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Stokes VJ, Nielsen MF, Hannan FM, Thakker RV. Hypercalcemic Disorders in Children. J Bone Miner Res 2017; 32:2157-2170. [PMID: 28914984 PMCID: PMC5703166 DOI: 10.1002/jbmr.3296] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Revised: 09/07/2017] [Accepted: 09/13/2017] [Indexed: 12/20/2022]
Abstract
Hypercalcemia is defined as a serum calcium concentration that is greater than two standard deviations above the normal mean, which in children may vary with age and sex, reflecting changes in the normal physiology at each developmental stage. Hypercalcemic disorders in children may present with hypotonia, poor feeding, vomiting, constipation, abdominal pain, lethargy, polyuria, dehydration, failure to thrive, and seizures. In severe cases renal failure, pancreatitis and reduced consciousness may also occur and older children and adolescents may present with psychiatric symptoms. The causes of hypercalcemia in children can be classified as parathyroid hormone (PTH)-dependent or PTH-independent, and may be congenital or acquired. PTH-independent hypercalcemia, ie, hypercalcemia associated with a suppressed PTH, is commoner in children than PTH-dependent hypercalcemia. Acquired causes of PTH-independent hypercalcemia in children include hypervitaminosis; granulomatous disorders, and endocrinopathies. Congenital syndromes associated with PTH-independent hypercalcemia include idiopathic infantile hypercalcemia (IIH), William's syndrome, and inborn errors of metabolism. PTH-dependent hypercalcemia is usually caused by parathyroid tumors, which may give rise to primary hyperparathyroidism (PHPT) or tertiary hyperparathyroidism, which usually arises in association with chronic renal failure and in the treatment of hypophosphatemic rickets. Acquired causes of PTH-dependent hypercalcemia in neonates include maternal hypocalcemia and extracorporeal membrane oxygenation. PHPT usually occurs as an isolated nonsyndromic and nonhereditary endocrinopathy, but may also occur as a hereditary hypercalcemic disorder such as familial hypocalciuric hypercalcemia, neonatal severe primary hyperparathyroidism, and familial isolated primary hyperparathyroidism, and less commonly, as part of inherited complex syndromic disorders such as multiple endocrine neoplasia (MEN). Advances in identifying the genetic causes have resulted in increased understanding of the underlying biological pathways and improvements in diagnosis. The management of symptomatic hypercalcemia includes interventions such as fluids, antiresorptive medications, and parathyroid surgery. This article presents a clinical, biochemical, and genetic approach to investigating the causes of pediatric hypercalcemia. © 2017 American Society for Bone and Mineral Research.
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Affiliation(s)
- Victoria J Stokes
- Academic Endocrine UnitRadcliffe Department of MedicineUniversity of OxfordOxfordUK
| | - Morten F Nielsen
- Academic Endocrine UnitRadcliffe Department of MedicineUniversity of OxfordOxfordUK
- Department of Clinical ResearchFaculty of HealthUniversity of Southern DenmarkOdenseDenmark
| | - Fadil M Hannan
- Academic Endocrine UnitRadcliffe Department of MedicineUniversity of OxfordOxfordUK
- Department of Musculoskeletal BiologyInstitute of Ageing and Chronic DiseaseUniversity of LiverpoolOxfordUK
| | - Rajesh V Thakker
- Academic Endocrine UnitRadcliffe Department of MedicineUniversity of OxfordOxfordUK
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52
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Atypical skeletal manifestations of rickets in a familial hypocalciuric hypercalcemia patient. Bone Res 2017; 5:17001. [PMID: 28690912 PMCID: PMC5486235 DOI: 10.1038/boneres.2017.1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Revised: 10/03/2016] [Accepted: 11/15/2016] [Indexed: 11/19/2022] Open
Abstract
Familial hypocalciuric hypercalcemia (FHH) is caused by inactivating mutations in the calcium-sensing receptor (CaSR) gene. The loss of function of CaSR presents with rickets as the predominant skeletal abnormality in mice, but is rarely reported in humans. Here we report a case of a 16-year-old boy with FHH who presented with skeletal manifestations of rickets. To identify the possible pathogenic mutation, the patient was evaluated clinically, biochemically, and radiographically. The patient and his family members were screened for genetic mutations. Physical examination revealed a pigeon breast deformity and X-ray examinations showed epiphyseal broadening, both of which indicate rickets. Biochemical tests also showed increased parathyroid hormone (PTH), 1,25-dihydroxyvitamin D, and elevated ionized calcium. Based on these results, a diagnosis of FHH was suspected. Sequence analysis of the patient’s CaSR gene revealed a new missense mutation (c.2279T>A) in exon 7, leading to the damaging amino change (p.I760N) in the mature CaSR protein, confirming the diagnosis of FHH. Moreover, the skeletal abnormities may be related to but not limited to vitamin D abnormity. Elevated PTH levels and a rapid skeletal growth period in adolescence may have also contributed. Our study revealed that rickets-like features have a tendency to present atypically in FHH patients who have a mild vitamin D deficiency, and that CaSR mutations may have a partial role in the pathogenesis of skeletal deformities.
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53
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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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54
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Abrahamsen B. The calcium and vitamin D controversy. Ther Adv Musculoskelet Dis 2017; 9:107-114. [PMID: 28458722 DOI: 10.1177/1759720x16685547] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2016] [Accepted: 11/24/2016] [Indexed: 11/17/2022] Open
Abstract
Areas of the world where vitamin D levels are low for months of the year and intakes of calcium are high have a high prevalence of osteoporosis and cardiovascular disease. This suggests a public health message of avoiding calcium supplements and increasing vitamin D intake. No message could be more welcome as vitamin D can be given as a bolus while calcium must be taken daily and may be poorly tolerated. This approach is based on no evidence from intervention studies. Randomized controlled trials (RCTs) suggest that vitamin D given with calcium elicits a small reduction in fracture risk and deaths. This has not been demonstrated for D given alone. The cardiovascular safety of calcium and vitamin D (CaD) supplements is difficult to ascertain due to weaknesses in RCT designs and adjudication that cannot be remedied by subanalysis. Moreover, no major new RCTs are in process to provide better evidence. It remains unclear that calcium from dietary sources has health advantages over supplements. Benefits may be confined to patients with poor nutritional intake and the small effects at societal levels may be derived from large effects in a small number of patients. This has been impossible to confirm given the limited information about baseline vitamin D and calcium status at entry into trials. Future intervention studies should carefully capture baseline characteristics as these may determine the strength of the response, and make more efficient use of randomization strategies allowing subsequent disassembly or subanalyses while maintaining balancing. Though large clinical RCTs currently evaluate the effects of higher vitamin D doses (equivalent to 50-83 µg/d) there is no current research effort regarding the calcium controversy. In the absence of such studies it is not possible to provide clinicians with evidence-based recommendations regarding the best use of CaD supplementation.
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Affiliation(s)
- Bo Abrahamsen
- Odense Patient Data Explorative Network, University of Southern Denmark, Department of Medicine, Holbæk Hospital, Smedelundsgade 60, DK-4300 Holbæk, Odense, Denmark
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Yousefichijan P, Dorreh F, Rezagholi Zamenjany M. Bartter’s syndrome type 5; a case report. J Renal Inj Prev 2017. [DOI: 10.15171/jrip.2017.46] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
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Roszko KL, Bi RD, Mannstadt M. Autosomal Dominant Hypocalcemia (Hypoparathyroidism) Types 1 and 2. Front Physiol 2016; 7:458. [PMID: 27803672 PMCID: PMC5067375 DOI: 10.3389/fphys.2016.00458] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2016] [Accepted: 09/23/2016] [Indexed: 12/15/2022] Open
Abstract
Extracellular calcium is essential for life and its concentration in the blood is maintained within a narrow range. This is achieved by a feedback loop that receives input from the calcium-sensing receptor (CASR), expressed on the surface of parathyroid cells. In response to low ionized calcium, the parathyroids increase secretion of parathyroid hormone (PTH) which increases serum calcium. The CASR is also highly expressed in the kidneys, where it regulates the reabsorption of calcium from the primary filtrate. Autosomal dominant hypocalcemia (ADH) type 1 is caused by heterozygous activating mutations in the CASR which increase the sensitivity of the CASR to extracellular ionized calcium. Consequently, PTH synthesis and secretion are suppressed at normal ionized calcium concentrations. Patients present with hypocalcemia, hyperphosphatemia, low magnesium levels, and low or low-normal levels of PTH. Urinary calcium excretion is typically increased due to the decrease in circulating PTH concentrations and by the activation of the renal tubular CASR. Therapeutic attempts using CASR antagonists (calcilytics) to treat ADH are currently under investigation. Recently, heterozygous mutations in the alpha subunit of the G protein G11 (Gα11) have been identified in patients with ADH, and this has been classified as ADH type 2. ADH2 mutations lead to a gain-of-function of Gα11, a key mediator of CASR signaling. Therefore, the mechanism of hypocalcemia appears similar to that of activating mutations in the CASR, namely an increase in the sensitivity of parathyroid cells to extracellular ionized calcium. Studies of activating mutations in the CASR and gain-of-function mutations in Gα11 can help define new drug targets and improve medical management of patients with ADH types 1 and 2.
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Affiliation(s)
- Kelly L Roszko
- Endocrine Unit, Massachusetts General Hospital and Harvard Medical School Boston, MA, USA
| | - Ruiye D Bi
- Endocrine Unit, Massachusetts General Hospital and Harvard Medical School Boston, MA, USA
| | - Michael Mannstadt
- Endocrine Unit, Massachusetts General Hospital and Harvard Medical School Boston, MA, USA
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57
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Breum Jakobsen NF, Laugesen E, Rolighed L, Nissen PH, Poulsen PL, Pedersen EB, Mosekilde L, Rejnmark L. The cardiovascular system in familial hypocalciuric hypercalcemia: a cross-sectional study on physiological effects of inactivating variants in the calcium-sensing receptor gene. Eur J Endocrinol 2016; 175:299-309. [PMID: 27418061 DOI: 10.1530/eje-16-0369] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Accepted: 07/14/2016] [Indexed: 01/10/2023]
Abstract
OBJECTIVE Loss-of-function variants in the gene encoding the calcium-sensing receptor (CASR) result in familial hypocalciuric hypercalcemia (FHH), causing hypercalcemia with high normal or elevated parathyroid hormone levels. The CASR may also influence electrolyte and water homeostasis. It is unknown whether FHH affects cardiovascular health. We, therefore investigated whether FHH is associated with changes in the regulation of the cardiovascular system by measuring 24-h blood pressure (BP), arterial stiffness and vasoactive hormones. DESIGN Cross-sectional study comparing 50 patients with FHH to age- and gender-matched controls. RESULTS Studied subjects (69% women) had a mean age of 56years. A similar number of patients and controls (33%) were on treatment with antihypertensive drugs. Overall, no differences were found between groups in 24-h ambulatory BP or pulse wave velocity. However, compared with controls, diastolic BP during nighttime was lower in FHH females (60±5 vs 66±9mmHg, P<0.01) and higher in FHH males (69±6 vs 64±5mmHg, P=0.02). FHH was associated with a significantly higher plasma osmolality (P<0.01), higher plasma levels of vasopressin (P<0.01) and a higher renal excretion of epithelial sodium channels (ENaCs) (P=0.03), whereas urine aquaporin-2 and plasma sodium, aldosterone and renin did not differ between groups. FHH patients had a lower urinary volume with an increased osmolality if analyses were restricted to those not on treatments with antihypertensive drugs. CONCLUSIONS FHH does not seem to be associated with an increased risk of CVD.
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Affiliation(s)
| | - Esben Laugesen
- Department of Endocrinology and Internal MedicineAarhus University Hospital, Aarhus, Denmark Danish Diabetes AcademyOdense University Hospital, Odense, Denmark Department of Clinical MedicineAarhus University, Aarhus, Denmark
| | | | - Peter H Nissen
- Clinical BiochemistryAarhus University Hospital, Aarhus, Denmark
| | - Per Løgstrup Poulsen
- Department of Endocrinology and Internal MedicineAarhus University Hospital, Aarhus, Denmark
| | - Erling Bjerregaard Pedersen
- Department of Clinical MedicineAarhus University, Aarhus, Denmark University Clinic in Nephrology and HypertensionHolstebro Hospital, Hospital Jutland West, Holstebro, Denmark
| | - Leif Mosekilde
- Department of Endocrinology and Internal MedicineAarhus University Hospital, Aarhus, Denmark
| | - Lars Rejnmark
- Department of Endocrinology and Internal MedicineAarhus University Hospital, Aarhus, Denmark Department of Clinical MedicineAarhus University, Aarhus, Denmark
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58
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Hannan FM, Babinsky VN, Thakker RV. Disorders of the calcium-sensing receptor and partner proteins: insights into the molecular basis of calcium homeostasis. J Mol Endocrinol 2016; 57:R127-42. [PMID: 27647839 PMCID: PMC5064759 DOI: 10.1530/jme-16-0124] [Citation(s) in RCA: 104] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Accepted: 08/08/2016] [Indexed: 12/20/2022]
Abstract
The extracellular calcium (Ca(2+) o)-sensing receptor (CaSR) is a family C G protein-coupled receptor, which detects alterations in Ca(2+) o concentrations and modulates parathyroid hormone secretion and urinary calcium excretion. The central role of the CaSR in Ca(2+) o homeostasis has been highlighted by the identification of mutations affecting the CASR gene on chromosome 3q21.1. Loss-of-function CASR mutations cause familial hypocalciuric hypercalcaemia (FHH), whereas gain-of-function mutations lead to autosomal dominant hypocalcaemia (ADH). However, CASR mutations are only detected in ≤70% of FHH and ADH cases, referred to as FHH type 1 and ADH type 1, respectively, and studies in other FHH and ADH kindreds have revealed these disorders to be genetically heterogeneous. Thus, loss- and gain-of-function mutations of the GNA11 gene on chromosome 19p13.3, which encodes the G-protein α-11 (Gα11) subunit, lead to FHH type 2 and ADH type 2, respectively; whilst loss-of-function mutations of AP2S1 on chromosome 19q13.3, which encodes the adaptor-related protein complex 2 sigma (AP2σ) subunit, cause FHH type 3. These studies have demonstrated Gα11 to be a key mediator of downstream CaSR signal transduction, and also revealed a role for AP2σ, which is involved in clathrin-mediated endocytosis, in CaSR signalling and trafficking. Moreover, FHH type 3 has been demonstrated to represent a more severe FHH variant that may lead to symptomatic hypercalcaemia, low bone mineral density and cognitive dysfunction. In addition, calcimimetic and calcilytic drugs, which are positive and negative CaSR allosteric modulators, respectively, have been shown to be of potential benefit for these FHH and ADH disorders.
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Affiliation(s)
- Fadil M Hannan
- Academic Endocrine UnitRadcliffe Department of Medicine, University of Oxford, Oxford, UK Department of Musculoskeletal BiologyInstitute of Ageing and Chronic Disease, University of Liverpool, Liverpool, UK
| | - Valerie N Babinsky
- Academic Endocrine UnitRadcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - Rajesh V Thakker
- Academic Endocrine UnitRadcliffe Department of Medicine, University of Oxford, Oxford, UK
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59
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Hendy GN, Canaff L. Calcium-Sensing Receptor Gene: Regulation of Expression. Front Physiol 2016; 7:394. [PMID: 27679579 PMCID: PMC5020072 DOI: 10.3389/fphys.2016.00394] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Accepted: 08/23/2016] [Indexed: 12/13/2022] Open
Abstract
The human calcium-sensing receptor gene (CASR) has 8 exons, and localizes to chromosome 3q. Exons 1A and 1B encode alternative 5′-untranslated regions (UTRs) that splice to exon 2 encoding the AUG initiation codon. Exons 2–7 encode the CaSR protein of 1078 amino acids. Promoter P1 has TATA and CCAAT boxes upstream of exon 1A, and promoter P2 has Sp1/3 motifs at the start site of exon 1B. Exon 1A transcripts from the P1 promoter are reduced in parathyroid tumors and colon carcinomas. Studies of colon carcinomas and neuroblastomas have emphasized the importance of epigenetic changes—promoter methylation of the GC-rich P2 promoter, histone acetylation—as well as involvement of microRNAs in bringing about CASR gene silencing and reduced CaSR expression. Functional cis-elements in the CASR promoters responsive to 1,25-dihydroxyvitamin D [1,25(OH)2D], proinflammatory cytokines, and the transcription factor glial cells missing-2 (GCM2) have been characterized. Reduced levels of CaSR and reduced responsiveness to active vitamin D in parathyroid neoplasia and colon carcinoma may blunt the “tumor suppressor” activity of the CaSR. The hypocalcemia of critically ill patients with burn injury or sepsis is associated with CASR gene upregulation by TNF-alpha and IL-1beta via kappaB elements, and by IL-6 via Stat1/3 and Sp1/3 elements in the CASR gene promoters, respectively. The CASR is transactivated by GCM2—the expression of which is essential for parathyroid gland development. Hyperactive forms of GCM2 may contribute to later parathyroid hyperactivity or tumorigenesis. The expression of the CaSR—the calciostat—is regulated physiologically and pathophysiologically at the gene level.
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Affiliation(s)
- Geoffrey N Hendy
- Experimental Therapeutics and Metabolism, McGill University Health Centre-Research Institute, Departments of Medicine, Physiology, and Human Genetics, McGill University Montréal, QC, Canada
| | - Lucie Canaff
- Experimental Therapeutics and Metabolism, McGill University Health Centre-Research Institute, Departments of Medicine, Physiology, and Human Genetics, McGill University Montréal, QC, Canada
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60
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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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61
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Gagliardi L, Burt MG, Feng J, Poplawski NK, Scott HS. Autosomal dominant hypocalcaemia due to a novel CASR mutation: clinical and genetic implications. Clin Endocrinol (Oxf) 2016; 85:495-7. [PMID: 27177819 DOI: 10.1111/cen.13104] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Lucia Gagliardi
- Endocrine and Metabolic Unit, Royal Adelaide Hospital, Adelaide, SA, Australia.
- Department of Genetics and Molecular Pathology, SA Pathology, Adelaide, SA, Australia.
- Department of Medicine, University of Adelaide, Adelaide, SA, Australia.
| | - Morton G Burt
- Southern Adelaide Diabetes and Endocrine Services, Repatriation General Hospital, Daw Park, SA, Australia
- School of Medicine, Flinders University, Bedford Park, SA, Australia
| | - Jinghua Feng
- ACRF Cancer Genomics Facility, Centre for Cancer Biology, SA Pathology, Adelaide, SA, Australia
- School of Biological Sciences, University of Adelaide, Adelaide, SA, Australia
- School of Pharmacy and Medical Sciences, Division of Health Sciences, University of South Australia, Adelaide, SA, Australia
| | - Nicola K Poplawski
- Adult Genetics Unit, South Australian Clinical Genetics Service, SA Pathology at Women's and Children's Hospital, North Adelaide, SA, Australia
- University Department of Paediatrics, University of Adelaide, Adelaide, SA, Australia
| | - Hamish S Scott
- Department of Genetics and Molecular Pathology, SA Pathology, Adelaide, SA, Australia
- Department of Medicine, University of Adelaide, Adelaide, SA, Australia
- ACRF Cancer Genomics Facility, Centre for Cancer Biology, SA Pathology, Adelaide, SA, Australia
- School of Biological Sciences, University of Adelaide, Adelaide, SA, Australia
- School of Pharmacy and Medical Sciences, Division of Health Sciences, University of South Australia, Adelaide, SA, Australia
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Savas-Erdeve S, Sagsak E, Keskin M, Magdelaine C, Lienhardt-Roussie A, Kurnaz E, Cetinkaya S, Aycan Z. Treatment experience and long-term follow-up data in two severe neonatal hyperparathyroidism cases. J Pediatr Endocrinol Metab 2016; 29:1103-10. [PMID: 27390877 DOI: 10.1515/jpem-2015-0261] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Accepted: 05/26/2016] [Indexed: 12/20/2022]
Abstract
The calcium sensing receptor (CASR) is expressed most abundantly in the parathyroid glands and the kidney. CASR regulates calcium homeostasis through its ability to modulate parathormone secretion and renal calcium reabsorption. Inactivating mutations in the CASR gene may result in disorders of calcium homeostasis manifesting as familial benign hypocalciuric hypercalcemia (FBHH) and neonatal severe hyperparathyroidsm (NSHPT). Two cases were referred with severe hypercalcemia in the neonatal period. Laboratory evaluation revealed severe hypercalcemia and elevated PTH. The parents also had mild hypercalcemia. The serum calcium level did not normalize with conventional hypercalcemia treatment and there was also no response to cinacalcet in case 1. Total parathyroidectomy was performed when the patient was 70 days old. Genetic analysis revealed a novel homozygous p.Arg544* mutation in the CASR gene. Case 2 underwent total parathyroidectomy and autoimplantation when she was 97 days old, but the parathyroid gland implanted into the forearm was removed 27 days later because the hypercalcemia continued. Genetic evaluation revealed a novel homozygous p.Pro682Leu mutation with normal anthropometric measurements. The neurological development is consistent with age in both cases while case 2 has mild mental retardation. No bone deformity or fracture is present in either case and normocalcemia is ensured with calcitriol in both cases.
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63
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Papadopoulou A, Gole E, Melachroinou K, Meristoudis C, Siahanidou T, Papadimitriou A. Identification and Functional Characterization of a Calcium-Sensing Receptor Mutation in an Infant with Familial Hypocalciuric Hypercalcemia. J Clin Res Pediatr Endocrinol 2016; 8:341-6. [PMID: 27087013 PMCID: PMC5096500 DOI: 10.4274/jcrpe.2800] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Familial hypocalciuric hypercalcemia (FHH) is an autosomal dominant disorder, associated with inactivating mutations of the calcium-sensing receptor (CaSR). To evaluate the functional significance of a CaSR mutation, identified in a young infant who presented with hypercalcemia and hypocalciuria. The CaSR gene coding sequences were analyzed by polymerase chain reaction amplification and direct sequencing analysis. The mutation identified was introduced by site-directed mutagenesis into a wild-type (WT) CaSR plasmid, and human embryonic kidney 293 T cells were transfected with either the WT or mutant CaSR. The function of the mutated CaSR protein was analyzed by evaluating the free intracellular calcium [(Ca2+)i] response after challenge with extracellular calcium (Ca2+). We identified a heterozygous mutation c.772_773delGTinsA in exon 4 resulting in the substitution of amino acid valine (Val) with amino acid arginine (Arg) and the premature pause of the translation 46 amino acids later (Val258ArgfsTer47). Functional assay showed that cells transfected with the mutant CaSR had a significantly poorer response to extracellular Ca2+ stimulation compared with the WT. We have shown that the c.772_773delGTinsA mutation causes a significant alteration of CaSR function leading to features of FHH in an affected young infant since the first months of life.
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Affiliation(s)
- Anna Papadopoulou
- Athens University Medical School, University General Hospital "Attikon", Third Department of Pediatrics, Athens, Greece, Phone: +30 2105832228 E-mail:
| | - Evangelia Gole
- Athens University Medical School, University General Hospital “Attikon”, Third Department of Pediatrics, Athens, Greece
| | - Katerina Melachroinou
- Biomedical Research Foundation of the Academy of Athens, Division of Basic Neurosciences, Athens, Greece
| | - Christos Meristoudis
- University of Ioannina, Department of Biological Applications and Technology, Ioannina, Greece
| | - Tania Siahanidou
- Athens University Medical School, “Aghia Sophia” Children’s Hospital, First Department of Pediatrics, Athens, Greece
| | - Anastasios Papadimitriou
- Athens University Medical School, University General Hospital “Attikon”, Third Department of Pediatrics, Athens, Greece
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Wang XM, Wu YW, Li ZJ, Zhao XH, Lv SM, Wang XH. Polymorphisms of CASR gene increase the risk of primary hyperparathyroidism. J Endocrinol Invest 2016; 39:617-25. [PMID: 26710757 DOI: 10.1007/s40618-015-0405-5] [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: 07/29/2015] [Accepted: 10/27/2015] [Indexed: 12/25/2022]
Abstract
OBJECTIVE To evaluate correlations between polymorphisms of calcium-sensing receptor (CASR) gene [A986S (rs1081725), R990G (rs1042636) and Q1011E (rs1801726)] and the risk of primary hyperparathyroidism (PHPT) among human population. METHODS Relevant studies were retrieved from online databases using computer-based search strategies, which were then supplemented by manual search strategies. Case-control studies related to our topic were identified based on strict inclusion and exclusion criteria. Statistical analyses were conducted using the Comprehensive Meta-analysis 2.0 (Biostat Inc., Englewood, NJ, USA). RESULTS We retrieved 202 studies from online databases and other sources initially and eventually enrolled six studies into our meta-analysis. These six studies contained a sum of 693 PHPT patients and 1252 healthy controls. Our meta-analysis results showed that single nucleotide polymorphisms (SNPs) of CASR gene A986S (rs1081725) and R990G (rs1042636), but not Q1011E (rs1801726), may increase the risk of PHPT [A986S (rs1081725): allele model: P = 0.013; dominant model: P = 0.044; R990G (rs1042636): allele model: P = 0.023; dominant model: P = 0.026)]. Subgroup analyses based on ethnicity showed that among Asians, A986S (rs1081725) increased the PHPT risk (P = 0.04) under the allele model, but not under the dominant model. Among Caucasians, there was no association between gene frequencies and PHPT under both the allele and dominant model. In Asians, no significant association was observed between R990G (rs1042636) and PHPT risk, but in Caucasians, R990G (rs1042636) significantly increased the incidence of PHPT [R990G (rs1042636): allele model: P = 0.015; dominant model: P = 0.009)]. CONCLUSION Our results indicate that SNPs of CASR gene A986S (rs1081725) and R990G (rs1042636) may increase the risk of PHPT, and the polymorphisms can potentially be used as important biological markers for early diagnosis of PHPT.
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Affiliation(s)
- X-M Wang
- Department of Nephrology, Shaanxi Provincial People's Hospital, Xi'an, 710068, Shaanxi, China
| | - Y-W Wu
- Second Department of Gastroenterology, Shaanxi Provincial People's Hospital, No. 256 West Youyi Road, Xi'an, 710068, Shaanxi, China
| | - Z-J Li
- Department of Nephrology, Shaanxi Provincial People's Hospital, Xi'an, 710068, Shaanxi, China
| | - X-H Zhao
- Department of Nephrology, Shaanxi Provincial People's Hospital, Xi'an, 710068, Shaanxi, China
| | - S-M Lv
- Second Department of Gastroenterology, Shaanxi Provincial People's Hospital, No. 256 West Youyi Road, Xi'an, 710068, Shaanxi, China.
| | - X-H Wang
- Department of Nephrology, Shaanxi Provincial People's Hospital, Xi'an, 710068, Shaanxi, China
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Piret SE, Gorvin CM, Pagnamenta AT, Howles SA, Cranston T, Rust N, Nesbit MA, Glaser B, Taylor JC, Buchs AE, Hannan FM, Thakker RV. Identification of a G-Protein Subunit-α11 Gain-of-Function Mutation, Val340Met, in a Family With Autosomal Dominant Hypocalcemia Type 2 (ADH2). J Bone Miner Res 2016; 31:1207-14. [PMID: 26818911 PMCID: PMC4915495 DOI: 10.1002/jbmr.2797] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Revised: 01/18/2016] [Accepted: 01/22/2016] [Indexed: 01/24/2023]
Abstract
Autosomal dominant hypocalcemia (ADH) is characterized by hypocalcemia, inappropriately low serum parathyroid hormone concentrations and hypercalciuria. ADH is genetically heterogeneous with ADH type 1 (ADH1), the predominant form, being caused by germline gain-of-function mutations of the G-protein coupled calcium-sensing receptor (CaSR), and ADH2 caused by germline gain-of-function mutations of G-protein subunit α-11 (Gα11 ). To date Gα11 mutations causing ADH2 have been reported in only five probands. We investigated a multigenerational nonconsanguineous family, from Iran, with ADH and keratoconus which are not known to be associated, for causative mutations by whole-exome sequencing in two individuals with hypoparathyroidism, of whom one also had keratoconus, followed by cosegregation analysis of variants. This identified a novel heterozygous germline Val340Met Gα11 mutation in both individuals, and this was also present in the other two relatives with hypocalcemia that were tested. Three-dimensional modeling revealed the Val340Met mutation to likely alter the conformation of the C-terminal α5 helix, which may affect G-protein coupled receptor binding and G-protein activation. In vitro functional expression of wild-type (Val340) and mutant (Met340) Gα11 proteins in HEK293 cells stably expressing the CaSR, demonstrated that the intracellular calcium responses following stimulation with extracellular calcium, of the mutant Met340 Gα11 led to a leftward shift of the concentration-response curve with a significantly (p < 0.0001) reduced mean half-maximal concentration (EC50 ) value of 2.44 mM (95% CI, 2.31 to 2.77 mM) when compared to the wild-type EC50 of 3.14 mM (95% CI, 3.03 to 3.26 mM), consistent with a gain-of-function mutation. A novel His403Gln variant in transforming growth factor, beta-induced (TGFBI), that may be causing keratoconus was also identified, indicating likely digenic inheritance of keratoconus and ADH2 in this family. In conclusion, our identification of a novel germline gain-of-function Gα11 mutation, Val340Met, causing ADH2 demonstrates the importance of the Gα11 C-terminal region for G-protein function and CaSR signal transduction. © 2016 American Society for Bone and Mineral Research.
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Affiliation(s)
- Sian E Piret
- Academic Endocrine Unit, University of Oxford, Oxford Centre for Diabetes, Endocrinology and Metabolism, Churchill Hospital, Oxford, UK
| | - Caroline M Gorvin
- Academic Endocrine Unit, University of Oxford, Oxford Centre for Diabetes, Endocrinology and Metabolism, Churchill Hospital, Oxford, UK
| | - Alistair T Pagnamenta
- Wellcome Trust Centre for Human Genetics, Roosevelt Drive, Oxford, UK.,Oxford NIHR Comprehensive Biomedical Research Centre, Oxford, UK
| | - Sarah A Howles
- Academic Endocrine Unit, University of Oxford, Oxford Centre for Diabetes, Endocrinology and Metabolism, Churchill Hospital, Oxford, UK
| | - Treena Cranston
- Oxford University Hospitals NHS Trust, Oxford Medical Genetics Laboratories, Churchill Hospital, Oxford, UK
| | - Nigel Rust
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford, UK
| | - M Andrew Nesbit
- Academic Endocrine Unit, University of Oxford, Oxford Centre for Diabetes, Endocrinology and Metabolism, Churchill Hospital, Oxford, UK.,Biomedical Sciences Research Institute, Ulster University, Coleraine, UK
| | - Ben Glaser
- Department of Internal Medicine, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Jenny C Taylor
- Wellcome Trust Centre for Human Genetics, Roosevelt Drive, Oxford, UK.,Oxford NIHR Comprehensive Biomedical Research Centre, Oxford, UK
| | - Andreas E Buchs
- Department of Medicine D, Assaf Harofe Medical Center, Zerifin, Israel
| | - Fadil M Hannan
- Academic Endocrine Unit, University of Oxford, Oxford Centre for Diabetes, Endocrinology and Metabolism, Churchill Hospital, Oxford, UK.,Department of Musculoskeletal Biology, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, UK
| | - Rajesh V Thakker
- Academic Endocrine Unit, University of Oxford, Oxford Centre for Diabetes, Endocrinology and Metabolism, Churchill Hospital, Oxford, UK.,Oxford NIHR Comprehensive Biomedical Research Centre, Oxford, UK
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Gorvin CM, Cranston T, Hannan FM, Rust N, Qureshi A, Nesbit MA, Thakker RV. A G-protein Subunit-α11 Loss-of-Function Mutation, Thr54Met, Causes Familial Hypocalciuric Hypercalcemia Type 2 (FHH2). J Bone Miner Res 2016; 31:1200-6. [PMID: 26729423 PMCID: PMC4949650 DOI: 10.1002/jbmr.2778] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/13/2015] [Revised: 01/02/2015] [Accepted: 01/04/2015] [Indexed: 11/29/2022]
Abstract
Familial hypocalciuric hypercalcemia (FHH) is a genetically heterogeneous disorder with three variants, FHH1 to FHH3. FHH1 is caused by loss-of-function mutations of the calcium-sensing receptor (CaSR), a G-protein coupled receptor that predominantly signals via G-protein subunit alpha-11 (Gα11 ) to regulate calcium homeostasis. FHH2 is the result of loss-of-function mutations in Gα11 , encoded by GNA11, and to date only two FHH2-associated Gα11 missense mutations (Leu135Gln and Ile200del) have been reported. FHH3 is the result of loss-of-function mutations of the adaptor protein-2 σ-subunit (AP2σ), which plays a pivotal role in clathrin-mediated endocytosis. We describe a 65-year-old woman who had hypercalcemia with normal circulating parathyroid hormone concentrations and hypocalciuria, features consistent with FHH, but she did not have CaSR and AP2σ mutations. Mutational analysis of the GNA11 gene was therefore undertaken, using leucocyte DNA, and this identified a novel heterozygous GNA11 mutation (c.161C>T; p.Thr54Met). The effect of the Gα11 variant was assessed by homology modeling of the related Gαq protein and by measuring the CaSR-mediated intracellular calcium (Ca(2+) i ) responses of HEK293 cells, stably expressing CaSR, to alterations in extracellular calcium (Ca(2+) o ) using flow cytometry. Three-dimensional modeling revealed the Thr54Met mutation to be located at the interface between the Gα11 helical and GTPase domains, and to likely impair GDP binding and interdomain interactions. Expression of wild-type and the mutant Gα11 in HEK293 cells stably expressing CaSR demonstrate that the Ca(2+) i responses after stimulation with Ca(2+) o of the mutant Met54 Gα11 led to a rightward shift of the concentration-response curve with a significantly (p < 0.01) increased mean half-maximal concentration (EC50 ) value of 3.88 mM (95% confidence interval [CI] 3.76-4.01 mM), when compared with the wild-type EC50 of 2.94 mM (95% CI 2.81-3.07 mM) consistent with a loss-of-function. Thus, our studies have identified a third Gα11 mutation (Thr54Met) causing FHH2 and reveal a critical role for the Gα11 interdomain interface in CaSR signaling and Ca(2+) o homeostasis. © 2016 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, UK
| | - Treena Cranston
- Oxford Molecular Genetics Laboratory, Churchill Hospital, Oxford, UK
| | - Fadil M Hannan
- Academic Endocrine Unit, Radcliffe Department of Medicine, University of Oxford, Oxford, UK.,Department of Musculoskeletal Biology, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, UK
| | - Nigel Rust
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
| | - Asjid Qureshi
- Department of Diabetes and Endocrinology, Northwest London NHS Trust, London, UK
| | - M Andrew Nesbit
- Academic Endocrine Unit, Radcliffe Department of Medicine, University of Oxford, Oxford, UK.,School of Biomedical Sciences, University of Ulster, Coleraine, Londonderry, UK
| | - Rajesh V Thakker
- Academic Endocrine Unit, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
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Zhang C, Zhang T, Zou J, Miller CL, Gorkhali R, Yang JY, Schilmiller A, Wang S, Huang K, Brown EM, Moremen KW, Hu J, Yang JJ. Structural basis for regulation of human calcium-sensing receptor by magnesium ions and an unexpected tryptophan derivative co-agonist. SCIENCE ADVANCES 2016; 2:e1600241. [PMID: 27386547 PMCID: PMC4928972 DOI: 10.1126/sciadv.1600241] [Citation(s) in RCA: 97] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Accepted: 04/29/2016] [Indexed: 06/06/2023]
Abstract
Ca(2+)-sensing receptors (CaSRs) modulate calcium and magnesium homeostasis and many (patho)physiological processes by responding to extracellular stimuli, including divalent cations and amino acids. We report the first crystal structure of the extracellular domain (ECD) of human CaSR bound with Mg(2+) and a tryptophan derivative ligand at 2.1 Å. The structure reveals key determinants for cooperative activation by metal ions and aromatic amino acids. The unexpected tryptophan derivative was bound in the hinge region between two globular ECD subdomains, and represents a novel high-affinity co-agonist of CaSR. The dissection of structure-function relations by mutagenesis, biochemical, and functional studies provides insights into the molecular basis of human diseases arising from CaSR mutations. The data also provide a novel paradigm for understanding the mechanism of CaSR-mediated signaling that is likely shared by the other family C GPCR [G protein (heterotrimeric guanine nucleotide-binding protein)-coupled receptor] members and can facilitate the development of novel CaSR-based therapeutics.
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Affiliation(s)
- Chen Zhang
- Department of Chemistry, Center for Diagnostics and Therapeutics, Georgia State University, 50 Decatur Street, Atlanta, GA 30303, USA
| | - Tuo Zhang
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824, USA
| | - Juan Zou
- Department of Chemistry, Center for Diagnostics and Therapeutics, Georgia State University, 50 Decatur Street, Atlanta, GA 30303, USA
| | - Cassandra Lynn Miller
- Department of Chemistry, Center for Diagnostics and Therapeutics, Georgia State University, 50 Decatur Street, Atlanta, GA 30303, USA
| | - Rakshya Gorkhali
- Department of Chemistry, Center for Diagnostics and Therapeutics, Georgia State University, 50 Decatur Street, Atlanta, GA 30303, USA
| | - Jeong-Yeh Yang
- Department of Biochemistry and Molecular Biology and the Complex Carbohydrate Research Center, University of Georgia, 315 Riverbend Road, Athens, GA 30602, USA
| | - Anthony Schilmiller
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824, USA
| | - Shuo Wang
- Department of Biochemistry and Molecular Biology and the Complex Carbohydrate Research Center, University of Georgia, 315 Riverbend Road, Athens, GA 30602, USA
| | - Kenneth Huang
- Department of Chemistry, Center for Diagnostics and Therapeutics, Georgia State University, 50 Decatur Street, Atlanta, GA 30303, USA
| | - Edward M. Brown
- Division of Endocrinology, Diabetes and Hypertension, Department of Medicine, Brigham and Women’s Hospital and Harvard Medical School, 221 Longwood Avenue, Boston, MA 02115, USA
| | - Kelley W. Moremen
- Department of Biochemistry and Molecular Biology and the Complex Carbohydrate Research Center, University of Georgia, 315 Riverbend Road, Athens, GA 30602, USA
| | - Jian Hu
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824, USA
- Department of Chemistry, Michigan State University, East Lansing, MI 48824, USA
| | - Jenny J. Yang
- Department of Chemistry, Center for Diagnostics and Therapeutics, Georgia State University, 50 Decatur Street, Atlanta, GA 30303, USA
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Nemeth EF, Goodman WG. Calcimimetic and Calcilytic Drugs: Feats, Flops, and Futures. Calcif Tissue Int 2016; 98:341-58. [PMID: 26319799 DOI: 10.1007/s00223-015-0052-z] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/11/2015] [Accepted: 08/10/2015] [Indexed: 01/28/2023]
Abstract
The actions of extracellular Ca(2+) in regulating parathyroid gland and kidney functions are mediated by the extracellular calcium receptor (CaR), a G protein-coupled receptor. The CaR is one of the essential molecules maintaining systemic Ca(2+) homeostasis and is a molecular target for drugs useful in treating bone and mineral disorders. Ligands that activate the CaR are termed calcimimetics and are classified as either agonists (type I) or positive allosteric modulators (type II); calcimimetics inhibit the secretion of parathyroid hormone (PTH). Cinacalcet is a type II calcimimetic that is used to treat secondary hyperparathyroidism in patients receiving dialysis and to treat hypercalcemia in some forms of primary hyperparathyroidism. The use of cinacalcet among patients with secondary hyperparathyroidism who are managed with dialysis effectively lowers circulating PTH levels, reduces serum phosphorus and FGF23 concentrations, improves bone histopathology, and may diminish skeletal fracture rates and the need for parathyroidectomy. A second generation type II calcimimetic (AMG 416) is currently under regulatory review. Calcilytics are CaR antagonists that stimulate the secretion of PTH. Several calcilytic compounds have been evaluated as orally active anabolic therapies for postmenopausal osteoporosis but clinical development of all of them has been abandoned because they lacked clinical efficacy. Calcilytics might be repurposed for new indications like autosomal dominant hypocalcemia or other disorders beyond those involving systemic Ca(2+) homeostasis.
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Affiliation(s)
- E F Nemeth
- MetisMedica, 13 Poplar Plains Road, Toronto, ON, M4V 2M7, Canada.
| | - W G Goodman
- , 22102 Palais Place, Calabasas, CA, 91302, USA
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69
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Babinsky VN, Hannan FM, Gorvin CM, Howles SA, Nesbit MA, Rust N, Hanyaloglu AC, Hu J, Spiegel AM, Thakker RV. Allosteric Modulation of the Calcium-sensing Receptor Rectifies Signaling Abnormalities Associated with G-protein α-11 Mutations Causing Hypercalcemic and Hypocalcemic Disorders. J Biol Chem 2016; 291:10876-85. [PMID: 26994139 PMCID: PMC4865932 DOI: 10.1074/jbc.m115.696401] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2015] [Indexed: 11/06/2022] Open
Abstract
Germline loss- and gain-of-function mutations of G-protein α-11 (Gα11), which couples the calcium-sensing receptor (CaSR) to intracellular calcium (Ca2+i) signaling, lead to familial hypocalciuric hypercalcemia type 2 (FHH2) and autosomal dominant hypocalcemia type 2 (ADH2), respectively, whereas somatic Gα11 mutations mediate uveal melanoma development by constitutively up-regulating MAPK signaling. Cinacalcet and NPS-2143 are allosteric CaSR activators and inactivators, respectively, that ameliorate signaling disturbances associated with CaSR mutations, but their potential to modulate abnormalities of the downstream Gα11 protein is unknown. This study investigated whether cinacalcet and NPS-2143 may rectify Ca2+i alterations associated with FHH2- and ADH2-causing Gα11 mutations, and evaluated the influence of germline gain-of-function Gα11 mutations on MAPK signaling by measuring ERK phosphorylation, and assessed the effect of NPS-2143 on a uveal melanoma Gα11 mutant. WT and mutant Gα11 proteins causing FHH2, ADH2 or uveal melanoma were transfected in CaSR-expressing HEK293 cells, and Ca2+i and ERK phosphorylation responses measured by flow-cytometry and Alphascreen immunoassay following exposure to extracellular Ca2+ (Ca2+o) and allosteric modulators. Cinacalcet and NPS-2143 rectified the Ca2+i responses of FHH2- and ADH2-associated Gα11 loss- and gain-of-function mutations, respectively. ADH2-causing Gα11 mutations were demonstrated not to be constitutively activating and induced ERK phosphorylation following Ca2+o stimulation only. The increased ERK phosphorylation associated with ADH2 and uveal melanoma mutants was rectified by NPS-2143. These findings demonstrate that CaSR-targeted compounds can rectify signaling disturbances caused by germline and somatic Gα11 mutations, which respectively lead to calcium disorders and tumorigenesis; and that ADH2-causing Gα11 mutations induce non-constitutive alterations in MAPK signaling.
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Affiliation(s)
- Valerie N Babinsky
- From the Radcliffe Department of Medicine, University of Oxford, Oxford OX3 7LJ, United Kingdom
| | - Fadil M Hannan
- From the Radcliffe Department of Medicine, University of Oxford, Oxford OX3 7LJ, United Kingdom, Department of Musculoskeletal Biology, University of Liverpool, Liverpool L69 3GA, United Kingdom
| | - Caroline M Gorvin
- From the Radcliffe Department of Medicine, University of Oxford, Oxford OX3 7LJ, United Kingdom
| | - Sarah A Howles
- From the Radcliffe Department of Medicine, University of Oxford, Oxford OX3 7LJ, United Kingdom
| | - M Andrew Nesbit
- From the Radcliffe Department of Medicine, University of Oxford, Oxford OX3 7LJ, United Kingdom, Biomedical Sciences Research Institute, Ulster University, Coleraine BT52 1SA, United Kingdom
| | - Nigel Rust
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, United Kingdom
| | - Aylin C Hanyaloglu
- Department of Surgery and Cancer, Institute of Reproductive Biology and Development, Imperial College London, London W12 0NN, United Kingdom
| | - Jianxin Hu
- Laboratory of Bioorganic Chemistry, NIDDK, National Institutes of Health, Bethesda, Maryland 20892, and
| | | | - Rajesh V Thakker
- From the Radcliffe Department of Medicine, University of Oxford, Oxford OX3 7LJ, United Kingdom,
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70
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Fielden MR, Dean C, Black K, Sawant SG, Subramanian R, Tomlinson JE, Walter S, Zimmermann C, Griggs MW, McKeon ME, Lewis EM, Beevers C, Pyrah I. Nonclinical Safety Profile of Etelcalcetide, a Novel Peptide Calcimimetic for the Treatment of Secondary Hyperparathyroidism. Int J Toxicol 2016; 35:294-308. [DOI: 10.1177/1091581816633407] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Etelcalcetide is a novel d-amino acid peptide that functions as an allosteric activator of the calcium-sensing receptor and is being developed as an intravenous calcimimetic for the treatment of secondary hyperparathyroidism in patients with chronic kidney disease on hemodialysis. To support clinical development and marketing authorization, a comprehensive nonclinical safety package was generated. Primary adverse effects included hypocalcemia, tremoring, and convulsions. Other adverse effects were considered sequelae of stress associated with hypocalcemia. Cardiovascular safety evaluations in the dog revealed an anticipated prolongation of the corrected QT interval that was related to reductions in serum calcium. Etelcalcetide did not affect the human ether-a-go-go gene ion channel current. Etelcalcetide was mutagenic in some strains of Salmonella, however, based on the negative results in 2 in vitro and 2 in vivo mammalian genotoxicity assays, including a 28-day Muta mouse study, etelcalcetide is considered nongenotoxic. Further support for a lack of genotoxicity was provided due to the fact that etelcalcetide was not carcinogenic in a 6-month transgenic rasH2 mouse model or a 2-year study in rats. There were no effects on fertility, embryo–fetal development, and prenatal and postnatal development. All of the adverse effects observed in both rat and dog were considered directly or secondarily related to the pharmacologic activity of etelcalcetide and the expected sequelae associated with dose-related reductions in serum calcium due to suppression of parathyroid hormone secretion. These nonclinical data indicate no safety signal of concern for human risk beyond that associated with hypocalcemia and associated QT prolongation.
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Affiliation(s)
- Mark R. Fielden
- Comparative Biology and Safety Sciences, Amgen Inc, Thousand Oaks, CA, USA
| | - Charles Dean
- Comparative Biology and Safety Sciences, Amgen Inc, Thousand Oaks, CA, USA
| | - Kurt Black
- Comparative Biology and Safety Sciences, Amgen Inc, Thousand Oaks, CA, USA
| | - Satin G. Sawant
- Comparative Biology and Safety Sciences, Amgen Inc, Thousand Oaks, CA, USA
| | - Raju Subramanian
- Pharmacokinetics and Drug Metabolism, Amgen Inc, Thousand Oaks, CA, USA
| | | | - Sarah Walter
- Cardiometabolic Disorders, Amgen Inc, Thousand Oaks, CA, USA
| | - Cameron Zimmermann
- Comparative Biology and Safety Sciences, Amgen Inc, Thousand Oaks, CA, USA
| | | | | | | | | | - Ian Pyrah
- Comparative Biology and Safety Sciences, Amgen Inc, Thousand Oaks, CA, USA
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71
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Murphy H, Patrick J, Báez-Irizarry E, Lacassie Y, Gómez R, Vargas A, Barkemeyer B, Kanotra S, Zambrano RM. Neonatal severe hyperparathyroidism caused by homozygous mutation in CASR: A rare cause of life-threatening hypercalcemia. Eur J Med Genet 2016; 59:227-31. [PMID: 26855056 DOI: 10.1016/j.ejmg.2016.02.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2015] [Revised: 01/27/2016] [Accepted: 02/01/2016] [Indexed: 11/15/2022]
Abstract
Neonatal severe hyperparathyroidism (NSHPT) is a rare, life-threatening condition that presents with severe hypercalcemia, hyperparathyroidism, and osteopenia in the newborn period. Treatment of NSHPT traditionally includes hydration and bisphosphonates; however newer calcimimetic agents, such as cinacalcet, are now being utilized to prevent or delay parathyroidectomy which is technically difficult in the newborn. Medical treatment success is related to calcium sensing receptor (CaSR) genotype. We report a 4-day-old infant who presented with hyperbilirubinemia, poor feeding, weight loss, severe hypotonia and was ultimately diagnosed with NSHPT. The patient's total serum calcium level of 36.8 mg/dL (reference range: 8.5-10.4 mg/dL) is, to our knowledge, the highest ever documented in this setting. Exome data previously obtained on the infant's parents was re-analyzed demonstrating bi-parental heterozygosity for a mutation of the CASR gene: c.206G > A, and Sanger sequencing data confirmed the patient was a homozygote for the same mutation. Though a patient with the same CaSR gene mutation described here has responded to cinacalcet, our patient did not respond and required parathyroidectomy. Though this case has previously been published as a surgical case report, a full report of the medical management and underlying genetic etiology is warranted; this case underscores the importance of disclosing bi-parental heterozygosity for a gene causing severe neonatal disease particularly when treatment is available and illustrates the need for further in vitro studies of this CaSR mutation.
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Affiliation(s)
- Heidi Murphy
- Department of Pediatrics, Louisiana State University Health Science Center, USA
| | - Jessica Patrick
- Division of Neonatology, Department of Pediatrics, Louisiana State University Health Science Center, USA
| | - Eileen Báez-Irizarry
- Division of Endocrinology, Department of Pediatrics, Louisiana State University Health Science Center, USA
| | - Yves Lacassie
- Division of Genetics, Department of Pediatrics, Louisiana State University Health Science Center, USA; Department of Genetics, Children's Hospital of New Orleans, USA
| | - Ricardo Gómez
- Division of Endocrinology, Department of Pediatrics, Louisiana State University Health Science Center, USA; Department of Endocrinology, Children's Hospital of New Orleans, USA
| | - Alfonso Vargas
- Division of Endocrinology, Department of Pediatrics, Louisiana State University Health Science Center, USA; Department of Endocrinology, Children's Hospital of New Orleans, USA
| | - Brian Barkemeyer
- Division of Neonatology, Department of Pediatrics, Louisiana State University Health Science Center, USA; Department of Neonatology, Children's Hospital of New Orleans, USA
| | - Sohit Kanotra
- Division of Otorlaryngology, Department of Pediatrics, Louisiana State University Health Science Center, USA; Department of Otolaryngology Children's Hospital of New Orleans, USA
| | - Regina M Zambrano
- Division of Genetics, Department of Pediatrics, Louisiana State University Health Science Center, USA; Department of Genetics, Children's Hospital of New Orleans, USA.
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Changcharoen B, Motosue M, Wong L, Arakaki R. A Woman and Her Father with Calcium-Sensing Receptor Mutation and Autosomal Dominant Hypocalcemia. AACE Clin Case Rep 2016. [DOI: 10.4158/ep15716.cr] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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73
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Hendy GN, Canaff L. Calcium-sensing receptor, proinflammatory cytokines and calcium homeostasis. Semin Cell Dev Biol 2015; 49:37-43. [PMID: 26612442 DOI: 10.1016/j.semcdb.2015.11.006] [Citation(s) in RCA: 78] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2015] [Accepted: 11/12/2015] [Indexed: 12/22/2022]
Abstract
The calcium-sensing receptor (CaSR) expressed in the parathyroid gland and the kidney tubule acts as the calciostat and orchestrates blood calcium homeostasis by modulating production and release of parathyroid hormone (PTH) and active vitamin D that influence Ca(2+) fluxes across the bone, kidney and intestine. Here we consider the role of the CaSR as a responder to proinflammatory cytokines released as part of the innate immune response to tissue injury and inflammation with resetting of the calciostat on the one hand and as a promoter and mediator of the initial inflammatory response on the other. The importance of the CaSR in systemic calcium homeostasis is exemplified by the fact that inactivating and activating mutations in the gene result in hypercalcemia and hypocalcemia, respectively. Proinflammatory cytokines interleukin-1β and interleukin-6 upregulate CaSR expression in parathyroid and kidney and do this through defined response elements in the CASR gene promoters. This results in decreased serum PTH and 1,25-dihydroxyvitamin D and calcium levels. This is likely to underlie the hypocalcemia that commonly occurs in critically ill patients, those with burn injury and sepsis, for example. The level of calcium in extracellular fluid bathing necrotic cells is often elevated and acts as a chemokine to attract monocytes/macrophages that express the CaSR to sites of tissue injury. Elevated levels of calcium acting via the CaSR can function as a danger signal that stimulates assembly of myeloid cell cytosolic multiprotein inflammasomes resulting in maturation of the proinflammatory cytokine IL-1β by caspase-1. Thus the CaSR is both promoter of and responder to the inflammation.
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Affiliation(s)
- Geoffrey N Hendy
- Experimental Therapeutics and Metabolism, McGill University Health Centre-Research Institute, and Departments of Medicine, Physiology and Human Genetics, McGill University, Montreal, Quebec, H4A 3J1, Canada.
| | - Lucie Canaff
- Experimental Therapeutics and Metabolism, McGill University Health Centre-Research Institute, and Departments of Medicine, Physiology and Human Genetics, McGill University, Montreal, Quebec, H4A 3J1, Canada
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74
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Plain A, Wulfmeyer VC, Milatz S, Klietz A, Hou J, Bleich M, Himmerkus N. Corticomedullary difference in the effects of dietary Ca²⁺ on tight junction properties in thick ascending limbs of Henle's loop. Pflugers Arch 2015; 468:293-303. [PMID: 26497703 DOI: 10.1007/s00424-015-1748-7] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Revised: 10/13/2015] [Accepted: 10/16/2015] [Indexed: 11/26/2022]
Abstract
The thick ascending limb of Henle's loop (TAL) drives an important part of the reabsorption of divalent cations. This reabsorption occurs via the paracellular pathway formed by the tight junction (TJ), which in the TAL shows cation selectivity. Claudins, a family of TJ proteins, determine the permeability and selectivity of this pathway. Mice were fed with normal or high-Ca(2+) diet, and effects on the reabsorptive properties of cortical and medullary TAL segments were analysed by tubule microdissection and microperfusion. Claudin expression was investigated by immunostaining and quantitative PCR. We show that the TAL adapted to high Ca(2+) load in a sub-segment-specific manner. In medullary TAL, transcellular NaCl transport was attenuated. The transepithelial voltage decreased from 10.9 ± 0.6 mV at control diet to 8.3 ± 0.5 mV at high Ca(2+) load, thereby reducing the driving force for Ca(2+) and Mg(2+) uptake. Cortical TAL showed a reduction in paracellular Ca(2+) and Mg(2+) permeabilities from 8.2 ± 0.7 to 6.2 ± 0.5 ∙ 10(-4) cm/s and from 4.8 ± 0.5 to 3.0 ± 0.2 · 10(-4) cm/s at control and high-Ca(2+) diet, respectively. Expression, localisation and regulation of claudins 10, 14, 16 and 19 differed along the corticomedullary axis: Towards the cortex, the main site of divalent cation reabsorption in TAL, high-Ca(2+) intake led to a strong upregulation of claudin-14 within TAL TJs while claudin-16 and -19 were unaltered. Towards the inner medulla, only claudin-10 was present in TAL TJ strands. In summary, high-Ca(2+) diet induced a reduction of divalent cation reabsorption via a diminution of NaCl transport and driving force in mTAL and via decreased paracellular permeabilities in cTAL. We reveal an important regulatory pattern along the corticomedullary axis and improve the understanding how the kidney disposes of detrimental excess Ca(2+).
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Affiliation(s)
- Allein Plain
- Institute of Physiology, Christian-Albrechts-University Kiel, Olshausenstraße 40, Kiel, 24098, Germany
| | - Vera C Wulfmeyer
- Institute of Physiology, Christian-Albrechts-University Kiel, Olshausenstraße 40, Kiel, 24098, Germany
| | - Susanne Milatz
- Institute of Physiology, Christian-Albrechts-University Kiel, Olshausenstraße 40, Kiel, 24098, Germany
| | - Adrian Klietz
- Institute of Physiology, Christian-Albrechts-University Kiel, Olshausenstraße 40, Kiel, 24098, Germany
| | - Jianghui Hou
- Washington University Renal Division, St. Louis, MO, USA
| | - Markus Bleich
- Institute of Physiology, Christian-Albrechts-University Kiel, Olshausenstraße 40, Kiel, 24098, Germany
| | - Nina Himmerkus
- Institute of Physiology, Christian-Albrechts-University Kiel, Olshausenstraße 40, Kiel, 24098, Germany.
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75
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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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Vignali E, Cetani F, Chiavistelli S, Meola A, Saponaro F, Centoni R, Cianferotti L, Marcocci C. Normocalcemic primary hyperparathyroidism: a survey in a small village of Southern Italy. Endocr Connect 2015; 4:172-8. [PMID: 26155986 PMCID: PMC4496527 DOI: 10.1530/ec-15-0030] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/05/2022]
Abstract
We investigated the prevalence of normocalcemic primary hyperparathyroidism (NPHPT) in the adult population living in a village in Southern Italy. All residents in 2010 (n=2045) were invited by calls and 1046 individuals accepted to participate. Medical history, calcium intake, calcium, albumin, creatinine, parathyroid hormone (PTH) and 25OHD were evaluated. NPHPT was defined by normal albumin-adjusted serum calcium, elevated plasma PTH, and exclusion of common causes of secondary hyperparathyroidism (SHPT) (serum 25OHD <30 ng/ml, estimated glomerular filtration rate (eGFR) <60 ml/min per 1.73 m(2) and thiazide diuretics use), overt gastrointestinal and metabolic bone diseases. Complete data were available for 685 of 1046 subjects. Twenty subjects did not meet the inclusion criteria and 341 could not be evaluated because of thawing of plasma samples. Classical PHPT was diagnosed in four women (0.58%). For diagnosing NPHPT the upper normal limit of PTH was established in the sample of the population (n=100) who had 25OHD ≥30 ng/ml and eGFR ≥60 ml/min per 1.73 m(2) and was set at the mean+3s.d. Three males (0.44%) met the diagnostic criteria of NPHPT. These subjects were younger and with lower BMI than those with classical PHPT. Our data suggest, in line with previous studies, that NPHPT might be a distinct clinical entity, being either an early phenotype of asymptomatic PHPT or a distinct variant of it. However, we cannot exclude that NPHPT might also represent an early phase of non-classical SHPT, since other variables, in addition to those currently taken into account for the diagnosis of NPHPT, might cumulate in a normocalcemic subject to increase PTH secretion.
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Affiliation(s)
- E Vignali
- Endocrine Unit 2University Hospital of Pisa, Via Paradisa 2, 56124 Pisa, ItalyDepartment of Clinical and Experimental MedicineUniversity of Pisa, Pisa, ItalyLaboratory of Chemistry and EndocrinologyUniversity Hospital of Pisa, Pisa, Italy
| | - F Cetani
- Endocrine Unit 2University Hospital of Pisa, Via Paradisa 2, 56124 Pisa, ItalyDepartment of Clinical and Experimental MedicineUniversity of Pisa, Pisa, ItalyLaboratory of Chemistry and EndocrinologyUniversity Hospital of Pisa, Pisa, Italy
| | - S Chiavistelli
- Endocrine Unit 2University Hospital of Pisa, Via Paradisa 2, 56124 Pisa, ItalyDepartment of Clinical and Experimental MedicineUniversity of Pisa, Pisa, ItalyLaboratory of Chemistry and EndocrinologyUniversity Hospital of Pisa, Pisa, Italy
| | - A Meola
- Endocrine Unit 2University Hospital of Pisa, Via Paradisa 2, 56124 Pisa, ItalyDepartment of Clinical and Experimental MedicineUniversity of Pisa, Pisa, ItalyLaboratory of Chemistry and EndocrinologyUniversity Hospital of Pisa, Pisa, Italy
| | - F Saponaro
- Endocrine Unit 2University Hospital of Pisa, Via Paradisa 2, 56124 Pisa, ItalyDepartment of Clinical and Experimental MedicineUniversity of Pisa, Pisa, ItalyLaboratory of Chemistry and EndocrinologyUniversity Hospital of Pisa, Pisa, Italy
| | - R Centoni
- Endocrine Unit 2University Hospital of Pisa, Via Paradisa 2, 56124 Pisa, ItalyDepartment of Clinical and Experimental MedicineUniversity of Pisa, Pisa, ItalyLaboratory of Chemistry and EndocrinologyUniversity Hospital of Pisa, Pisa, Italy
| | - L Cianferotti
- Endocrine Unit 2University Hospital of Pisa, Via Paradisa 2, 56124 Pisa, ItalyDepartment of Clinical and Experimental MedicineUniversity of Pisa, Pisa, ItalyLaboratory of Chemistry and EndocrinologyUniversity Hospital of Pisa, Pisa, Italy
| | - C Marcocci
- Endocrine Unit 2University Hospital of Pisa, Via Paradisa 2, 56124 Pisa, ItalyDepartment of Clinical and Experimental MedicineUniversity of Pisa, Pisa, ItalyLaboratory of Chemistry and EndocrinologyUniversity Hospital of Pisa, Pisa, Italy Endocrine Unit 2University Hospital of Pisa, Via Paradisa 2, 56124 Pisa, ItalyDepartment of Clinical and Experimental MedicineUniversity of Pisa, Pisa, ItalyLaboratory of Chemistry and EndocrinologyUniversity Hospital of Pisa, Pisa, Italy
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77
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Hannan FM, Walls GV, Babinsky VN, Nesbit MA, Kallay E, Hough TA, Fraser WD, Cox RD, Hu J, Spiegel AM, Thakker RV. The Calcilytic Agent NPS 2143 Rectifies Hypocalcemia in a Mouse Model With an Activating Calcium-Sensing Receptor (CaSR) Mutation: Relevance to Autosomal Dominant Hypocalcemia Type 1 (ADH1). Endocrinology 2015; 156:3114-21. [PMID: 26052899 PMCID: PMC4541614 DOI: 10.1210/en.2015-1269] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Autosomal dominant hypocalcemia type 1 (ADH1) is caused by germline gain-of-function mutations of the calcium-sensing receptor (CaSR) and may lead to symptomatic hypocalcemia, inappropriately low serum PTH concentrations and hypercalciuria. Negative allosteric CaSR modulators, known as calcilytics, have been shown to normalize the gain-of-function associated with ADH-causing CaSR mutations in vitro and represent a potential targeted therapy for ADH1. However, the effectiveness of calcilytic drugs for the treatment of ADH1-associated hypocalcemia remains to be established. We have investigated NPS 2143, a calcilytic compound, for the treatment of ADH1 by in vitro and in vivo studies involving a mouse model, known as Nuf, which harbors a gain-of-function CaSR mutation, Leu723Gln. Wild-type (Leu723) and Nuf mutant (Gln723) CaSRs were expressed in HEK293 cells, and the effect of NPS 2143 on their intracellular calcium responses was determined by flow cytometry. NPS 2143 was also administered as a single ip bolus to wild-type and Nuf mice and plasma concentrations of calcium and PTH, and urinary calcium excretion measured. In vitro administration of NPS 2143 decreased the intracellular calcium responses of HEK293 cells expressing the mutant Gln723 CaSR in a dose-dependent manner, thereby rectifying the gain-of-function associated with the Nuf mouse CaSR mutation. Intraperitoneal injection of NPS 2143 in Nuf mice led to significant increases in plasma calcium and PTH without elevating urinary calcium excretion. These studies of a mouse model with an activating CaSR mutation demonstrate NPS 2143 to normalize the gain-of-function causing ADH1 and improve the hypocalcemia associated with this disorder.
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Affiliation(s)
- Fadil M Hannan
- Academic Endocrine Unit (F.M.H., G.V.W., V.N.B., M.A.N., E.K., R.V.T.), Radcliffe Department of Medicine, Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Oxford, OX3 7LJ, United Kingdom; Medical Research Council (MRC) Mammalian Genetics Unit and Mary Lyon Centre (T.A.H., R.D.C.), MRC Harwell, Harwell Science and Innovation Campus, Oxfordshire, OX11 0RD, United Kingdom; Department of Medicine (W.D.F.), Norwich Medical School, University of East Anglia, Norwich, NR4 7TJ, United Kingdom; Laboratory of Bioorganic Chemistry (J.H.), National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Maryland 20892; and Albert Einstein College of Medicine (A.M.S.), Bronx, New York 10461
| | - Gerard V Walls
- Academic Endocrine Unit (F.M.H., G.V.W., V.N.B., M.A.N., E.K., R.V.T.), Radcliffe Department of Medicine, Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Oxford, OX3 7LJ, United Kingdom; Medical Research Council (MRC) Mammalian Genetics Unit and Mary Lyon Centre (T.A.H., R.D.C.), MRC Harwell, Harwell Science and Innovation Campus, Oxfordshire, OX11 0RD, United Kingdom; Department of Medicine (W.D.F.), Norwich Medical School, University of East Anglia, Norwich, NR4 7TJ, United Kingdom; Laboratory of Bioorganic Chemistry (J.H.), National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Maryland 20892; and Albert Einstein College of Medicine (A.M.S.), Bronx, New York 10461
| | - Valerie N Babinsky
- Academic Endocrine Unit (F.M.H., G.V.W., V.N.B., M.A.N., E.K., R.V.T.), Radcliffe Department of Medicine, Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Oxford, OX3 7LJ, United Kingdom; Medical Research Council (MRC) Mammalian Genetics Unit and Mary Lyon Centre (T.A.H., R.D.C.), MRC Harwell, Harwell Science and Innovation Campus, Oxfordshire, OX11 0RD, United Kingdom; Department of Medicine (W.D.F.), Norwich Medical School, University of East Anglia, Norwich, NR4 7TJ, United Kingdom; Laboratory of Bioorganic Chemistry (J.H.), National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Maryland 20892; and Albert Einstein College of Medicine (A.M.S.), Bronx, New York 10461
| | - M Andrew Nesbit
- Academic Endocrine Unit (F.M.H., G.V.W., V.N.B., M.A.N., E.K., R.V.T.), Radcliffe Department of Medicine, Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Oxford, OX3 7LJ, United Kingdom; Medical Research Council (MRC) Mammalian Genetics Unit and Mary Lyon Centre (T.A.H., R.D.C.), MRC Harwell, Harwell Science and Innovation Campus, Oxfordshire, OX11 0RD, United Kingdom; Department of Medicine (W.D.F.), Norwich Medical School, University of East Anglia, Norwich, NR4 7TJ, United Kingdom; Laboratory of Bioorganic Chemistry (J.H.), National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Maryland 20892; and Albert Einstein College of Medicine (A.M.S.), Bronx, New York 10461
| | - Enikö Kallay
- Academic Endocrine Unit (F.M.H., G.V.W., V.N.B., M.A.N., E.K., R.V.T.), Radcliffe Department of Medicine, Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Oxford, OX3 7LJ, United Kingdom; Medical Research Council (MRC) Mammalian Genetics Unit and Mary Lyon Centre (T.A.H., R.D.C.), MRC Harwell, Harwell Science and Innovation Campus, Oxfordshire, OX11 0RD, United Kingdom; Department of Medicine (W.D.F.), Norwich Medical School, University of East Anglia, Norwich, NR4 7TJ, United Kingdom; Laboratory of Bioorganic Chemistry (J.H.), National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Maryland 20892; and Albert Einstein College of Medicine (A.M.S.), Bronx, New York 10461
| | - Tertius A Hough
- Academic Endocrine Unit (F.M.H., G.V.W., V.N.B., M.A.N., E.K., R.V.T.), Radcliffe Department of Medicine, Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Oxford, OX3 7LJ, United Kingdom; Medical Research Council (MRC) Mammalian Genetics Unit and Mary Lyon Centre (T.A.H., R.D.C.), MRC Harwell, Harwell Science and Innovation Campus, Oxfordshire, OX11 0RD, United Kingdom; Department of Medicine (W.D.F.), Norwich Medical School, University of East Anglia, Norwich, NR4 7TJ, United Kingdom; Laboratory of Bioorganic Chemistry (J.H.), National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Maryland 20892; and Albert Einstein College of Medicine (A.M.S.), Bronx, New York 10461
| | - William D Fraser
- Academic Endocrine Unit (F.M.H., G.V.W., V.N.B., M.A.N., E.K., R.V.T.), Radcliffe Department of Medicine, Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Oxford, OX3 7LJ, United Kingdom; Medical Research Council (MRC) Mammalian Genetics Unit and Mary Lyon Centre (T.A.H., R.D.C.), MRC Harwell, Harwell Science and Innovation Campus, Oxfordshire, OX11 0RD, United Kingdom; Department of Medicine (W.D.F.), Norwich Medical School, University of East Anglia, Norwich, NR4 7TJ, United Kingdom; Laboratory of Bioorganic Chemistry (J.H.), National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Maryland 20892; and Albert Einstein College of Medicine (A.M.S.), Bronx, New York 10461
| | - Roger D Cox
- Academic Endocrine Unit (F.M.H., G.V.W., V.N.B., M.A.N., E.K., R.V.T.), Radcliffe Department of Medicine, Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Oxford, OX3 7LJ, United Kingdom; Medical Research Council (MRC) Mammalian Genetics Unit and Mary Lyon Centre (T.A.H., R.D.C.), MRC Harwell, Harwell Science and Innovation Campus, Oxfordshire, OX11 0RD, United Kingdom; Department of Medicine (W.D.F.), Norwich Medical School, University of East Anglia, Norwich, NR4 7TJ, United Kingdom; Laboratory of Bioorganic Chemistry (J.H.), National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Maryland 20892; and Albert Einstein College of Medicine (A.M.S.), Bronx, New York 10461
| | - Jianxin Hu
- Academic Endocrine Unit (F.M.H., G.V.W., V.N.B., M.A.N., E.K., R.V.T.), Radcliffe Department of Medicine, Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Oxford, OX3 7LJ, United Kingdom; Medical Research Council (MRC) Mammalian Genetics Unit and Mary Lyon Centre (T.A.H., R.D.C.), MRC Harwell, Harwell Science and Innovation Campus, Oxfordshire, OX11 0RD, United Kingdom; Department of Medicine (W.D.F.), Norwich Medical School, University of East Anglia, Norwich, NR4 7TJ, United Kingdom; Laboratory of Bioorganic Chemistry (J.H.), National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Maryland 20892; and Albert Einstein College of Medicine (A.M.S.), Bronx, New York 10461
| | - Allen M Spiegel
- Academic Endocrine Unit (F.M.H., G.V.W., V.N.B., M.A.N., E.K., R.V.T.), Radcliffe Department of Medicine, Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Oxford, OX3 7LJ, United Kingdom; Medical Research Council (MRC) Mammalian Genetics Unit and Mary Lyon Centre (T.A.H., R.D.C.), MRC Harwell, Harwell Science and Innovation Campus, Oxfordshire, OX11 0RD, United Kingdom; Department of Medicine (W.D.F.), Norwich Medical School, University of East Anglia, Norwich, NR4 7TJ, United Kingdom; Laboratory of Bioorganic Chemistry (J.H.), National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Maryland 20892; and Albert Einstein College of Medicine (A.M.S.), Bronx, New York 10461
| | - Rajesh V Thakker
- Academic Endocrine Unit (F.M.H., G.V.W., V.N.B., M.A.N., E.K., R.V.T.), Radcliffe Department of Medicine, Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Oxford, OX3 7LJ, United Kingdom; Medical Research Council (MRC) Mammalian Genetics Unit and Mary Lyon Centre (T.A.H., R.D.C.), MRC Harwell, Harwell Science and Innovation Campus, Oxfordshire, OX11 0RD, United Kingdom; Department of Medicine (W.D.F.), Norwich Medical School, University of East Anglia, Norwich, NR4 7TJ, United Kingdom; Laboratory of Bioorganic Chemistry (J.H.), National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Maryland 20892; and Albert Einstein College of Medicine (A.M.S.), Bronx, New York 10461
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78
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The calcium-sensing receptor as a mediator of inflammation. Semin Cell Dev Biol 2015; 49:52-6. [PMID: 26303192 DOI: 10.1016/j.semcdb.2015.08.006] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2015] [Accepted: 08/17/2015] [Indexed: 02/07/2023]
Abstract
The teleologic link between increased production of pro-inflammatory cytokines resulting from a systemic inflammatory response to a burn injury and consequent stimulation of bone resorption is unclear. While it is known that cytokines can stimulate osteocytic and osteoblastic production of the ligand of the receptor activator of NFκB, or RANKL, it is not certain why this occurs. It was therefore hypothesized that the subsequent osteoclastic bone resorption liberates calcium from the bone matrix and somehow affects the inflammatory response. In this paper we show how the cytokine-mediated inflammatory response following severe burn injury in children results in simultaneous increase in bone resorption and up-regulation of the parathyroid calcium-sensing receptor. The acute bone resorption leads to release of calcium from the bone matrix with consequent calcium accumulation in the circulation. The up-regulation of the parathyroid calcium-sensing receptor suppresses the release of parathyroid hormone resulting in a lowering of blood calcium concentration. The simultaneous occurrences of these processes could regulate blood calcium concentration and if calcium concentration affects the inflammatory response, then the calcium-sensing receptor could, at the very least, modulate the inflammatory response by adjusting the blood calcium concentration. We describe in vitro studies in which we demonstrated that peripheral blood mononuclear cells in culture produce the chemokines MIP-1α and RANTES in proportion to the medium calcium concentration and they produce the chemokine MCP-1 in quantities inversely related to medium calcium concentration. CD14+monocytes in culture will also produce MIP-1α in direct relationship to medium calcium concentration but the correlation coefficient is markedly reduced compared to that with peripheral blood mononuclear cells. These monocytes, which possess the calcium-sensing receptor, do not produce MCP-1 in either direct or inverse relationship to medium calcium concentration. Therefore, it is possible that other peripheral blood mononuclear cells are primarily responsible for the production of chemokines in relation to calcium concentration but these cells have not yet been defined.
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79
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Hannan FM, Howles SA, Rogers A, Cranston T, Gorvin CM, Babinsky VN, Reed AA, Thakker CE, Bockenhauer D, Brown RS, Connell JM, Cook J, Darzy K, Ehtisham S, Graham U, Hulse T, Hunter SJ, Izatt L, Kumar D, McKenna MJ, McKnight JA, Morrison PJ, Mughal MZ, O'Halloran D, Pearce SH, Porteous ME, Rahman M, Richardson T, Robinson R, Scheers I, Siddique H, Van't Hoff WG, Wang T, Whyte MP, Nesbit MA, Thakker RV. Adaptor protein-2 sigma subunit mutations causing familial hypocalciuric hypercalcaemia type 3 (FHH3) demonstrate genotype-phenotype correlations, codon bias and dominant-negative effects. Hum Mol Genet 2015; 24:5079-92. [PMID: 26082470 PMCID: PMC4550820 DOI: 10.1093/hmg/ddv226] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2015] [Accepted: 06/12/2015] [Indexed: 12/05/2022] Open
Abstract
The adaptor protein-2 sigma subunit (AP2σ2) is pivotal for clathrin-mediated endocytosis of plasma membrane constituents such as the calcium-sensing receptor (CaSR). Mutations of the AP2σ2 Arg15 residue result in familial hypocalciuric hypercalcaemia type 3 (FHH3), a disorder of extracellular calcium (Ca2+o) homeostasis. To elucidate the role of AP2σ2 in Ca2+o regulation, we investigated 65 FHH probands, without other FHH-associated mutations, for AP2σ2 mutations, characterized their functional consequences and investigated the genetic mechanisms leading to FHH3. AP2σ2 mutations were identified in 17 probands, comprising 5 Arg15Cys, 4 Arg15His and 8 Arg15Leu mutations. A genotype–phenotype correlation was observed with the Arg15Leu mutation leading to marked hypercalcaemia. FHH3 probands harboured additional phenotypes such as cognitive dysfunction. All three FHH3-causing AP2σ2 mutations impaired CaSR signal transduction in a dominant-negative manner. Mutational bias was observed at the AP2σ2 Arg15 residue as other predicted missense substitutions (Arg15Gly, Arg15Pro and Arg15Ser), which also caused CaSR loss-of-function, were not detected in FHH probands, and these mutations were found to reduce the numbers of CaSR-expressing cells. FHH3 probands had significantly greater serum calcium (sCa) and magnesium (sMg) concentrations with reduced urinary calcium to creatinine clearance ratios (CCCR) in comparison with FHH1 probands with CaSR mutations, and a calculated index of sCa × sMg/100 × CCCR, which was ≥ 5.0, had a diagnostic sensitivity and specificity of 83 and 86%, respectively, for FHH3. Thus, our studies demonstrate AP2σ2 mutations to result in a more severe FHH phenotype with genotype–phenotype correlations, and a dominant-negative mechanism of action with mutational bias at the Arg15 residue.
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Affiliation(s)
- Fadil M Hannan
- Academic Endocrine Unit, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - Sarah A Howles
- Academic Endocrine Unit, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - Angela Rogers
- Academic Endocrine Unit, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - Treena Cranston
- Oxford Molecular Genetics Laboratory, Churchill Hospital, Oxford, UK
| | - Caroline M Gorvin
- Academic Endocrine Unit, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - Valerie N Babinsky
- Academic Endocrine Unit, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - Anita A Reed
- Academic Endocrine Unit, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - Clare E Thakker
- Academic Endocrine Unit, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - Detlef Bockenhauer
- Renal Unit, Great Ormond Street Hospital for Children NHS Foundation Trust and UCL Institute of Child Health, London, UK
| | - Rosalind S Brown
- Division of Endocrinology, Boston Children's Hospital, Boston, MA, USA
| | - John M Connell
- School of Medicine, Ninewells Hospital, University of Dundee, Dundee, UK
| | - Jacqueline Cook
- Clinical Genetics Department, Sheffield Children's Hospital NHS Foundation Trust, Sheffield, UK
| | - Ken Darzy
- Queen Elizabeth II Hospital, Welwyn Garden City, UK
| | - Sarah Ehtisham
- Department of Paediatric Endocrinology, Royal Manchester Children's Hospital, Manchester, UK
| | - Una Graham
- Regional Centre for Endocrinology and Diabetes, Royal Victoria Hospital, Belfast, UK
| | - Tony Hulse
- Department of Paediatrics, Evelina London Children's Hospital, St. Thomas' Hospital, London, UK
| | - Steven J Hunter
- Regional Centre for Endocrinology and Diabetes, Royal Victoria Hospital, Belfast, UK
| | - Louise Izatt
- Department of Clinical Genetics, Guy's Hospital, London, UK
| | - Dhavendra Kumar
- Institute of Cancer and Genetics, University Hospital of Wales, Cardiff, UK
| | - Malachi J McKenna
- Department of Endocrinology, St. Vincent's University Hospital, Dublin, Ireland
| | - John A McKnight
- Metabolic Unit, Western General Hospital, NHS Lothian and University of Edinburgh, Edinburgh, UK
| | - Patrick J Morrison
- Centre for Cancer Research and Cell Biology, Queens University of Belfast, Belfast, UK, Department of Genetic Medicine, Belfast HSC Trust, Belfast, UK
| | - M Zulf Mughal
- Department of Paediatric Endocrinology, Royal Manchester Children's Hospital, Manchester, UK
| | | | - Simon H Pearce
- Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK
| | - Mary E Porteous
- SE Scotland Genetic Service, Western General Hospital, Edinburgh, UK
| | - Mushtaqur Rahman
- Department of Endocrinology, Northwick Park Hospital, London, UK
| | - Tristan Richardson
- Diabetes and Endocrine Centre, Royal Bournemouth Hospital, Bournemouth, UK
| | - Robert Robinson
- Department of Endocrinology, Chesterfield Royal Hospital NHS Foundation Trust, Derbyshire, UK
| | - Isabelle Scheers
- Pediatric Gastroenterology, Hepatology and Nutrition Unit, Cliniques Universitaires Saint-Luc, Brussels, Belgium
| | - Haroon Siddique
- Department of Endocrinology, Russells Hall Hospital, Dudley, UK
| | - William G Van't Hoff
- Renal Unit, Great Ormond Street Hospital for Children NHS Foundation Trust and UCL Institute of Child Health, London, UK
| | - Timothy Wang
- Department of Clinical Biochemistry, Frimley Park Hospital, Surrey, UK and
| | - Michael P Whyte
- Center for Metabolic Bone Disease and Molecular Research, Shriners Hospital for Children, St. Louis, Missouri, USA
| | - M Andrew Nesbit
- Academic Endocrine Unit, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - Rajesh V Thakker
- Academic Endocrine Unit, Radcliffe Department of Medicine, University of Oxford, Oxford, UK,
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Palermo A, Jacques R, Gossiel F, Reid DM, Roux C, Felsenberg D, Glueer CC, Eastell R. Normocalcaemic hypoparathyroidism: prevalence and effect on bone status in older women. The OPUS study. Clin Endocrinol (Oxf) 2015; 82:816-23. [PMID: 25640980 DOI: 10.1111/cen.12732] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/11/2014] [Revised: 12/03/2014] [Accepted: 01/27/2015] [Indexed: 11/30/2022]
Abstract
OBJECTIVE There are no consistent data on the prevalence and bone status of normocalcaemic hypoparathyroidism (NHYPO) as defined by normal adjusted calcium and low PTH level. Our aim was to determine the prevalence and the metabolic bone profile of NHYPO in older women, assessing its evolution over time. The second objective was to evaluate the prevalence of other calcium metabolic disorders. DESIGN The Osteoporosis and Ultrasound Study (OPUS) is a 6-yr prospective study of fracture-related factors. PARTICIPANTS A total of 2419 older women (age 55-79 yrs) and 258 younger women (age 30-40 yrs) participated. Complete follow-up data were available in 1416 subjects. MEASUREMENTS After calculating the adjusted calcium according to James' formula, we identified 'abnormal' calcium and PTH using Mahalanobis distances and allocated older women into different pathological categories using reference intervals from the healthy young women. RESULTS We identified 57 subjects with NHYPO (2·4%). These women had lower than expected bone turnover as assessed by bone alkaline phosphatase (-14·5%, 95% CI: -26·2 to -3·0, P = 0·007), CTX (-66·3%, 95% CI: -74·0 to -56·4, P < 0·001) and osteocalcin (-36·8%, 95% CI: -45·6 to -26·6, P < 0·001). After 6 years, of the 35 NHYPO subjects with follow-up data, none developed overt hypoparathyroidism and only 15 (0·6%) subjects had persistent evidence of NHYPO. We also identified 86 subjects (3·6%) affected by hyperparathyroid hypercalcaemia. CONCLUSION This is the first large population-based study to investigate NHYPO in older women. NHYPO is fairly common, not always persistent and is characterized by low bone turnover.
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Affiliation(s)
- Andrea Palermo
- Academic Unit of Bone Metabolism, University of Sheffield, Sheffield, UK
- Department of Endocrinology and Diabetes, University Campus Bio-Medico, Rome, Italy
| | - Richard Jacques
- School of Health and Related Research, University of Sheffield, Sheffield, UK
| | - Fatma Gossiel
- Academic Unit of Bone Metabolism, University of Sheffield, Sheffield, UK
| | - David M Reid
- School of Medicine and Dentistry, University of Aberdeen, Aberdeen, UK
| | - Christian Roux
- Cochin Hospital, Paris Descartes University, Paris, France
| | - Dieter Felsenberg
- Zentrum für Muskel- & Knochenforschung, Charité, Universitätsmedizin Berlin, Berlin, Germany
| | - Claus-C Glueer
- Sektion Biomedizinische Bildgebung, Klinik für Radiologie und Neuroradiologie, Universitätsklinikum Schleswig-Holstein, Kiel, Germany
| | - Richard Eastell
- Academic Unit of Bone Metabolism, University of Sheffield, Sheffield, UK
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81
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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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Abstract
The extracellular calcium-sensing receptor, CaSR, is a member of the G protein-coupled receptor superfamily and has a critical role in modulating Ca(2+) homeostasis via its role in the parathyroid glands and kidneys. New evidence suggests that CaSR expression in cartilage and bone also directly regulates skeletal homeostasis. This Review discusses the role of CaSR in chondrocytes, through which CaSR contributes to the development of the cartilaginous growth plate, as well as in osteoblasts and osteoclasts, through which CaSR has effects on skeletal development and bone turnover in young and mature animals. The interaction of skeletal CaSR activation with parathyroid hormone (PTH), which is secreted by the parathyroid gland, can lead to net bone formation in trabecular bone or net bone resorption in cortical bone. Allosteric modulators of CaSR are beneficial in some clinical conditions, with effects that are mediated by the ability of these agents to alter levels of PTH and improve Ca(2+) homeostasis. However, further insights into the action of CaSR in bone cells might lead to CaSR-based drugs that maximize not only the effects of the receptor on the parathyroid glands and kidneys but also on bone.
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Affiliation(s)
- David Goltzman
- Department of Medicine, McGill University, 687 Pine Avenue West, Montreal, QC H3A 1A1, Canada
| | - Geoffrey N Hendy
- Department of Medicine, McGill University, 687 Pine Avenue West, Montreal, QC H3A 1A1, Canada
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83
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Thakker RV. The calcium-sensing receptor: And its involvement in parathyroid pathology. ANNALES D'ENDOCRINOLOGIE 2015; 76:81-3. [PMID: 25910996 DOI: 10.1016/j.ando.2015.03.013] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2015] [Accepted: 03/13/2015] [Indexed: 11/28/2022]
Affiliation(s)
- Rajesh V Thakker
- Academic Endocrine Unit, University of Oxford, Radcliffe Department of Clinical Medicine, OCDEM, Churchill Hospital, Headington, OX3 7LJ Oxford, United Kingdom.
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84
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Carmosino M, Gerbino A, Hendy GN, Torretta S, Rizzo F, Debellis L, Procino G, Svelto M. NKCC2 activity is inhibited by the Bartter's syndrome type 5 gain-of-function CaR-A843E mutant in renal cells. Biol Cell 2015; 107:98-110. [PMID: 25631355 DOI: 10.1111/boc.201400069] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2014] [Accepted: 01/23/2015] [Indexed: 01/01/2023]
Abstract
BACKGROUND INFORMATION The gain-of-function A843E mutation of the calcium sensing receptor (CaR) causes Bartter syndrome type 5. Patients carrying this CaR variant show a remarkably reduced renal NaCl reabsorption in the thick ascending limb (TAL) of Henle's loop resulting in renal loss of NaCl in the absence of mutations in renal Na(+) and Cl(-) ion transporters. The molecular mechanisms underlying this clinical phenotype are incompletely understood. We investigated, in human embryonic kidney 293 (HEK 293) cells and porcine kidney epithelial (LLC-PK1) cells, the functional cross-talk of CaR-A843E with the Na(+):K(+):2Cl(-) co-transporter, NKCC2, which provides NaCl reabsorption in the TAL. RESULTS The expression of the CaR mutant did not alter the apical localisation of NKCC2 in LLC-PK1 cells. However, the steady-state NKCC2 phosphorylation and activity were decreased in cells transfected with CaR-A843E compared with the control wild-type CaR (CaR WT)-transfected cells. Of note, low-Cl(-)-dependent NKCC2 activation was also strongly inhibited upon the expression of CaR-A843E mutant. The use of either P450 ω-hydroxylase (CYP4)- or phospholipase A2 (PLA2)-blockers suggests that this effect is likely mediated by arachidonic acid (AA) metabolites. CONCLUSIONS The data suggested that the activated CaR affects intracellular pathways modulating NKCC2 activity rather than NKCC2 intracellular trafficking in renal cells, and throw further light on the pathological role played by active CaR mutants in Bartter syndrome type 5.
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Affiliation(s)
- Monica Carmosino
- Department of Biosciences, Biotechnologies, and Biopharmaceutics, University of Bari, 70125 Bari, Italy; Department of Sciences, University of Basilicata, 85100 Potenza, Italy
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85
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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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86
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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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87
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Goolam MA, Ward JH, Avlani VA, Leach K, Christopoulos A, Conigrave AD. Roles of intraloops-2 and -3 and the proximal C-terminus in signalling pathway selection from the human calcium-sensing receptor. FEBS Lett 2014; 588:3340-6. [PMID: 25080008 DOI: 10.1016/j.febslet.2014.07.022] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2014] [Revised: 07/03/2014] [Accepted: 07/16/2014] [Indexed: 12/24/2022]
Abstract
The calcium-sensing receptor (CaSR) couples to signalling pathways via intracellular loops 2 and 3, and the C-terminus. However, the requirements for signalling are largely undefined. We investigated the impacts of selected point mutations in iL-2 (F706A) and iL-3 (L797A and E803A), and a truncation of the C-terminus (R866X) on extracellular Ca(2+) (Ca(2+)o)-stimulated phosphatidylinositol-specific phospholipase-C (PI-PLC) and various other signalling responses. CaSR-mediated activation of PI-PLC was markedly attenuated in all four mutants and similar suppressions were observed for Ca(2+)o-stimulated ERK1/2 phosphorylation. Ca(2+)o-stimulated intracellular Ca(2+) (Ca(2+)i) mobilization, however, was relatively preserved for the iL-2 and iL-3 mutants and suppression of adenylyl cyclase was unaffected by either E803A or R866X. The CaSR selects for specific signalling pathways via the proximal C-terminus and key residues in iL-2, iL-3.
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Affiliation(s)
- Mahvash A Goolam
- School of Molecular Bioscience, University of Sydney, NSW 2006, Australia
| | - James H Ward
- School of Molecular Bioscience, University of Sydney, NSW 2006, Australia
| | - Vimesh A Avlani
- School of Molecular Bioscience, University of Sydney, NSW 2006, Australia
| | - Katie Leach
- Monash Institute of Pharmaceutical Sciences and Department of Pharmacology, Monash University, Parkville, Victoria 3052, Australia
| | - Arthur Christopoulos
- Monash Institute of Pharmaceutical Sciences and Department of Pharmacology, Monash University, Parkville, Victoria 3052, Australia
| | - Arthur D Conigrave
- School of Molecular Bioscience, University of Sydney, NSW 2006, Australia.
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88
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Rogers A, Nesbit MA, Hannan FM, Howles SA, Gorvin CM, Cranston T, Allgrove J, Bevan JS, Bano G, Brain C, Datta V, Grossman AB, Hodgson SV, Izatt L, Millar-Jones L, Pearce SH, Robertson L, Selby PL, Shine B, Snape K, Warner J, Thakker RV. Mutational analysis of the adaptor protein 2 sigma subunit (AP2S1) gene: search for autosomal dominant hypocalcemia type 3 (ADH3). J Clin Endocrinol Metab 2014; 99:E1300-5. [PMID: 24708097 PMCID: PMC4447854 DOI: 10.1210/jc.2013-3909] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
CONTEXT Autosomal dominant hypocalcemia (ADH) types 1 and 2 are due to calcium-sensing receptor (CASR) and G-protein subunit-α11 (GNA11) gain-of-function mutations, respectively, whereas CASR and GNA11 loss-of-function mutations result in familial hypocalciuric hypercalcemia (FHH) types 1 and 2, respectively. Loss-of-function mutations of adaptor protein-2 sigma subunit (AP2σ 2), encoded by AP2S1, cause FHH3, and we therefore sought for gain-of-function AP2S1 mutations that may cause an additional form of ADH, which we designated ADH3. OBJECTIVE The objective of the study was to investigate the hypothesis that gain-of-function AP2S1 mutations may cause ADH3. DESIGN The sample size required for the detection of at least one mutation with a greater than 95% likelihood was determined by binomial probability analysis. Nineteen patients (including six familial cases) with hypocalcemia in association with low or normal serum PTH concentrations, consistent with ADH, but who did not have CASR or GNA11 mutations, were ascertained. Leukocyte DNA was used for sequence and copy number variation analysis of AP2S1. RESULTS Binomial probability analysis, using the assumption that AP2S1 mutations would occur in hypocalcemic patients at a prevalence of 20%, which is observed in FHH patients without CASR or GNA11 mutations, indicated that the likelihood of detecting at least one AP2S1 mutation was greater than 95% and greater than 98% in sample sizes of 14 and 19 hypocalcemic patients, respectively. AP2S1 mutations and copy number variations were not detected in the 19 hypocalcemic patients. CONCLUSION The absence of AP2S1 abnormalities in hypocalcemic patients, suggests that ADH3 may not occur or otherwise represents a rare hypocalcemic disorder.
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Affiliation(s)
- Angela Rogers
- Academic Endocrine Unit (A.R., M.A.N., F.M.H., S.A.H., C.M.G., R.V.T.), Nuffield Department of Clinical Medicine, and Academic Endocrine Unit (A.R., M.A.N., F.M.H., S.A.H., C.M.G., R.V.T.), Radcliffe Department of Medicine, University of Oxford, Oxford OX3 7LJ, United Kingdom; Oxford Molecular Genetics Laboratory (T.C.) and Oxford Centre for Diabetes, Endocrinology, and Metabolism (A.B.G.), Churchill Hospital, Oxford OX3 7LJ, United Kingdom; Department of Paediatric Endocrinology (J.A., C.B.), Great Ormond Street Hospital, London WC1N 3JH, United Kingdom; Department of Paediatric Endocrinology (J.A.), Royal London Hospital, London E1 1BB, United Kingdom; Department of Endocrinology (J.S.B.), Aberdeen Royal Infirmary, Aberdeen AB25 2ZN, United Kingdom; Departments of Diabetes and Endocrinology (G.B.) and Clinical Genetics (S.V.H., K.S.), St George's Hospital, London SW17 0RE, United Kingdom; Jenny Lind Children's Department (V.D.), Norfolk and Norwich University Hospitals National Health Service Foundation Trust, Norfolk NR4 7UY, United Kingdom; Department of Clinical Genetics (L.I.), Guy's and St Thomas' Foundation Trust, Guy's Hospital, London SE1 9RT, United Kingdom; Department of Paediatrics (L.M.-J.), Royal Glamorgan Hospital, Glamorgan CF72 8XR, United Kingdom; Endocrine Unit (S.H.P.), Royal Victoria Infirmary, Newcastle upon Tyne NE1 4LP, United Kingdom; Department of Clinical Genetics (L.R.), Leicester Royal Infirmary, Leicester LE1 5WW, United Kingdom; Department of Medicine (P.L.S.), Manchester Royal Infirmary, Manchester M13 9WL, United Kingdom; Department of Clinical Biochemistry (B.S.), John Radcliffe Hospital, Oxford OX3 9DU, United Kingdom; and Department of Paediatrics (J.W.), University Hospital of Wales, Cardiff CF14 4XW, United Kingdom
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89
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Atay Z, Bereket A, Haliloglu B, Abali S, Ozdogan T, Altuncu E, Canaff L, Vilaça T, Wong BYL, Cole DEC, Hendy GN, Turan S. Novel homozygous inactivating mutation of the calcium-sensing receptor gene (CASR) in neonatal severe hyperparathyroidism-lack of effect of cinacalcet. Bone 2014; 64:102-7. [PMID: 24735972 DOI: 10.1016/j.bone.2014.04.010] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/21/2014] [Revised: 03/21/2014] [Accepted: 04/07/2014] [Indexed: 11/15/2022]
Abstract
BACKGROUND NSHPT is a life-threatening disorder caused by homozygous inactivating calcium-sensing receptor (CASR) mutations. In some cases, the CaSR allosteric activator, cinacalcet, may reduce serum PTH and calcium levels, but surgery is the treatment of choice. OBJECTIVE To describe a case of NSHPT unresponsive to cinacalcet. PATIENT AND RESULTS A 23-day-old girl was admitted with hypercalcemia, hypotonia, bell-shaped chest and respiratory distress. The parents were first-degree cousins once removed. Serum Ca was 4.75 mmol/l (N: 2.10-2.62), P: 0.83 mmol/l (1.55-2.64), PTH: 1096 pg/ml (9-52) and urinary Ca/Cr ratio: 0.5mg/mg. First, calcitonin was given (10 IU/kg × 4/day), and then 2 days later, pamidronate (0.5mg/kg) for 2 days. Doses of cinacalcet were given daily from day 28 of life starting at 30 mg/m2 and increasing to 90 mg/m2 on day 43. On day 33, 6 days after pamidronate, serum Ca levels had fallen to 2.5 mmol/l but, thereafter, rose to 5 mmol/l despite the cinacalcet. Total parathyroidectomy was performed at day 45. Hungry bone disease after surgery required daily Ca replacement and calcitriol for 18 days. At 3 months, the girl was mildly hypercalcemic, with no supplementation, and at 6 months, she developed hypocalcemia and has since been maintained on Ca and calcitriol. By CASR mutation analysis, the infant was homozygous and both parents heterozygous for a deletion-frameshift mutation. CONCLUSION The predicted nonfunctional CaSR is consistent with lack of response to cinacalcet, but total parathyroidectomy was successful. An empiric trial of the drug and/or prompt mutation testing should help minimize the period of unnecessary pharmacotherapy.
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Affiliation(s)
- Zeynep Atay
- Department of Pediatric Endocrinology, Marmara University, Pendik, Istanbul 34899, Turkey.
| | - Abdullah Bereket
- Department of Pediatric Endocrinology, Marmara University, Pendik, Istanbul 34899, Turkey
| | - Belma Haliloglu
- Department of Pediatric Endocrinology, Marmara University, Pendik, Istanbul 34899, Turkey
| | - Saygin Abali
- Department of Pediatric Endocrinology, Marmara University, Pendik, Istanbul 34899, Turkey
| | - Tutku Ozdogan
- Department of Neonatology, Marmara University, Pendik, Istanbul 34899, Turkey
| | - Emel Altuncu
- Department of Neonatology, Marmara University, Pendik, Istanbul 34899, Turkey
| | - Lucie Canaff
- Department of Medicine, Physiology and Human Genetics, McGill University, Montreal, Quebec H3A 0G4, Canada; Calcium Research Laboratory and Hormones and Cancer Research Unit, Royal Victoria Hospital, Montreal, Quebec H3A 1A1, Canada
| | - Tatiane Vilaça
- Department of Medicine, Physiology and Human Genetics, McGill University, Montreal, Quebec H3A 0G4, Canada; Department of Medicine, Physiology and Human Genetics, McGill University, Montreal, Quebec H3A 0G4, Canada
| | - Betty Y L Wong
- Departments of Laboratory Medicine and Pathobiology, Medicine, and Genetics, University of Toronto, Toronto, Ontario M5G IL5, Canada
| | - David E C Cole
- Departments of Laboratory Medicine and Pathobiology, Medicine, and Genetics, University of Toronto, Toronto, Ontario M5G IL5, Canada
| | - Geoffrey N Hendy
- Department of Medicine, Physiology and Human Genetics, McGill University, Montreal, Quebec H3A 0G4, Canada; Calcium Research Laboratory and Hormones and Cancer Research Unit, Royal Victoria Hospital, Montreal, Quebec H3A 1A1, Canada
| | - Serap Turan
- Department of Pediatric Endocrinology, Marmara University, Pendik, Istanbul 34899, Turkey
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90
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Seino A, Iguchi A, Ito T, Saeki T, Makita N, Iiri T, Yamazaki H. A Case of Acquired Hypocalciuric Hypercalcemia due to Autoantibody against the Calcium-sensing Receptor. ACTA ACUST UNITED AC 2014; 103:1180-2. [DOI: 10.2169/naika.103.1180] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Azusa Seino
- Department of Medicine, Nagaoka Red Cross Hospital
| | - Akira Iguchi
- Department of Medicine, Nagaoka Red Cross Hospital
| | - Tomoyuki Ito
- Department of Medicine, Nagaoka Red Cross Hospital
| | - Takako Saeki
- Department of Medicine, Nagaoka Red Cross Hospital
| | - Noriko Makita
- Department of Endocrinology and Nephrology, University of Tokyo
| | - Taroh Iiri
- Department of Endocrinology and Nephrology, University of Tokyo
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