, University of Milan, Milan, Italy
| | - Maura Arosio
- Unit of Endocrinology, Fondazione Istituto di Ricovero e Cura a Carattere Scientifico Ca' Granda—Ospedale Maggiore Policlinico, Milan, Italy
- Department of Clinical Sciences and Community Health, University of Milan, Milan, Italy
| | - Cristina Eller-Vainicher
- Unit of Endocrinology, Fondazione Istituto di Ricovero e Cura a Carattere Scientifico Ca' Granda—Ospedale Maggiore Policlinico, Milan, Italy
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Ulloa-Aguirre A, Zariñán T, Gutiérrez-Sagal R, Tao YX. Targeting trafficking as a therapeutic avenue for misfolded GPCRs leading to endocrine diseases. Front Endocrinol (Lausanne) 2022; 13:934685. [PMID: 36093106 PMCID: PMC9452723 DOI: 10.3389/fendo.2022.934685] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Accepted: 07/13/2022] [Indexed: 02/05/2023] Open
Abstract
G protein-coupled receptors (GPCRs) are plasma membrane proteins associated with an array of functions. Mutations in these receptors lead to a number of genetic diseases, including diseases involving the endocrine system. A particular subset of loss-of-function mutant GPCRs are misfolded receptors unable to traffic to their site of function (i.e. the cell surface plasma membrane). Endocrine disorders in humans caused by GPCR misfolding include, among others, hypo- and hyper-gonadotropic hypogonadism, morbid obesity, familial hypocalciuric hypercalcemia and neonatal severe hyperparathyroidism, X-linked nephrogenic diabetes insipidus, congenital hypothyroidism, and familial glucocorticoid resistance. Several in vitro and in vivo experimental approaches have been employed to restore function of some misfolded GPCRs linked to endocrine disfunction. The most promising approach is by employing pharmacological chaperones or pharmacoperones, which assist abnormally and incompletely folded proteins to refold correctly and adopt a more stable configuration to pass the scrutiny of the cell's quality control system, thereby correcting misrouting. This review covers the most important aspects that regulate folding and traffic of newly synthesized proteins, as well as the experimental approaches targeted to overcome protein misfolding, with special focus on GPCRs involved in endocrine diseases.
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Affiliation(s)
- Alfredo Ulloa-Aguirre
- Red de Apoyo a la Investigación (RAI), National University of Mexico and Instituto Nacional de Ciencias Médicas y Nutrición SZ, Mexico City, Mexico
- *Correspondence: Alfredo Ulloa-Aguirre,
| | - Teresa Zariñán
- Red de Apoyo a la Investigación (RAI), National University of Mexico and Instituto Nacional de Ciencias Médicas y Nutrición SZ, Mexico City, Mexico
| | - Rubén Gutiérrez-Sagal
- Red de Apoyo a la Investigación (RAI), National University of Mexico and Instituto Nacional de Ciencias Médicas y Nutrición SZ, Mexico City, Mexico
| | - Ya-Xiong Tao
- Department of Anatomy, Physiology & Pharmacology, Auburn University College of Veterinary Medicine, Auburn, AL, United States
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Agarwal S, Sudhini YR, Polat OK, Reiser J, Altintas MM. Renal cell markers: lighthouses for managing renal diseases. Am J Physiol Renal Physiol 2021; 321:F715-F739. [PMID: 34632812 DOI: 10.1152/ajprenal.00182.2021] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Kidneys, one of the vital organs in our body, are responsible for maintaining whole body homeostasis. The complexity of renal function (e.g., filtration, reabsorption, fluid and electrolyte regulation, and urine production) demands diversity not only at the level of cell types but also in their overall distribution and structural framework within the kidney. To gain an in depth molecular-level understanding of the renal system, it is imperative to discern the components of kidney and the types of cells residing in each of the subregions. Recent developments in labeling, tracing, and imaging techniques have enabled us to mark, monitor, and identify these cells in vivo with high efficiency in a minimally invasive manner. In this review, we summarize different cell types, specific markers that are uniquely associated with those cell types, and their distribution in the kidney, which altogether make kidneys so special and different. Cellular sorting based on the presence of certain proteins on the cell surface allowed for the assignment of multiple markers for each cell type. However, different studies using different techniques have found contradictions in cell type-specific markers. Thus, the term "cell marker" might be imprecise and suboptimal, leading to uncertainty when interpreting the data. Therefore, we strongly believe that there is an unmet need to define the best cell markers for a cell type. Although the compendium of renal-selective marker proteins presented in this review is a resource that may be useful to researchers, we acknowledge that the list may not be necessarily exhaustive.
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Affiliation(s)
- Shivangi Agarwal
- Department of Internal Medicine, Rush University, Chicago, Illinois
| | | | - Onur K Polat
- Department of Internal Medicine, Rush University, Chicago, Illinois
| | - Jochen Reiser
- Department of Internal Medicine, Rush University, Chicago, Illinois
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12
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Tan RSG, Lee CHL, Dimke H, Todd Alexander R. The role of calcium-sensing receptor signaling in regulating transepithelial calcium transport. Exp Biol Med (Maywood) 2021; 246:2407-2419. [PMID: 33926258 DOI: 10.1177/15353702211010415] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The calcium-sensing receptor (CaSR) plays a critical role in sensing extracellular calcium (Ca2+) and signaling to maintain Ca2+ homeostasis. In the parathyroid, the CaSR regulates secretion of parathyroid hormone, which functions to increase extracellular Ca2+ levels. The CaSR is also located in other organs imperative to Ca2+ homeostasis including the kidney and intestine, where it modulates Ca2+ reabsorption and absorption, respectively. In this review, we describe CaSR expression and its function in transepithelial Ca2+ transport in the kidney and intestine. Activation of the CaSR leads to G protein dependent and independent signaling cascades. The known CaSR signal transduction pathways involved in modulating paracellular and transcellular epithelial Ca2+ transport are discussed. Mutations in the CaSR cause a range of diseases that manifest in altered serum Ca2+ levels. Gain-of-function mutations in the CaSR result in autosomal dominant hypocalcemia type 1, while loss-of-function mutations cause familial hypocalciuric hypercalcemia. Additionally, the putative serine protease, FAM111A, is discussed as a potential regulator of the CaSR because mutations in FAM111A cause Kenny Caffey syndrome type 2, gracile bone dysplasia, and osteocraniostenosis, diseases that are characterized by hypocalcemia, hypoparathyroidism, and bony abnormalities, i.e. share phenotypic features of autosomal dominant hypocalcemia. Recent work has helped to elucidate the effect of CaSR signaling cascades on downstream proteins involved in Ca2+ transport across renal and intestinal epithelia; however, much remains to be discovered.
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Affiliation(s)
- Rebecca Siu Ga Tan
- Department of Physiology, University of Alberta, Edmonton T6G 1C9, Canada.,Membrane Protein Disease Research Group, University of Alberta, Edmonton T6G 1C9, Canada
| | | | - Henrik Dimke
- Department of Cardiovascular and Renal Research, Institute of Molecular Medicine, University of Southern Denmark, Odense 5000, Denmark.,Department of Nephrology, Odense University Hospital, Odense 5000, Denmark
| | - R Todd Alexander
- Department of Physiology, University of Alberta, Edmonton T6G 1C9, Canada.,Membrane Protein Disease Research Group, University of Alberta, Edmonton T6G 1C9, Canada.,Department of Pediatrics, University of Alberta, Edmonton T6G 1C9, Canada
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Structural mechanism of cooperative activation of the human calcium-sensing receptor by Ca 2+ ions and L-tryptophan. Cell Res 2021; 31:383-394. [PMID: 33603117 PMCID: PMC8115157 DOI: 10.1038/s41422-021-00474-0] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2020] [Accepted: 01/06/2021] [Indexed: 02/07/2023] Open
Abstract
The human calcium-sensing receptor (CaSR) is a class C G protein-coupled receptor (GPCR) responsible for maintaining Ca2+ homeostasis in the blood. The general consensus is that extracellular Ca2+ is the principal agonist of CaSR. Aliphatic and aromatic L-amino acids, such as L-Phe and L-Trp, increase the sensitivity of CaSR towards Ca2+ and are considered allosteric activators. Crystal structures of the extracellular domain (ECD) of CaSR dimer have demonstrated Ca2+ and L-Trp binding sites and conformational changes of the ECD upon Ca2+/L-Trp binding. However, it remains to be understood at the structural level how Ca2+/L-Trp binding to the ECD leads to conformational changes in transmembrane domains (TMDs) and consequent CaSR activation. Here, we determined the structures of full-length human CaSR in the inactive state, Ca2+- or L-Trp-bound states, and Ca2+/L-Trp-bound active state using single-particle cryo-electron microscopy. Structural studies demonstrate that L-Trp binding induces the closure of the Venus flytrap (VFT) domain of CaSR, bringing the receptor into an intermediate active state. Ca2+ binding relays the conformational changes from the VFT domains to the TMDs, consequently inducing close contact between the two TMDs of dimeric CaSR, activating the receptor. Importantly, our structural and functional studies reveal that Ca2+ ions and L-Trp activate CaSR cooperatively. Amino acids are not able to activate CaSR alone, but can promote the receptor activation in the presence of Ca2+. Our data provide complementary insights into the activation of class C GPCRs and may aid in the development of novel drugs targeting CaSR.
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Tőke J, Czirják G, Enyedi P, Tóth M. Rare diseases caused by abnormal calcium sensing and signalling. Endocrine 2021; 71:611-617. [PMID: 33528764 PMCID: PMC8016752 DOI: 10.1007/s12020-021-02620-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/07/2020] [Accepted: 01/08/2021] [Indexed: 12/20/2022]
Abstract
The calcium-sensing receptor (CaSR) provides the major mechanism for the detection of extracellular calcium concentration in several cell types, via the induction of G-protein-coupled signalling. Accordingly, CaSR plays a pivotal role in calcium homeostasis, and the CaSR gene defects are related to diseases characterized by serum calcium level changes. Activating mutations of the CaSR gene cause enhanced sensitivity to extracellular calcium concentration resulting in autosomal dominant hypocalcemia or Bartter-syndrome type V. Inactivating CaSR gene mutations lead to resistance to extracellular calcium. In these cases, familial hypocalciuric hypercalcaemia (FHH1) or neonatal severe hyperparathyroidism (NSHPT) can develop. FHH2 and FHH3 are associated with mutations of genes of partner proteins of calcium signal transduction. The common polymorphisms of the CaSR gene have been reported not to affect the calcium homeostasis itself; however, they may be associated with the increased risk of malignancies.
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Affiliation(s)
- Judit Tőke
- Department of Internal Medicine and Oncology, Semmelweis University, Budapest, Hungary
| | - Gábor Czirják
- Department of Physiology, Semmelweis University, Budapest, Hungary
| | - Péter Enyedi
- Department of Physiology, Semmelweis University, Budapest, Hungary
| | - Miklós Tóth
- Department of Internal Medicine and Oncology, Semmelweis University, Budapest, Hungary.
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15
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Brent MB, Lodberg A, Bromer FD, van der Eerden BCJ, Eijken M, Brüel A, Thomsen JS. Activin type IIA decoy receptor and intermittent parathyroid hormone in combination overturns the bone loss in disuse-osteopenic mice. Bone 2021; 142:115692. [PMID: 33069923 DOI: 10.1016/j.bone.2020.115692] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Revised: 09/25/2020] [Accepted: 10/09/2020] [Indexed: 12/17/2022]
Abstract
Damage of the lower motor neuron cell bodies or their axons results in reduced or abolished voluntary movement accompanied by a substantial loss of bone and muscle mass. Intermittent parathyroid hormone 1-34 (PTH) (teriparatide) is one of the most potent bone-anabolic treatment regimens. ActRIIA-mFc is an activin type IIA decoy receptor that increases bone mass mediated by inhibition of the activin receptor signaling pathway. We investigated whether PTH or ActRIIA-mFc alone or in combination could prevent loss of bone and muscle mass induced by injecting botulinum toxin A (BTX) into the right hind limb in mice. Seventy-two 16-week-old female C57BL/6 mice were allocated to the following groups: Baseline, Control, BTX, BTX + ActRIIA-mFc (10 mg/kg), BTX + PTH (100 μg/kg), and BTX + ActRIIA-mFc + PTH. The mice were sacrificed after three weeks of disuse and treatment. In contrast to monotherapy with PTH, ActRIIA-mFc alone or in combination with PTH was able partly or completely to prevent disuse-induced loss of whole femoral bone mass, trabecular thickness, and bone strength. Moreover, an additive effect of ActRIIA-mFc and PTH on areal bone mineral density and trabecular bone volume was found. In summary, ActRIIA-mFc and PTH in combination were more effective in preventing disuse-induced bone loss and deterioration of trabecular micro-architecture than either treatment alone.
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Affiliation(s)
| | | | | | - Bram C J van der Eerden
- Department of Internal Medicine, Erasmus University Medical Center, Rotterdam, the Netherlands
| | - Marco Eijken
- Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
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Taylor-Miller T, Allgrove J. Endocrine Diseases of Newborn: Epidemiology, Pathogenesis, Therapeutic Options, and Outcome "Current Insights Into Disorders of Calcium and Phosphate in the Newborn". Front Pediatr 2021; 9:600490. [PMID: 33614549 PMCID: PMC7892781 DOI: 10.3389/fped.2021.600490] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/30/2020] [Accepted: 01/13/2021] [Indexed: 11/13/2022] Open
Abstract
The physiology and regulation of bone minerals in the fetus and the newborn is significantly different from children and adults. The bone minerals calcium, phosphate and magnesium are all maintained at higher concentrations in utero to achieve adequate bone accretion. This is an integral component of normal fetal development which facilitates safe neonatal transition to post-natal life. When deciphering the cause of bone mineral disorders in newborns, the potential differential diagnosis list is broad and complex, including several extremely rare conditions. Also, significant discoveries including new embryological molecular genetic transcription factors, the role of active placental mineral transport, and hormone regulation factors have changed the understanding of calcium and phosphate homeostasis in the fetus and the newborn. This article will guide clinicians through an updated review of calcium and phosphate physiology, then review specific conditions pertinent to successful neonatal care. Furthermore, with the advancement of increasingly rapid molecular genetic testing, genomics will continue to play a greater role in this area of fetal diagnostics and prognostication.
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Affiliation(s)
- Tashunka Taylor-Miller
- Department of Endocrinology and Metabolic Medicine, Great Ormond Street Hospital for Children NHS Foundation Trust, London, United Kingdom
| | - Jeremy Allgrove
- Department of Endocrinology and Metabolic Medicine, Great Ormond Street Hospital for Children NHS Foundation Trust, London, United Kingdom
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17
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Changes in Bone Metabolism and Structure in Primary Hyperparathyroidism. ACTA MEDICA BULGARICA 2020. [DOI: 10.2478/amb-2020-0050] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Abstract
Parathyroid hormone (PTH) is a key regulator of bone turnover. Depending on the duration of action, the hormone causes catabolic and anabolic effects by binding with specific receptors (PTHR1) in the bone. Various cells expressing PTHR1 on their surface are involved in the process – osteoblasts, osteocytes, bone marrow stromal cells, T-lymphocytes and macrophages. In physiological conditions PTH balances the bone metabolism. Intermittent pharmacological doses of PTH lead to the prevalence of bone formation and are used in the treatment of osteoporosis. Persistently elevated levels of PTH stimulate bone resorption by impacting mainly the cortical bone. New imaging and analysis techniques show that high PTH levels can also have an adverse effect on trabecular microarchitecture. Primary hyperparathyroidism (PHPT) is a disease characterized by increased bone metabolism, decreased bone mineral density (BMD), inadequate osteoid mineralization and an increased risk of fractures. Prolonged overproduction of PTH leads to stimulation of bone resorption and defects in bone formation, mainly causing loss of cortical bone mass, while in the trabecular bone predominate demineralization processes. One explanation of these findings is the enhanced stimulation of RANKL expression by osteoblasts with decreased OPG expression and bone formation at the same time.
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Sadacharan D, Mahadevan S, Rao SS, Kumar AP, Swathi S, Kumar S, Kannan S. Neonatal Severe Primary Hyperparathyroidism: A Series of Four Cases and their Long-term Management in India. Indian J Endocrinol Metab 2020; 24:196-201. [PMID: 32699790 PMCID: PMC7333741 DOI: 10.4103/ijem.ijem_53_20] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Revised: 02/03/2020] [Accepted: 03/04/2020] [Indexed: 11/04/2022] Open
Abstract
CONTEXT Neonatal severe primary hyperparathyroidism (NSPHPT) is an extremely rare autosomal recessive disorder, requiring a high index of suspicion. Infants affected with this disorder present with severe life-threatening hypercalcemia early in life, requiring adequate preoperative medical management followed by surgery. AIMS We report four newborns with NSPHPT who were managed over 10 years. SUBJECTS AND METHODS Demography, clinical presentation, treatment, and follow-up data were retrospectively studied with descriptive analysis to highlight the utility of long-term medical management, surgery, and genetic testing reported in the literature. STATISTICAL ANALYSIS USED Descriptive Analysis. RESULTS We had three males and one female infant with a mean age of diagnosis at 28.7 days, calcium 29.2+/-2.8 mg/dL, and parathormone (PTH) 1963+/-270.4 pg/mL. All four infants presented with failure to thrive, hypotonia, and respiratory distress. All infants were treated medically followed by total parathyroidectomy plus transcervical thymectomy, with an additional hemithyroidectomy in one of them. Imaging was negative in all four cases. Three babies became hypocalcemic while the fourth infant had a drop in PTH and is on the tab. cinacalcet 30 mg/day. CaSR mutation was positive in three infants. CONCLUSIONS Diagnosing NSPHPT needs expert clinical acumen. It requires emergency medical management to control calcium levels. The crisis may present later, necessitating parathyroidectomy in these cases once the child is fit for surgery. Surgery offers a cure for this unusual lethal hypercalcemia while the role of cinacalcet needs a special mention. Sound knowledge in endocrinology with parathyroid embryology and morphology is of paramount importance. Our case series might add a few insights into managing this unusual genetic disorder.
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Affiliation(s)
- Dhalapathy Sadacharan
- Department of Endocrine Surgery, Rajiv Gandhi Govt. General Hospital, Madras Medical College, Porur, Chennai, India
| | - Shriraam Mahadevan
- Department of Endocrinology, Diabetes and Metabolism, Sri Ramachandra Medical Centre, Porur, Chennai, India
| | - Smitha S. Rao
- Department of Endocrine Surgery, Rajiv Gandhi Govt. General Hospital, Madras Medical College, Porur, Chennai, India
| | - A Prem Kumar
- Diaplus Clinic, Salem, Anna Nagar, Chennai, India
| | - S Swathi
- Sundaram Medical Foundation, Anna Nagar, Chennai, India
| | - Senthil Kumar
- Ramalingam Hospital, Itteri Road, Salem, Tamil Nadu, India
| | - Subramanian Kannan
- Department of Endocrinology, Diabetes and Metabolism, Narayana Hrudayala Hospitals, Hosur Road, Bengaluru, Karnataka, India
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Abstract
There are many causes of hypercalcaemia including hyperparathyroidism, drugs, granulomatous disorders and malignancy. Parathyroid hormone (PTH) related hypercalcaemia is most commonly caused by primary hyperparathyroidism (PHPT) and more rarely by familial hypocalciuric hypercalcaemia (FHH). Algorithms for diagnosis of PTH related hypercalcaemia require assessment of a 24-h urinary calcium and creatinine excretion to calculate calcium/creatinine clearance ratio and radiological investigations including ultrasound scan and 99mTc-sestamibi-SPECT/CT. To illustrate investigations and management of parathyroid-related hypercalcaemia, we present a selection of distinct cases of PHPT due to eutopic and ectopic parathyroid adenomas, as well as a case with a syndromic form of PHPT (multiple endocrine neoplasia type 1), and a case with FHH type 1 due to a CASR inactivating mutation. Additional cases with normocalcaemic hyperparathyroidism and secondary hyperparathyroidism are included for completeness of differential diagnosis. The common eutopic parathyroid adenomas are easily treated with parathyroidectomy while the less common ectopic parathyroid adenomas require more complex investigations and operative procedures such as video-assisted thoracoscopic surgery. On the other hand, the much less common FHH does not require treatment. Assessment of kin with FHH is important to identify members with this inherited condition in order to prevent unnecessary interventions.
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Affiliation(s)
- Chau H Han
- Stanhope Surgery, Stanhope Road, Waltham Cross, EN8 7DJ, UK
| | - Christopher H Fry
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, UK
| | - Pankaj Sharma
- Institute of Cardiovascular Research, Royal Holloway, University of London, Egham, UK
| | - Thang S Han
- Institute of Cardiovascular Research, Royal Holloway, University of London, Egham, UK.
- Department of Endocrinology, Ashford and St Peter's NHS Foundation Trust, Chertsey, UK.
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20
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Clinical and Biochemical Features in a Case of Familial Hypocalciuric Hypercalcemia Type 3 with AP2S1 Gene Mutation in Codon Arg15His. Case Rep Pediatr 2020; 2020:7312894. [PMID: 32047691 PMCID: PMC7007930 DOI: 10.1155/2020/7312894] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Accepted: 01/07/2020] [Indexed: 11/20/2022] Open
Abstract
Familial hypocalciuric hypercalcemia (FHH) is usually a benign condition divided into three types. FHH-3 occurs in about 20% of the cases and is caused due to missense mutations in AP2S1 (adaptor-related protein complex 2 subunit sigma 1) involving the codon Arg15 (p.R15). We report a case of FHH-3 with a heterozygous mutation in the AP2S1 gene on chr19_47349359 C>T, c.44G>A, p.Arg15His. There are a handful of reports describing the clinical features in patients diagnosed with FHH-3. Herein, we describe the laboratory and clinical features associated with a case of FHH-3 with mutation in the Arg15His codon of the AP2S1 gene.
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21
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Li M, He Y, Tong G, Yang D. [Prolonged continuous infusion of teriparatide promotes bone metabolism in normal but not in castrated mice]. NAN FANG YI KE DA XUE XUE BAO = JOURNAL OF SOUTHERN MEDICAL UNIVERSITY 2019; 39:1045-1051. [PMID: 31640962 DOI: 10.12122/j.issn.1673-4254.2019.09.07] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
OBJECTIVE To investigate the effects of continuous pumping of teriparatide (TPTD) on bone metabolism in ovariectomized and normal mice and provide experimental evidence for the selection of animal models for studying the effects of TPTD and its related peptides on osteoclasts. METHODS Twenty-four female C57BL mice (6-weeks old) were subjected to ovariectomy (OVX) or sham operation followed 7 days later by continuous pumping of TPTD or the solvent vehicle (VEH) via a micropump (SHAM-VEH, SHAM-TPTD, OVX-VEH, and OVX-TPTD groups; n=6). Two weeks later, the tibial and femoral bones were harvested for micro-CT scanning to measure the parameters of the tibia and the femoral cortical bone. Histopathological examinations of the tibial tissue were conducted using HE staining and TRAP staining and the number of osteoclasts and the growth plate thickness were determined. The serum Ca2 + levels of the mice were measured. The primary osteoblasts from the cranial bone were treated with estradiol (E2) and TPTD for 48 h, and the expressions of β-catenin and RANKL protein in the cells were analyzed. RESULTS The trabecular bone mass of OVX mice was significantly lower than that of sham-operated mice (P < 0.05). Continuous TPTD pumping significantly reduced tibial cancellous bone mass and femoral cortical bone area in the sham-operated mice, while in the castrated mice, TPTD pumping increased the cancellous bone mass without changing the cortical bone area. TRAP staining showed that cancellous osteoblasts in the tibia increased significantly in the castrated mice as compared with the sham-operated mice, and TPTD pumping significantly increased the number of cancellous osteoblasts in the sham-operated mice (P < 0.05). In the primary cultured osteoblasts, treatment with both E2 and TPTD obviously lowered the expression of β-catenin and increased the expression of RANKL as compared with TPTD treatment alone. CONCLUSIONS Continuous pumping of TPTD promotes bone resorption in normal mice but does not produce obvious bone resorption effect in the ovariectomized mice, suggesting that castrated mice are not suitable models for studying the effect of TPTD and the related peptides on the osteoclasts.
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Affiliation(s)
- Minghan Li
- Department of Spinal Surgery, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China
| | - Youhua He
- Department of Spinal Surgery, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China
| | - Guojun Tong
- Department of Spinal Surgery, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China
| | - Dehong Yang
- Department of Spinal Surgery, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China
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22
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Sun X, Huang L, Wu J, Tao Y, Yang F. Novel homozygous inactivating mutation of the calcium-sensing receptor gene in neonatal severe hyperparathyroidism responding to cinacalcet therapy: A case report and literature review. Medicine (Baltimore) 2018; 97:e13128. [PMID: 30407334 PMCID: PMC6250440 DOI: 10.1097/md.0000000000013128] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
RATIONALE Calcium-sensing receptor (CaSR) mutations can cause life-threatening neonatal severe hyperparathyroidism (NSHPT). The medical management of NSHPT is often challenging and complex. Here, we present a case of NSHPT caused by a novel homozygous CaSR mutation. PATIENT CONCERNS A Chinese female infant presented with poor feeding, constipation, severe hypotonia, and periodic bradycardia. Biochemistry tests revealed markedly elevated serum levels of Ca and parathyroid hormone (PTH). DIAGNOSES Genetic sequencing revealed a previously undescribed CaSR mutation in exon 3 (c.242T>A; p.I81K). A diagnosis of NSHPT secondary to homozygously inherited familial hypocalciuric hypercalcemia syndrome was established. INTERVENTIONS Cinacalcet was administered after the common treatments (low-calcium intake, hydration, and furosemide), calcitonin, and pamidronate therapy all failed. OUTCOMES Serum Ca decreased and stabilized with cinacalcet therapy. During a 10-month follow-up, total calcium was maintained within the high-normal range and PTH was normalized. LESSONS A trial of cinacalcet therapy might be undertaken in cases of NSHPT while definitive results of the genetic analysis are awaited.
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MESH Headings
- Calcimimetic Agents/therapeutic use
- Calcium/blood
- Cinacalcet/therapeutic use
- Female
- Genetic Testing
- Homozygote
- Humans
- Hyperparathyroidism, Primary/diagnosis
- Hyperparathyroidism, Primary/drug therapy
- Hyperparathyroidism, Primary/genetics
- Infant
- Infant, Newborn
- Infant, Newborn, Diseases/diagnosis
- Infant, Newborn, Diseases/drug therapy
- Infant, Newborn, Diseases/genetics
- Mutation
- Parathyroid Hormone/blood
- Receptors, Calcium-Sensing/genetics
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Affiliation(s)
- Xiaomei Sun
- Department of Pediatrics
- Key Laboratory of Birth Defects and Related Diseases of Women and Children, Ministry of Education
| | - Liang Huang
- Key Laboratory of Birth Defects and Related Diseases of Women and Children, Ministry of Education
- Department of Pharmacy/Evidence-Based Pharmacy Center, West China Second University Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Jin Wu
- Department of Pediatrics
- Key Laboratory of Birth Defects and Related Diseases of Women and Children, Ministry of Education
| | - Yuhong Tao
- Department of Pediatrics
- Key Laboratory of Birth Defects and Related Diseases of Women and Children, Ministry of Education
| | - Fan Yang
- Department of Pediatrics
- Key Laboratory of Birth Defects and Related Diseases of Women and Children, Ministry of Education
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23
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Capozza M, Chinellato I, Guarnieri V, Di Lorgi N, Accadia M, Traggiai C, Mattioli G, Di Mauro A, Laforgia N. Case report: acute clinical presentation and neonatal management of primary hyperparathyroidism due to a novel CaSR mutation. BMC Pediatr 2018; 18:340. [PMID: 30376845 PMCID: PMC6208175 DOI: 10.1186/s12887-018-1319-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Accepted: 10/23/2018] [Indexed: 11/18/2022] Open
Abstract
Background Neonatal severe primary hyperparathyroidism (NSHPT) is a rare autosomal recessive disorder of calcium homeostasis, characterized by striking hyperparathyroidism, marked hypercalcemia and hyperparathyroid bone disease. We report the case of a newborn with a novel homozygous mutation of the CaSR, treated by successful subtotal parathyroidectomy, who had an acute presentation of the disease, i.e. out-of hospital cardiorespiratory arrest. . Case presentation A 8-day-old female newborn was admitted to the NICU of University of Bari “Aldo Moro” (Italy) after a cardiorespiratory arrest occurred at home. Severe hypercalcemia was found and different drug therapies were employed (Furosemide, Cinacalcet and bisphosphonate), as well as hyperhydration, until subtotal parathyroidectomy, was performed at day 32. Our patient’s mutation was never described before so that a strict and individualized long-term follow-up was started. Conclusions This case of NSHPT suggests that a near-miss event, labelled as a possible case of SIDS, could also be due to severe hypercalcemia and evidentiates the difficulties of the neonatal management of NSHPT. Furthermore, the identification of the specific CaSR mutation provides the substrate for prenatal diagnosis.
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Affiliation(s)
- Manuela Capozza
- Neonatology and Neonatal Intensive Care Unit, Department of Biomedical Science ad Human Oncology, University of Bari "Aldo Moro", Bari, Italy. .,Policlinico Hospital, Piazza Giulio Cesare n. 11, 70124, Bari, Italy.
| | | | - Vito Guarnieri
- Medical Genetics, IRCCS Casa Sollievo della Sofferenza Hospital, San Giovanni Rotondo, Foggia, Italy
| | - Natascia Di Lorgi
- Department of Pediatrics, Endocrine, Diabetes and Metabolic Unit, Istituto Giannina Gaslini, University of Genova, Genoa, Italy
| | - Maria Accadia
- Medical Genetics, IRCCS Casa Sollievo della Sofferenza Hospital, San Giovanni Rotondo, Foggia, Italy
| | - Cristina Traggiai
- Neonatology and Neonatal Intensive Care Unit, Istituto Giannina Gaslini, Genoa, Italy
| | - Girolamo Mattioli
- Pediatric Surgery Unit, Istituto Giannina Gaslini, University of Genoa, Genoa, Italy
| | - Antonio Di Mauro
- Neonatology and Neonatal Intensive Care Unit, Department of Biomedical Science ad Human Oncology, University of Bari "Aldo Moro", Bari, Italy
| | - Nicola Laforgia
- Neonatology and Neonatal Intensive Care Unit, Department of Biomedical Science ad Human Oncology, University of Bari "Aldo Moro", Bari, Italy
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TRPV6 Variants Interfere with Maternal-Fetal Calcium Transport through the Placenta and Cause Transient Neonatal Hyperparathyroidism. Am J Hum Genet 2018; 102:1104-1114. [PMID: 29861107 DOI: 10.1016/j.ajhg.2018.04.006] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2017] [Accepted: 04/06/2018] [Indexed: 11/22/2022] Open
Abstract
Transient neonatal hyperparathyroidism (TNHP) is etiologically a heterogeneous condition. One of the etiologies is an insufficient maternal-fetal calcium transport through the placenta. We report six subjects with homozygous and/or compound-heterozygous mutations in the gene encoding the transient receptor potential cation channel, subfamily V, member 6 (TRPV6), an epithelial Ca2+-selective channel associated with this condition. Exome sequencing on two neonates with skeletal findings consistent with neonatal hyperparathyroidism identified homozygous frameshift mutations before the first transmembrane domain in a subject born to first-cousins parents of Pakistani descent as well as compound-heterozygous mutations (a combination of a frameshift mutation and an intronic mutation that alters mRNA splicing) in an individual born to a non-consanguineous couple of African descent. Subsequently, targeted mutation analysis of TRPV6 performed on four other individuals (born to non-consanguineous Japanese parents) with similar X-rays findings identified compound-heterozygous mutations. The skeletal findings improved or resolved in most subjects during the first few months of life. We identified three missense variants (at the outer edges of the second and third transmembrane domains) that alter the localization of the TRPV6: one recurrent variant at the S2-S3 loop and two recurrent variants (in the fourth ankyrin repeat domain) that impair TRPV6 stability. Compound heterozygous loss-of-function mutations for the pathogenic frameshift allele and the allele with an intronic c.607+5G>A mutation resulted in the most severe phenotype. These results suggest that TNHP is an autosomal-recessive disease caused by TRPV6 mutations that affect maternal-fetal calcium transport.
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25
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Catalano A, Chilà D, Bellone F, Nicocia G, Martino G, Loddo I, Morabito N, Benvenga S, Loddo S. Incidence of hypocalcemia and hypercalcemia in hospitalized patients: Is it changing? JOURNAL OF CLINICAL AND TRANSLATIONAL ENDOCRINOLOGY 2018; 13:9-13. [PMID: 30023309 PMCID: PMC6047106 DOI: 10.1016/j.jcte.2018.05.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Revised: 05/15/2018] [Accepted: 05/27/2018] [Indexed: 12/04/2022]
Abstract
Disorders of calcium metabolism are frequently encountered in clinical practice. Hypocalcemia accounted for 27.72% and hypercalcemia for 4.74% of inpatients. Incidence of hypo- and hypercalcemia changed over time.
Disorders of calcium metabolism are frequently encountered in routine clinical practice. However limited data are available on the epidemiology of hypocalcemia and hypercalcemia in hospitalized patients. Our aim was to evaluate the frequency of hypocalcemia and hypercalcemia in hospitalized patients. This is a retrospective study based on the laboratory results of all hospitalized subjects (n = 12,334) whose calcemia was determined between January 1st, 2011 and December 31st, 2014. Measurements of serum calcium were carried out by a single centralized laboratory. Hypocalcemia was defined as serum calcium levels <8.2 mg/dl and hypercalcemia as serum calcium levels >10.4 mg/dl. Albumin correction was applied to adjust serum calcium values. Overall, hypocalcemia accounted for 27.72% (n = 3420) and hypercalcemia for 4.74% (n = 585) of the 12,334 inpatients. The highest prevalence of hypocalcemia was found in patients over 65 yr. (n = 2097, 61.31%) vs. younger subjects, while the highest prevalence of hypercalcemia was observed in patients aged 0–18 yr. (n = 380, 64.95%). Hypocalcemia was more often encountered in males (n = 1952, 57.07%) while no gender differences were found regarding hypercalcemia. Incidence of hypocalcemia changed over time varying from 35.42% (n = 1061) in 2011 to 21.93% (n = 672) in 2014 (r = −0.98; p = 0.01). Differently, incidence of hypercalcemia did not significantly increase significantly from 3.47% (n = 104) in 2011 to 6.92% (n = 211) in 2014 (r = 0.94; p = 0.052). Despite increased awareness about electrolytes disturbance, physicians should consider calcium levels because of life-threatening consequences associated to hypo- and hypercalcemia. Patient’s gender and age could be associated to a different risk of calcium disturbance in hospitalized patients.
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Affiliation(s)
- A Catalano
- Department of Clinical and Experimental Medicine, University Hospital of Messina, Messina, Italy
| | - D Chilà
- Department of Clinical and Experimental Medicine, University Hospital of Messina, Messina, Italy
| | - F Bellone
- Department of Clinical and Experimental Medicine, University Hospital of Messina, Messina, Italy
| | - G Nicocia
- Department of Clinical and Experimental Medicine, University Hospital of Messina, Messina, Italy
| | - G Martino
- Department of Cognitive Sciences, Psychology, Education and Cultural Studies, University of Messina, Messina, Italy
| | - I Loddo
- Department of Laboratory Medicine and Advanced Biotechnologies, Mediterranean Institute for Transplantation and Advanced Specialized Therapies - ISMETT - IRCCS, Palermo, Italy
| | - N Morabito
- Department of Clinical and Experimental Medicine, University Hospital of Messina, Messina, Italy
| | - S Benvenga
- Department of Clinical and Experimental Medicine, University Hospital of Messina, Messina, Italy.,Master Program on Childhood, Adolescent and Women's Endocrine Health, University of Messina, Italy.,Interdepartmental Program of Molecular & Clinical Endocrinology and Women's Endocrine Health, University Hospital Policlinico G. Martino, Messina, Italy
| | - S Loddo
- Department of Clinical and Experimental Medicine, University Hospital of Messina, Messina, Italy
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26
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Affiliation(s)
- Allen W. Root
- Department of Pediatrics, Johns Hopkins Medicine – All Children’s Hospital, St. Petersburg, FL, USA
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27
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Ahmad N, Bahasan M, Al-Ghamdi BAA, Al-Enizi HF, Al-Zahrani AS. Neonatal severe hyperparathyroidism secondary to a novel homozygous CASR gene mutation. ACTA ACUST UNITED AC 2017; 14:354-358. [PMID: 29354167 DOI: 10.11138/ccmbm/2017.14.3.354] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Neonatal severe hyperparathyroidism (NSHPT) is a rare autosomal recessive disease. Children present within the first 6 months of life and more commonly in the first few weeks. Common presentation is poor feeding, polyuria, dehydration, lethargy, failure to thrive, hypotonia, gastrointestinal dysmotility, osteopenia and symptoms of respiratory distress due to a poorly developed chest cage. We present a case of a 2-month old girl with severe hypercalcemia and hyperparathyroidism. She was found to have a novel homozygous mutation in the acceptor splicing site of intron 4 (c.1378 -2A>G) of the calcium sensing receptor gene (CASR). This mutation causes frame shift deletion of exon 5 and insensitivity of CASR to calcium. The patient was treated with intravenous fluids, fruosemide, calcitonin, intravenous pamidronate and oral cinacalcet. She did not respond to medical treatment. Parathyroid gland imaging including ultrasound, MRI and sestamibi nuclear scan were not helpful in localizing the glands. Her symptoms resolved following total parathyroidectomy. She is being treated with alfacalcidiol and calcium supplements to maintain normal serum calcium and phosphate. She achieved her normal developmental milestones.
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Affiliation(s)
- Noman Ahmad
- King Faisal Specialist Hospital and Research Centre Jeddah, Saudi Arabia
| | - Mona Bahasan
- King Faisal Specialist Hospital and Research Centre Jeddah, Saudi Arabia
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Wang L, Widatalla SE, Whalen DS, Ochieng J, Sakwe AM. Association of calcium sensing receptor polymorphisms at rs1801725 with circulating calcium in breast cancer patients. BMC Cancer 2017; 17:511. [PMID: 28764683 PMCID: PMC5540567 DOI: 10.1186/s12885-017-3502-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Accepted: 07/24/2017] [Indexed: 01/04/2023] Open
Abstract
BACKGROUND Breast cancer (BC) patients with late-stage and/or rapidly growing tumors are prone to develop high serum calcium levels which have been shown to be associated with larger and aggressive breast tumors in post and premenopausal women respectively. Given the pivotal role of the calcium sensing receptor (CaSR) in calcium homeostasis, we evaluated whether polymorphisms of the CASR gene at rs1801725 and rs1801726 SNPs in exon 7, are associated with circulating calcium levels in African American and Caucasian control subjects and BC cases. METHODS In this retrospective case-control study, we assessed the mean circulating calcium levels, the distribution of two inactivating CaSR SNPs at rs1801725 and rs1801726 in 199 cases and 384 age-matched controls, and used multivariable regression analysis to determine whether these SNPs are associated with circulating calcium in control subjects and BC cases. RESULTS We found that the mean circulating calcium levels in African American subjects were higher than those in Caucasian subjects (p < 0.001). As expected, the mean calcium levels were higher in BC cases compared to control subjects (p < 0.001), but the calcium levels in BC patients were independent of race. We also show that in BC cases and control subjects, the major alleles at rs1801725 (G/T, A986S) and at rs1801726 (C/G, Q1011E) were common among Caucasians and African Americans respectively. Compared to the wild type alleles, polymorphisms at the rs1801725 SNP were associated with higher calcium levels (p = 0.006) while those at rs1801726 were not. Using multivariable linear mixed-effects models and adjusting for age and race, we show that circulating calcium levels in BC cases were associated with tumor grade (p = 0.009), clinical stage (p = 0.003) and more importantly, with inactivating mutations of the CASR at the rs1801725 SNP (p = 0.038). CONCLUSIONS These data suggest that decreased sensitivity of the CaSR to calcium due to inactivating polymorphisms at rs1801725, may predispose up to 20% of BC cases to high circulating calcium-associated larger and/or aggressive breast tumors.
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Affiliation(s)
- Li Wang
- Vanderbilt Center for Quantitative Sciences, Department of Biostatistics, Vanderbilt University, Nashville, TN, USA
| | - Sarrah E Widatalla
- Department of Biochemistry and Cancer Biology, School of Graduate Studies and Research, Meharry Medical College, Nashville, TN, 37208, USA
| | - Diva S Whalen
- Department of Biochemistry and Cancer Biology, School of Graduate Studies and Research, Meharry Medical College, Nashville, TN, 37208, USA
| | - Josiah Ochieng
- Department of Biochemistry and Cancer Biology, School of Graduate Studies and Research, Meharry Medical College, Nashville, TN, 37208, USA
| | - Amos M Sakwe
- Department of Biochemistry and Cancer Biology, School of Graduate Studies and Research, Meharry Medical College, Nashville, TN, 37208, USA.
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Gorvin CM, Rogers A, Stewart M, Paudyal A, Hough TA, Teboul L, Wells S, Brown SD, Cox RD, Thakker RV. N-ethyl-N-nitrosourea-Induced Adaptor Protein 2 Sigma Subunit 1 ( Ap2s1) Mutations Establish Ap2s1 Loss-of-Function Mice. JBMR Plus 2017; 1:3-15. [PMID: 29479578 PMCID: PMC5824975 DOI: 10.1002/jbm4.10001] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
The adaptor protein‐2 sigma subunit (AP2σ), encoded by AP2S1, forms a heterotetrameric complex, with AP2α, AP2β, and AP2μ subunits, that is pivotal for clathrin‐mediated endocytosis, and AP2σ loss‐of‐function mutations impair internalization of the calcium‐sensing receptor (CaSR), a G‐protein–coupled receptor, and cause familial hypocalciuric hypercalcemia type‐3 (FHH3). Mice with AP2σ mutations that would facilitate investigations of the in vivo role of AP2σ, are not available, and we therefore embarked on establishing such mice. We screened >10,000 mice treated with the mutagen N‐ethyl‐N‐nitrosourea (ENU) for Ap2s1 mutations and identified 5 Ap2s1 variants, comprising 2 missense (Tyr20Asn and Ile123Asn) and 3 intronic base substitutions, one of which altered the invariant donor splice site dinucleotide gt to gc. Three‐dimensional modeling and cellular expression of the missense Ap2s1 variants did not reveal them to alter AP2σ structure or CaSR‐mediated signaling, but investigation of the donor splice site variant revealed it to result in an in‐frame deletion of 17 evolutionarily conserved amino acids (del17) that formed part of the AP2σ α1‐helix, α1‐β3 loop, and β3 strand. Heterozygous mutant mice (Ap2s1+/del17) were therefore established, and these had AP2σ haplosufficiency but were viable with normal appearance and growth. Ap2s1+/del17 mice, when compared with Ap2s1+/+ mice, also had normal plasma concentrations of calcium, phosphate, magnesium, creatinine, urea, sodium, potassium, and alkaline phosphatase activity; normal urinary fractional excretion of calcium, phosphate, sodium, and potassium; and normal plasma parathyroid hormone (PTH) and 1,25‐dihydroxyvitamin D (1,25(OH)2) concentrations. However, homozygous Ap2s1del17/del17 mice were non‐viable and died between embryonic days 3.5 and 9.5 (E3.5–9.5), thereby indicating that AP2σ likely has important roles at the embryonic patterning stages and organogenesis of the heart, thyroid, liver, gut, lungs, pancreas, and neural systems. Thus, our studies have established a mutant mouse model that is haplosufficient for AP2σ. © 2017 The Authors. JBMR Plus is published by Wiley Periodicals, Inc. on behalf of the American Society for Bone and Mineral Research.
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Affiliation(s)
- Caroline M Gorvin
- Academic Endocrine Unit, Radcliffe Department of Medicine, University of Oxford, Oxford Centre for Diabetes, Endocrinology, and Metabolism (OCDEM), Churchill Hospital, Oxford, UK
| | - Angela Rogers
- Academic Endocrine Unit, Radcliffe Department of Medicine, University of Oxford, Oxford Centre for Diabetes, Endocrinology, and Metabolism (OCDEM), Churchill Hospital, Oxford, UK
| | - Michelle Stewart
- Mary Lyon Centre and Mammalian Genetics Unit, Medical Research Council Harwell Institute, Harwell Campus, Oxfordshire, UK
| | - Anju Paudyal
- Mary Lyon Centre and Mammalian Genetics Unit, Medical Research Council Harwell Institute, Harwell Campus, Oxfordshire, UK
| | - Tertius A Hough
- Mary Lyon Centre and Mammalian Genetics Unit, Medical Research Council Harwell Institute, Harwell Campus, Oxfordshire, UK
| | - Lydia Teboul
- Mary Lyon Centre and Mammalian Genetics Unit, Medical Research Council Harwell Institute, Harwell Campus, Oxfordshire, UK
| | - Sara Wells
- Mary Lyon Centre and Mammalian Genetics Unit, Medical Research Council Harwell Institute, Harwell Campus, Oxfordshire, UK
| | - Steve Dm Brown
- Mary Lyon Centre and Mammalian Genetics Unit, Medical Research Council Harwell Institute, Harwell Campus, Oxfordshire, UK
| | - Roger D Cox
- Mary Lyon Centre and Mammalian Genetics Unit, Medical Research Council Harwell Institute, Harwell Campus, Oxfordshire, UK
| | - Rajesh V Thakker
- Academic Endocrine Unit, Radcliffe Department of Medicine, University of Oxford, Oxford Centre for Diabetes, Endocrinology, and Metabolism (OCDEM), Churchill Hospital, Oxford, UK
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30
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Balenga N, Azimzadeh P, Hogue JA, Staats PN, Shi Y, Koh J, Dressman H, Olson JA. Orphan Adhesion GPCR GPR64/ADGRG2 Is Overexpressed in Parathyroid Tumors and Attenuates Calcium-Sensing Receptor-Mediated Signaling. J Bone Miner Res 2017; 32:654-666. [PMID: 27760455 PMCID: PMC7211037 DOI: 10.1002/jbmr.3023] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Revised: 09/30/2016] [Accepted: 10/17/2016] [Indexed: 12/19/2022]
Abstract
Abnormal feedback of serum calcium to parathyroid hormone (PTH) secretion is the hallmark of primary hyperparathyroidism (PHPT). Although the molecular pathogenesis of parathyroid neoplasia in PHPT has been linked to abnormal expression of genes involved in cell growth (e.g., cyclin D1, retinoblastoma, and β-catenin), the molecular basis of abnormal calcium sensing by calcium-sensing receptor (CaSR) and PTH hypersecretion in PHPT are incompletely understood. Through gene expression profiling, we discovered that an orphan adhesion G protein-coupled receptor (GPCR), GPR64/ADGRG2, is expressed in human normal parathyroid glands and is overexpressed in parathyroid tumors from patients with PHPT. Using immunohistochemistry, Western blotting, and coimmunoprecipitation, we found that GPR64 is expressed on the cell surface of parathyroid cells, is overexpressed in parathyroid tumors, and physically interacts with the CaSR. By using reporter gene assay and GPCR second messenger readouts we identified Gαs, 3',5'-cyclic adenosine monophosphate (cAMP), protein kinase A, and cAMP response element binding protein (CREB) as the signaling cascade downstream of GPR64. Furthermore, we found that an N-terminally truncated human GPR64 is constitutively active and a 15-amino acid-long peptide C-terminal to the GPCR proteolysis site (GPS) of GPR64 activates this receptor. Functional characterization of GPR64 demonstrated its ability to increase PTH release from human parathyroid cells at a range of calcium concentrations. We discovered that the truncated constitutively active, but not the full-length GPR64 physically interacts with CaSR and attenuates the CaSR-mediated intracellular Ca2+ signaling and cAMP suppression in HEK293 cells. Our results indicate that GPR64 may be a physiologic regulator of PTH release that is dysregulated in parathyroid tumors, and suggest a role for GPR64 in pathologic calcium sensing in PHPT. © 2016 American Society for Bone and Mineral Research.
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Affiliation(s)
- Nariman Balenga
- Division of General & Oncologic Surgery, Department of Surgery, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Pedram Azimzadeh
- Division of General & Oncologic Surgery, Department of Surgery, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Joyce A Hogue
- Department of Surgery, Duke University Medical Center, Durham, NC, USA
| | - Paul N Staats
- Department of Pathology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Yuhong Shi
- Division of General & Oncologic Surgery, Department of Surgery, University of Maryland School of Medicine, Baltimore, MD, USA
| | - James Koh
- Department of Surgery, Duke University Medical Center, Durham, NC, USA
| | - Holly Dressman
- Department of Molecular Genetics and Microbiology, Duke University, Durham, NC, USA
| | - John A Olson
- Division of General & Oncologic Surgery, Department of Surgery, University of Maryland School of Medicine, Baltimore, MD, USA
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Maruca K, Brambilla I, Mingione A, Bassi L, Capelli S, Brasacchio C, Soldati L, Cisternino M, Mora S. Autosomal dominant hypocalcemia due to a truncation in the C-tail of the calcium-sensing receptor. Mol Cell Endocrinol 2017; 439:187-193. [PMID: 27561204 DOI: 10.1016/j.mce.2016.08.032] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Revised: 08/01/2016] [Accepted: 08/21/2016] [Indexed: 10/21/2022]
Abstract
Autosomal Dominant Hypocalcemia (ADH) is an endocrine disorder due to activating mutations of the calcium-sensing receptor (CASR) gene. We report on a young boy who presented low serum calcium with hypercalciuria, hyperphosphatemia and low serum concentration of parathyroid hormone, not accompanied by classic clinical signs of hypocalcemia. Treatment with calcitriol and calcium did not normalize serum calcium and renal calcium excretion. The use of thiazide diuretics slightly reduced calciuria. Despite high calcium excretion, no signs of nephrocalcinosis were detected. The patient had a prolonged Q-T interval at ECG, which did not normalize during treatment. PCR amplification of CASR coding sequence and direct sequencing of PCR products. showed a novel heterozygous deletion of a cytosine (c.2682delC), responsible for a frameshift (p.S895Pfs*44) and a premature stop codon resulting in a truncation of the CaSR's C-tail. Functional studies indicated increased activity of mutant receptor compared to the wild-type.
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Affiliation(s)
- Katia Maruca
- Laboratory of Pediatric Endocrinology, IRCCS San Raffaele Scientific Institute, via Olgettina 60, 20132, Milan, Italy
| | - Ilaria Brambilla
- Department of Pediatrics, IRCCS Policlinico San Matteo, University of Pavia, viale C. Golgi 19, 27100, Pavia, Italy
| | - Alessandra Mingione
- Department of Health Sciences, Università degli Studi di Milano, via A. di Rudinì 8, 20124, Milan, Italy
| | - Lorenzo Bassi
- Department of Pediatrics, IRCCS Policlinico San Matteo, University of Pavia, viale C. Golgi 19, 27100, Pavia, Italy
| | - Silvia Capelli
- Laboratory of Pediatric Endocrinology, IRCCS San Raffaele Scientific Institute, via Olgettina 60, 20132, Milan, Italy
| | - Caterina Brasacchio
- Department of Health Sciences, Università degli Studi di Milano, via A. di Rudinì 8, 20124, Milan, Italy
| | - Laura Soldati
- Department of Health Sciences, Università degli Studi di Milano, via A. di Rudinì 8, 20124, Milan, Italy
| | - Mariangela Cisternino
- Department of Pediatrics, IRCCS Policlinico San Matteo, University of Pavia, viale C. Golgi 19, 27100, Pavia, Italy
| | - Stefano Mora
- Laboratory of Pediatric Endocrinology, IRCCS San Raffaele Scientific Institute, via Olgettina 60, 20132, Milan, Italy.
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Osagie-Clouard L, Sanghani A, Coathup M, Briggs T, Bostrom M, Blunn G. Parathyroid hormone 1-34 and skeletal anabolic action: The use of parathyroid hormone in bone formation. Bone Joint Res 2017; 6:14-21. [PMID: 28062525 PMCID: PMC5227055 DOI: 10.1302/2046-3758.61.bjr-2016-0085.r1] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/10/2016] [Accepted: 10/24/2016] [Indexed: 12/19/2022] Open
Abstract
Intermittently administered parathyroid hormone (PTH 1-34) has been shown to promote bone formation in both human and animal studies. The hormone and its analogues stimulate both bone formation and resorption, and as such at low doses are now in clinical use for the treatment of severe osteoporosis. By varying the duration of exposure, parathyroid hormone can modulate genes leading to increased bone formation within a so-called 'anabolic window'. The osteogenic mechanisms involved are multiple, affecting the stimulation of osteoprogenitor cells, osteoblasts, osteocytes and the stem cell niche, and ultimately leading to increased osteoblast activation, reduced osteoblast apoptosis, upregulation of Wnt/β-catenin signalling, increased stem cell mobilisation, and mediation of the RANKL/OPG pathway. Ongoing investigation into their effect on bone formation through 'coupled' and 'uncoupled' mechanisms further underlines the impact of intermittent PTH on both cortical and cancellous bone. Given the principally catabolic actions of continuous PTH, this article reviews the skeletal actions of intermittent PTH 1-34 and the mechanisms underlying its effect. CITE THIS ARTICLE L. Osagie-Clouard, A. Sanghani, M. Coathup, T. Briggs, M. Bostrom, G. Blunn. Parathyroid hormone 1-34 and skeletal anabolic action: The use of parathyroid hormone in bone formation. Bone Joint Res 2017;6:14-21. DOI: 10.1302/2046-3758.61.BJR-2016-0085.R1.
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Affiliation(s)
- L Osagie-Clouard
- Institute of Orthopaedics and Musculoskeletal Sciences, University College London, Royal National Orthopaedic Hospital, Stanmore, Middlesex HA7 4LP, London, UK
| | - A Sanghani
- Institute of Orthopaedics and Musculoskeletal Sciences, University College London, Royal National Orthopaedic Hospital, Stanmore, Middlesex HA7 4LP, London, UK
| | - M Coathup
- Institute of Orthopaedics and Musculoskeletal Sciences, University College London, Royal National Orthopaedic Hospital, Stanmore, Middlesex HA7 4LP, London, UK
| | - T Briggs
- Institute of Orthopaedics and Musculoskeletal Sciences, University College London, Royal National Orthopaedic Hospital, Stanmore, Middlesex HA7 4LP, London, UK
| | - M Bostrom
- Hospital for Special Surgery, New York, New York, USA
| | - G Blunn
- Institute of Orthopaedics and Musculoskeletal Sciences, University College London, Royal National Orthopaedic Hospital, Stanmore, Middlesex HA7 4LP, London, UK
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Lodefalk M, Frykholm C, Esbjörner E, Ljunggren Ö. Hypercalcaemia in a Patient with 2p13.2-p16.1 Duplication. Horm Res Paediatr 2016; 85:213-8. [PMID: 26675490 DOI: 10.1159/000442747] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Accepted: 11/25/2015] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Partial duplication of 2p is a rare condition that causes facial anomalies, psychomotor delay, and growth failure. Hypercalcaemia is rare in children. So far, duplication of 2p has never been associated with hypercalcaemia. METHODS Here, we report a girl with a partial duplication of 2p presenting with moderate to severe hypercalcaemia at the age of 2 years. She also had hypercalciuria, nephrocalcinosis, decreased renal function, and secondary hyperparathyroidism at presentation. She was thoroughly investigated, including genetic testing of the CYP24A1, CASR, ALPL, and NOD2 genes, to determine the cause of hypercalcaemia. RESULTS 1,25-dihydroxyvitamin D levels were increased. Hypercalcaemia and hypercalciuria responded well to glucocorticoids but not to cinacalcet. Hyperparathyroidism resolved with improving renal function. Apart from the known duplication of 2p, no pathogenic variants were detected in the studied genes. The duplication of 2p contains the PPP3R1 gene, which encodes for the calcineurin B subunit. CONCLUSION We conclude that partial duplication of 2p can be associated with hypercalcaemia and hypercalciuria and hypothesise that the underlying mechanism is an increased extra-renal, parathyroid hormone-independent 25-hydroxyvitamin D 1α-hydroxylase activity, leading to raised amounts of 1,25-dihydroxyvitamin D. The increased enzymatic activity could possibly be caused by calcineurin B subunit-related macrophage stimulation.
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Affiliation(s)
- Maria Lodefalk
- Department of Paediatrics, Faculty of Medicine and Health, x00D6;rebro University, x00D6;rebro, Sweden
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Conigrave AD. The Calcium-Sensing Receptor and the Parathyroid: Past, Present, Future. Front Physiol 2016; 7:563. [PMID: 28018229 PMCID: PMC5156698 DOI: 10.3389/fphys.2016.00563] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2016] [Accepted: 11/07/2016] [Indexed: 12/13/2022] Open
Abstract
Parathyroid hormone (PTH) defends the extracellular fluid from hypocalcemia and has powerful and well-documented actions on the skeleton and renal tubular system. To achieve a satisfactory stable plasma calcium level, the secretion of PTH, and the resulting serum PTH level, is titrated carefully to the prevailing plasma ionized Ca2+ concentration via a Ca2+ sensing mechanism that mediates feedback inhibition of PTH secretion. Herein, I consider the properties of the parathyroid Ca2+ sensing mechanism, the identity of the Ca2+ sensor, the intracellular biochemical mechanisms that it controls, the manner of its integration with other components of the PTH secretion control mechanism, and its modulation by other nutrients. Together the well-established, recently elucidated, and yet-to-be discovered elements of the story constitute the past, present, and future of the parathyroid and its calcium-sensing receptor (CaSR).
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Affiliation(s)
- Arthur D Conigrave
- Faculties of Science and Medicine, School of Life and Environmental Sciences, Charles Perkins Centre, University of Sydney Sydney, NSW, Australia
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35
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Glaudo M, Letz S, Quinkler M, Bogner U, Elbelt U, Strasburger CJ, Schnabel D, Lankes E, Scheel S, Feldkamp J, Haag C, Schulze E, Frank-Raue K, Raue F, Mayr B, Schöfl C. Heterozygous inactivating CaSR mutations causing neonatal hyperparathyroidism: function, inheritance and phenotype. Eur J Endocrinol 2016; 175:421-31. [PMID: 27666534 DOI: 10.1530/eje-16-0223] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/14/2016] [Accepted: 08/30/2016] [Indexed: 12/20/2022]
Abstract
BACKGROUND Homozygous inactivating mutations of the calcium-sensing receptor (CaSR) lead to neonatal severe hyperparathyroidism (NSHPT), whereas heterozygous inactivating mutations result in familial hypocalciuric hypercalcemia (FHH). It is unknown why in some cases heterozygous CaSR mutations cause neonatal hyperparathyroidism (NHPT) clinically similar to NSHPT but with only moderately elevated serum calcium. METHODS A literature survey was conducted to identify patients with heterozygous CaSR mutations and NHPT. The common NHPT CaSR mutants R185Q and R227L were compared with 15 mutants causing only FHH in the heterozygous state. We studied in vitro calcium signaling including the functional consequences of co-expression of mutant and wild-type (wt) CaSR, patients' phenotype, age of disease manifestation and mode of inheritance. RESULTS All inactivating CaSR mutants impaired calcium signaling of wt-CaSR regardless of the patients' clinical phenotype. The absolute intracellular calcium signaling response to physiologic extracellular calcium concentrations in vitro showed a high correlation with patients' serum calcium concentrations in vivo, which is similar in NHPT and FHH patients with the same genotype. Pedigrees of FHH families revealed that paternal inheritance per se does not necessarily lead to NHPT but may only cause FHH. CONCLUSIONS There is a significant correlation between in vitro functional impairment of the CaSR at physiologic calcium concentrations and the severity of alterations in calcium homeostasis in patients. Whether a particular genotype leads to NHPT or FHH appears to depend on additional predisposing genetic or environmental factors. An individual therapeutic approach appears to be warranted for NHPT patients.
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Affiliation(s)
- Markus Glaudo
- Division of Endocrinology and DiabetesDepartment of Medicine I, Universitätsklinikum Erlangen, Erlangen, Germany
| | - Saskia Letz
- Division of Endocrinology and DiabetesDepartment of Medicine I, Universitätsklinikum Erlangen, Erlangen, Germany
| | | | | | - Ulf Elbelt
- Department of EndocrinologyDiabetes and Nutrition
| | | | - Dirk Schnabel
- Center for Chronic Sick ChildrenPediatric Endocrinology and Diabetes, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Erwin Lankes
- Center for Chronic Sick ChildrenPediatric Endocrinology and Diabetes, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Sandra Scheel
- Endocrinology and DiabetologyKlinikum Bielefeld, Bielefeld, Germany
| | - Joachim Feldkamp
- Endocrinology and DiabetologyKlinikum Bielefeld, Bielefeld, Germany
| | | | | | | | | | - Bernhard Mayr
- Division of Endocrinology and DiabetesDepartment of Medicine I, Universitätsklinikum Erlangen, Erlangen, Germany
| | - Christof Schöfl
- Division of Endocrinology and DiabetesDepartment of Medicine I, Universitätsklinikum Erlangen, Erlangen, Germany
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Regala J, Cavaco B, Domingues R, Limbert C, Lopes L. Novel Mutation in the CASR Gene (p.Leu123Ser) in a Case of Autosomal Dominant Hypocalcemia. J Pediatr Genet 2016; 4:29-33. [PMID: 27617113 DOI: 10.1055/s-0035-1554979] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Autosomal dominant hypocalcemia, caused by activating mutations of the calcium-sensing receptor (CASR) gene, is characterized by hypocalcemia with an inappropriately low concentration of parathyroid hormone (PTH). In this report, we describe the identification of a novel missense mutation in the CASR gene, in a boy with autosomal dominant hypocalcemia. Polymerase chain reaction (PCR)-single strand and DNA sequencing revealed a heterozygous mutation in CASR gene that causes a leucine substitution for serine at codon 123 (p.Leu123Ser). This mutation was absent in DNA from 50 control patients. In silico studies suggest that the identified variant was likely pathogenic. Sequencing analysis in the mother suggested mosaicism for the same variant, and she was clinically and biochemically unaffected. Clinical manifestations of the index case started with seizures at 14 months of age; cognitive impairment and several neuropsychological disabilities were noted during childhood. Extrapyramidal signs and basal ganglia calcification developed later, namely, hand tremor and rigidity at the age of 7 and 18 years, respectively. Laboratory analysis revealed hypocalcemia, hyperphosphatemia, and low-serum PTH with hypomagnesemia and mild hypercalciuria. After 2 years of treatment with calcium supplements and calcitriol, some brief periods of clinical improvement were reported; as well as an absence of nephrocalcinosis.
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Affiliation(s)
- Joana Regala
- Pediatric Endocrinology Unit, Dona Estefânia Pediatric Hospital, Hospital Centre of Central Lisbon, Lisbon, Portugal
| | - Branca Cavaco
- Molecular Pathobiology Research Centre, Portuguese Institute of Oncology Francisco Gentil, Lisbon, Portugal; Chronic Diseases Research Center, NOVA Medical School, NOVA University of Lisbon, Lisbon, Portugal
| | - Rita Domingues
- Molecular Pathobiology Research Centre, Portuguese Institute of Oncology Francisco Gentil, Lisbon, Portugal; Chronic Diseases Research Center, NOVA Medical School, NOVA University of Lisbon, Lisbon, Portugal
| | - Catarina Limbert
- Pediatric Endocrinology Unit, Dona Estefânia Pediatric Hospital, Hospital Centre of Central Lisbon, Lisbon, Portugal
| | - Lurdes Lopes
- Pediatric Endocrinology Unit, Dona Estefânia Pediatric Hospital, Hospital Centre of Central Lisbon, Lisbon, Portugal
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Mayr B, Schnabel D, Dörr HG, Schöfl C. GENETICS IN ENDOCRINOLOGY: Gain and loss of function mutations of the calcium-sensing receptor and associated proteins: current treatment concepts. Eur J Endocrinol 2016; 174:R189-208. [PMID: 26646938 DOI: 10.1530/eje-15-1028] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/19/2015] [Accepted: 12/08/2015] [Indexed: 12/26/2022]
Abstract
The calcium-sensing receptor (CASR) is the main calcium sensor in the maintenance of calcium metabolism. Mutations of the CASR, the G protein alpha 11 (GNA11) and the adaptor-related protein complex 2 sigma 1 subunit (AP2S1) genes can shift the set point for calcium sensing causing hyper- or hypo-calcemic disorders. Therapeutic concepts for these rare diseases range from general therapies of hyper- and hypo-calcemic conditions to more pathophysiology oriented approaches such as parathyroid hormone (PTH) substitution and allosteric CASR modulators. Cinacalcet is a calcimimetic that enhances receptor function and has gained approval for the treatment of hyperparathyroidism. Calcilytics in turn attenuate CASR activity and are currently under investigation for the treatment of various diseases. We conducted a literature search for reports about treatment of patients harboring inactivating or activating CASR, GNA11 or AP2S1 mutants and about in vitro effects of allosteric CASR modulators on mutated CASR. The therapeutic concepts for patients with familial hypocalciuric hypercalcemia (FHH), neonatal hyperparathyroidism (NHPT), neonatal severe hyperparathyroidism (NSHPT) and autosomal dominant hypocalcemia (ADH) are reviewed. FHH is usually benign, but symptomatic patients benefit from cinacalcet. In NSHPT patients pamidronate effectively lowers serum calcium, but most patients require parathyroidectomy. In some patients cinacalcet can obviate the need for surgery, particularly in heterozygous NHPT. Symptomatic ADH patients respond to vitamin D and calcium supplementation but this may increase calciuria and renal complications. PTH treatment can reduce relative hypercalciuria. None of the currently available therapies for ADH, however, prevent tissue calcifications and complications, which may become possible with calcilytics that correct the underlying pathophysiologic defect.
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Affiliation(s)
- Bernhard Mayr
- Division of Endocrinology and DiabetesDepartment of Medicine I, Universitätsklinikum Erlangen, Friedrich-Alexander University Erlangen-Nuremberg, Ulmenweg 18, 91054 Erlangen, GermanyCenter for Chronic Sick ChildrenPediatric Endocrinology and Diabetes, Charité University Medicine Berlin, Berlin, GermanyDivision of Paediatric Endocrinology and DiabetesDepartment of Paediatrics, Universitätsklinikum Erlangen, Friedrich-Alexander University Erlangen-Nuremberg, Erlangen, Germany
| | - Dirk Schnabel
- Division of Endocrinology and DiabetesDepartment of Medicine I, Universitätsklinikum Erlangen, Friedrich-Alexander University Erlangen-Nuremberg, Ulmenweg 18, 91054 Erlangen, GermanyCenter for Chronic Sick ChildrenPediatric Endocrinology and Diabetes, Charité University Medicine Berlin, Berlin, GermanyDivision of Paediatric Endocrinology and DiabetesDepartment of Paediatrics, Universitätsklinikum Erlangen, Friedrich-Alexander University Erlangen-Nuremberg, Erlangen, Germany
| | - Helmuth-Günther Dörr
- Division of Endocrinology and DiabetesDepartment of Medicine I, Universitätsklinikum Erlangen, Friedrich-Alexander University Erlangen-Nuremberg, Ulmenweg 18, 91054 Erlangen, GermanyCenter for Chronic Sick ChildrenPediatric Endocrinology and Diabetes, Charité University Medicine Berlin, Berlin, GermanyDivision of Paediatric Endocrinology and DiabetesDepartment of Paediatrics, Universitätsklinikum Erlangen, Friedrich-Alexander University Erlangen-Nuremberg, Erlangen, Germany
| | - Christof Schöfl
- Division of Endocrinology and DiabetesDepartment of Medicine I, Universitätsklinikum Erlangen, Friedrich-Alexander University Erlangen-Nuremberg, Ulmenweg 18, 91054 Erlangen, GermanyCenter for Chronic Sick ChildrenPediatric Endocrinology and Diabetes, Charité University Medicine Berlin, Berlin, GermanyDivision of Paediatric Endocrinology and DiabetesDepartment of Paediatrics, Universitätsklinikum Erlangen, Friedrich-Alexander University Erlangen-Nuremberg, Erlangen, Germany
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Li D, Tian L, Hou C, Kim CE, Hakonarson H, Levine MA. Association of Mutations in SLC12A1 Encoding the NKCC2 Cotransporter With Neonatal Primary Hyperparathyroidism. J Clin Endocrinol Metab 2016; 101:2196-200. [PMID: 26963954 PMCID: PMC4870850 DOI: 10.1210/jc.2016-1211] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
CONTEXT Primary hyperparathyroidism with hypercalciuria has not been described in the newborn period. OBJECTIVE Our objectives are to identify the genetic basis for neonatal primary hyperparathyroidism in a family with 2 affected children. SUBJECTS An African American boy presenting with mild neonatal primary hyperparathyroidism and hypercalciuria was evaluated at The Children's Hospital of Philadelphia. His older brother with neonatal primary hyperparathyroidism had died in infancy of multiple organ failure. METHODS We collected clinical and biochemical data and performed exome sequencing analysis on DNA from the patient and his unaffected mother after negative genetic testing for known causes of primary hyperparathyroidism. RESULTS Exome sequencing followed by Sanger sequencing disclosed 2 heterozygous mutations, c.1883C>A, p.(A628D) and c.2786_2787insC, p.(T931fsX10), in the SLC12A1 gene, which was previously implicated in antenatal type 1 Bartter syndrome. Sanger sequencing confirmed the 2 mutations in the proband and his deceased brother; both parents were heterozygous for different mutations and an unaffected sister was homozygous for wild-type alleles. CONCLUSIONS These results demonstrate a previously unrecognized association between neonatal primary hyperparathyroidism and mutation of SLC12A1, the cause of antenatal Bartter syndrome type 1, and suggest that the loss of sodium-potassium-chloride cotransporter-2 cotransporter activity influences parathyroid gland function.
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Affiliation(s)
- Dong Li
- The Center for Applied Genomics (D.L., L.T., C.H., C.E.K., H.H.), The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104; Department of Pediatrics (H.H., M.A.L.), University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania 19104; and Division of Endocrinology and Diabetes and the Center for Bone Health (M.A.L.), The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104
| | - Lifeng Tian
- The Center for Applied Genomics (D.L., L.T., C.H., C.E.K., H.H.), The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104; Department of Pediatrics (H.H., M.A.L.), University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania 19104; and Division of Endocrinology and Diabetes and the Center for Bone Health (M.A.L.), The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104
| | - Cuiping Hou
- The Center for Applied Genomics (D.L., L.T., C.H., C.E.K., H.H.), The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104; Department of Pediatrics (H.H., M.A.L.), University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania 19104; and Division of Endocrinology and Diabetes and the Center for Bone Health (M.A.L.), The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104
| | - Cecilia E Kim
- The Center for Applied Genomics (D.L., L.T., C.H., C.E.K., H.H.), The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104; Department of Pediatrics (H.H., M.A.L.), University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania 19104; and Division of Endocrinology and Diabetes and the Center for Bone Health (M.A.L.), The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104
| | - Hakon Hakonarson
- The Center for Applied Genomics (D.L., L.T., C.H., C.E.K., H.H.), The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104; Department of Pediatrics (H.H., M.A.L.), University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania 19104; and Division of Endocrinology and Diabetes and the Center for Bone Health (M.A.L.), The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104
| | - Michael A Levine
- The Center for Applied Genomics (D.L., L.T., C.H., C.E.K., H.H.), The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104; Department of Pediatrics (H.H., M.A.L.), University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania 19104; and Division of Endocrinology and Diabetes and the Center for Bone Health (M.A.L.), The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104
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Iacobone M, Carnaille B, Palazzo FF, Vriens M. Hereditary hyperparathyroidism--a consensus report of the European Society of Endocrine Surgeons (ESES). Langenbecks Arch Surg 2015; 400:867-86. [PMID: 26450137 DOI: 10.1007/s00423-015-1342-7] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Accepted: 09/15/2015] [Indexed: 11/30/2022]
Abstract
BACKGROUND Hereditary hyperparathyroidism has been reported to occur in 5-10 % of cases of primary hyperparathyroidism in the context of multiple endocrine neoplasia (MEN) types 1, 2A and 4; hyperparathyroidism-jaw tumour (HPT-JT); familial isolated hyperparathyroidism (FIHPT); familial hypocalciuric hypercalcaemia (FHH); neonatal severe hyperparathyroidism (NSHPT) and autosomal dominant moderate hyperparathyroidism (ADMH). This paper aims to review the controversies in the main genetic, clinical and pathological features and surgical management of hereditary hyperparathyroidism. METHODS A peer review literature analysis on hereditary hyperparathyroidism was carried out and analyzed in an evidence-based perspective. Results were discussed at the 2015 Workshop of the European Society of Endocrine Surgeons devoted to hyperparathyroidism due to multiple gland disease. RESULTS Literature reports scarcity of prospective randomized studies; thus, a low level of evidence may be achieved. CONCLUSIONS Hereditary hyperparathyroidism typically presents at an earlier age than the sporadic variants. Gene penetrance and expressivity varies. Parathyroid multiple gland involvement is common, but in some variants, it may occur metachronously often with long disease-free intervals, simulating a single-gland involvement. Bilateral neck exploration with subtotal parathyroidectomy or total parathyroidectomy + autotransplantation should be performed, especially in MEN 1, in order to decrease the persistent and recurrent hyperparathyroidism rates; in some variants (MEN 2A, HPT-JT), limited parathyroidectomy can achieve long-term normocalcemia. In FHH, surgery is contraindicated; in NSHPT, urgent total parathyroidectomy is required. In FIHPT, MEN 4 and ADMH, a tailored case-specific approach is recommended.
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Affiliation(s)
- Maurizio Iacobone
- Endocrine Surgery Unit, Department of Surgery, Oncology and Gastroenterology, University of Padua, Via Giustiniani 2, 35128, Padova, Italy.
| | - Bruno Carnaille
- Department of Endocrine Surgery, Université de Lille, Lille, France
| | - F Fausto Palazzo
- Department of Endocrine and Thyroid Surgery, Hammersmith Hospital and Imperial College, London, UK
| | - Menno Vriens
- Department of Surgical Oncology and Endocrine Surgery, Cancer Center, University Medical Center Utrecht, Utrecht, The Netherlands
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Cianferotti L, Gomes AR, Fabbri S, Tanini A, Brandi ML. The calcium-sensing receptor in bone metabolism: from bench to bedside and back. Osteoporos Int 2015; 26:2055-71. [PMID: 26100412 DOI: 10.1007/s00198-015-3203-1] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/29/2014] [Accepted: 06/08/2015] [Indexed: 12/11/2022]
Abstract
UNLABELLED The calcium-sensing receptor (CaSR), a key player in the maintenance of calcium homeostasis, can influence bone modeling and remodeling by directly acting on bone cells, as demonstrated by in vivo and in vitro evidence. The modulation of CaSR signaling can play a role in bone anabolism. INTRODUCTION The calcium-sensing receptor (CaSR) is a key player in the maintenance of calcium homeostasis through the regulation of PTH secretion and calcium homeostasis, thus indirectly influencing bone metabolism. In addition to this role, in vitro and in vivo evidence points to direct effects of CaSR in bone modeling and remodeling. In addition, the activation of the CaSR is one of the anabolic mechanisms implicated in the action of strontium ranelate, to reduce fracture risk. METHODS This review is based upon the acquisition of data from a PubMed enquiry using the terms "calcium sensing receptor," "CaSR" AND "bone remodeling," "bone modeling," "bone turnover," "osteoblast," "osteoclast," "osteocyte," "chondrocyte," "bone marrow," "calcilytics," "calcimimetics," "strontium," "osteoporosis," "skeletal homeostasis," and "bone metabolism." RESULTS A fully functional CaSR is expressed in osteoblasts and osteoclasts, so that these cells are able to sense changes in the extracellular calcium and as a result modulate their behavior. CaSR agonists (calcimimetics) or antagonists (calcilytics) have the potential to indirectly influence skeletal homeostasis through the modulation of PTH secretion by the parathyroid glands. The bone anabolic effect of strontium ranelate, a divalent cation used as a treatment for postmenopausal and male osteoporosis, might be explained, at least in part, by the activation of CaSR in bone cells. CONCLUSIONS Calcium released in the bone microenvironment during remodeling is a major factor in regulating bone cells. Osteoblast and osteoclast proliferation, differentiation, and apoptosis are influenced by local extracellular calcium concentration. Thus, the calcium-sensing properties of skeletal cells can be exploited in order to modulate bone turnover and can explain the bone anabolic effects of agents developed and employed to revert osteoporosis.
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Affiliation(s)
- L Cianferotti
- Metabolic Bone Diseases Unit, Department of Surgery and Translational Medicine, University of Florence, 50134, Florence, Italy
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Baran N, ter Braak M, Saffrich R, Woelfle J, Schmitz U. Novel activating mutation of human calcium-sensing receptor in a family with autosomal dominant hypocalcaemia. Mol Cell Endocrinol 2015; 407:18-25. [PMID: 25766501 DOI: 10.1016/j.mce.2015.02.021] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/07/2013] [Revised: 01/13/2015] [Accepted: 02/19/2015] [Indexed: 12/24/2022]
Abstract
INTRODUCTION Autosomal dominant hypocalcaemia (ADH) is caused by activating mutations in the calcium sensing receptor gene (CaR) and characterised by mostly asymptomatic mild to moderate hypocalcaemia with low, inappropriately serum concentration of PTH. OBJECTIVE The purpose of the present study was to biochemically and functionally characterise a novel mutation of CaR. PATIENTS A female proband presenting with hypocalcaemia was diagnosed to have "idiopathic hypoparathyroidism" at the age of 10 with a history of muscle pain and cramps. Further examinations demonstrated hypocalcaemia in nine additional family members, affecting three generations. MAIN OUTCOME MEASURE P136L CaR mutation was predicted to cause gain of function of CaR. RESULTS Affected family members showed relevant hypocalcaemia (mean ± SD; 1.9 ± 0.1 mmol/l). Patient history included mild seizures and recurrent nephrolithiasis. Genetic analysis confirmed that hypocalcaemia cosegregated with a heterozygous mutation at codon 136 (CCC → CTC/Pro → Leu) in exon 3 of CaR confirming the diagnosis of ADH. For in vitro studies P136L mutant CaR was generated by site-directed mutagenesis and examined in transiently transfected HEK293 cells. Extracellular calcium stimulation of transiently transfected HEK293 cells showed significantly increased intracellular Ca(2+) mobilisation and MAPK activity for mutant P136L CaR compared to wild type CaR. CONCLUSIONS The present study gives insight about a novel activating mutation of CaR and confirms that the novel P136L-CaR mutation is responsible for ADH in this family.
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Affiliation(s)
- Natalia Baran
- Department of Endocrinology and Diabetology, University of Bonn, Sigmund-Freud-Str. 25, 53127 Bonn, Germany; Department of Medicine V, University of Heidelberg, INF 410, 69120 Heidelberg, Germany.
| | - Michael ter Braak
- Institut of Pharmacology, University of Essen, Hufelandstr. 55, 45122 Essen, Germany
| | - Rainer Saffrich
- Department of Medicine V, University of Heidelberg, INF 410, 69120 Heidelberg, Germany
| | - Joachim Woelfle
- Pediatric Endocrinology Division, University of Bonn, Adenauerallee 119, 53113 Bonn, Germany
| | - Udo Schmitz
- Department of Endocrinology and Diabetology, University of Bonn, Sigmund-Freud-Str. 25, 53127 Bonn, Germany
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Brickman TM, Stark MW, Jeyakumar A. Unusual case of neonatal hypercalcemia. Int J Pediatr Otorhinolaryngol 2015; 79:758-9. [PMID: 25792032 DOI: 10.1016/j.ijporl.2015.02.029] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/22/2015] [Revised: 02/23/2015] [Accepted: 02/25/2015] [Indexed: 11/25/2022]
Abstract
We present a rare case of neonatal hyperparathyroidism secondary to a homozygous calcium sensing receptor (CASR) mutation, diagnosed by the genetics team. The CASR mutation is a homozygous inactivating mutation at the calcium sensing receptor. Inactivation of the receptor leads to hypercalcemia and activation leads to hypocalcemia. Heterozygous mutations can cause mild forms of asymptomatic hypercalcemia that often run in families. The homozygous mutation causes a rare form of neonatal severe hyperparathyroidism.
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Affiliation(s)
- Todd M Brickman
- Department of Otorhinolaryngology, Louisiana State University-Health Science Center, New Orleans, LA 70112, United States
| | - Matthew W Stark
- Department of Pathology, Louisiana State University-Health Science Center, New Orleans, LA 70112, United States
| | - Anita Jeyakumar
- Department of Otorhinolaryngology, 200 Henry Clay Avenue, Ste 4119 New Orleans, LA 70118, United States.
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Silva BC, Bilezikian JP. Parathyroid hormone: anabolic and catabolic actions on the skeleton. Curr Opin Pharmacol 2015; 22:41-50. [PMID: 25854704 DOI: 10.1016/j.coph.2015.03.005] [Citation(s) in RCA: 312] [Impact Index Per Article: 34.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2015] [Accepted: 03/24/2015] [Indexed: 12/16/2022]
Abstract
Parathyroid hormone (PTH) is essential for the maintenance of calcium homeostasis through, in part, its actions to regulate bone remodeling. While PTH stimulates both bone formation and bone resorption, the duration and periodicity of exposure to PTH governs the net effect on bone mass, that is whether it is catabolic or anabolic. PTH receptor signaling in osteoblasts and osteocytes can increase the RANKL/OPG ratio, increasing both osteoclast recruitment and osteoclast activity, and thereby stimulating bone resorption. In contrast, PTH-induced bone formation is explained, at least in part, by its ability to downregulate SOST/sclerostin expression in osteocytes, permitting the anabolic Wnt signaling pathway to proceed. The two modes of administration of PTH, that is, continuous vs. intermittent, can regulate, in bone cells, different sets of genes; alternatively, the same sets of genes exposed to PTH in sustained vs. transient way, will favor bone resorption or bone formation, respectively. This article reviews the effects of PTH on bone cells that lead to these dual catabolic and anabolic actions on the skeleton.
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Affiliation(s)
- Barbara C Silva
- Santa Casa de Belo Horizonte and Felicio Rocho Hospital, Division of Endocrinology, Brazil
| | - John P Bilezikian
- Metabolic Bone Diseases Unit, Division of Endocrinology, Department of Medicine, College of Physicians and Surgeons, Columbia University, United States.
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Abstract
Phosphate is essential for growth and maintenance of the skeleton and for generating high-energy phosphate compounds. Evolutionary adaptation to high dietary phosphorous in humans and other terrestrial vertebrates involves regulated mechanisms assuring the efficient renal elimination of excess phosphate. These mechanisms prominently include PTH, FGF23, and Vitamin D, which directly and indirectly regulate phosphate transport. Disordered phosphate homeostasis is associated with pathologies ranging from kidney stones to kidney failure. Chronic kidney disease results in hyperphosphatemia, an elevated calcium×phosphate product with considerable morbidity and mortality, mostly associated with adverse cardiovascular events. This chapter highlights recent findings and insights regarding the hormonal regulation of renal phosphate transport along with imbalances of phosphate balance due to acquired or inherited diseases states.
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Szalat A, Shahar M, Shpitzen S, Nachmias B, Munter G, Gillis D, Durst R, Mevorach D, Leitersdorf E, Meiner V, Rosen H. Calcium-sensing receptor sequencing in 21 patients with idiopathic or familial parathyroid disorder: pitfalls and characterization of a novel I32 V loss-of-function mutation. Endocrine 2015; 48:444-53. [PMID: 25091521 DOI: 10.1007/s12020-014-0370-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/06/2014] [Accepted: 07/19/2014] [Indexed: 12/22/2022]
Abstract
The calcium-sensing receptor (CaSR) is a G-protein-coupled receptor with a crucial role in calcium homeostasis. Mutations in the CaSR gene may lead to specific parathyroid disorders due to either gain-of-function (autosomal dominant hypercalciuric hypocalcemia; ADHH) or loss-of-function (familial hypocalciuric hypercalcemia; FHH). Our aim was to evaluate CaSR mutations as a cause of disease in selected patients. We identified and recruited patients with phenotypes suggestive of CaSR-related parathyroid disorders. DNA was extracted, and CaSR gene was sequenced. Live-ratiometric measurements of intracellular [Ca(2+)] and Western blot assays for evaluation of MAPK phosphorylation in response to changes in extracellular [Ca(2+)] were performed in transiently transfected HEK-293T cells to functionally characterize mutants. A total of 21 patients were evaluated, seven of them with idiopathic hypoparathyroidism (suspected ADHH) and 14 with hyperparathyroidism (suspected FHH). In the latter group two patients were found to harbor missense mutations: a novel heterozygous I32 V mutation in a female index case and a sporadic known R185Q mutation in a 1-year-old girl. In-vitro functional studies showed that I32 V is an inactivating mutation. In our study, most patients had normal CaSR sequencing. This suggests that phenotypic pitfalls may occur at time of patients' selection for CaSR sequencing. In one patient with strong positive pre-test probability based on both familial history and appropriate phenotype, a novel I32 V mutation leading to FHH was identified and characterized. In cases of familial parathyroid disorders, CaSR sequencing should be performed, but if negative, one should consider involvement of alternative genes or mechanisms.
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Affiliation(s)
- Auryan Szalat
- Endocrinology and Metabolism Service, Department of Internal Medicine, Hadassah-Hebrew University Medical Center, POB 24035, 91240, Jerusalem, Israel,
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Marcucci G, Cianferotti L, Beck-Peccoz P, Capezzone M, Cetani F, Colao A, Davì MV, degli Uberti E, Del Prato S, Elisei R, Faggiano A, Ferone D, Foresta C, Fugazzola L, Ghigo E, Giacchetti G, Giorgino F, Lenzi A, Malandrino P, Mannelli M, Marcocci C, Masi L, Pacini F, Opocher G, Radicioni A, Tonacchera M, Vigneri R, Zatelli MC, Brandi ML. Rare diseases in clinical endocrinology: a taxonomic classification system. J Endocrinol Invest 2015; 38:193-259. [PMID: 25376364 DOI: 10.1007/s40618-014-0202-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/19/2014] [Accepted: 10/17/2014] [Indexed: 02/05/2023]
Abstract
PURPOSE Rare endocrine-metabolic diseases (REMD) represent an important area in the field of medicine and pharmacology. The rare diseases of interest to endocrinologists involve all fields of endocrinology, including rare diseases of the pituitary, thyroid and adrenal glands, paraganglia, ovary and testis, disorders of bone and mineral metabolism, energy and lipid metabolism, water metabolism, and syndromes with possible involvement of multiple endocrine glands, and neuroendocrine tumors. Taking advantage of the constitution of a study group on REMD within the Italian Society of Endocrinology, consisting of basic and clinical scientists, a document on the taxonomy of REMD has been produced. METHODS AND RESULTS This document has been designed to include mainly REMD manifesting or persisting into adulthood. The taxonomy of REMD of the adult comprises a total of 166 main disorders, 338 including all variants and subtypes, described into 11 tables. CONCLUSIONS This report provides a complete taxonomy to classify REMD of the adult. In the future, the creation of registries of rare endocrine diseases to collect data on cohorts of patients and the development of common and standardized diagnostic and therapeutic pathways for each rare endocrine disease is advisable. This will help planning and performing intervention studies in larger groups of patients to prove the efficacy, effectiveness, and safety of a specific treatment.
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Affiliation(s)
- G Marcucci
- Head, Bone Metablic Diseases Unit, Department of Surgery and Translational Medicine, University of Florence, Viale Pieraccini 6, 50139, Florence, Italy.
| | - L Cianferotti
- Head, Bone Metablic Diseases Unit, Department of Surgery and Translational Medicine, University of Florence, Viale Pieraccini 6, 50139, Florence, Italy
| | - P Beck-Peccoz
- Department of Clinical Sciences and Community Health, University of Milan and Endocrine Unit, Fondazione IRCCS Ca' Granda, Milan, Italy
| | - M Capezzone
- Section of Endocrinology and Metabolism, Department of Internal Medicine, Endocrinology and Metabolism and Biochemistry, University of Siena, Policlinico Santa Maria alle Scotte, Siena, Italy
| | - F Cetani
- Unit of Endocrinology, Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - A Colao
- Dipartimento di Medicina Clinica e Chirurgia, Università Federico II di Napoli, Naples, Italy
| | - M V Davì
- Section D, Department of Medicine, Clinic of Internal Medicine, University of Verona, Verona, Italy
| | - E degli Uberti
- Section of Endocrinology, Department of Medical Sciences, University of Ferrara, Ferrara, Italy
| | - S Del Prato
- Section of Metabolic Diseases and Diabetes, Department of Endocrinology and Metabolism, University of Pisa, Pisa, Italy
| | - R Elisei
- Unit of Endocrinology, Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - A Faggiano
- Dipartimento di Medicina Clinica e Chirurgia, Università Federico II di Napoli, Naples, Italy
| | - D Ferone
- Endocrinology, Department of Internal Medicine and Medical Specialties and Center of Excellence for Biomedical Research, IRCCS AOU San Martino-IST, University of Genoa, Genoa, Italy
| | - C Foresta
- Department of Medicine and Centre for Human Reproduction Pathology, University of Padova, Padua, Italy
| | - L Fugazzola
- Department of Clinical Sciences and Community Health, University of Milan and Endocrine Unit, Fondazione IRCCS Ca' Granda, Milan, Italy
| | - E Ghigo
- Division of Endocrinology, Diabetology and Metabolism Department of Medical Sciences, University Hospital Città Salute e Scienza, Turin, Italy
| | - G Giacchetti
- Division of Endocrinology, Azienda Ospedaliero-Universitaria, Ospedali Riuniti Umberto I-GM Lancisi-G Salesi, Università Politecnica delle Marche, Ancona, Italy
| | - F Giorgino
- Section of Internal Medicine, Endocrinology, Andrology and Metabolic Diseases, Department of Emergency and Organ Transplantation, University of Bari Aldo Moro, Bari, Italy
| | - A Lenzi
- Chair of Endocrinology, Section Medical Pathophysiology, Food Science and Endocrinology, Department Exp. Medicine, Sapienza University of Rome, Policlinico Umberto I, Rome, Italy
| | - P Malandrino
- Endocrinology, Department of Clinical and Molecular Biomedicine, Garibaldi-Nesima Medical Center, University of Catania, Catania, Italy
| | - M Mannelli
- Endocrinology Unit, Department of Experimental and Clinical Biomedical Sciences, University of Florence, Florence, Italy
| | - C Marcocci
- Department of Endocrinology and Metabolism, University of Pisa, Pisa, Italy
| | - L Masi
- Department of Orthopedic, Metabolic Bone Diseases Unit AOUC-Careggi Hospital, Largo Palagi, 1, Florence, Italy
| | - F Pacini
- Section of Endocrinology and Metabolism, University of Siena, Siena, Italy
| | - G Opocher
- Familial Cancer Clinic and Oncoendocrinology, Veneto Institute of Oncology, IRCCS, Padua, Italy
- Department of Medicine DIMED, University of Padova, Padova, Italy
| | - A Radicioni
- Department of Experimental Medicine, Sapienza University of Rome, Rome, Italy
| | - M Tonacchera
- Unit of Endocrinology, Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - R Vigneri
- Department of Clinical and Molecular Biomedicine, University of Catania, and Humanitas Catania Center of Oncology, Catania, Italy
| | - M C Zatelli
- Section of Endocrinology, Department of Medical Sciences, University of Ferrara, Ferrara, Italy
| | - M L Brandi
- Head, Bone Metablic Diseases Unit, Department of Surgery and Translational Medicine, University of Florence, Viale Pieraccini 6, 50139, Florence, Italy.
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Aljahdali A. Severe neonatal hypercalcemia in 4-month-old, presented with respiratory distress and chest wall deformity. JOURNAL OF PEDIATRIC SURGERY CASE REPORTS 2015. [DOI: 10.1016/j.epsc.2014.11.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
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Letz S, Haag C, Schulze E, Frank-Raue K, Raue F, Hofner B, Mayr B, Schöfl C. Amino alcohol- (NPS-2143) and quinazolinone-derived calcilytics (ATF936 and AXT914) differentially mitigate excessive signalling of calcium-sensing receptor mutants causing Bartter syndrome Type 5 and autosomal dominant hypocalcemia. PLoS One 2014; 9:e115178. [PMID: 25506941 PMCID: PMC4266668 DOI: 10.1371/journal.pone.0115178] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2014] [Accepted: 11/19/2014] [Indexed: 11/24/2022] Open
Abstract
INTRODUCTION Activating calcium sensing receptor (CaSR) mutations cause autosomal dominant hypocalcemia (ADH) characterized by low serum calcium, inappropriately low PTH and relative hypercalciuria. Four activating CaSR mutations cause additional renal wasting of sodium, chloride and other salts, a condition called Bartter syndrome (BS) type 5. Until today there is no specific medical treatment for BS type 5 and ADH. We investigated the effects of different allosteric CaSR antagonists (calcilytics) on activating CaSR mutants. METHODS All 4 known mutations causing BS type 5 and five ADH mutations were expressed in HEK 293T cells and receptor signalling was studied by measurement of intracellular free calcium in response to extracellular calcium ([Ca2+]o). To investigate the effect of calcilytics, cells were stimulated with 3 mM [Ca2+]o in the presence or absence of NPS-2143, ATF936 or AXT914. RESULTS All BS type 5 and ADH mutants showed enhanced signalling activity to [Ca2+]o with left shifted dose response curves. In contrast to the amino alcohol NPS-2143, which was only partially effective, the quinazolinone calcilytics ATF936 and AXT914 significantly mitigated excessive cytosolic calcium signalling of all BS type 5 and ADH mutants studied. When these mutants were co-expressed with wild-type CaSR to approximate heterozygosity in patients, ATF936 and AXT914 were also effective on all mutants. CONCLUSION The calcilytics ATF936 and AXT914 are capable of attenuating enhanced cytosolic calcium signalling activity of CaSR mutations causing BS type 5 and ADH. Quinazolinone calcilytics might therefore offer a novel treatment option for patients with activating CaSR mutations.
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Affiliation(s)
- Saskia Letz
- Division of Endocrinology and Diabetes, Department of Medicine I, Universitätsklinikum Erlangen, Erlangen, Germany
| | | | | | | | | | - Benjamin Hofner
- Department of Medical Informatics, Biometry and Epidemiology, Friedrich-Alexander-University Erlangen-Nuremberg, Erlangen, Germany
| | - Bernhard Mayr
- Division of Endocrinology and Diabetes, Department of Medicine I, Universitätsklinikum Erlangen, Erlangen, Germany
| | - Christof Schöfl
- Division of Endocrinology and Diabetes, Department of Medicine I, Universitätsklinikum Erlangen, Erlangen, Germany
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Thim SB, Birkebaek NH, Nissen PH, Høst C. Activating calcium-sensing receptor gene variants in children: a case study of infant hypocalcaemia and literature review. Acta Paediatr 2014; 103:1117-25. [PMID: 25039540 DOI: 10.1111/apa.12743] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/15/2013] [Revised: 05/02/2014] [Accepted: 07/08/2014] [Indexed: 12/17/2022]
Abstract
UNLABELLED Autosomal dominant hypocalcaemia (ADH) is caused by activating variants in the calcium-sensing receptor (CASR) gene, but detailed information on the paediatric phenotype is limited. The current paper presents a case of severe ADH and systematically reviews the literature on ADH in children. CONCLUSION We found that the severity of clinical neurological symptoms was inversely related to serum calcium levels and a high prevalence of renal calcifications and/or basal ganglia calcifications in children with ADH.
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Affiliation(s)
- Signe B Thim
- Department of Paediatrics; Aarhus University Hospital; Aarhus Denmark
| | - Niels H Birkebaek
- Department of Paediatrics; Aarhus University Hospital; Aarhus Denmark
| | - Peter H Nissen
- Department of Clinical Biochemistry; Aarhus University Hospital; Aarhus Denmark
| | - Christian Høst
- Department of Paediatrics; Aarhus University Hospital; Aarhus Denmark
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50
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Abstract
Recent studies of inherited disorders of phosphate metabolism have shed new light on the understanding of phosphate metabolism. Phosphate has important functions in the body and several mechanisms have evolved to regulate phosphate balance including vitamin D, parathyroid hormone and phosphatonins such as fibroblast growth factor-23 (FGF23). Disorders of phosphate homeostasis leading to hypo- and hyperphosphataemia are common and have clinical and biochemical consequences. Notably, recent studies have linked hyperphosphataemia with an increased risk of cardiovascular disease. This review outlines the recent advances in the understanding of phosphate homeostasis and describes the causes, investigation and management of hypo- and hyperphosphataemia.
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Affiliation(s)
- P Manghat
- Department of Chemical Pathology, Darent Valley Hospital, Dartford, UK
| | - R Sodi
- Department of Biochemistry, NHS Lanarkshire, East Kilbride, UK
| | - R Swaminathan
- Department of Chemical Pathology, St. Thomas Hospital, London, UK
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