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Höppner J, Jüppner H. Rare genetic disorders that impair parathyroid hormone synthesis, secretion, or bioactivity provide insights into the diagnostic utility of different parathyroid hormone assays. Curr Opin Nephrol Hypertens 2024; 33:375-382. [PMID: 38701324 DOI: 10.1097/mnh.0000000000000999] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/05/2024]
Abstract
PURPOSE OF REVIEW Parathyroid hormone (PTH) is the major peptide hormone regulator of blood calcium homeostasis. Abnormal PTH levels can be observed in patients with various congenital and acquired disorders, including chronic kidney disease (CKD). This review will focus on rare human diseases caused by PTH mutations that have provided insights into the regulation of PTH synthesis and secretion as well as the diagnostic utility of different PTH assays. RECENT FINDINGS Over the past years, numerous diseases affecting calcium and phosphate homeostasis have been defined at the molecular level that are responsible for reduced or increased serum PTH levels. The underlying genetic mutations impair parathyroid gland development, involve the PTH gene itself, or alter function of the calcium-sensing receptor (CaSR) or its downstream signaling partners that contribute to regulation of PTH synthesis or secretion. Mutations in the pre sequence of the mature PTH peptide can, for instance, impair hormone synthesis or intracellular processing, while amino acid substitutions affecting the secreted PTH(1-84) impair PTH receptor (PTH1R) activation, or cause defective cleavage of the pro-sequence and thus secretion of a pro- PTH with much reduced biological activity. Mutations affecting the secreted hormone can alter detection by different PTH assays, thus requiring detailed knowledge of the utilized diagnostic test. SUMMARY Rare diseases affecting PTH synthesis and secretion have offered helpful insights into parathyroid biology and the diagnostic utility of commonly used PTH assays, which may have implications for the interpretation of PTH measurements in more common disorders such as CKD.
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Affiliation(s)
| | - Harald Jüppner
- Endocrine Unit
- Pediatric Nephrology Unit, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, USA
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2
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Hammill AM, Boscolo E. Capillary malformations. J Clin Invest 2024; 134:e172842. [PMID: 38618955 PMCID: PMC11014659 DOI: 10.1172/jci172842] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/16/2024] Open
Abstract
Capillary malformation (CM), or port wine birthmark, is a cutaneous congenital vascular anomaly that occurs in 0.1%-2% of newborns. Patients with a CM localized on the forehead have an increased risk of developing a neurocutaneous disorder called encephalotrigeminal angiomatosis or Sturge-Weber syndrome (SWS), with complications including seizure, developmental delay, glaucoma, and vision loss. In 2013, a groundbreaking study revealed causative activating somatic mutations in the gene (GNAQ) encoding guanine nucleotide-binding protein Q subunit α (Gαq) in CM and SWS patient tissues. In this Review, we discuss the disease phenotype, the causative GNAQ mutations, and their cellular origin. We also present the endothelial Gαq-related signaling pathways, the current animal models to study CM and its complications, and future options for therapeutic treatment. Further work remains to fully elucidate the cellular and molecular mechanisms underlying the formation and maintenance of the abnormal vessels.
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Affiliation(s)
- Adrienne M. Hammill
- Division of Hematology, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, USA
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA
| | - Elisa Boscolo
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA
- Division of Experimental Hematology and Cancer Biology, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, USA
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Takahashi S, Fuchigami T, Suzuki J, Morioka I. A pediatric case of autosomal dominant hypocalcemia type 2. J Pediatr Endocrinol Metab 2023; 36:974-977. [PMID: 37579049 DOI: 10.1515/jpem-2023-0097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Accepted: 07/18/2023] [Indexed: 08/16/2023]
Abstract
OBJECTIVES Autosomal dominant hypocalcemia (ADH) is characterized by hypocalcemia and hyperphosphatemia secondary to hypoparathyroidism. It is classified as type 1, caused by gain-of-function mutations of the calcium-sensing receptor (CASR), and type 2, caused by activating mutations in GNA11, which is a crucial mediator of CASR signaling. What is new? We report a rare pediatric case of ADH type 2. CASE PRESENTATION The patient was a 15-year-old girl with short stature. Blood tests demonstrated hypocalcemia and hyperphosphatemia without elevated parathyroid hormone levels. Brain computed tomography revealed calcification in the bilateral basal ganglia. Genetic testing revealed the rare GNA11 mutation, c.1023C>G (p.Phe341Leu). The patient was diagnosed with ADH type 2. She had experienced numbness and tetany in her hands for several years, which improved with alfacalcidol therapy. CONCLUSIONS Our patient is the third female and first pediatric reported case of a variant mutation in the GNA11 gene (ADH type 2), c.1023C>G (p.Phe341Leu).
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Affiliation(s)
- Satoko Takahashi
- Department of Pediatrics, IMS Fujimi General Hospital, Fujimi City, Japan
- Department of Pediatrics and Child Health, Nihon University School of Medicine, Itabashi-ku, Japan
| | - Tatsuo Fuchigami
- Department of Pediatrics, IMS Fujimi General Hospital, Fujimi City, Japan
- Department of Pediatrics and Child Health, Nihon University School of Medicine, Itabashi-ku, Japan
| | - Junichi Suzuki
- Department of Pediatrics and Child Health, Nihon University School of Medicine, Itabashi-ku, Japan
| | - Ichiro Morioka
- Department of Pediatrics and Child Health, Nihon University School of Medicine, Itabashi-ku, Japan
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Zung A, Barash G, Banne E, Levine MA. Novel Calcium-Sensing Receptor (CASR) Mutation in a Family with Autosomal Dominant Hypocalcemia Type 1 (ADH1): Genetic Study over Three Generations and Clinical Characteristics. Horm Res Paediatr 2023; 96:473-482. [PMID: 36812896 PMCID: PMC10442457 DOI: 10.1159/000529833] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2022] [Accepted: 02/10/2023] [Indexed: 02/24/2023] Open
Abstract
INTRODUCTION Activating mutation of the calcium-sensing receptor gene (CASR) reduces parathyroid hormone secretion and renal tubular reabsorption of calcium, defined as autosomal dominant hypocalcemia type 1 (ADH1). Patients with ADH1 may present with hypocalcemia-induced seizures. Calcitriol and calcium supplementation in symptomatic patients may exacerbate hypercalciuria, leading to nephrocalcinosis, nephrolithiasis, and compromised renal function. METHODS We report on a family with seven members over three generations with ADH1 due to a novel heterozygous mutation in exon 4 of CASR: c.416T>C. RESULTS This mutation leads to substitution of isoleucine with threonine in the ligand-binding domain of CASR. HEK293T cells transfected with wild type or mutant cDNAs demonstrated that p.Ile139Thr substitution led to increased sensitivity of the CASR to activation by extracellular calcium relative to the wild-type CASR (EC50 of 0.88 ± 0.02 mM vs. 1.1 ± 0.23 mM, respectively, p < 0.005). Clinical characteristics included seizures (2 patients), nephrocalcinosis and nephrolithiasis (3 patients), and early lens opacity (2 patients). In 3 of the patients, serum calcium and urinary calcium-to-creatinine ratio levels obtained simultaneously over 49 patient-years were highly correlated. Using the age-specific maximal-normal levels of calcium-to-creatinine ratio in the correlation equation, we obtained age-adjusted serum calcium levels that are high enough to reduce hypocalcemia-induced seizures and low enough to reduce hypercalciuria. CONCLUSION We report on a novel CASR mutation in a three-generation kindred. Comprehensive clinical data enabled us to suggest age-specific upper limit of serum calcium levels, considering the association between serum calcium and renal calcium excretion.
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Affiliation(s)
- Amnon Zung
- Division of Pediatrics and Pediatric Endocrinology Unit, Kaplan Medical Center, Rehovot, Israel
- The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Galia Barash
- Pediatric Endocrinology Unit, Shamir (Assaf Harofeh) Medical Center, Tzrifin, Israel
| | - Ehud Banne
- The Genetic Institute, Edith Wolfson Medical Center, Holon, Israel
| | - Michael A. Levine
- Center for Bone Health and Division of Endocrinology and Diabetes, Children’s Hospital of Philadelphia and University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
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Tan XY, Roberts MB, Khan LZ, Stewart J, Wang X. The Case | A pregnant female with refractory hypocalcemia. Kidney Int 2022; 102:453-454. [PMID: 35870823 DOI: 10.1016/j.kint.2022.02.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Revised: 01/26/2022] [Accepted: 02/22/2022] [Indexed: 10/18/2022]
Affiliation(s)
- Xin Yee Tan
- Department of Kidney Medicine, Glickman Urology and Kidney Institute, Cleveland Clinic, Cleveland, Ohio, USA
| | - Mary-Beth Roberts
- Center for Personalized Genetic Healthcare, Cleveland Clinic Community Care and Population Health, Cleveland, Ohio, USA
| | - Leila Z Khan
- Calcium and Parathyroid Center, Endocrinology and Metabolism Institute, Cleveland Clinic, Cleveland, Ohio, USA; Department of Medicine, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, Ohio, USA
| | - John Stewart
- Department of Maternal Fetal Medicine, Cleveland Clinic, Cleveland, Ohio, USA
| | - Xiangling Wang
- Department of Kidney Medicine, Glickman Urology and Kidney Institute, Cleveland Clinic, Cleveland, Ohio, USA; Center for Personalized Genetic Healthcare, Cleveland Clinic Community Care and Population Health, Cleveland, Ohio, USA; Department of Molecular Medicine, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, Ohio, USA; Genomic Medicine Institute, Cleveland Clinic Lerner Research Institute, Cleveland, Ohio, USA.
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Hawkes CP, Al Jubeh JM, Li D, Tucker SE, Rajiyah T, Levine MA. Novel PTH Gene Mutations Causing Isolated Hypoparathyroidism. J Clin Endocrinol Metab 2022; 107:e2449-e2458. [PMID: 35165722 PMCID: PMC9113798 DOI: 10.1210/clinem/dgac086] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/15/2022] [Indexed: 11/19/2022]
Abstract
CONTEXT Parathyroid hormone (PTH) gene mutations represent a rare cause of familial isolated hypoparathyroidism (FIH). These defects can cause hypoparathyroidism with increased or decreased serum levels of PTH through 1) impaired PTH synthesis; 2) induction of parathyroid cell apoptosis; or 3) secretion of bioinactive PTH molecules. Eight pathogenic mutations of this gene have been described previously. OBJECTIVE Through describing 2 novel mutations of the PTH gene, we aim to extend the molecular basis for FIH and further refine the proposed mechanisms by which PTH mutations cause hypoparathyroidism. METHODS Proband case reports were compiled with extended family analysis. The probands in both kindreds presented before age 10 days with hypocalcemia and elevated phosphate levels. Proband A had low PTH levels, whereas these levels were elevated in Proband B. Proband B was initially diagnosed with pseudohypoparathyroidism. Methylation analysis was performed of CpG dinucleotides within 3 GNAS differentially methylated regions; whole-genome sequencing; and PTH infusion with analysis of nephrogenous 3',5'-cyclic adenosine 5'-monophosphate. RESULTS Proband A had a novel heterozygous sequence change in exon 2 of the PTH gene, c.46_47delinsAA (p.Ala16Lys), and proband B had a novel homozygous nucleotide transition in PTH exon 3 (c.128G > A; p.G43E) that led to replacement of glycine by glutamic acid at position 12 of PTH 1-84. PTH 1-34 infusion demonstrated that renal responsiveness to PTH was intact and not antagonized by circulating bioinactive PTH. CONCLUSION PTH gene mutations are uncommon causes of hypoparathyroidism, but can be misdiagnosed as disorders of gland development or receptor function if PTH levels are decreased or elevated, respectively. Genetic testing should be considered early in the diagnostic approach to these presentations.
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Affiliation(s)
- Colin P Hawkes
- Division of Endocrinology and Diabetes, The Children’s Hospital of Philadelphia (CHOP), Philadelphia, Pennsylvania, USA
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
- Department of Paediatrics and Child Health, University College Cork, Cork, Ireland
| | - Jamal M Al Jubeh
- Department of Pediatrics, Sheikh Khalifa Medical City, Abu Dhabi, United Arab Emirates
| | - Dong Li
- Center for Applied Genomics, CHOP, Philadelphia, Pennsylvania, USA
| | - Susan E Tucker
- Section of Adult and Pediatric Endocrinology, Diabetes, and Metabolism, The University of Chicago, Chicago, Illinois, USA
| | - Tara Rajiyah
- Section of Adult and Pediatric Endocrinology, Diabetes, and Metabolism, The University of Chicago, Chicago, Illinois, USA
| | - Michael A Levine
- Division of Endocrinology and Diabetes, The Children’s Hospital of Philadelphia (CHOP), Philadelphia, Pennsylvania, USA
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
- Correspondence: Michael A. Levine, MD, Division of Pediatric Endocrinology and Diabetes, The Children’s Hospital of Philadelphia, ARC510A, 3615 Civic Center Blvd, Philadelphia, PA 19104, USA.
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Zhang Q, Zhang LJ, Yuan SS, Quan XJ, Zhang BY, Zhao D. Hypoparathyroidism Associated with the DNA Variants in Non-Coding Sequence Region of Calcium-Sensing Receptor. ENDOCRINE AND METABOLIC SCIENCE 2021. [DOI: 10.1016/j.endmts.2021.100106] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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Papadopoulou A, Bountouvi E, Karachaliou FE. The Molecular Basis of Calcium and Phosphorus Inherited Metabolic Disorders. Genes (Basel) 2021; 12:genes12050734. [PMID: 34068220 PMCID: PMC8153134 DOI: 10.3390/genes12050734] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Revised: 04/30/2021] [Accepted: 05/05/2021] [Indexed: 02/07/2023] Open
Abstract
Calcium (Ca) and Phosphorus (P) hold a leading part in many skeletal and extra-skeletal biological processes. Their tight normal range in serum mirrors their critical role in human well-being. The signalling “voyage” starts at Calcium Sensing Receptor (CaSR) localized on the surface of the parathyroid glands, which captures the “oscillations” of extracellular ionized Ca and transfers the signal downstream. Parathyroid hormone (PTH), Vitamin D, Fibroblast Growth Factor (FGF23) and other receptors or ion-transporters, work synergistically and establish a highly regulated signalling circuit between the bone, kidneys, and intestine to ensure the maintenance of Ca and P homeostasis. Any deviation from this well-orchestrated scheme may result in mild or severe pathologies expressed by biochemical and/or clinical features. Inherited disorders of Ca and P metabolism are rare. However, delayed diagnosis or misdiagnosis may cost patient’s quality of life or even life expectancy. Unravelling the thread of the molecular pathways involving Ca and P signaling, we can better understand the link between genetic alterations and biochemical and/or clinical phenotypes and help in diagnosis and early therapeutic intervention.
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Tiemann‐Boege I, Mair T, Yasari A, Zurovec M. Pathogenic postzygotic mosaicism in the tyrosine receptor kinase pathway: potential unidentified human disease hidden away in a few cells. FEBS J 2021; 288:3108-3119. [PMID: 32810928 PMCID: PMC8247027 DOI: 10.1111/febs.15528] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2020] [Revised: 07/17/2020] [Accepted: 08/14/2020] [Indexed: 01/19/2023]
Abstract
Mutations occurring during embryonic development affect only a subset of cells resulting in two or more distinct cell populations that are present at different levels, also known as postzygotic mosaicism (PZM). Although PZM is a common biological phenomenon, it is often overlooked as a source of disease due to the challenges associated with its detection and characterization, especially for very low-frequency variants. Moreover, PZM can cause a different phenotype compared to constitutional mutations. Especially, lethal mutations in receptor tyrosine kinase (RTK) pathway genes, which exist only in a mosaic state, can have completely new clinical manifestations and can look very different from the associated monogenic disorder. However, some key questions are still not addressed, such as the level of mosaicism resulting in a pathogenic phenotype and how the clinical outcome changes with the development and age. Addressing these questions is not trivial as we require methods with the sensitivity to capture some of these variants hidden away in very few cells. Recent ultra-accurate deep-sequencing approaches can now identify these low-level mosaics and will be central to understand systemic and local effects of mosaicism in the RTK pathway. The main focus of this review is to highlight the importance of low-level mosaics and the need to include their detection in studies of genomic variation associated with disease.
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Affiliation(s)
| | - Theresa Mair
- Institute of BiophysicsJohannes Kepler UniversityLinzAustria
| | - Atena Yasari
- Institute of BiophysicsJohannes Kepler UniversityLinzAustria
| | - Michal Zurovec
- Biology Centre of the Czech Academy of SciencesInstitute of EntomologyCeske BudejoviceCzech Republic
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10
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Diao J, DeBono A, Josephs TM, Bourke JE, Capuano B, Gregory KJ, Leach K. Therapeutic Opportunities of Targeting Allosteric Binding Sites on the Calcium-Sensing Receptor. ACS Pharmacol Transl Sci 2021; 4:666-679. [PMID: 33860192 DOI: 10.1021/acsptsci.1c00046] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Indexed: 01/24/2023]
Abstract
The CaSR is a class C G protein-coupled receptor (GPCR) that acts as a multimodal chemosensor to maintain diverse homeostatic functions. The CaSR is a clinical therapeutic target in hyperparathyroidism and has emerged as a putative target in several other diseases. These include hyper- and hypocalcaemia caused either by mutations in the CASR gene or in genes that regulate CaSR signaling and expression, and more recently in asthma. The development of CaSR-targeting drugs is complicated by the fact that the CaSR possesses many different binding sites for endogenous and exogenous agonists and allosteric modulators. Binding sites for endogenous and exogenous ligands are located throughout the large CaSR protein and are interconnected in ways that we do not yet fully understand. This review summarizes our current understanding of CaSR physiology, signaling, and structure and how the many different binding sites of the CaSR may be targeted to treat disease.
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Affiliation(s)
- Jiayin Diao
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, Victoria 3052, Australia
| | - Aaron DeBono
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, Victoria 3052, Australia.,Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, Victoria 3052, Australia
| | - Tracy M Josephs
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, Victoria 3052, Australia
| | - Jane E Bourke
- Department of Pharmacology, Biomedicine Discovery Institute, Monash University, 9 Ancora Imparo Way, Clayton, Victoria 3800, Australia
| | - Ben Capuano
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, Victoria 3052, Australia
| | - Karen J Gregory
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, Victoria 3052, Australia.,Department of Pharmacology, Biomedicine Discovery Institute, Monash University, 9 Ancora Imparo Way, Clayton, Victoria 3800, Australia
| | - Katie Leach
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, Victoria 3052, Australia.,Department of Pharmacology, Biomedicine Discovery Institute, Monash University, 9 Ancora Imparo Way, Clayton, Victoria 3800, Australia
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Tőke J, Czirják G, Enyedi P, Tóth M. Rare diseases caused by abnormal calcium sensing and signalling. Endocrine 2021; 71:611-617. [PMID: 33528764 PMCID: PMC8016752 DOI: 10.1007/s12020-021-02620-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/07/2020] [Accepted: 01/08/2021] [Indexed: 12/20/2022]
Abstract
The calcium-sensing receptor (CaSR) provides the major mechanism for the detection of extracellular calcium concentration in several cell types, via the induction of G-protein-coupled signalling. Accordingly, CaSR plays a pivotal role in calcium homeostasis, and the CaSR gene defects are related to diseases characterized by serum calcium level changes. Activating mutations of the CaSR gene cause enhanced sensitivity to extracellular calcium concentration resulting in autosomal dominant hypocalcemia or Bartter-syndrome type V. Inactivating CaSR gene mutations lead to resistance to extracellular calcium. In these cases, familial hypocalciuric hypercalcaemia (FHH1) or neonatal severe hyperparathyroidism (NSHPT) can develop. FHH2 and FHH3 are associated with mutations of genes of partner proteins of calcium signal transduction. The common polymorphisms of the CaSR gene have been reported not to affect the calcium homeostasis itself; however, they may be associated with the increased risk of malignancies.
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Affiliation(s)
- Judit Tőke
- Department of Internal Medicine and Oncology, Semmelweis University, Budapest, Hungary
| | - Gábor Czirják
- Department of Physiology, Semmelweis University, Budapest, Hungary
| | - Péter Enyedi
- Department of Physiology, Semmelweis University, Budapest, Hungary
| | - Miklós Tóth
- Department of Internal Medicine and Oncology, Semmelweis University, Budapest, Hungary.
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Targeting primary and metastatic uveal melanoma with a G protein inhibitor. J Biol Chem 2021; 296:100403. [PMID: 33577798 PMCID: PMC7948511 DOI: 10.1016/j.jbc.2021.100403] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Revised: 01/25/2021] [Accepted: 02/08/2021] [Indexed: 12/18/2022] Open
Abstract
Uveal melanoma (UM) is the most common intraocular tumor in adults. Nearly half of UM patients develop metastatic disease and often succumb within months because effective therapy is lacking. A novel therapeutic approach has been suggested by the discovery that UM cell lines driven by mutant constitutively active Gq or G11 can be targeted by FR900359 (FR) or YM-254890, which are bioavailable, selective inhibitors of the Gq/11/14 subfamily of heterotrimeric G proteins. Here, we have addressed the therapeutic potential of FR for UM. We found that FR inhibited all oncogenic Gq/11 mutants reported in UM. FR arrested growth of all Gq/11-driven UM cell lines tested, but induced apoptosis only in a few. Similarly, FR inhibited growth of, but did not efficiently kill, UM tumor cells from biopsies of primary or metastatic tumors. FR evoked melanocytic redifferentiation of UM tumor cells with low (class 1), but not high (class 2), metastatic potential. FR administered systemically below its LD50 strongly inhibited growth of PDX-derived class 1 and class 2 UM tumors in mouse xenograft models and reduced blood pressure transiently. FR did not regress xenografted UM tumors or significantly affect heart rate, liver function, hematopoiesis, or behavior. These results indicated the existence of a therapeutic window in which FR can be explored for treating UM and potentially other diseases caused by constitutively active Gq/11.
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Hawkes CP, Shulman DI, Levine MA. Recombinant human parathyroid hormone (1-84) is effective in CASR-associated hypoparathyroidism. Eur J Endocrinol 2020; 183:K13-K21. [PMID: 33112267 PMCID: PMC7853300 DOI: 10.1530/eje-20-0710] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Accepted: 09/29/2020] [Indexed: 11/08/2022]
Abstract
INTRODUCTION Gain-of-function mutations in the CASR gene cause Autosomal Dominant Hypocalcemia Type 1 (ADH1), the most common genetic cause of isolated hypoparathyroidism. Subjects have increased calcium sensitivity in the renal tubule, leading to increased urinary calcium excretion, nephrocalcinosis and nephrolithiasis when compared with other causes of hypoparathyroidism. The traditional approach to treatment includes activated vitamin D but this further increases urinary calcium excretion. METHODS In this case series, we describe the use of recombinant human parathyroid hormone (rhPTH)1-84 to treat subjects with ADH1, with improved control of serum and urinary calcium levels. RESULTS We describe two children and one adult with ADH1 due to heterozygous CASR mutations who were treated with rhPTH(1-84). Case 1 was a 9.4-year-old female whose 24-h urinary calcium decreased from 7.5 to 3.9 mg/kg at 1 year. Calcitriol and calcium supplementation were discontinued after titration of rhPTH(1-84). Case 2 was a 9.5-year-old male whose 24-h urinary calcium decreased from 11.7 to 1.7 mg/kg at 1 year, and calcitriol was also discontinued. Case 3 was a 24-year-old female whose treatment was switched from multi-dose teriparatide to daily rhPTH(1-84). All three subjects achieved or maintained target serum levels of calcium and normal or improved urinary calcium levels with daily rhPTH(1-84) monotherapy. CONCLUSIONS We have described three subjects with ADH1 who were treated effectively with rhPTH(1-84). In all cases, hypercalciuria improved by comparison to treatment with conventional therapy consisting of calcium supplementation and calcitriol.
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Affiliation(s)
- Colin Patrick Hawkes
- Division of Endocrinology and Diabetes, The Children’s Hospital of Philadelphia, Philadelphia, PA, USA
- University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Dorothy I Shulman
- University of South Florida Diabetes Center, USF Morsani College of Medicine, Tampa, FL, USA
| | - Michael A Levine
- Division of Endocrinology and Diabetes, The Children’s Hospital of Philadelphia, Philadelphia, PA, USA
- University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
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Abstract
Parathyroid hormone is an essential regulator of extracellular calcium and phosphate. PTH enhances calcium reabsorption while inhibiting phosphate reabsorption in the kidneys, increases the synthesis of 1,25-dihydroxyvitamin D, which then increases gastrointestinal absorption of calcium, and increases bone resorption to increase calcium and phosphate. Parathyroid disease can be an isolated endocrine disorder or part of a complex syndrome. Genetic mutations can account for diseases of parathyroid gland formulation, dysregulation of parathyroid hormone synthesis or secretion, and destruction of the parathyroid glands. Over the years, a number of different options are available for the treatment of different types of parathyroid disease. Therapeutic options include surgical removal of hypersecreting parathyroid tissue, administration of parathyroid hormone, vitamin D, activated vitamin D, calcium, phosphate binders, calcium-sensing receptor, and vitamin D receptor activators to name a few. The accurate assessment of parathyroid hormone also provides essential biochemical information to properly diagnose parathyroid disease. Currently available immunoassays may overestimate or underestimate bioactive parathyroid hormone because of interferences from truncated parathyroid hormone fragments, phosphorylation of parathyroid hormone, and oxidation of amino acids of parathyroid hormone.
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Affiliation(s)
- Edward Ki Yun Leung
- Department of Pathology and Laboratory Medicine, Children's Hospital Los Angeles, Los Angeles, CA, United States; Department of Pathology, Keck School of Medicine of University of Southern California, Los Angeles, CA, United States.
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Leach K, Hannan FM, Josephs TM, Keller AN, Møller TC, Ward DT, Kallay E, Mason RS, Thakker RV, Riccardi D, Conigrave AD, Bräuner-Osborne H. International Union of Basic and Clinical Pharmacology. CVIII. Calcium-Sensing Receptor Nomenclature, Pharmacology, and Function. Pharmacol Rev 2020; 72:558-604. [PMID: 32467152 PMCID: PMC7116503 DOI: 10.1124/pr.119.018531] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The calcium-sensing receptor (CaSR) is a class C G protein-coupled receptor that responds to multiple endogenous agonists and allosteric modulators, including divalent and trivalent cations, L-amino acids, γ-glutamyl peptides, polyamines, polycationic peptides, and protons. The CaSR plays a critical role in extracellular calcium (Ca2+ o) homeostasis, as demonstrated by the many naturally occurring mutations in the CaSR or its signaling partners that cause Ca2+ o homeostasis disorders. However, CaSR tissue expression in mammals is broad and includes tissues unrelated to Ca2+ o homeostasis, in which it, for example, regulates the secretion of digestive hormones, airway constriction, cardiovascular effects, cellular differentiation, and proliferation. Thus, although the CaSR is targeted clinically by the positive allosteric modulators (PAMs) cinacalcet, evocalcet, and etelcalcetide in hyperparathyroidism, it is also a putative therapeutic target in diabetes, asthma, cardiovascular disease, and cancer. The CaSR is somewhat unique in possessing multiple ligand binding sites, including at least five putative sites for the "orthosteric" agonist Ca2+ o, an allosteric site for endogenous L-amino acids, two further allosteric sites for small molecules and the peptide PAM, etelcalcetide, and additional sites for other cations and anions. The CaSR is promiscuous in its G protein-coupling preferences, and signals via Gq/11, Gi/o, potentially G12/13, and even Gs in some cell types. Not surprisingly, the CaSR is subject to biased agonism, in which distinct ligands preferentially stimulate a subset of the CaSR's possible signaling responses, to the exclusion of others. The CaSR thus serves as a model receptor to study natural bias and allostery. SIGNIFICANCE STATEMENT: The calcium-sensing receptor (CaSR) is a complex G protein-coupled receptor that possesses multiple orthosteric and allosteric binding sites, is subject to biased signaling via several different G proteins, and has numerous (patho)physiological roles. Understanding the complexities of CaSR structure, function, and biology will aid future drug discovery efforts seeking to target this receptor for a diversity of diseases. This review summarizes what is known to date regarding key structural, pharmacological, and physiological features of the CaSR.
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Affiliation(s)
- Katie Leach
- Drug Discovery Biology, Monash Institute of Pharmaceutical Science, Monash University, Parkville, Australia (K.L., T.M.J., A.N.K.); Nuffield Department of Women's & Reproductive Health (F.M.H.) and Academic Endocrine Unit, Radcliffe Department of Clinical Medicine (F.M.H., R.V.T.), University of Oxford, Oxford, United Kingdom; Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark (T.C.M., H.B.-O.); Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom (D.T.W.); Department of Pathophysiology and Allergy Research, Medical University of Vienna, Vienna, Austria (E.K.); Physiology, School of Medical Sciences and Bosch Institute (R.S.M.) and School of Life & Environmental Sciences, Charles Perkins Centre (A.D.C.), University of Sydney, Sydney, Australia; and School of Biosciences, Cardiff University, Cardiff, United Kingdom (D.R.)
| | - Fadil M Hannan
- Drug Discovery Biology, Monash Institute of Pharmaceutical Science, Monash University, Parkville, Australia (K.L., T.M.J., A.N.K.); Nuffield Department of Women's & Reproductive Health (F.M.H.) and Academic Endocrine Unit, Radcliffe Department of Clinical Medicine (F.M.H., R.V.T.), University of Oxford, Oxford, United Kingdom; Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark (T.C.M., H.B.-O.); Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom (D.T.W.); Department of Pathophysiology and Allergy Research, Medical University of Vienna, Vienna, Austria (E.K.); Physiology, School of Medical Sciences and Bosch Institute (R.S.M.) and School of Life & Environmental Sciences, Charles Perkins Centre (A.D.C.), University of Sydney, Sydney, Australia; and School of Biosciences, Cardiff University, Cardiff, United Kingdom (D.R.)
| | - Tracy M Josephs
- Drug Discovery Biology, Monash Institute of Pharmaceutical Science, Monash University, Parkville, Australia (K.L., T.M.J., A.N.K.); Nuffield Department of Women's & Reproductive Health (F.M.H.) and Academic Endocrine Unit, Radcliffe Department of Clinical Medicine (F.M.H., R.V.T.), University of Oxford, Oxford, United Kingdom; Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark (T.C.M., H.B.-O.); Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom (D.T.W.); Department of Pathophysiology and Allergy Research, Medical University of Vienna, Vienna, Austria (E.K.); Physiology, School of Medical Sciences and Bosch Institute (R.S.M.) and School of Life & Environmental Sciences, Charles Perkins Centre (A.D.C.), University of Sydney, Sydney, Australia; and School of Biosciences, Cardiff University, Cardiff, United Kingdom (D.R.)
| | - Andrew N Keller
- Drug Discovery Biology, Monash Institute of Pharmaceutical Science, Monash University, Parkville, Australia (K.L., T.M.J., A.N.K.); Nuffield Department of Women's & Reproductive Health (F.M.H.) and Academic Endocrine Unit, Radcliffe Department of Clinical Medicine (F.M.H., R.V.T.), University of Oxford, Oxford, United Kingdom; Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark (T.C.M., H.B.-O.); Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom (D.T.W.); Department of Pathophysiology and Allergy Research, Medical University of Vienna, Vienna, Austria (E.K.); Physiology, School of Medical Sciences and Bosch Institute (R.S.M.) and School of Life & Environmental Sciences, Charles Perkins Centre (A.D.C.), University of Sydney, Sydney, Australia; and School of Biosciences, Cardiff University, Cardiff, United Kingdom (D.R.)
| | - Thor C Møller
- Drug Discovery Biology, Monash Institute of Pharmaceutical Science, Monash University, Parkville, Australia (K.L., T.M.J., A.N.K.); Nuffield Department of Women's & Reproductive Health (F.M.H.) and Academic Endocrine Unit, Radcliffe Department of Clinical Medicine (F.M.H., R.V.T.), University of Oxford, Oxford, United Kingdom; Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark (T.C.M., H.B.-O.); Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom (D.T.W.); Department of Pathophysiology and Allergy Research, Medical University of Vienna, Vienna, Austria (E.K.); Physiology, School of Medical Sciences and Bosch Institute (R.S.M.) and School of Life & Environmental Sciences, Charles Perkins Centre (A.D.C.), University of Sydney, Sydney, Australia; and School of Biosciences, Cardiff University, Cardiff, United Kingdom (D.R.)
| | - Donald T Ward
- Drug Discovery Biology, Monash Institute of Pharmaceutical Science, Monash University, Parkville, Australia (K.L., T.M.J., A.N.K.); Nuffield Department of Women's & Reproductive Health (F.M.H.) and Academic Endocrine Unit, Radcliffe Department of Clinical Medicine (F.M.H., R.V.T.), University of Oxford, Oxford, United Kingdom; Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark (T.C.M., H.B.-O.); Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom (D.T.W.); Department of Pathophysiology and Allergy Research, Medical University of Vienna, Vienna, Austria (E.K.); Physiology, School of Medical Sciences and Bosch Institute (R.S.M.) and School of Life & Environmental Sciences, Charles Perkins Centre (A.D.C.), University of Sydney, Sydney, Australia; and School of Biosciences, Cardiff University, Cardiff, United Kingdom (D.R.)
| | - Enikö Kallay
- Drug Discovery Biology, Monash Institute of Pharmaceutical Science, Monash University, Parkville, Australia (K.L., T.M.J., A.N.K.); Nuffield Department of Women's & Reproductive Health (F.M.H.) and Academic Endocrine Unit, Radcliffe Department of Clinical Medicine (F.M.H., R.V.T.), University of Oxford, Oxford, United Kingdom; Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark (T.C.M., H.B.-O.); Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom (D.T.W.); Department of Pathophysiology and Allergy Research, Medical University of Vienna, Vienna, Austria (E.K.); Physiology, School of Medical Sciences and Bosch Institute (R.S.M.) and School of Life & Environmental Sciences, Charles Perkins Centre (A.D.C.), University of Sydney, Sydney, Australia; and School of Biosciences, Cardiff University, Cardiff, United Kingdom (D.R.)
| | - Rebecca S Mason
- Drug Discovery Biology, Monash Institute of Pharmaceutical Science, Monash University, Parkville, Australia (K.L., T.M.J., A.N.K.); Nuffield Department of Women's & Reproductive Health (F.M.H.) and Academic Endocrine Unit, Radcliffe Department of Clinical Medicine (F.M.H., R.V.T.), University of Oxford, Oxford, United Kingdom; Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark (T.C.M., H.B.-O.); Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom (D.T.W.); Department of Pathophysiology and Allergy Research, Medical University of Vienna, Vienna, Austria (E.K.); Physiology, School of Medical Sciences and Bosch Institute (R.S.M.) and School of Life & Environmental Sciences, Charles Perkins Centre (A.D.C.), University of Sydney, Sydney, Australia; and School of Biosciences, Cardiff University, Cardiff, United Kingdom (D.R.)
| | - Rajesh V Thakker
- Drug Discovery Biology, Monash Institute of Pharmaceutical Science, Monash University, Parkville, Australia (K.L., T.M.J., A.N.K.); Nuffield Department of Women's & Reproductive Health (F.M.H.) and Academic Endocrine Unit, Radcliffe Department of Clinical Medicine (F.M.H., R.V.T.), University of Oxford, Oxford, United Kingdom; Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark (T.C.M., H.B.-O.); Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom (D.T.W.); Department of Pathophysiology and Allergy Research, Medical University of Vienna, Vienna, Austria (E.K.); Physiology, School of Medical Sciences and Bosch Institute (R.S.M.) and School of Life & Environmental Sciences, Charles Perkins Centre (A.D.C.), University of Sydney, Sydney, Australia; and School of Biosciences, Cardiff University, Cardiff, United Kingdom (D.R.)
| | - Daniela Riccardi
- Drug Discovery Biology, Monash Institute of Pharmaceutical Science, Monash University, Parkville, Australia (K.L., T.M.J., A.N.K.); Nuffield Department of Women's & Reproductive Health (F.M.H.) and Academic Endocrine Unit, Radcliffe Department of Clinical Medicine (F.M.H., R.V.T.), University of Oxford, Oxford, United Kingdom; Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark (T.C.M., H.B.-O.); Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom (D.T.W.); Department of Pathophysiology and Allergy Research, Medical University of Vienna, Vienna, Austria (E.K.); Physiology, School of Medical Sciences and Bosch Institute (R.S.M.) and School of Life & Environmental Sciences, Charles Perkins Centre (A.D.C.), University of Sydney, Sydney, Australia; and School of Biosciences, Cardiff University, Cardiff, United Kingdom (D.R.)
| | - Arthur D Conigrave
- Drug Discovery Biology, Monash Institute of Pharmaceutical Science, Monash University, Parkville, Australia (K.L., T.M.J., A.N.K.); Nuffield Department of Women's & Reproductive Health (F.M.H.) and Academic Endocrine Unit, Radcliffe Department of Clinical Medicine (F.M.H., R.V.T.), University of Oxford, Oxford, United Kingdom; Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark (T.C.M., H.B.-O.); Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom (D.T.W.); Department of Pathophysiology and Allergy Research, Medical University of Vienna, Vienna, Austria (E.K.); Physiology, School of Medical Sciences and Bosch Institute (R.S.M.) and School of Life & Environmental Sciences, Charles Perkins Centre (A.D.C.), University of Sydney, Sydney, Australia; and School of Biosciences, Cardiff University, Cardiff, United Kingdom (D.R.)
| | - Hans Bräuner-Osborne
- Drug Discovery Biology, Monash Institute of Pharmaceutical Science, Monash University, Parkville, Australia (K.L., T.M.J., A.N.K.); Nuffield Department of Women's & Reproductive Health (F.M.H.) and Academic Endocrine Unit, Radcliffe Department of Clinical Medicine (F.M.H., R.V.T.), University of Oxford, Oxford, United Kingdom; Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark (T.C.M., H.B.-O.); Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom (D.T.W.); Department of Pathophysiology and Allergy Research, Medical University of Vienna, Vienna, Austria (E.K.); Physiology, School of Medical Sciences and Bosch Institute (R.S.M.) and School of Life & Environmental Sciences, Charles Perkins Centre (A.D.C.), University of Sydney, Sydney, Australia; and School of Biosciences, Cardiff University, Cardiff, United Kingdom (D.R.)
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16
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Gild ML, Bullock M, Luxford C, Field M, Clifton-Bligh RJ. Congenital Hypoparathyroidism Associated With Elevated Circulating Nonfunctional Parathyroid Hormone Due to Novel PTH Mutation. J Clin Endocrinol Metab 2020; 105:5839775. [PMID: 32421798 DOI: 10.1210/clinem/dgaa279] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Accepted: 05/13/2020] [Indexed: 11/19/2022]
Abstract
CONTEXT Familial hypoparathyroidism has a heterogeneous presentation where patients usually have low parathyroid hormone (PTH) levels due to impaired production or secretion. This contrasts with pseudohypoparathyroidism, in which PTH resistance is usually associated with an elevated serum PTH. High levels of circulating PTH can also be due to bioinactive PTH, which is difficult to distinguish from pseudohypoparathyroidism on biochemical grounds. CASE DESCRIPTION We report on 2 sisters from consanguineous parents who presented with tetany at birth and were diagnosed with congenital hypocalcemia. Serum PTH levels were normal for many years, but progressively increased in midadulthood to greater than 100x the upper limit of normal on multiple assays. Homozygosity mapping was performed on 1 sister that demonstrated loss of heterozygosity (LOH) around PTH. Sequencing revealed a previously unreported variant, c.94T>C, predicting a codon change of p.Ser32Pro that is biologically inactive. CONCLUSIONS This case report shows a previously unreported unusual biochemical phenotype of a rising PTH in the context of a novel PTH mutation. This expands the evolving genotypes associated with hypoparathyroidism without established gene mutations.
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Affiliation(s)
- Matti L Gild
- Cancer Genetics, Kolling Institute of Medical Research, Sydney, North South Wales, Australia
- Department of Genetics, Royal North Shore Hospital, Sydney, Australia
| | - Martyn Bullock
- Cancer Genetics, Kolling Institute of Medical Research, Sydney, North South Wales, Australia
| | - Catherine Luxford
- Cancer Genetics, Kolling Institute of Medical Research, Sydney, North South Wales, Australia
| | - Michael Field
- Cancer Genetics, Kolling Institute of Medical Research, Sydney, North South Wales, Australia
- Department of Endocrinology and Diabetes, Royal North Shore Hospital, Sydney, Australia
| | - Roderick J Clifton-Bligh
- Cancer Genetics, Kolling Institute of Medical Research, Sydney, North South Wales, Australia
- Department of Genetics, Royal North Shore Hospital, Sydney, Australia
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17
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Abstract
BACKGROUND Hypoparathyroidism is a rare endocrine disorder characterized by hypocalcemia and low or undetectable levels of parathyroid hormone. METHODS This review is an evidence-based summary of hypoparathyroidism in terms of relevant pathophysiological, clinical, and therapeutic concepts. RESULTS Many clinical manifestations of hypoparathyroidism are due to the lack of the physiological actions of parathyroid hormone on its 2 major target organs: the skeleton and the kidney. The skeleton is inactive, accruing bone without remodeling it. The kidneys lose the calcium-conserving actions of parathyroid hormone and, thus, excrete a greater fraction of calcium. Biochemical manifestations, besides hypocalcemia and low or undetectable levels of parathyroid hormone, include hyperphosphatemia and low levels of 1,25-dihydroxyvitamin D. Calcifications in the kidney, brain, and other soft tissues are common. Removal of, or damage to, the parathyroid glands at the time of anterior neck surgery is, by far, the most likely etiology. Autoimmune destruction of the parathyroid glands and other genetic causes represent most of the other etiologies. Conventional treatment with calcium and active vitamin D can maintain the serum calcium level but high doses may be required, adding to the risk of long-term soft tissue calcifications. The advent of replacement therapy with recombinant human PTH(1-84) represents a major step in the therapeutics of this disease. CONCLUSIONS Advances in our knowledge of hypoparathyroidism have led to greater understanding of the disease itself and our approach to it.
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Affiliation(s)
- John P Bilezikian
- Department of Medicine, Division of Endocrinology, Vagelos College of Physicians and Surgeons, Columbia University, New York, New York
- Correspondence and Reprint Requests: John P. Bilezikian, Vice-Chair, International Research and Education, Department of Medicine, Vagelos College of Physicians and Surgeons, 630 W. 168th Street, New York, NY 10032. E-mail:
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18
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Gorvin CM, Stokes VJ, Boon H, Cranston T, Glück AK, Bahl S, Homfray T, Aung T, Shine B, Lines KE, Hannan FM, Thakker RV. Activating Mutations of the G-protein Subunit α 11 Interdomain Interface Cause Autosomal Dominant Hypocalcemia Type 2. J Clin Endocrinol Metab 2020; 105:5671666. [PMID: 31820785 PMCID: PMC7048683 DOI: 10.1210/clinem/dgz251] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/06/2019] [Accepted: 12/09/2019] [Indexed: 12/30/2022]
Abstract
CONTEXT Autosomal dominant hypocalcemia types 1 and 2 (ADH1 and ADH2) are caused by germline gain-of-function mutations of the calcium-sensing receptor (CaSR) and its signaling partner, the G-protein subunit α 11 (Gα 11), respectively. More than 70 different gain-of-function CaSR mutations, but only 6 different gain-of-function Gα 11 mutations are reported to date. METHODS We ascertained 2 additional ADH families and investigated them for CaSR and Gα 11 mutations. The effects of identified variants on CaSR signaling were evaluated by transiently transfecting wild-type (WT) and variant expression constructs into HEK293 cells stably expressing CaSR (HEK-CaSR), and measuring intracellular calcium (Ca2+i) and MAPK responses following stimulation with extracellular calcium (Ca2+e). RESULTS CaSR variants were not found, but 2 novel heterozygous germline Gα 11 variants, p.Gly66Ser and p.Arg149His, were identified. Homology modeling of these revealed that the Gly66 and Arg149 residues are located at the interface between the Gα 11 helical and GTPase domains, which is involved in guanine nucleotide binding, and this is the site of 3 other reported ADH2 mutations. The Ca2+i and MAPK responses of cells expressing the variant Ser66 or His149 Gα 11 proteins were similar to WT cells at low Ca2+e, but significantly increased in a dose-dependent manner following Ca2+e stimulation, thereby indicating that the p.Gly66Ser and p.Arg149His variants represent pathogenic gain-of-function Gα 11 mutations. Treatment of Ser66- and His149-Gα 11 expressing cells with the CaSR negative allosteric modulator NPS 2143 normalized Ca2+i and MAPK responses. CONCLUSION Two novel ADH2-causing mutations that highlight the Gα 11 interdomain interface as a hotspot for gain-of-function Gα 11 mutations have been identified.
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Affiliation(s)
- Caroline M Gorvin
- Academic Endocrine Unit, Radcliffe Department of Medicine, Oxford Centre for Diabetes, Endocrinology and Metabolism (OCDEM), University of Oxford, Oxford, UK
- Oxford NIHR Biomedical Research Centre, University of Oxford, Churchill Hospital, Oxford, UK
| | - Victoria J Stokes
- Academic Endocrine Unit, Radcliffe Department of Medicine, Oxford Centre for Diabetes, Endocrinology and Metabolism (OCDEM), University of Oxford, Oxford, UK
- Oxford NIHR Biomedical Research Centre, University of Oxford, Churchill Hospital, Oxford, UK
| | - Hannah Boon
- Oxford Molecular Genetics Laboratory, Churchill Hospital, Oxford, UK
| | - Treena Cranston
- Oxford Molecular Genetics Laboratory, Churchill Hospital, Oxford, UK
| | - Anna K Glück
- Academic Endocrine Unit, Radcliffe Department of Medicine, Oxford Centre for Diabetes, Endocrinology and Metabolism (OCDEM), University of Oxford, Oxford, UK
| | - Shailini Bahl
- Department of Paediatrics, Ashford and St. Peter’s Hospitals NHS Foundation Trust, Surrey, UK
| | - Tessa Homfray
- Department of Clinical Genetics, St George’s University Hospital, London, UK
| | - Theingi Aung
- The Centre for Diabetes and Endocrinology, Royal Berkshire NHS Foundation Trust, Reading, UK
| | - Brian Shine
- Department of Clinical Biochemistry, John Radcliffe Hospital, Oxford University Hospitals NHS Trust, Oxford, UK
| | - Kate E Lines
- Academic Endocrine Unit, Radcliffe Department of Medicine, Oxford Centre for Diabetes, Endocrinology and Metabolism (OCDEM), University of Oxford, Oxford, UK
| | - Fadil M Hannan
- Academic Endocrine Unit, Radcliffe Department of Medicine, Oxford Centre for Diabetes, Endocrinology and Metabolism (OCDEM), University of Oxford, Oxford, UK
| | - Rajesh V Thakker
- Academic Endocrine Unit, Radcliffe Department of Medicine, Oxford Centre for Diabetes, Endocrinology and Metabolism (OCDEM), University of Oxford, Oxford, UK
- Oxford NIHR Biomedical Research Centre, University of Oxford, Churchill Hospital, Oxford, UK
- Correspondence and Reprint Requests: Rajesh V. Thakker, Academic Endocrine Unit, Radcliffe Department of Medicine, Oxford Centre for Diabetes, Endocrinology and Metabolism (OCDEM), Churchill Hospital, Oxford OX3 7LJ, United Kingdom. E-mail:
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19
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Li J, Ge Y, Huang JX, Strømgaard K, Zhang X, Xiong XF. Heterotrimeric G Proteins as Therapeutic Targets in Drug Discovery. J Med Chem 2019; 63:5013-5030. [PMID: 31841625 DOI: 10.1021/acs.jmedchem.9b01452] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Heterotrimeric G proteins are molecular switches in GPCR signaling pathways and regulate a plethora of physiological and pathological processes. GPCRs are efficient drug targets, and more than 30% of the drugs in use target them. However, selectively targeting an individual GPCR may be undesirable in various multifactorial diseases in which multiple receptors are involved. In addition, abnormal activation or expression of G proteins is frequently associated with diseases. Furthermore, G proteins harboring mutations often result in malignant diseases. Thus, targeting G proteins instead of GPCRs might provide alternative approaches for combating these diseases. In this review, we discuss the biochemistry of heterotrimeric G proteins, describe the G protein-associated diseases, and summarize the currently known modulators that can regulate the activities of G proteins. The outlook for targeting G proteins to treat diverse diseases is also included in this manuscript.
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Affiliation(s)
- Jian Li
- Guangdong Key Laboratory of Chiral Molecule and Drug Discovery, School of Pharmaceutical Sciences, Sun Yat-sen University, 510006 Guangzhou, Guangdong, P. R. China
| | - Yang Ge
- Guangdong Key Laboratory of Chiral Molecule and Drug Discovery, School of Pharmaceutical Sciences, Sun Yat-sen University, 510006 Guangzhou, Guangdong, P. R. China
| | - Jun-Xiang Huang
- Guangdong Key Laboratory of Chiral Molecule and Drug Discovery, School of Pharmaceutical Sciences, Sun Yat-sen University, 510006 Guangzhou, Guangdong, P. R. China
| | - Kristian Strømgaard
- Department of Drug Design and Pharmacology, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark
| | - Xiaolei Zhang
- Guangdong Key Laboratory of Chiral Molecule and Drug Discovery, School of Pharmaceutical Sciences, Sun Yat-sen University, 510006 Guangzhou, Guangdong, P. R. China
| | - Xiao-Feng Xiong
- Guangdong Key Laboratory of Chiral Molecule and Drug Discovery, School of Pharmaceutical Sciences, Sun Yat-sen University, 510006 Guangzhou, Guangdong, P. R. China
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20
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Hannan FM, Kallay E, Chang W, Brandi ML, Thakker RV. The calcium-sensing receptor in physiology and in calcitropic and noncalcitropic diseases. Nat Rev Endocrinol 2018; 15:33-51. [PMID: 30443043 PMCID: PMC6535143 DOI: 10.1038/s41574-018-0115-0] [Citation(s) in RCA: 189] [Impact Index Per Article: 31.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The Ca2+-sensing receptor (CaSR) is a dimeric family C G protein-coupled receptor that is expressed in calcitropic tissues such as the parathyroid glands and the kidneys and signals via G proteins and β-arrestin. The CaSR has a pivotal role in bone and mineral metabolism, as it regulates parathyroid hormone secretion, urinary Ca2+ excretion, skeletal development and lactation. The importance of the CaSR for these calcitropic processes is highlighted by loss-of-function and gain-of-function CaSR mutations that cause familial hypocalciuric hypercalcaemia and autosomal dominant hypocalcaemia, respectively, and also by the fact that alterations in parathyroid CaSR expression contribute to the pathogenesis of primary and secondary hyperparathyroidism. Moreover, the CaSR is an established therapeutic target for hyperparathyroid disorders. The CaSR is also expressed in organs not involved in Ca2+ homeostasis: it has noncalcitropic roles in lung and neuronal development, vascular tone, gastrointestinal nutrient sensing, wound healing and secretion of insulin and enteroendocrine hormones. Furthermore, the abnormal expression or function of the CaSR is implicated in cardiovascular and neurological diseases, as well as in asthma, and the CaSR is reported to protect against colorectal cancer and neuroblastoma but increase the malignant potential of prostate and breast cancers.
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Affiliation(s)
- Fadil M Hannan
- Department of Musculoskeletal Biology, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, UK
- Academic Endocrine Unit, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - Enikö Kallay
- Department of Pathophysiology and Allergy Research, Medical University of Vienna, Vienna, Austria
| | - Wenhan Chang
- Endocrine Research Unit, Veterans Affairs Medical Center, University of California, San Francisco, San Francisco, CA, USA
| | - Maria Luisa Brandi
- Metabolic Bone Diseases Unit, Department of Surgery and Translational Medicine, University of Florence, Florence, Italy.
| | - Rajesh V Thakker
- Academic Endocrine Unit, Radcliffe Department of Medicine, University of Oxford, Oxford, UK.
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Abstract
Hypoparathyroidism is characterized by hypocalcemia and hyperphosphatemia and is due to insufficient levels of circulating parathyroid hormone. Hypoparathyroidism may be an isolated condition or a component of a complex syndrome. Although genetic disorders are not the most common cause of hypoparathyroidism, molecular analyses have identified a growing number of genes that when defective result in impaired formation of the parathyroid glands, disordered synthesis or secretion of parathyroid hormone, or postnatal destruction of the parathyroid glands.
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Affiliation(s)
- Rebecca J Gordon
- Division of Endocrinology and Diabetes, The Center for Bone Health, The Children's Hospital of Philadelphia, Department of Pediatrics, University of Pennsylvania Perelman School of Medicine, 11 Northwest Tower, Suite 30, 3401 Civic Center Boulevard, Philadelphia, PA 19104, USA.
| | - Michael A Levine
- Division of Endocrinology and Diabetes, The Center for Bone Health, The Children's Hospital of Philadelphia, Department of Pediatrics, University of Pennsylvania Perelman School of Medicine, 3615 Civic Center Boulevard, Abramson Research Building, Room 510A, Philadelphia, PA 19104, USA
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22
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Li D, Gordon CT, Oufadem M, Amiel J, Kanwar HS, Bakay M, Wang T, Hakonarson H, Levine MA. Heterozygous Mutations in TBX1 as a Cause of Isolated Hypoparathyroidism. J Clin Endocrinol Metab 2018; 103:4023-4032. [PMID: 30137364 PMCID: PMC6194809 DOI: 10.1210/jc.2018-01260] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Accepted: 08/13/2018] [Indexed: 12/17/2022]
Abstract
CONTEXT Most cases of autosomal dominant isolated hypoparathyroidism are caused by gain-of-function mutations in CASR or GNA11 or dominant negative mutations in GCM2 or PTH. OBJECTIVE To identify the genetic etiology for dominantly transmitted isolated hypoparathyroidism in two multigenerational families with 14 affected family members. METHODS We performed whole exome sequencing of DNA from two families and examined the consequences of mutations by minigene splicing assay. RESULTS We discovered disease-causing mutations in both families. A splice-altering mutation in TBX1 (c.1009+1G>C) leading to skipping of exon 8 (101 bp) was identified in 10 affected family members and five unaffected subjects of family A, indicating reduced penetrance for this point mutation. In a second family from France (family B), we identified another splice-altering mutation (c.1009+2T>C) adjacent to the mutation identified in family A that results in skipping of the same exon; two subjects in family B had isolated hypoparathyroidism, whereas a third subject manifested the clinical triad of the 22q11.2 deletion syndrome, indicative of variable expressivity. CONCLUSIONS We report evidence that heterozygous TBX1 mutations can cause isolated hypoparathyroidism. This study adds knowledge to the increasingly expanding list of causative and candidate genes in isolated hypoparathyroidism.
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Affiliation(s)
- Dong Li
- Center for Applied Genomics, The Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Christopher T Gordon
- Laboratory of Embryology and Genetics of Congenital Malformations, INSERM UMR 1163, Institut Imagine, Paris, France
- Paris Descartes, Sorbonne Paris Cité Université, Institut Imagine, Paris, France
| | - Myriam Oufadem
- Laboratory of Embryology and Genetics of Congenital Malformations, INSERM UMR 1163, Institut Imagine, Paris, France
- Paris Descartes, Sorbonne Paris Cité Université, Institut Imagine, Paris, France
| | - Jeanne Amiel
- Laboratory of Embryology and Genetics of Congenital Malformations, INSERM UMR 1163, Institut Imagine, Paris, France
- Paris Descartes, Sorbonne Paris Cité Université, Institut Imagine, Paris, France
- Service de Génétique, Hôpital Necker-Enfants Malades, Assistance Publique ‒ Hôpitaux de Paris, Paris, France
| | - Harsh S Kanwar
- Center for Bone Health, The Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Marina Bakay
- Center for Applied Genomics, The Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Tiancheng Wang
- Center for Applied Genomics, The Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Hakon Hakonarson
- Center for Applied Genomics, The Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania
- Department of Pediatrics, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania
| | - Michael A Levine
- Center for Bone Health, The Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania
- Department of Pediatrics, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania
- Division of Endocrinology and Diabetes, The Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania
- Correspondence and Reprint Requests: Michael A. Levine, MD, Division of Endocrinology and Diabetes, The Children’s Hospital of Philadelphia, Abramson Research Building, Room 510A, 3615 Civic Center Boulevard, Philadelphia, Pennsylvania 19104. E-mail:
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23
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Gorvin CM, Frost M, Malinauskas T, Cranston T, Boon H, Siebold C, Jones EY, Hannan FM, Thakker RV. Calcium-sensing receptor residues with loss- and gain-of-function mutations are located in regions of conformational change and cause signalling bias. Hum Mol Genet 2018; 27:3720-3733. [PMID: 30052933 PMCID: PMC6196656 DOI: 10.1093/hmg/ddy263] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2018] [Revised: 07/06/2018] [Accepted: 07/09/2018] [Indexed: 12/20/2022] Open
Abstract
The calcium-sensing receptor (CaSR) is a homodimeric G-protein-coupled receptor that signals via intracellular calcium (Ca2+i) mobilisation and phosphorylation of extracellular signal-regulated kinase 1/2 (ERK) to regulate extracellular calcium (Ca2+e) homeostasis. The central importance of the CaSR in Ca2+e homeostasis has been demonstrated by the identification of loss- or gain-of-function CaSR mutations that lead to familial hypocalciuric hypercalcaemia (FHH) or autosomal dominant hypocalcaemia (ADH), respectively. However, the mechanisms determining whether the CaSR signals via Ca2+i or ERK have not been established, and we hypothesised that some CaSR residues, which are the site of both loss- and gain-of-function mutations, may act as molecular switches to direct signalling through these pathways. An analysis of CaSR mutations identified in >300 hypercalcaemic and hypocalcaemic probands revealed five 'disease-switch' residues (Gln27, Asn178, Ser657, Ser820 and Thr828) that are affected by FHH and ADH mutations. Functional expression studies using HEK293 cells showed disease-switch residue mutations to commonly display signalling bias. For example, two FHH-associated mutations (p.Asn178Asp and p.Ser820Ala) impaired Ca2+i signalling without altering ERK phosphorylation. In contrast, an ADH-associated p.Ser657Cys mutation uncoupled signalling by leading to increased Ca2+i mobilization while decreasing ERK phosphorylation. Structural analysis of these five CaSR disease-switch residues together with four reported disease-switch residues revealed these residues to be located at conformationally active regions of the CaSR such as the extracellular dimer interface and transmembrane domain. Thus, our findings indicate that disease-switch residues are located at sites critical for CaSR activation and play a role in mediating signalling bias.
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Affiliation(s)
- Caroline M Gorvin
- Academic Endocrine Unit, Radcliffe Department of Medicine, Oxford Centre for Diabetes, Endocrinology and Metabolism (OCDEM), University of Oxford, Oxford OX3 7LJ, UK
| | - Morten Frost
- Academic Endocrine Unit, Radcliffe Department of Medicine, Oxford Centre for Diabetes, Endocrinology and Metabolism (OCDEM), University of Oxford, Oxford OX3 7LJ, UK
- University of Southern Denmark, Odense C, Denmark
| | - Tomas Malinauskas
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK
| | - Treena Cranston
- Oxford Molecular Genetics Laboratory, Churchill Hospital, Oxford OX3 7LJ, UK
| | - Hannah Boon
- Oxford Molecular Genetics Laboratory, Churchill Hospital, Oxford OX3 7LJ, UK
| | - Christian Siebold
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK
| | - E Yvonne Jones
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK
| | - Fadil M Hannan
- Academic Endocrine Unit, Radcliffe Department of Medicine, Oxford Centre for Diabetes, Endocrinology and Metabolism (OCDEM), University of Oxford, Oxford OX3 7LJ, UK
- Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, UK
| | - Rajesh V Thakker
- Academic Endocrine Unit, Radcliffe Department of Medicine, Oxford Centre for Diabetes, Endocrinology and Metabolism (OCDEM), University of Oxford, Oxford OX3 7LJ, UK
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24
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Saraff V, Rothenbuhler A, Högler W, Linglart A. Continuous Subcutaneous Recombinant Parathyroid Hormone (1-34) Infusion in the Management of Childhood Hypoparathyroidism Associated with Malabsorption. Horm Res Paediatr 2018; 89:271-277. [PMID: 28926829 DOI: 10.1159/000479867] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Accepted: 07/26/2017] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND/AIMS Hypoparathyroidism associated with malabsorption can be particularly challenging to manage due to limited and erratic intestinal absorption of calcium and vitamin D analogues, resulting in episodes of hypo- or hypercalcaemia. We evaluated the role of continuous subcutaneous recombinant parathyroid hormone (rhPTH 1-34) infusion (CSPI) in children with hypoparathyroidism associated with intestinal malabsorption resistant to conventional therapy. METHOD Four patients (8-13 years of age), with symptomatic hypocalcaemia resistant to conventional therapy, were started on CSPI (follow-up 3-8 years) in two paediatric endocrinology units in Europe. RESULTS Serum calcium normalized within 48 h of commencing treatment in all 4 patients. An average rhPTH 1-34 dose of 0.4 µg/kg/day resulted in a substantial reduction in symptomatic hypocalcaemia and hypo-/hypercalcaemia-related hospital admissions. An increased alkaline phosphatase activity was noted in the first 6 months on CSPI, indicating an increase in bone turnover. In 2 patients with elevated urinary calcium excretion before CSPI, this normalized in the first year on treatment. No significant side effects were noticed in the short or long term, with patient-reported preference of CSPI over conventional treatment. CONCLUSION CSPI is a promising and effective treatment option for managing hypocalcaemia and hyperphosphataemia in children with hypoparathyroidism associated with intestinal malabsorption.
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Affiliation(s)
- Vrinda Saraff
- Department of Endocrinology and Diabetes, Birmingham Children's Hospital, Birmingham, United Kingdom
| | - Anya Rothenbuhler
- Department of Pediatric Endocrinology, Bicêtre Hospital, Paris, France
| | - Wolfgang Högler
- Department of Endocrinology and Diabetes, Birmingham Children's Hospital, Birmingham, United Kingdom.,Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, United Kingdom
| | - Agnès Linglart
- Department of Pediatric Endocrinology, Bicêtre Hospital, Paris, France
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25
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Abstract
Calcium is vital for life, and extracellular calcium concentrations must constantly be maintained within a precise concentration range. Low serum calcium (hypocalcemia) occurs in conjunction with multiple disorders and can be life-threatening if severe. Symptoms of acute hypocalcemia include neuromuscular irritability, tetany, and seizures, which are rapidly resolved with intravenous administration of calcium gluconate. However, disorders that lead to chronic hypocalcemia often have more subtle manifestations. Hypoparathyroidism, characterized by impaired secretion of parathyroid hormone (PTH), a key regulatory hormone for maintaining calcium homeostasis, is a classic cause of chronic hypocalcemia. Disorders that disrupt the metabolism of vitamin D can also lead to chronic hypocalcemia, as vitamin D is responsible for increasing the gut absorption of dietary calcium. Treatment and management options for chronic hypocalcemia vary depending on the underlying disorder. For example, in patients with hypoparathyroidism, calcium and vitamin D supplementation must be carefully titrated to avoid symptoms of hypocalcemia while keeping serum calcium in the low-normal range to minimize hypercalciuria, which can lead to renal dysfunction. Management of chronic hypocalcemia requires knowledge of the factors that influence the complex regulatory axes of calcium homeostasis in a given disorder. This chapter discusses common and rare disorders of hypocalcemia, symptoms and workup, and management options including replacement of PTH in hypoparathyroidism.
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Affiliation(s)
- Erin Bove-Fenderson
- Endocrine Unit, Massachusetts General Hospital and Harvard Medical School, Thier 1101, 50 Blossom St, Boston, MA, 02114, USA
| | - Michael Mannstadt
- Endocrine Unit, Massachusetts General Hospital and Harvard Medical School, Thier 1101, 50 Blossom St, Boston, MA, 02114, USA.
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26
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Gorvin CM. Insights into calcium-sensing receptor trafficking and biased signalling by studies of calcium homeostasis. J Mol Endocrinol 2018; 61:R1-R12. [PMID: 29599414 DOI: 10.1530/jme-18-0049] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Accepted: 03/29/2018] [Indexed: 12/18/2022]
Abstract
The calcium-sensing receptor (CASR) is a class C G-protein-coupled receptor (GPCR) that detects extracellular calcium concentrations, and modulates parathyroid hormone secretion and urinary calcium excretion to maintain calcium homeostasis. The CASR utilises multiple heterotrimeric G-proteins to mediate signalling effects including activation of intracellular calcium release; mitogen-activated protein kinase (MAPK) pathways; membrane ruffling; and inhibition of cAMP production. By studying germline mutations in the CASR and proteins within its signalling pathway that cause hyper- and hypocalcaemic disorders, novel mechanisms governing GPCR signalling and trafficking have been elucidated. This review focusses on two recently described pathways that provide novel insights into CASR signalling and trafficking mechanisms. The first, identified by studying a CASR gain-of-function mutation that causes autosomal dominant hypocalcaemia (ADH), demonstrated a structural motif located between the third transmembrane domain and the second extracellular loop of the CASR that mediates biased signalling by activating a novel β-arrestin-mediated G-protein-independent pathway. The second, in which the mechanism by which adaptor protein-2 σ-subunit (AP2σ) mutations cause familial hypocalciuric hypercalcaemia (FHH) was investigated, demonstrated that AP2σ mutations impair CASR internalisation and reduce multiple CASR-mediated signalling pathways. Furthermore, these studies showed that the CASR can signal from the cell surface using multiple G-protein pathways, whilst sustained signalling is mediated only by the Gq/11 pathway. Thus, studies of FHH- and ADH-associated mutations have revealed novel steps by which CASR mediates signalling and compartmental bias, and these pathways could provide new targets for therapies for patients with calcaemic disorders.
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Affiliation(s)
- Caroline M Gorvin
- Institute of Metabolism and Systems Research (IMSR), University of Birmingham, Birmingham, UK
- Centre for Endocrinology, Diabetes and Metabolism (CEDAM), Birmingham Health Partners, Birmingham, UK
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27
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Dixon J, Miller S. Successful pregnancies and reduced treatment requirement while breast feeding in a patient with congenital hypoparathyroidism due to homozygous c.68C>A null parathyroid hormone gene mutation. BMJ Case Rep 2018; 2018:bcr-2017-223811. [PMID: 29804071 PMCID: PMC5976074 DOI: 10.1136/bcr-2017-223811] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/27/2018] [Indexed: 11/03/2022] Open
Abstract
A female patient with consanguineous parents presented at the age of 4 with isolated hypoparathyroidism due to a parathyroid hormone (PTH) gene mutation. She was managed with alfacalcidol and calcium supplements, and developed normally. Her consanguineous parents described symptoms suggestive of hypocalcaemia but had normal serum calcium and low normal PTH levels. A molecular diagnosis obtained in her adulthood revealed the presence of homozygous point mutation (c.68C>A) in exon 2 introducing a premature stop codon resulting in a non-functional precursor protein. This mutation has been reported only once before. Our patient remained on stable doses of alfacalcidol during pregnancy, but stopped all supplementation while breast feeding. This case confirms that alternative mechanisms (likely breast-derived parathyroid hormone-related protein) contribute to calcium homeostasis during breast feeding. Heterozygotes for the c.68C>A mutation may have latent hypoparathyroidism and maintain calcium homeostasis except during prolonged hypocalcaemia. This would suggest incomplete dominance, or a dose effect of the wild-type PTH allele.
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Affiliation(s)
- Joanne Dixon
- Endocrinology Department, Waitemata District Health Board, Auckland, New Zealand
| | - Steven Miller
- Endocrinology Department, Waitemata District Health Board, Auckland, New Zealand
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28
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Roizen JD, Li D, O’Lear L, Javaid MK, Shaw NJ, Ebeling PR, Nguyen HH, Rodda CP, Thummel KE, Thacher TD, Hakonarson H, Levine MA. CYP3A4 mutation causes vitamin D-dependent rickets type 3. J Clin Invest 2018; 128:1913-1918. [PMID: 29461981 PMCID: PMC5919884 DOI: 10.1172/jci98680] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Accepted: 02/13/2018] [Indexed: 01/08/2023] Open
Abstract
Genetic forms of vitamin D-dependent rickets (VDDRs) are due to mutations impairing activation of vitamin D or decreasing vitamin D receptor responsiveness. Here we describe two unrelated patients with early-onset rickets, reduced serum levels of the vitamin D metabolites 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D, and deficient responsiveness to parent and activated forms of vitamin D. Neither patient had a mutation in any genes known to cause VDDR; however, using whole exome sequencing analysis, we identified a recurrent de novo missense mutation, c.902T>C (p.I301T), in CYP3A4 in both subjects that alters the conformation of substrate recognition site 4 (SRS-4). In vitro, the mutant CYP3A4 oxidized 1,25-dihydroxyvitamin D with 10-fold greater activity than WT CYP3A4 and 2-fold greater activity than CYP24A1, the principal inactivator of vitamin D metabolites. As CYP3A4 mutations have not previously been linked to rickets, these findings provide insight into vitamin D metabolism and demonstrate that accelerated inactivation of vitamin D metabolites represents a mechanism for vitamin D deficiency.
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Affiliation(s)
| | - Dong Li
- Center for Applied Genomics, The Children’s Hospital of Philadelphia (CHOP), University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
| | | | - Muhammad K. Javaid
- Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, University of Oxford, Oxford, United Kingdom
| | - Nicholas J. Shaw
- Department of Endocrinology and Diabetes, Birmingham Children’s Hospital and Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, United Kingdom
| | - Peter R. Ebeling
- Department of Medicine, School of Clinical Sciences, Monash University, Clayton, Victoria, Australia
| | - Hanh H. Nguyen
- Department of Medicine, School of Clinical Sciences, Monash University, Clayton, Victoria, Australia
| | - Christine P. Rodda
- Australian Institute for Musculoskeletal Science, Sunshine Hospital, and Department of Paediatrics, University of Melbourne,Parkville, Victoria, Australia
| | - Kenneth E. Thummel
- Department of Pharmaceutics, University of Washington, Seattle, Washington, USA
| | - Tom D. Thacher
- Department of Family Medicine, Mayo Clinic, Rochester, Minnesota, USA
| | - Hakon Hakonarson
- Center for Applied Genomics, The Children’s Hospital of Philadelphia (CHOP), University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
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29
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Gorvin CM, Babinsky VN, Malinauskas T, Nissen PH, Schou AJ, Hanyaloglu AC, Siebold C, Jones EY, Hannan FM, Thakker RV. A calcium-sensing receptor mutation causing hypocalcemia disrupts a transmembrane salt bridge to activate β-arrestin-biased signaling. Sci Signal 2018; 11:eaan3714. [PMID: 29463778 PMCID: PMC6166785 DOI: 10.1126/scisignal.aan3714] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The calcium-sensing receptor (CaSR) is a G protein-coupled receptor (GPCR) that signals through Gq/11 and Gi/o to stimulate cytosolic calcium (Ca2+i) and mitogen-activated protein kinase (MAPK) signaling to control extracellular calcium homeostasis. Studies of loss- and gain-of-function CASR mutations, which cause familial hypocalciuric hypercalcemia type 1 (FHH1) and autosomal dominant hypocalcemia type 1 (ADH1), respectively, have revealed that the CaSR signals in a biased manner. Thus, some mutations associated with FHH1 lead to signaling predominantly through the MAPK pathway, whereas mutations associated with ADH1 preferentially enhance Ca2+i responses. We report a previously unidentified ADH1-associated R680G CaSR mutation, which led to the identification of a CaSR structural motif that mediates biased signaling. Expressing CaSRR680G in HEK 293 cells showed that this mutation increased MAPK signaling without altering Ca2+i responses. Moreover, this gain of function in MAPK activity occurred independently of Gq/11 and Gi/o and was mediated instead by a noncanonical pathway involving β-arrestin proteins. Homology modeling and mutagenesis studies showed that the R680G CaSR mutation selectively enhanced β-arrestin signaling by disrupting a salt bridge formed between Arg680 and Glu767, which are located in CaSR transmembrane domain 3 and extracellular loop 2, respectively. Thus, our results demonstrate CaSR signaling through β-arrestin and the importance of the Arg680-Glu767 salt bridge in mediating signaling bias.
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Affiliation(s)
- Caroline M Gorvin
- Academic Endocrine Unit, Oxford Centre for Diabetes, Endocrinology and Metabolism, Radcliffe Department of Medicine, University of Oxford, Oxford OX3 7LJ, UK
| | - Valerie N Babinsky
- Academic Endocrine Unit, Oxford Centre for Diabetes, Endocrinology and Metabolism, Radcliffe Department of Medicine, University of Oxford, Oxford OX3 7LJ, UK
| | - Tomas Malinauskas
- Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK
| | - Peter H Nissen
- Department of Clinical Biochemistry, Aarhus University Hospital, DK-8200 Aarhus N, Denmark
| | - Anders J Schou
- Hans Christian Andersen Children's Hospital, Odense University Hospital, 5000 Odense C, Denmark
| | - Aylin C Hanyaloglu
- Institute of Reproductive and Developmental Biology, Faculty of Medicine, Imperial College London W12 0NN, UK
| | - Christian Siebold
- Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK
| | - E Yvonne Jones
- Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK
| | - Fadil M Hannan
- Academic Endocrine Unit, Oxford Centre for Diabetes, Endocrinology and Metabolism, Radcliffe Department of Medicine, University of Oxford, Oxford OX3 7LJ, UK.
- Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool L7 8TX, UK
| | - Rajesh V Thakker
- Academic Endocrine Unit, Oxford Centre for Diabetes, Endocrinology and Metabolism, Radcliffe Department of Medicine, University of Oxford, Oxford OX3 7LJ, UK.
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30
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Vogiatzi MG, Li D, Tian L, Garifallou JP, Kim CE, Hakonarson H, Levine MA. A novel dominant COL11A1 mutation in a child with Stickler syndrome type II is associated with recurrent fractures. Osteoporos Int 2018; 29:247-251. [PMID: 28971234 DOI: 10.1007/s00198-017-4229-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Accepted: 09/14/2017] [Indexed: 10/18/2022]
Abstract
UNLABELLED This case describes a child with blindness, recurrent low-impact fractures, low bone mass, and intermittent joint pain who was found to have a novel missense mutation in COL11A1, consistent with Stickler syndrome type II. The case illustrates the phenotypic variability of the syndrome, which may include increased fragility in childhood. INTRODUCTION Stickler syndrome type II is an autosomal dominant disorder caused by mutations in the gene that encodes the type XI collagen chain α1 (COL11A1). Manifestations include craniofacial dysmorphology and ocular abnormalities that may lead to blindness, hearing loss, and skeletal anomalies that range from joint pain and arthritis to scoliosis and hypermobility. METHODS Herein, we describe a child who carried the presumed diagnosis of osteoporosis-pseudoglioma syndrome because of the combined findings of recurrent low-impact fractures due to low bone mass and blindness. The child also suffered from joint pain but had no facial dysmorphism or hearing loss. RESULTS Targeted sequencing and deletion analysis of the LRP5, COL1A1, and COL1A2 genes failed to identify any mutations, and whole exome sequence analysis revealed a novel missense mutation (c.3032C>A:p.P1011Q) in COL11A1, consistent with Stickler type II. CONCLUSION This case highlights the phenotypic variability of Stickler type II, broadens the list of differential diagnosis of increased bone fragility in childhood, and highlights utility of unbiased genetic testing towards establishing the correct diagnosis in children with frequent fractures.
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Affiliation(s)
- M G Vogiatzi
- Division of Endocrinology and Diabetes, Children's Hospital of Philadelphia, 3401 Civic Center Blvd., Suite 11NW 30, Philadelphia, PA, 19104, USA.
| | - D Li
- Center for Applied Genomics, The Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA
| | - L Tian
- Center for Applied Genomics, The Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA
| | - J P Garifallou
- Center for Applied Genomics, The Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA
| | - C E Kim
- Center for Applied Genomics, The Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA
| | - H Hakonarson
- Center for Applied Genomics, The Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA
| | - M A Levine
- Division of Endocrinology and Diabetes, Children's Hospital of Philadelphia, 3401 Civic Center Blvd., Suite 11NW 30, Philadelphia, PA, 19104, USA
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31
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Howles SA, Hannan FM, Gorvin CM, Piret SE, Paudyal A, Stewart M, Hough TA, Nesbit MA, Wells S, Brown SD, Cox RD, Thakker RV. Cinacalcet corrects hypercalcemia in mice with an inactivating Gα11 mutation. JCI Insight 2017; 2:96540. [PMID: 29046478 PMCID: PMC5846897 DOI: 10.1172/jci.insight.96540] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Accepted: 09/19/2017] [Indexed: 11/17/2022] Open
Abstract
Loss-of-function mutations of GNA11, which encodes G-protein subunit α11 (Gα11), a signaling partner for the calcium-sensing receptor (CaSR), result in familial hypocalciuric hypercalcemia type 2 (FHH2). FHH2 is characterized by hypercalcemia, inappropriately normal or raised parathyroid hormone (PTH) concentrations, and normal or low urinary calcium excretion. A mouse model for FHH2 that would facilitate investigations of the in vivo role of Gα11 and the evaluation of calcimimetic drugs, which are CaSR allosteric activators, is not available. We therefore screened DNA from > 10,000 mice treated with the chemical mutagen N-ethyl-N-nitrosourea (ENU) for GNA11 mutations and identified a Gα11 variant, Asp195Gly (D195G), which downregulated CaSR-mediated intracellular calcium signaling in vitro, consistent with it being a loss-of-function mutation. Treatment with the calcimimetic cinacalcet rectified these signaling responses. In vivo studies showed mutant heterozygous (Gna11+/195G) and homozygous (Gna11195G/195G) mice to be hypercalcemic with normal or increased plasma PTH concentrations and normal urinary calcium excretion. Cinacalcet (30mg/kg orally) significantly reduced plasma albumin–adjusted calcium and PTH concentrations in Gna11+/195G and Gna11195G/195G mice. Thus, our studies have established a mouse model with a germline loss-of-function Gα11 mutation that is representative for FHH2 in humans and demonstrated that cinacalcet can correct the associated abnormalities of plasma calcium and PTH. Cinacalcet corrects hypercalcemia in a mouse model for familial hypocalciuric hypercalcemia type 2 (FHH2) caused by a germline loss-of-function G-protein subunit α11 (Gα11) mutation, Asp195Gly.
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Affiliation(s)
- Sarah A Howles
- Academic Endocrine Unit, Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Fadil M Hannan
- Academic Endocrine Unit, Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom.,Department of Musculoskeletal Biology, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, United Kingdom
| | - Caroline M Gorvin
- Academic Endocrine Unit, Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Sian E Piret
- Academic Endocrine Unit, Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Anju Paudyal
- Mammalian Genetics Unit and Mary Lyon Centre, Medical Research Council (MRC) Harwell Institute, Harwell Science and Innovation Campus, United Kingdom
| | - Michelle Stewart
- Mammalian Genetics Unit and Mary Lyon Centre, Medical Research Council (MRC) Harwell Institute, Harwell Science and Innovation Campus, United Kingdom
| | - Tertius A Hough
- Mammalian Genetics Unit and Mary Lyon Centre, Medical Research Council (MRC) Harwell Institute, Harwell Science and Innovation Campus, United Kingdom
| | - M Andrew Nesbit
- Academic Endocrine Unit, Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom.,Biomedical Sciences Research Institute, Ulster University, Coleraine, United Kingdom
| | - Sara Wells
- Mammalian Genetics Unit and Mary Lyon Centre, Medical Research Council (MRC) Harwell Institute, Harwell Science and Innovation Campus, United Kingdom
| | - Stephen Dm Brown
- Mammalian Genetics Unit and Mary Lyon Centre, Medical Research Council (MRC) Harwell Institute, Harwell Science and Innovation Campus, United Kingdom
| | - Roger D Cox
- Mammalian Genetics Unit and Mary Lyon Centre, Medical Research Council (MRC) Harwell Institute, Harwell Science and Innovation Campus, United Kingdom
| | - Rajesh V Thakker
- Academic Endocrine Unit, Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom
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32
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Abstract
Hypoparathyroidism is a disease characterized by inadequately low circulating concentrations of parathyroid hormone (PTH) resulting in low calcium levels and increased phosphate levels in the blood. Symptoms of the disease result from increased neuromuscular irritability caused by hypocalcaemia and include tingling, muscle cramps and seizures. The most common cause of the disease is inadvertent removal of, or injury to, the parathyroid glands during neck surgery, followed by genetic, idiopathic and autoimmune aetiologies. Conventional treatment includes activated vitamin D and/or calcium supplements, but this treatment does not fully replace the functions of PTH and can lead to short-term problems (such as hypocalcaemia, hypercalcaemia and increased urinary calcium excretion) and long-term complications (which include nephrocalcinosis, kidney stones and brain calcifications). PTH replacement has emerged as a new treatment option. Clinical trials using human PTH(1-34) and PTH(1-84) showed that this treatment was safe and effective in studies lasting up to 6 years. Recombinant human PTH(1-84) has been approved in the United States and Europe for the management of hypoparathyroidism; however, its effect on long-term complications is still being evaluated. Clinical practice guidelines, which describe the consensus of experts in the field, have been published and recognize the need for more research to optimize care. In this Primer, we summarize current knowledge of the prevalence, pathophysiology, clinical presentation and management of hypoparathyroidism.
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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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Li D, Streeten EA, Chan A, Lwin W, Tian L, Pellegrino da Silva R, Kim CE, Anderson MS, Hakonarson H, Levine MA. Exome Sequencing Reveals Mutations in AIRE as a Cause of Isolated Hypoparathyroidism. J Clin Endocrinol Metab 2017; 102:1726-1733. [PMID: 28323927 PMCID: PMC5443324 DOI: 10.1210/jc.2016-3836] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Accepted: 02/16/2017] [Indexed: 01/26/2023]
Abstract
Context Most cases of autosomal recessive hypoparathyroidism (HYPO) are caused by loss-of-function mutations in GCM2 or PTH. Objective The objective of this study was to identify the underlying genetic basis for isolated HYPO in a kindred in which 3 of 10 siblings were affected. Subjects We studied the parents and the three adult affected subjects, each of whom was diagnosed with HYPO in the first decade of life. Methods We collected clinical and biochemical data and performed whole exome sequencing analysis on DNA from the three affected subjects after negative genetic testing for known causes of HYPO. Results Whole exome sequencing followed by Sanger sequencing revealed that all three affected subjects were compound heterozygous for two previously reported mutations, c.967_979delCTGTCCCCTCCGC:p.(L323SfsX51) and c.995+(3_5)delGAGinsTAT, in AIRE, which encodes the autoimmune regulator protein that is defective in autoimmune polyglandular syndrome type 1 (APS-1). Each parent carries one mutation, and all of the children of the patients are either heterozygous for one mutation or wild type. The affected sister developed premature ovarian failure, but the two affected brothers have no other features of APS-1 despite elevated serum levels of anti-interferon-α antibodies. Conclusions Our findings indicate that biallelic mutations in AIRE can cause isolated HYPO as well as syndromic APS-1. The presence of antibodies to interferon-α provides a highly sensitive indicator for loss of AIRE function and represents a useful marker for isolated HYPO due to AIRE mutations.
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Affiliation(s)
- Dong Li
- Center for Applied Genomics, The Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania 19104
| | - Elizabeth A. Streeten
- Division of Endocrinology, University of Maryland School of Medicine, Baltimore, Maryland 21201
- Division of Diabetes, University of Maryland School of Medicine, Baltimore, Maryland 21201
- Division of Nutrition and Genetics, University of Maryland School of Medicine, Baltimore, Maryland 21201
| | - Alice Chan
- Department of Pediatrics, University of California-San Francisco, San Francisco, California 94143
| | - Wint Lwin
- Diabetes Center, University of California-San Francisco, San Francisco, California 94143
- Department of Medicine, University of California-San Francisco, San Francisco, California 94143
| | - Lifeng Tian
- Center for Applied Genomics, The Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania 19104
| | | | - Cecilia E. Kim
- Center for Applied Genomics, The Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania 19104
| | - Mark S. Anderson
- Diabetes Center, University of California-San Francisco, San Francisco, California 94143
- Department of Medicine, University of California-San Francisco, San Francisco, California 94143
| | - Hakon Hakonarson
- Center for Applied Genomics, The Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania 19104
- Department of Pediatrics, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104
| | - Michael A. Levine
- Division of Endocrinology and Diabetes, The Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania 19104
- Department of Pediatrics, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104
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Bastepe M, Turan S, He Q. Heterotrimeric G proteins in the control of parathyroid hormone actions. J Mol Endocrinol 2017; 58:R203-R224. [PMID: 28363951 PMCID: PMC5650080 DOI: 10.1530/jme-16-0221] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/09/2017] [Accepted: 02/17/2017] [Indexed: 12/17/2022]
Abstract
Parathyroid hormone (PTH) is a key regulator of skeletal physiology and calcium and phosphate homeostasis. It acts on bone and kidney to stimulate bone turnover, increase the circulating levels of 1,25 dihydroxyvitamin D and calcium and inhibit the reabsorption of phosphate from the glomerular filtrate. Dysregulated PTH actions contribute to or are the cause of several endocrine disorders. This calciotropic hormone exerts its actions via binding to the PTH/PTH-related peptide receptor (PTH1R), which couples to multiple heterotrimeric G proteins, including Gs and Gq/11 Genetic mutations affecting the activity or expression of the alpha-subunit of Gs, encoded by the GNAS complex locus, are responsible for several human diseases for which the clinical findings result, at least partly, from aberrant PTH signaling. Here, we review the bone and renal actions of PTH with respect to the different signaling pathways downstream of these G proteins, as well as the disorders caused by GNAS mutations.
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Affiliation(s)
- Murat Bastepe
- Endocrine UnitDepartment of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, USA
| | - Serap Turan
- Department of Pediatric EndocrinologyMarmara University School of Medicine, Istanbul, Turkey
| | - Qing He
- Endocrine UnitDepartment of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, USA
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Gorvin CM, Hannan FM, Howles SA, Babinsky VN, Piret SE, Rogers A, Freidin AJ, Stewart M, Paudyal A, Hough TA, Nesbit MA, Wells S, Vincent TL, Brown SD, Cox RD, Thakker RV. G α11 mutation in mice causes hypocalcemia rectifiable by calcilytic therapy. JCI Insight 2017; 2:e91103. [PMID: 28194447 PMCID: PMC5291742 DOI: 10.1172/jci.insight.91103] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2016] [Accepted: 01/03/2017] [Indexed: 12/11/2022] Open
Abstract
Heterozygous germline gain-of-function mutations of G-protein subunit α11 (Gα11), a signaling partner for the calcium-sensing receptor (CaSR), result in autosomal dominant hypocalcemia type 2 (ADH2). ADH2 may cause symptomatic hypocalcemia with low circulating parathyroid hormone (PTH) concentrations. Effective therapies for ADH2 are currently not available, and a mouse model for ADH2 would help in assessment of potential therapies. We hypothesized that a previously reported dark skin mouse mutant (Dsk7) - which has a germline hypermorphic Gα11 mutation, Ile62Val - may be a model for ADH2 and allow evaluation of calcilytics, which are CaSR negative allosteric modulators, as a targeted therapy for this disorder. Mutant Dsk7/+ and Dsk7/Dsk7 mice were shown to have hypocalcemia and reduced plasma PTH concentrations, similar to ADH2 patients. In vitro studies showed the mutant Val62 Gα11 to upregulate CaSR-mediated intracellular calcium and MAPK signaling, consistent with a gain of function. Treatment with NPS-2143, a calcilytic compound, normalized these signaling responses. In vivo, NPS-2143 induced a rapid and marked rise in plasma PTH and calcium concentrations in Dsk7/Dsk7 and Dsk7/+ mice, which became normocalcemic. Thus, these studies have established Dsk7 mice, which harbor a germline gain-of-function Gα11 mutation, as a model for ADH2 and have demonstrated calcilytics as a potential targeted therapy.
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Affiliation(s)
- Caroline M. Gorvin
- Academic Endocrine Unit, Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Fadil M. Hannan
- Academic Endocrine Unit, Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom
- Department of Musculoskeletal Biology, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, United Kingdom
| | - Sarah A. Howles
- Academic Endocrine Unit, Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Valerie N. Babinsky
- Academic Endocrine Unit, Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Sian E. Piret
- Academic Endocrine Unit, Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Angela Rogers
- Academic Endocrine Unit, Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Andrew J. Freidin
- ARUK Centre for Osteoarthritis Pathogenesis, The Kennedy Institute of Rheumatology, University of Oxford, Oxford, United Kingdom
| | - Michelle Stewart
- Medical Research Council (MRC) Mammalian Genetics Unit and Mary Lyon Centre, MRC Harwell Institute, Harwell Science and Innovation Campus, United Kingdom
| | - Anju Paudyal
- Medical Research Council (MRC) Mammalian Genetics Unit and Mary Lyon Centre, MRC Harwell Institute, Harwell Science and Innovation Campus, United Kingdom
| | - Tertius A. Hough
- Medical Research Council (MRC) Mammalian Genetics Unit and Mary Lyon Centre, MRC Harwell Institute, Harwell Science and Innovation Campus, United Kingdom
| | - M. Andrew Nesbit
- Academic Endocrine Unit, Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom
- Biomedical Sciences Research Institute, Ulster University, Coleraine, United Kingdom
| | - Sara Wells
- Medical Research Council (MRC) Mammalian Genetics Unit and Mary Lyon Centre, MRC Harwell Institute, Harwell Science and Innovation Campus, United Kingdom
| | - Tonia L. Vincent
- ARUK Centre for Osteoarthritis Pathogenesis, The Kennedy Institute of Rheumatology, University of Oxford, Oxford, United Kingdom
| | - Stephen D.M. Brown
- Medical Research Council (MRC) Mammalian Genetics Unit and Mary Lyon Centre, MRC Harwell Institute, Harwell Science and Innovation Campus, United Kingdom
| | - Roger D. Cox
- Medical Research Council (MRC) Mammalian Genetics Unit and Mary Lyon Centre, MRC Harwell Institute, Harwell Science and Innovation Campus, United Kingdom
| | - Rajesh V. Thakker
- Academic Endocrine Unit, Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom
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Roszko KL, Bi R, Gorvin CM, Bräuner-Osborne H, Xiong XF, Inoue A, Thakker RV, Strømgaard K, Gardella T, Mannstadt M. Knockin mouse with mutant G α11 mimics human inherited hypocalcemia and is rescued by pharmacologic inhibitors. JCI Insight 2017; 2:e91079. [PMID: 28194446 PMCID: PMC5291736 DOI: 10.1172/jci.insight.91079] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Heterotrimeric G proteins play critical roles in transducing extracellular signals generated by 7-transmembrane domain receptors. Somatic gain-of-function mutations in G protein α subunits are associated with a variety of diseases. Recently, we identified gain-of-function mutations in Gα11 in patients with autosomal-dominant hypocalcemia type 2 (ADH2), an inherited disorder of hypocalcemia, low parathyroid hormone (PTH), and hyperphosphatemia. We have generated knockin mice harboring the point mutation GNA11 c.C178T (p.Arg60Cys) identified in ADH2 patients. The mutant mice faithfully replicated human ADH2. They also exhibited low bone mineral density and increased skin pigmentation. Treatment with NPS 2143, a negative allosteric modulator of the calcium-sensing receptor (CASR), increased PTH and calcium concentrations in WT and mutant mice, suggesting that the gain-of-function effect of GNA11R6OC is partly dependent on coupling to the CASR. Treatment with the Gα11/q-specific inhibitor YM-254890 increased blood calcium in heterozygous but not in homozygous GNA11R60C mice, consistent with published crystal structure data showing that Arg60 forms a critical contact with YM-254890. This animal model of ADH2 provides insights into molecular mechanism of this G protein-related disease and potential paths toward new lines of therapy.
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Affiliation(s)
- Kelly L Roszko
- Endocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, USA
| | - Ruiye Bi
- Endocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, USA
- West China School of Stomatology, Sichuan University, Chengdu, Sichuan, China
| | - Caroline M Gorvin
- Academic Endocrine Unit, Radcliffe Department of Medicine, University of Oxford, Churchill Hospital, Oxford, England, United Kingdom
| | - Hans Bräuner-Osborne
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
| | - Xiao-Feng Xiong
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
| | - Asuka Inoue
- Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Japan
- Japan Science and Technology Agency (JST), Precursory Research for Embryonic Science and Technology (PRESTO), Kawaguchi, Saitama, Japan
| | - Rajesh V Thakker
- Academic Endocrine Unit, Radcliffe Department of Medicine, University of Oxford, Churchill Hospital, Oxford, England, United Kingdom
| | - Kristian Strømgaard
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
| | - Thomas Gardella
- Endocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, USA
| | - Michael Mannstadt
- Endocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, USA
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38
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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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39
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Li D, Yuan H, Ortiz-Gonzalez XR, Marsh ED, Tian L, McCormick EM, Kosobucki GJ, Chen W, Schulien AJ, Chiavacci R, Tankovic A, Naase C, Brueckner F, von Stülpnagel-Steinbeis C, Hu C, Kusumoto H, Hedrich UBS, Elsen G, Hörtnagel K, Aizenman E, Lemke JR, Hakonarson H, Traynelis SF, Falk MJ. GRIN2D Recurrent De Novo Dominant Mutation Causes a Severe Epileptic Encephalopathy Treatable with NMDA Receptor Channel Blockers. Am J Hum Genet 2016; 99:802-816. [PMID: 27616483 DOI: 10.1016/j.ajhg.2016.07.013] [Citation(s) in RCA: 123] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2016] [Accepted: 07/11/2016] [Indexed: 11/16/2022] Open
Abstract
N-methyl-D-aspartate receptors (NMDARs) are ligand-gated cation channels that mediate excitatory synaptic transmission. Genetic mutations in multiple NMDAR subunits cause various childhood epilepsy syndromes. Here, we report a de novo recurrent heterozygous missense mutation-c.1999G>A (p.Val667Ile)-in a NMDAR gene previously unrecognized to harbor disease-causing mutations, GRIN2D, identified by exome and candidate panel sequencing in two unrelated children with epileptic encephalopathy. The resulting GluN2D p.Val667Ile exchange occurs in the M3 transmembrane domain involved in channel gating. This gain-of-function mutation increases glutamate and glycine potency by 2-fold, increases channel open probability by 6-fold, and reduces receptor sensitivity to endogenous negative modulators such as extracellular protons. Moreover, this mutation prolongs the deactivation time course after glutamate removal, which controls the synaptic time course. Transfection of cultured neurons with human GRIN2D cDNA harboring c.1999G>A leads to dendritic swelling and neuronal cell death, suggestive of excitotoxicity mediated by NMDAR over-activation. Because both individuals' seizures had proven refractory to conventional antiepileptic medications, the sensitivity of mutant NMDARs to FDA-approved NMDAR antagonists was evaluated. Based on these results, oral memantine was administered to both children, with resulting mild to moderate improvement in seizure burden and development. The older proband subsequently developed refractory status epilepticus, with dramatic electroclinical improvement upon treatment with ketamine and magnesium. Overall, these results suggest that NMDAR antagonists can be useful as adjuvant epilepsy therapy in individuals with GRIN2D gain-of-function mutations. This work further demonstrates the value of functionally evaluating a mutation, enabling mechanistic understanding and therapeutic modeling to realize precision medicine for epilepsy.
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MESH Headings
- Amino Acid Sequence
- Base Sequence
- Cell Death
- Child
- DNA Mutational Analysis
- Dendrites/pathology
- Electroencephalography
- Exome/genetics
- Female
- Genes, Dominant/genetics
- Glutamic Acid/metabolism
- Humans
- Infant
- Infant, Newborn
- Ketamine/therapeutic use
- Magnesium/therapeutic use
- Memantine/administration & dosage
- Memantine/therapeutic use
- Models, Molecular
- Mutation
- Precision Medicine
- Receptors, N-Methyl-D-Aspartate/antagonists & inhibitors
- Receptors, N-Methyl-D-Aspartate/chemistry
- Receptors, N-Methyl-D-Aspartate/genetics
- Receptors, N-Methyl-D-Aspartate/metabolism
- Seizures/drug therapy
- Seizures/genetics
- Seizures/metabolism
- Spasms, Infantile/drug therapy
- Spasms, Infantile/genetics
- Spasms, Infantile/metabolism
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Affiliation(s)
- Dong Li
- Center for Applied Genomics, Department of Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Hongjie Yuan
- Department of Pharmacology and Center for Functional Evaluation of Rare Variant (CFERV), Emory University School of Medicine, Rollins Research Center, Atlanta, GA 30322, USA
| | - Xilma R Ortiz-Gonzalez
- Division of Neurology, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA; University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Eric D Marsh
- Division of Neurology, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA; University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Lifeng Tian
- Center for Applied Genomics, Department of Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Elizabeth M McCormick
- Center for Applied Genomics, Department of Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA; Division of Human Genetics, Department of Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Gabrielle J Kosobucki
- Department of Neurobiology, Pittsburgh Institute for Neurodegenerative Diseases, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
| | - Wenjuan Chen
- Department of Pharmacology and Center for Functional Evaluation of Rare Variant (CFERV), Emory University School of Medicine, Rollins Research Center, Atlanta, GA 30322, USA
| | - Anthony J Schulien
- Department of Neurobiology, Pittsburgh Institute for Neurodegenerative Diseases, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
| | - Rosetta Chiavacci
- Center for Applied Genomics, Department of Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Anel Tankovic
- Department of Pharmacology and Center for Functional Evaluation of Rare Variant (CFERV), Emory University School of Medicine, Rollins Research Center, Atlanta, GA 30322, USA
| | - Claudia Naase
- Children's Hospital Bayreuth, 95445 Bayreuth, Germany
| | - Frieder Brueckner
- Institute for Neuropediatrics and Social Pediatrics Hamburg East, 22111 Hamburg, Germany
| | - Celina von Stülpnagel-Steinbeis
- Hospital for Neuropediatrics and Neurological Rehabilitation, Epilepsy Center for Children and Adolescents, 83569 Vogtareuth, Germany; Institute for Transition, Rehabilitation and Palliation in Children and Adolescents, Paracelsus Medical University Salzburg, 5020 Salzburg, Austria
| | - Chun Hu
- Department of Pharmacology and Center for Functional Evaluation of Rare Variant (CFERV), Emory University School of Medicine, Rollins Research Center, Atlanta, GA 30322, USA
| | - Hirofumi Kusumoto
- Department of Pharmacology and Center for Functional Evaluation of Rare Variant (CFERV), Emory University School of Medicine, Rollins Research Center, Atlanta, GA 30322, USA
| | - Ulrike B S Hedrich
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tübingen, 72076 Tübingen, Germany
| | - Gina Elsen
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tübingen, 72076 Tübingen, Germany
| | | | - Elias Aizenman
- Department of Neurobiology, Pittsburgh Institute for Neurodegenerative Diseases, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
| | - Johannes R Lemke
- Institute of Human Genetics, University of Leipzig Hospitals and Clinics, 04103 Leipzig, Germany
| | - Hakon Hakonarson
- Center for Applied Genomics, Department of Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA; University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA; Division of Human Genetics, Department of Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Stephen F Traynelis
- Department of Pharmacology and Center for Functional Evaluation of Rare Variant (CFERV), Emory University School of Medicine, Rollins Research Center, Atlanta, GA 30322, USA
| | - Marni J Falk
- University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA; Division of Human Genetics, Department of Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA.
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40
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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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41
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Mayr B, Glaudo M, Schöfl C. Activating Calcium-Sensing Receptor Mutations: Prospects for Future Treatment with Calcilytics. Trends Endocrinol Metab 2016; 27:643-652. [PMID: 27339034 DOI: 10.1016/j.tem.2016.05.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/11/2016] [Revised: 05/17/2016] [Accepted: 05/20/2016] [Indexed: 12/20/2022]
Abstract
Activating mutations of the G protein-coupled receptor, calcium-sensing receptor (CaSR), cause autosomal dominant hypocalcemia and Bartter syndrome type 5. These mutations lower the set-point for extracellular calcium sensing, thereby causing decreased parathyroid hormone secretion and disturbed renal calcium handling with hypercalciuria. Available therapies increase serum calcium levels but raise the risk of complications in affected patients. Symptom relief and the prevention of adverse outcome is currently very difficult to achieve. Calcilytics act as CaSR antagonists that attenuate its activity, thereby correcting the molecular defect of activating CaSR proteins in vitro and elevating serum calcium in mice and humans in vivo, and have emerged as the most promising therapeutics for the treatment of these rare and difficult to treat diseases.
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Affiliation(s)
- Bernhard Mayr
- Division of Endocrinology and Diabetes, Department of Medicine I, Universitätsklinikum Erlangen, Friedrich-Alexander University Erlangen-Nuremberg, Germany.
| | - Markus Glaudo
- Division of Endocrinology and Diabetes, Department of Medicine I, Universitätsklinikum Erlangen, Friedrich-Alexander University Erlangen-Nuremberg, Germany
| | - Christof Schöfl
- Division of Endocrinology and Diabetes, Department of Medicine I, Universitätsklinikum Erlangen, Friedrich-Alexander University Erlangen-Nuremberg, Germany
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Tenhola S, Voutilainen R, Reyes M, Toiviainen-Salo S, Jüppner H, Mäkitie O. Impaired growth and intracranial calcifications in autosomal dominant hypocalcemia caused by a GNA11 mutation. Eur J Endocrinol 2016; 175:211-8. [PMID: 27334330 PMCID: PMC5149394 DOI: 10.1530/eje-16-0109] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/06/2016] [Accepted: 06/17/2016] [Indexed: 01/15/2023]
Abstract
OBJECTIVE Autosomal dominant hypocalcemia (ADH) is characterized by hypocalcemia and inappropriately low PTH concentrations. ADH type 1 is caused by activating mutations in the calcium-sensing receptor (CASR), a G-protein-coupled receptor signaling through α11 (Gα11) and αq (Gαq) subunits. Heterozygous activating mutations in GNA11, the gene encoding Gα11, underlie ADH type 2. This study describes disease characteristics in a family with ADH caused by a gain-of-function mutation in GNA11. DESIGN A three-generation family with seven members (3 adults, 4 children) presenting with ADH. METHODS Biochemical parameters of calcium metabolism, clinical, genetic and brain imaging findings were analyzed. RESULTS Sanger sequencing revealed a heterozygous GNA11 missense mutation (c.1018G>A, p.V340M) in all seven hypocalcemic subjects, but not in the healthy family members (n=4). The adult patients showed clinical symptoms of hypocalcemia, while the children were asymptomatic. Plasma ionized calcium ranged from 0.95 to 1.14mmol/L, yet plasma PTH was inappropriately low for the degree of hypocalcemia. Serum 25OHD was normal. Despite hypocalcemia 1,25(OH)2D and urinary calcium excretion were inappropriately in the reference range. None of the patients had nephrocalcinosis. Two adults and one child (of the two MRI scanned children) had distinct intracranial calcifications. All affected subjects had short stature (height s.d. scores ranging from -3.4 to -2.3 vs -0.5 in the unaffected children). CONCLUSIONS The identified GNA11 mutation results in biochemical abnormalities typical for ADH. Additional features, including short stature and early intracranial calcifications, cosegregated with the mutation. These findings may indicate a wider role for Gα11 signaling besides calcium regulation.
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Affiliation(s)
- Sirpa Tenhola
- Department of PediatricsKymenlaakso Central Hospital, Kotka, Finland Department of PediatricsKuopio University Hospital and University of Eastern Finland, Kuopio, Finland
| | - Raimo Voutilainen
- Department of PediatricsKuopio University Hospital and University of Eastern Finland, Kuopio, Finland
| | - Monica Reyes
- Endocrine UnitMassachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, USA
| | - Sanna Toiviainen-Salo
- Department of RadiologyHUS Medical Imaging Center, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - Harald Jüppner
- Endocrine UnitMassachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, USA
| | - Outi Mäkitie
- Children's HospitalUniversity of Helsinki and Helsinki University Hospital, Helsinki, Finland Folkhälsan Institute of GeneticsHelsinki, Finland Department of Molecular Medicine and SurgeryKarolinska Institutet and Department of Clinical Genetics, Karolinska University Hospital, Stockholm, Sweden
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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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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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Clarke BL, Brown EM, Collins MT, Jüppner H, Lakatos P, Levine MA, Mannstadt MM, Bilezikian JP, Romanischen AF, Thakker RV. Epidemiology and Diagnosis of Hypoparathyroidism. J Clin Endocrinol Metab 2016; 101:2284-99. [PMID: 26943720 PMCID: PMC5393595 DOI: 10.1210/jc.2015-3908] [Citation(s) in RCA: 164] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
CONTEXT Hypoparathyroidism is a disorder characterized by hypocalcemia due to insufficient secretion of PTH. Pseudohypoparathyroidism is a less common disorder due to target organ resistance to PTH. This report summarizes the results of the findings and recommendations of the Working Group on Epidemiology and Diagnosis of Hypoparathyroidism. EVIDENCE ACQUISITION Each contributing author reviewed the recent published literature regarding epidemiology and diagnosis of hypoparathyroidism using PubMed and other medical literature search engines. EVIDENCE SYNTHESIS The prevalence of hypoparathyroidism is an estimated 37 per 100 000 person-years in the United States and 22 per 100 000 person-years in Denmark. The incidence in Denmark is approximately 0.8 per 100 000 person-years. Estimates of prevalence and incidence of hypoparathyroidism are currently lacking in most other countries. Hypoparathyroidism increases the risk of renal insufficiency, kidney stones, posterior subcapsular cataracts, and intracerebral calcifications, but it does not appear to increase overall mortality, cardiovascular disease, fractures, or malignancy. The diagnosis depends upon accurate measurement of PTH by second- and third-generation assays. The most common etiology is postsurgical hypoparathyroidism, followed by autoimmune disorders and rarely genetic disorders. Even more rare are etiologies including parathyroid gland infiltration, external radiation treatment, and radioactive iodine therapy for thyroid disease. Differentiation between these different etiologies is aided by the clinical presentation, serum biochemistries, and in some cases, genetic testing. CONCLUSIONS Hypoparathyroidism is often associated with complications and comorbidities. It is important for endocrinologists and other physicians who care for these patients to be aware of recent advances in the epidemiology, diagnosis, and genetics of this disorder.
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Affiliation(s)
- Bart L Clarke
- Mayo Clinic (B.L.C.), Division of Endocrinology, Diabetes, Metabolism, and Nutrition, Rochester, Minnesota 55905; Harvard Medical School (E.M.B.), Division of Endocrinology, Diabetes and Hypertension, Boston, Massachusetts 02115; Skeletal Clinical Studies Unit (M.T.C.), Craniofacial and Skeletal Diseases Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, Maryland 20892; Endocrine Unit and Pediatric Nephrology Unit (H.J.), Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114; First Department of Medicine (P.L.), Semmelweis University Medical School, Budapest 1085, Hungary; Division of Endocrinology and Diabetes (M.A.L.), Children's Hospital of Philadelphia, Department of Pediatrics, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania 19104; Massachusetts General Hospital (M.M.M.), Boston, Massachusetts 02114; Columbia University College of Physicians & Surgeons (J.P.B.), New York, New York 10032; Department of Hospital Surgery and Oncology of St Petersburg State Pediatric Medical Academy (A.F.R.), St. Petersburg 194100, Russia; and Academic Endocrine Unit (R.V.T.), Radcliffe Department of Medicine, University of Oxford, Oxford Centre for Diabetes, Endocrinology and Metabolism, Churchill Hospital, Oxford, OX3 7LJ, United Kingdom
| | - Edward M Brown
- Mayo Clinic (B.L.C.), Division of Endocrinology, Diabetes, Metabolism, and Nutrition, Rochester, Minnesota 55905; Harvard Medical School (E.M.B.), Division of Endocrinology, Diabetes and Hypertension, Boston, Massachusetts 02115; Skeletal Clinical Studies Unit (M.T.C.), Craniofacial and Skeletal Diseases Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, Maryland 20892; Endocrine Unit and Pediatric Nephrology Unit (H.J.), Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114; First Department of Medicine (P.L.), Semmelweis University Medical School, Budapest 1085, Hungary; Division of Endocrinology and Diabetes (M.A.L.), Children's Hospital of Philadelphia, Department of Pediatrics, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania 19104; Massachusetts General Hospital (M.M.M.), Boston, Massachusetts 02114; Columbia University College of Physicians & Surgeons (J.P.B.), New York, New York 10032; Department of Hospital Surgery and Oncology of St Petersburg State Pediatric Medical Academy (A.F.R.), St. Petersburg 194100, Russia; and Academic Endocrine Unit (R.V.T.), Radcliffe Department of Medicine, University of Oxford, Oxford Centre for Diabetes, Endocrinology and Metabolism, Churchill Hospital, Oxford, OX3 7LJ, United Kingdom
| | - Michael T Collins
- Mayo Clinic (B.L.C.), Division of Endocrinology, Diabetes, Metabolism, and Nutrition, Rochester, Minnesota 55905; Harvard Medical School (E.M.B.), Division of Endocrinology, Diabetes and Hypertension, Boston, Massachusetts 02115; Skeletal Clinical Studies Unit (M.T.C.), Craniofacial and Skeletal Diseases Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, Maryland 20892; Endocrine Unit and Pediatric Nephrology Unit (H.J.), Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114; First Department of Medicine (P.L.), Semmelweis University Medical School, Budapest 1085, Hungary; Division of Endocrinology and Diabetes (M.A.L.), Children's Hospital of Philadelphia, Department of Pediatrics, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania 19104; Massachusetts General Hospital (M.M.M.), Boston, Massachusetts 02114; Columbia University College of Physicians & Surgeons (J.P.B.), New York, New York 10032; Department of Hospital Surgery and Oncology of St Petersburg State Pediatric Medical Academy (A.F.R.), St. Petersburg 194100, Russia; and Academic Endocrine Unit (R.V.T.), Radcliffe Department of Medicine, University of Oxford, Oxford Centre for Diabetes, Endocrinology and Metabolism, Churchill Hospital, Oxford, OX3 7LJ, United Kingdom
| | - Harald Jüppner
- Mayo Clinic (B.L.C.), Division of Endocrinology, Diabetes, Metabolism, and Nutrition, Rochester, Minnesota 55905; Harvard Medical School (E.M.B.), Division of Endocrinology, Diabetes and Hypertension, Boston, Massachusetts 02115; Skeletal Clinical Studies Unit (M.T.C.), Craniofacial and Skeletal Diseases Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, Maryland 20892; Endocrine Unit and Pediatric Nephrology Unit (H.J.), Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114; First Department of Medicine (P.L.), Semmelweis University Medical School, Budapest 1085, Hungary; Division of Endocrinology and Diabetes (M.A.L.), Children's Hospital of Philadelphia, Department of Pediatrics, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania 19104; Massachusetts General Hospital (M.M.M.), Boston, Massachusetts 02114; Columbia University College of Physicians & Surgeons (J.P.B.), New York, New York 10032; Department of Hospital Surgery and Oncology of St Petersburg State Pediatric Medical Academy (A.F.R.), St. Petersburg 194100, Russia; and Academic Endocrine Unit (R.V.T.), Radcliffe Department of Medicine, University of Oxford, Oxford Centre for Diabetes, Endocrinology and Metabolism, Churchill Hospital, Oxford, OX3 7LJ, United Kingdom
| | - Peter Lakatos
- Mayo Clinic (B.L.C.), Division of Endocrinology, Diabetes, Metabolism, and Nutrition, Rochester, Minnesota 55905; Harvard Medical School (E.M.B.), Division of Endocrinology, Diabetes and Hypertension, Boston, Massachusetts 02115; Skeletal Clinical Studies Unit (M.T.C.), Craniofacial and Skeletal Diseases Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, Maryland 20892; Endocrine Unit and Pediatric Nephrology Unit (H.J.), Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114; First Department of Medicine (P.L.), Semmelweis University Medical School, Budapest 1085, Hungary; Division of Endocrinology and Diabetes (M.A.L.), Children's Hospital of Philadelphia, Department of Pediatrics, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania 19104; Massachusetts General Hospital (M.M.M.), Boston, Massachusetts 02114; Columbia University College of Physicians & Surgeons (J.P.B.), New York, New York 10032; Department of Hospital Surgery and Oncology of St Petersburg State Pediatric Medical Academy (A.F.R.), St. Petersburg 194100, Russia; and Academic Endocrine Unit (R.V.T.), Radcliffe Department of Medicine, University of Oxford, Oxford Centre for Diabetes, Endocrinology and Metabolism, Churchill Hospital, Oxford, OX3 7LJ, United Kingdom
| | - Michael A Levine
- Mayo Clinic (B.L.C.), Division of Endocrinology, Diabetes, Metabolism, and Nutrition, Rochester, Minnesota 55905; Harvard Medical School (E.M.B.), Division of Endocrinology, Diabetes and Hypertension, Boston, Massachusetts 02115; Skeletal Clinical Studies Unit (M.T.C.), Craniofacial and Skeletal Diseases Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, Maryland 20892; Endocrine Unit and Pediatric Nephrology Unit (H.J.), Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114; First Department of Medicine (P.L.), Semmelweis University Medical School, Budapest 1085, Hungary; Division of Endocrinology and Diabetes (M.A.L.), Children's Hospital of Philadelphia, Department of Pediatrics, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania 19104; Massachusetts General Hospital (M.M.M.), Boston, Massachusetts 02114; Columbia University College of Physicians & Surgeons (J.P.B.), New York, New York 10032; Department of Hospital Surgery and Oncology of St Petersburg State Pediatric Medical Academy (A.F.R.), St. Petersburg 194100, Russia; and Academic Endocrine Unit (R.V.T.), Radcliffe Department of Medicine, University of Oxford, Oxford Centre for Diabetes, Endocrinology and Metabolism, Churchill Hospital, Oxford, OX3 7LJ, United Kingdom
| | - Michael M Mannstadt
- Mayo Clinic (B.L.C.), Division of Endocrinology, Diabetes, Metabolism, and Nutrition, Rochester, Minnesota 55905; Harvard Medical School (E.M.B.), Division of Endocrinology, Diabetes and Hypertension, Boston, Massachusetts 02115; Skeletal Clinical Studies Unit (M.T.C.), Craniofacial and Skeletal Diseases Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, Maryland 20892; Endocrine Unit and Pediatric Nephrology Unit (H.J.), Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114; First Department of Medicine (P.L.), Semmelweis University Medical School, Budapest 1085, Hungary; Division of Endocrinology and Diabetes (M.A.L.), Children's Hospital of Philadelphia, Department of Pediatrics, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania 19104; Massachusetts General Hospital (M.M.M.), Boston, Massachusetts 02114; Columbia University College of Physicians & Surgeons (J.P.B.), New York, New York 10032; Department of Hospital Surgery and Oncology of St Petersburg State Pediatric Medical Academy (A.F.R.), St. Petersburg 194100, Russia; and Academic Endocrine Unit (R.V.T.), Radcliffe Department of Medicine, University of Oxford, Oxford Centre for Diabetes, Endocrinology and Metabolism, Churchill Hospital, Oxford, OX3 7LJ, United Kingdom
| | - John P Bilezikian
- Mayo Clinic (B.L.C.), Division of Endocrinology, Diabetes, Metabolism, and Nutrition, Rochester, Minnesota 55905; Harvard Medical School (E.M.B.), Division of Endocrinology, Diabetes and Hypertension, Boston, Massachusetts 02115; Skeletal Clinical Studies Unit (M.T.C.), Craniofacial and Skeletal Diseases Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, Maryland 20892; Endocrine Unit and Pediatric Nephrology Unit (H.J.), Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114; First Department of Medicine (P.L.), Semmelweis University Medical School, Budapest 1085, Hungary; Division of Endocrinology and Diabetes (M.A.L.), Children's Hospital of Philadelphia, Department of Pediatrics, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania 19104; Massachusetts General Hospital (M.M.M.), Boston, Massachusetts 02114; Columbia University College of Physicians & Surgeons (J.P.B.), New York, New York 10032; Department of Hospital Surgery and Oncology of St Petersburg State Pediatric Medical Academy (A.F.R.), St. Petersburg 194100, Russia; and Academic Endocrine Unit (R.V.T.), Radcliffe Department of Medicine, University of Oxford, Oxford Centre for Diabetes, Endocrinology and Metabolism, Churchill Hospital, Oxford, OX3 7LJ, United Kingdom
| | - Anatoly F Romanischen
- Mayo Clinic (B.L.C.), Division of Endocrinology, Diabetes, Metabolism, and Nutrition, Rochester, Minnesota 55905; Harvard Medical School (E.M.B.), Division of Endocrinology, Diabetes and Hypertension, Boston, Massachusetts 02115; Skeletal Clinical Studies Unit (M.T.C.), Craniofacial and Skeletal Diseases Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, Maryland 20892; Endocrine Unit and Pediatric Nephrology Unit (H.J.), Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114; First Department of Medicine (P.L.), Semmelweis University Medical School, Budapest 1085, Hungary; Division of Endocrinology and Diabetes (M.A.L.), Children's Hospital of Philadelphia, Department of Pediatrics, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania 19104; Massachusetts General Hospital (M.M.M.), Boston, Massachusetts 02114; Columbia University College of Physicians & Surgeons (J.P.B.), New York, New York 10032; Department of Hospital Surgery and Oncology of St Petersburg State Pediatric Medical Academy (A.F.R.), St. Petersburg 194100, Russia; and Academic Endocrine Unit (R.V.T.), Radcliffe Department of Medicine, University of Oxford, Oxford Centre for Diabetes, Endocrinology and Metabolism, Churchill Hospital, Oxford, OX3 7LJ, United Kingdom
| | - Rajesh V Thakker
- Mayo Clinic (B.L.C.), Division of Endocrinology, Diabetes, Metabolism, and Nutrition, Rochester, Minnesota 55905; Harvard Medical School (E.M.B.), Division of Endocrinology, Diabetes and Hypertension, Boston, Massachusetts 02115; Skeletal Clinical Studies Unit (M.T.C.), Craniofacial and Skeletal Diseases Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, Maryland 20892; Endocrine Unit and Pediatric Nephrology Unit (H.J.), Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114; First Department of Medicine (P.L.), Semmelweis University Medical School, Budapest 1085, Hungary; Division of Endocrinology and Diabetes (M.A.L.), Children's Hospital of Philadelphia, Department of Pediatrics, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania 19104; Massachusetts General Hospital (M.M.M.), Boston, Massachusetts 02114; Columbia University College of Physicians & Surgeons (J.P.B.), New York, New York 10032; Department of Hospital Surgery and Oncology of St Petersburg State Pediatric Medical Academy (A.F.R.), St. Petersburg 194100, Russia; and Academic Endocrine Unit (R.V.T.), Radcliffe Department of Medicine, University of Oxford, Oxford Centre for Diabetes, Endocrinology and Metabolism, Churchill Hospital, Oxford, OX3 7LJ, United Kingdom
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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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47
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Mayr B, Schnabel D, Dörr HG, Schöfl C. GENETICS IN ENDOCRINOLOGY: Gain and loss of function mutations of the calcium-sensing receptor and associated proteins: current treatment concepts. Eur J Endocrinol 2016; 174:R189-208. [PMID: 26646938 DOI: 10.1530/eje-15-1028] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/19/2015] [Accepted: 12/08/2015] [Indexed: 12/26/2022]
Abstract
The calcium-sensing receptor (CASR) is the main calcium sensor in the maintenance of calcium metabolism. Mutations of the CASR, the G protein alpha 11 (GNA11) and the adaptor-related protein complex 2 sigma 1 subunit (AP2S1) genes can shift the set point for calcium sensing causing hyper- or hypo-calcemic disorders. Therapeutic concepts for these rare diseases range from general therapies of hyper- and hypo-calcemic conditions to more pathophysiology oriented approaches such as parathyroid hormone (PTH) substitution and allosteric CASR modulators. Cinacalcet is a calcimimetic that enhances receptor function and has gained approval for the treatment of hyperparathyroidism. Calcilytics in turn attenuate CASR activity and are currently under investigation for the treatment of various diseases. We conducted a literature search for reports about treatment of patients harboring inactivating or activating CASR, GNA11 or AP2S1 mutants and about in vitro effects of allosteric CASR modulators on mutated CASR. The therapeutic concepts for patients with familial hypocalciuric hypercalcemia (FHH), neonatal hyperparathyroidism (NHPT), neonatal severe hyperparathyroidism (NSHPT) and autosomal dominant hypocalcemia (ADH) are reviewed. FHH is usually benign, but symptomatic patients benefit from cinacalcet. In NSHPT patients pamidronate effectively lowers serum calcium, but most patients require parathyroidectomy. In some patients cinacalcet can obviate the need for surgery, particularly in heterozygous NHPT. Symptomatic ADH patients respond to vitamin D and calcium supplementation but this may increase calciuria and renal complications. PTH treatment can reduce relative hypercalciuria. None of the currently available therapies for ADH, however, prevent tissue calcifications and complications, which may become possible with calcilytics that correct the underlying pathophysiologic defect.
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Affiliation(s)
- Bernhard Mayr
- Division of Endocrinology and DiabetesDepartment of Medicine I, Universitätsklinikum Erlangen, Friedrich-Alexander University Erlangen-Nuremberg, Ulmenweg 18, 91054 Erlangen, GermanyCenter for Chronic Sick ChildrenPediatric Endocrinology and Diabetes, Charité University Medicine Berlin, Berlin, GermanyDivision of Paediatric Endocrinology and DiabetesDepartment of Paediatrics, Universitätsklinikum Erlangen, Friedrich-Alexander University Erlangen-Nuremberg, Erlangen, Germany
| | - Dirk Schnabel
- Division of Endocrinology and DiabetesDepartment of Medicine I, Universitätsklinikum Erlangen, Friedrich-Alexander University Erlangen-Nuremberg, Ulmenweg 18, 91054 Erlangen, GermanyCenter for Chronic Sick ChildrenPediatric Endocrinology and Diabetes, Charité University Medicine Berlin, Berlin, GermanyDivision of Paediatric Endocrinology and DiabetesDepartment of Paediatrics, Universitätsklinikum Erlangen, Friedrich-Alexander University Erlangen-Nuremberg, Erlangen, Germany
| | - Helmuth-Günther Dörr
- Division of Endocrinology and DiabetesDepartment of Medicine I, Universitätsklinikum Erlangen, Friedrich-Alexander University Erlangen-Nuremberg, Ulmenweg 18, 91054 Erlangen, GermanyCenter for Chronic Sick ChildrenPediatric Endocrinology and Diabetes, Charité University Medicine Berlin, Berlin, GermanyDivision of Paediatric Endocrinology and DiabetesDepartment of Paediatrics, Universitätsklinikum Erlangen, Friedrich-Alexander University Erlangen-Nuremberg, Erlangen, Germany
| | - Christof Schöfl
- Division of Endocrinology and DiabetesDepartment of Medicine I, Universitätsklinikum Erlangen, Friedrich-Alexander University Erlangen-Nuremberg, Ulmenweg 18, 91054 Erlangen, GermanyCenter for Chronic Sick ChildrenPediatric Endocrinology and Diabetes, Charité University Medicine Berlin, Berlin, GermanyDivision of Paediatric Endocrinology and DiabetesDepartment of Paediatrics, Universitätsklinikum Erlangen, Friedrich-Alexander University Erlangen-Nuremberg, Erlangen, Germany
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48
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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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49
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Thomas AC, Zeng Z, Rivière JB, O'Shaughnessy R, Al-Olabi L, St-Onge J, Atherton DJ, Aubert H, Bagazgoitia L, Barbarot S, Bourrat E, Chiaverini C, Chong WK, Duffourd Y, Glover M, Groesser L, Hadj-Rabia S, Hamm H, Happle R, Mushtaq I, Lacour JP, Waelchli R, Wobser M, Vabres P, Patton EE, Kinsler VA. Mosaic Activating Mutations in GNA11 and GNAQ Are Associated with Phakomatosis Pigmentovascularis and Extensive Dermal Melanocytosis. J Invest Dermatol 2016; 136:770-778. [PMID: 26778290 PMCID: PMC4803466 DOI: 10.1016/j.jid.2015.11.027] [Citation(s) in RCA: 107] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Revised: 10/31/2015] [Accepted: 11/02/2015] [Indexed: 11/04/2022]
Abstract
Common birthmarks can be an indicator of underlying genetic disease but are often overlooked. Mongolian blue spots (dermal melanocytosis) are usually localized and transient, but they can be extensive, permanent, and associated with extracutaneous abnormalities. Co-occurrence with vascular birthmarks defines a subtype of phakomatosis pigmentovascularis, a group of syndromes associated with neurovascular, ophthalmological, overgrowth, and malignant complications. Here, we discover that extensive dermal melanocytosis and phakomatosis pigmentovascularis are associated with activating mutations in GNA11 and GNAQ, genes that encode Gα subunits of heterotrimeric G proteins. The mutations were detected at very low levels in affected tissues but were undetectable in the blood, indicating that these conditions are postzygotic mosaic disorders. In vitro expression of mutant GNA11R183C and GNA11Q209L in human cell lines demonstrated activation of the downstream p38 MAPK signaling pathway and the p38, JNK, and ERK pathways, respectively. Transgenic mosaic zebrafish models expressing mutant GNA11R183C under promoter mitfa developed extensive dermal melanocytosis recapitulating the human phenotype. Phakomatosis pigmentovascularis and extensive dermal melanocytosis are therefore diagnoses in the group of mosaic heterotrimeric G-protein disorders, joining McCune-Albright and Sturge-Weber syndromes. These findings will allow accurate clinical and molecular diagnosis of this subset of common birthmarks, thereby identifying infants at risk for serious complications, and provide novel therapeutic opportunities.
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Affiliation(s)
- Anna C Thomas
- Genetics and Genomic Medicine, UCL Institute of Child Health, London, UK
| | - Zhiqiang Zeng
- MRC Institute of Genetics and Molecular Medicine, MRC Human Genetics Unit & Edinburgh Cancer Research UK Centre, Edinburgh, UK
| | - Jean-Baptiste Rivière
- Equipe d'Accueil 4271, Génétique des Anomalies du Développement, University of Burgundy, Dijon, France
| | - Ryan O'Shaughnessy
- Livingstone Skin Research Unit, UCL Institute of Child Health, London, UK
| | - Lara Al-Olabi
- Genetics and Genomic Medicine, UCL Institute of Child Health, London, UK
| | - Judith St-Onge
- Equipe d'Accueil 4271, Génétique des Anomalies du Développement, University of Burgundy, Dijon, France
| | - David J Atherton
- Paediatric Dermatology, Great Ormond Street Hospital for Children, London, UK
| | - Hélène Aubert
- Department of Dermatology, Nantes University Hospital, Nantes, France
| | | | | | - Emmanuelle Bourrat
- Dermatology, Saint-Louis Hospital, Paris, France; General Paediatrics, Robert-Debré Hospital, Paris, France
| | | | - W Kling Chong
- Neuroradiology, Great Ormond Street Hospital for Children, London, UK
| | - Yannis Duffourd
- Equipe d'Accueil 4271, Génétique des Anomalies du Développement, University of Burgundy, Dijon, France
| | - Mary Glover
- Paediatric Dermatology, Great Ormond Street Hospital for Children, London, UK
| | | | - Smail Hadj-Rabia
- Paediatric Dermatology, Necker Enfants-Malades Hospital, Paris, France
| | - Henning Hamm
- Dermatology, University Hospital Wuerzburg, Wuerzburg, Germany
| | - Rudolf Happle
- Dermatology, Freiburg University Medical Center, University of Freiburg, Freiburg, Germany
| | - Imran Mushtaq
- Paediatric Urology, Great Ormond Street Hospital for Children, London, UK
| | | | - Regula Waelchli
- Paediatric Dermatology, Great Ormond Street Hospital for Children, London, UK
| | - Marion Wobser
- Dermatology, University Hospital Wuerzburg, Wuerzburg, Germany
| | - Pierre Vabres
- Equipe d'Accueil 4271, Génétique des Anomalies du Développement, University of Burgundy, Dijon, France; Dermatology, Dijon University Hospital, Dijon, France
| | - E Elizabeth Patton
- MRC Institute of Genetics and Molecular Medicine, MRC Human Genetics Unit & Edinburgh Cancer Research UK Centre, Edinburgh, UK.
| | - Veronica A Kinsler
- Genetics and Genomic Medicine, UCL Institute of Child Health, London, UK; Paediatric Dermatology, Great Ormond Street Hospital for Children, London, UK.
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50
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Rejnmark L, Underbjerg L, Sikjaer T. Hypoparathyroidism: Replacement Therapy with Parathyroid Hormone. Endocrinol Metab (Seoul) 2015; 30:436-42. [PMID: 26394728 PMCID: PMC4722396 DOI: 10.3803/enm.2015.30.4.436] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/28/2015] [Revised: 09/16/2015] [Accepted: 09/21/2015] [Indexed: 11/24/2022] Open
Abstract
Hypoparathyroidism (HypoPT) is characterized by low serum calcium levels caused by an insufficient secretion of parathyroid hormone (PTH). Despite normalization of serum calcium levels by treatment with activated vitamin D analogues and calcium supplementation, patients are suffering from impaired quality of life (QoL) and are at increased risk of a number of comorbidities. Thus, despite normalization of calcium levels in response to conventional therapy, this should only be considered as an apparent normalization, as patients are suffering from a number of complications and calcium-phosphate homeostasis is not normalized in a physiological manner. In a number of recent studies, replacement therapy with recombinant human PTH (rhPTH(1-84)) as well as therapy with the N-terminal PTH fragment (rhPTH(1-34)) have been investigated. Both drugs have been shown to normalize serum calcium while reducing needs for activated vitamin D and calcium supplements. However, once a day injections cause large fluctuations in serum calcium. Twice a day injections diminish fluctuations, but don't restore the normal physiology of calcium homeostasis. Recent studies using pump-delivery have shown promising results on maintaining normocalcemia with minimal fluctuations in calcium levels. Further studies are needed to determine whether this may improve QoL and lower risk of complications. Such data are needed before replacement with the missing hormone can be recommended as standard therapy.
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Affiliation(s)
- Lars Rejnmark
- Department of Endocrinology and Internal Medicine, Aarhus University Hospital, Aarhus, Denmark.
| | - Line Underbjerg
- Department of Endocrinology and Internal Medicine, Aarhus University Hospital, Aarhus, Denmark
| | - Tanja Sikjaer
- Department of Endocrinology and Internal Medicine, Aarhus University Hospital, Aarhus, Denmark
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