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Jüppner H. Pseudohypoparathyroidism: complex disease variants with unfortunate names. J Mol Endocrinol 2024; 72:e230104. [PMID: 37965945 PMCID: PMC10843601 DOI: 10.1530/jme-23-0104] [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: 08/15/2023] [Accepted: 11/14/2023] [Indexed: 11/16/2023]
Abstract
Several human disorders are caused by genetic or epigenetic changes involving the GNAS locus on chromosome 20q13.3 that encodes the alpha-subunit of the stimulatory G protein (Gsα) and several splice variants thereof. Thus, pseudohypoparathyroidism type Ia (PHP1A) is caused by heterozygous inactivating mutations involving the maternal GNAS exons 1-13 resulting in characteristic abnormalities referred to as Albright's hereditary osteodystrophy (AHO) that are associated with resistance to several agonist ligands, particularly to parathyroid hormone (PTH), thereby leading to hypocalcemia and hyperphosphatemia. GNAS mutations involving the paternal Gsα exons also cause most of these AHO features, but without evidence for hormonal resistance, hence the term pseudopseudohypoparathyroidism (PPHP). Autosomal dominant pseudohypoparathyroidism type Ib (PHP1B) due to maternal GNAS or STX16 mutations (deletions, duplications, insertions, and inversions) is associated with epigenetic changes at one or several differentially methylated regions (DMRs) within GNAS. Unlike the inactivating Gsα mutations that cause PHP1A and PPHP, hormonal resistance is caused in all PHP1B variants by impaired Gsα expression due to loss of methylation at GNAS exon A/B, which can be associated in some familial cases with epigenetic changes at the other maternal GNAS DMRs. The genetic defect(s) responsible for sporadic PHP1B, the most frequent variant of this disorder, remain(s) unknown for the majority of patients. However, characteristic epigenetic GNAS changes can be readily detected that include a gain of methylation at the neuroendocrine secretory protein (NESP) DMR. Multiple genetic or epigenetic GNAS abnormalities can thus impair Gsα function or expression, consequently leading to inadequate cAMP-dependent signaling events downstream of various Gsα-coupled receptors.
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Affiliation(s)
- Harald Jüppner
- Endocrine Unit, Department of Medicine and Pediatric Nephrology Unit, Department of Pediatrics, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, 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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Huang S, He Y, Lin X, Sun S, Zheng F. Clinical and genetic analysis of pseudohypoparathyroidism complicated by hypokalemia: a case report and review of the literature. BMC Endocr Disord 2022; 22:98. [PMID: 35410271 PMCID: PMC9004107 DOI: 10.1186/s12902-022-01011-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Accepted: 03/30/2022] [Indexed: 11/24/2022] Open
Abstract
BACKGROUND Pseudohypoparathyroidism (PHP) encompasses a highly heterogenous group of disorders, characterized by parathyroid hormone (PTH) resistance caused by mutations in the GNAS gene or other upstream targets. Here, we investigate the characteristics of a female patient diagnosed with PHP complicated with hypokalemia, and her family members. CASE PRESENTATION AND GENE ANALYSIS A 27-year-old female patient occasionally exhibited asymptomatic hypocalcemia and hypokalemia during her pregnancy 1 year ago. Seven months after delivery, she experienced tetany and dysphonia with diarrhea. Tetany symptoms were relieved after intravenous calcium gluconate supplementation and she was then transferred to our Hospital. Laboratory assessments of the patient revealed hypokalemia, hypocalcemia and hyperphosphatemia despite elevated PTH levels. CT scanning of the brain revealed globus pallidus calcification. Possible mutations in GNAS and hypokalemia related genes were identified using WES, exon copies of STX16 were analized by MLPA and the methylation status of GNAS in three differential methylated regions (DMRs) was analyzed by methylation-specific polymerase chain reaction, followed by confirmation with gene sequencing. The patient was clinically diagnosed with PHP-1b. Loss of methylation in the A/B region and hypermethylation in the NESP55 region were detected. No other mutations in GNAS or hypokalemia related genes and no deletions of STX16 exons were detected. A negative family history and abnormal DMRs in GNAS led to a diagnosis of sporadic PHP-1b of the patient. CONCLUSIONS Hypokalemia is a rare disorder associated with PHP-1b. Analysis of genetic and epigenetic mutations can aid in the diagnosis and accurate subtyping of PHP.
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Affiliation(s)
- Shaohan Huang
- Department of endocrinology, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Yingzi He
- Department of endocrinology, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Xihua Lin
- Department of endocrinology, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Shuiya Sun
- Department of endocrinology, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Fenping Zheng
- Department of endocrinology, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
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Ramalho E Silva JD, da Rocha GFMA, Oliveira MJM. An intricate case of sporadic pseudohypoparathyroidism type 1B with a review of literature. ARCHIVES OF ENDOCRINOLOGY AND METABOLISM 2021; 65:112-116. [PMID: 33320452 PMCID: PMC10528691 DOI: 10.20945/2359-3997000000316] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Accepted: 09/17/2020] [Indexed: 11/23/2022]
Abstract
Pseudohypoparathyroidism comprehends an assorted group of genetically rare disorders that share end-organ resistance to parathyroid hormone. Genetic and epigenetic modifications on guanine nucleotide-binding protein alpha-stimulating gene locus are the most common underlying mechanisms associated with pseudohypoparathyroidism. Biochemical and molecular analysis stratify pseudohypoparathyroidism into types 1A, 1B, 1C, and 2. We describe an unusual case of sporadic pseudohypoparathyroidism type 1B. A 34-year-old Caucasian woman was admitted to the emergency department, with persistent asthenia, limb paresthesias, and tactile hyposensitivity. Her physical examination, previous personal and family histories were unsuspicious, except for mild, intermittent and self-limited complaints of paresthesia during her two pregnancies, but no detailed workup was done. No typical features of Albright hereditary osteodystrophy were observed. The initial laboratory investigation showed elevated parathyroid hormone level (311.2 pg/mL), hypocalcemia (albumin-corrected serum calcium 4.3 mg/dL), hypocalciuria, hyperphosphatemia, hypophosphaturia, and vitamin D deficiency. Combined calcium, vitamin D, and magnesium supplementation was commenced, with symptomatic and analytical improvement. Albeit resolution of vitamin D deficiency, the patient relapsed with mild and intermittent lower limb paresthesias. Pseudohypoparathyroidism was confirmed by molecular identification of the 3-kb STX16 deletion. The treatment was readjusted, and one year later, symptomatic remission was attained. Clinical and biochemical features, and their respective course, along with lack of distinctive features of Albright hereditary osteodystrophy pointed to pseudohypoparathyroidism type 1B. A careful follow-up is needed to avoid complications and recurrence. Once correction of hypocalcemia and hyperphosphatemia is achieved, with no reported complications and recurrence, a good prognosis is anticipated, comparable to the general population.
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Affiliation(s)
- José Diogo Ramalho E Silva
- Departamento de Endocrinologia e Nutrição, Centro Hospitalar de Vila Nova de Gaia/Espinho (CHVNG/E), Vila Nova de Gaia, Portugal,
| | | | - Maria João Martins Oliveira
- Departamento de Endocrinologia e Nutrição, Centro Hospitalar de Vila Nova de Gaia/Espinho (CHVNG/E), Vila Nova de Gaia, Portugal
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Danzig J, Li D, Jan de Beur S, Levine MA. High-throughput Molecular Analysis of Pseudohypoparathyroidism 1b Patients Reveals Novel Genetic and Epigenetic Defects. J Clin Endocrinol Metab 2021; 106:e4603-e4620. [PMID: 34157100 PMCID: PMC8677598 DOI: 10.1210/clinem/dgab460] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/25/2021] [Indexed: 11/19/2022]
Abstract
CONTEXT Patients with pseudohypoparathyroidism type 1b (PHP1b) show disordered imprinting of the maternal GNAS allele or paternal uniparental disomy (UPD). Genetic deletions in STX16 or in upstream exons of GNAS are present in many familial but not sporadic cases. OBJECTIVE Characterization of epigenetic and genetic defects in patients with PHP1b. DESIGN AND PATIENTS DNA from 84 subjects, including 26 subjects with sporadic PHP1b, 27 affected subjects and 17 unaffected and/or obligate gene carriers from 12 PHP1b families, 11 healthy individuals, and 3 subjects with PHP1a was subjected to quantitative pyrosequencing of GNAS differentially methylated regions (DMRs), microarray analysis, and microsatellite haplotype analysis. SETTING Academic medical center. MAIN OUTCOME MEASUREMENTS Molecular pathology of PHP1b. RESULTS Healthy subjects, unaffected family members and obligate carriers of paternal PHP1b alleles, and subjects with PHP1a showed normal methylation of all DMRs. All PHP1b subjects showed loss of methylation (LOM) at the exon A/B DMR. Affected members of 9 PHP1b kindreds showed LOM only at the exon A/B DMR, which was associated with a 3-kb deletion of STX16 exons 4 through 6 in 7 families and a novel deletion of STX16 and adjacent NEPEPL1 in 1 family. A novel NESP deletion was found in 1 of 2 other families with more extensive methylation defects. One sporadic PHP1b had UPD of 20q, 2 had 3-kb STX16 deletions, and 5 had apparent epigenetic mosaicism. CONCLUSIONS We found diverse patterns of defective methylation and identified novel or previously known mutations in 9 of 12 PHP1b families.
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Affiliation(s)
- Jennifer Danzig
- Division of Endocrinology and Diabetes, and The Children’s Hospital of Philadelphia and Department of Pediatrics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Dong Li
- Center for Applied Genomics, The Children’s Hospital of Philadelphia and Department of Pediatrics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Suzanne Jan de Beur
- Division of Endocrinology and Metabolism, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Michael A Levine
- Division of Endocrinology and Diabetes, and The Children’s Hospital of Philadelphia and Department of Pediatrics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
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Abstract
Pseudohypoparathyroidism (PHP) and pseudopseudohypoparathyroidism (PPHP) are caused by mutations and/or epigenetic changes at the complex GNAS locus on chromosome 20q13.3 that undergoes parent-specific methylation changes at several differentially methylated regions (DMRs). GNAS encodes the alpha-subunit of the stimulatory G protein (Gsα) and several splice variants thereof. PHP type Ia (PHP1A) is caused by heterozygous inactivating mutations involving the maternal exons 1-13. Heterozygosity of these maternal GNAS mutations cause PTH-resistant hypocalcemia and hyperphosphatemia because paternal Gsα expression is suppressed in certain organs thus leading to little or no Gsα protein in the proximal renal tubules and other tissues. Besides biochemical abnormalities, PHP1A patients show developmental abnormalities, referred to as Albright's hereditary osteodystrophy (AHO). Some, but not all of these AHO features are encountered also in patients affected by PPHP, who carry paternal Gsα-specific mutations and typically show no laboratory abnormalities. Autosomal dominant PHP type Ib (AD-PHP1B) is caused by heterozygous maternal deletions within GNAS or STX16, which are associated with loss of methylation at the A/B DMR alone or at all maternally methylated GNAS exons. Loss of methylation of exon A/B and the resulting biallelic expression of A/B transcript reduces Gsα expression thus leading to hormonal resistance. Epigenetic changes at all differentially methylated GNAS regions are also observed in sporadic PHP1B, which is the most frequent PHP1B variant. However, this disease variant remains unresolved at the molecular level, except for rare cases with paternal uniparental isodisomy or heterodisomy of chromosome 20q (patUPD20q).
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Affiliation(s)
- Harald Jüppner
- Endocrine Unit, Department of Medicine and Pediatric Nephrology Unit, Department of Pediatrics, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
- Correspondence: Harald Jüppner, MD, Endocrine Unit, Thier 10, 50 Blossom Street, Massachusetts General Hospital, Boston, MA 02114, USA.
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Chale-Matsau B, van Niekerk C, Kemp T, Pillay TS. Discordant Calcium and Parathyroid Hormone with Presumed Epileptic Seizures. Clin Chem 2019; 64:442-445. [PMID: 29490995 DOI: 10.1373/clinchem.2016.269555] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2016] [Accepted: 02/21/2017] [Indexed: 11/06/2022]
Affiliation(s)
- Bettina Chale-Matsau
- Department of Chemical Pathology, University of Pretoria and National Health Laboratory Service Tshwane Academic Division, Pretoria, South Africa
| | - Chantal van Niekerk
- Department of Chemical Pathology, University of Pretoria and National Health Laboratory Service Tshwane Academic Division, Pretoria, South Africa
| | - Tanja Kemp
- Division of Endocrinology, University of Pretoria, Pretoria, South Africa
| | - Tahir S Pillay
- Department of Chemical Pathology, University of Pretoria and National Health Laboratory Service Tshwane Academic Division, Pretoria, South Africa; .,Division of Chemical Pathology, University of Cape Town, Cape Town, South Africa
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Colson C, Decamp M, Gruchy N, Coudray N, Ballandonne C, Bracquemart C, Molin A, Mittre H, Takatani R, Jüppner H, Kottler ML, Richard N. High frequency of paternal iso or heterodisomy at chromosome 20 associated with sporadic pseudohypoparathyroidism 1B. Bone 2019; 123:145-152. [PMID: 30905746 PMCID: PMC6637416 DOI: 10.1016/j.bone.2019.03.023] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Revised: 03/04/2019] [Accepted: 03/18/2019] [Indexed: 12/20/2022]
Abstract
Pseudohypoparathyroidism 1B (PHP1B) is caused by maternal epigenetic defects in the imprinted GNAS cluster. PHP1B can follow an autosomal dominant mode of inheritance or occur sporadically (spor-PHP1B). These latter patients present broad methylation changes of two or more differentially methylated regions (DMR) that, when mimicking the paternal allele, raises the suspicious of the occurrence of paternal uniparental disomy of chromosome 20 (upd(20)pat). A cohort of 33 spor-PHP1B patients was screened for upd(20)pat using comparative genomic hybridization with SNP-chip. Methylation analyses were assessed by methylation specific-multiplex ligation-dependent probe amplification. Upd(20)pat was identified in 6 patients, all exhibiting typical paternal methylation pattern compared to normal controls, namely a complete loss of methylation of GNAS A/B:TSS-DMR, negligible methylation at GNAS-AS1:TSS-DMR and GNAS-XL:Ex1-DMR and complete gain of methylation at GNAS-NESP:TSS-DMR. The overall frequency of upd(20) is 18% in our cohort when searched considering both severe and partial loss of imprinting. However, twenty five patients displayed severe methylation pattern and the upd(20)pat frequency reaches 24% when searching in this group. Consequently, up to day, upd(20)pat is the most common anomaly than other genetic alterations in spor-PHP1B patients. Upd(20)pat occurrence is not linked to the parental age in contrast to upd(20)mat, strongly associated with an advanced maternal childbearing age. This study provides criteria to guide further investigations for upd(20)pat needed for an adequate genetic counseling.
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Affiliation(s)
- Cindy Colson
- Normandie Univ, UNICAEN, CHU de Caen Normandie, Department of Genetics, Reference Center fo Rare Diseases of Calcium and Phosphorus Metabolism, EA7450 BioTARGen, 14000 Caen, France
| | - Matthieu Decamp
- Normandie Univ, UNICAEN, CHU de Caen Normandie, Department of Genetics, Reference Center fo Rare Diseases of Calcium and Phosphorus Metabolism, EA7450 BioTARGen, 14000 Caen, France
| | - Nicolas Gruchy
- Normandie Univ, UNICAEN, CHU de Caen Normandie, Department of Genetics, Reference Center fo Rare Diseases of Calcium and Phosphorus Metabolism, EA7450 BioTARGen, 14000 Caen, France
| | - Nadia Coudray
- Normandie Univ, UNICAEN, CHU de Caen Normandie, Department of Genetics, Reference Center fo Rare Diseases of Calcium and Phosphorus Metabolism, EA7450 BioTARGen, 14000 Caen, France
| | - Céline Ballandonne
- Normandie Univ, UNICAEN, CHU de Caen Normandie, Department of Genetics, Reference Center fo Rare Diseases of Calcium and Phosphorus Metabolism, EA7450 BioTARGen, 14000 Caen, France
| | - Claire Bracquemart
- Normandie Univ, UNICAEN, CHU de Caen Normandie, Department of Genetics, Reference Center fo Rare Diseases of Calcium and Phosphorus Metabolism, EA7450 BioTARGen, 14000 Caen, France
| | - Arnaud Molin
- Normandie Univ, UNICAEN, CHU de Caen Normandie, Department of Genetics, Reference Center fo Rare Diseases of Calcium and Phosphorus Metabolism, EA7450 BioTARGen, 14000 Caen, France
| | - Hervé Mittre
- Normandie Univ, UNICAEN, CHU de Caen Normandie, Department of Genetics, Reference Center fo Rare Diseases of Calcium and Phosphorus Metabolism, EA7450 BioTARGen, 14000 Caen, France
| | - Rieko Takatani
- Department of Pediatrics, Graduate School of Medicine, Chiba University, Chiba, Japan
| | - Harald Jüppner
- Endocrine Unit and Pediatric Nephrology Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA
| | - Marie-Laure Kottler
- Normandie Univ, UNICAEN, CHU de Caen Normandie, Department of Genetics, Reference Center fo Rare Diseases of Calcium and Phosphorus Metabolism, EA7450 BioTARGen, 14000 Caen, France
| | - Nicolas Richard
- Normandie Univ, UNICAEN, CHU de Caen Normandie, Department of Genetics, Reference Center fo Rare Diseases of Calcium and Phosphorus Metabolism, EA7450 BioTARGen, 14000 Caen, France.
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Mantovani G, Bastepe M, Monk D, de Sanctis L, Thiele S, Usardi A, Ahmed SF, Bufo R, Choplin T, De Filippo G, Devernois G, Eggermann T, Elli FM, Freson K, García Ramirez A, Germain-Lee EL, Groussin L, Hamdy N, Hanna P, Hiort O, Jüppner H, Kamenický P, Knight N, Kottler ML, Le Norcy E, Lecumberri B, Levine MA, Mäkitie O, Martin R, Martos-Moreno GÁ, Minagawa M, Murray P, Pereda A, Pignolo R, Rejnmark L, Rodado R, Rothenbuhler A, Saraff V, Shoemaker AH, Shore EM, Silve C, Turan S, Woods P, Zillikens MC, Perez de Nanclares G, Linglart A. Diagnosis and management of pseudohypoparathyroidism and related disorders: first international Consensus Statement. Nat Rev Endocrinol 2018; 14:476-500. [PMID: 29959430 PMCID: PMC6541219 DOI: 10.1038/s41574-018-0042-0] [Citation(s) in RCA: 188] [Impact Index Per Article: 31.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
This Consensus Statement covers recommendations for the diagnosis and management of patients with pseudohypoparathyroidism (PHP) and related disorders, which comprise metabolic disorders characterized by physical findings that variably include short bones, short stature, a stocky build, early-onset obesity and ectopic ossifications, as well as endocrine defects that often include resistance to parathyroid hormone (PTH) and TSH. The presentation and severity of PHP and its related disorders vary between affected individuals with considerable clinical and molecular overlap between the different types. A specific diagnosis is often delayed owing to lack of recognition of the syndrome and associated features. The participants in this Consensus Statement agreed that the diagnosis of PHP should be based on major criteria, including resistance to PTH, ectopic ossifications, brachydactyly and early-onset obesity. The clinical and laboratory diagnosis should be confirmed by a molecular genetic analysis. Patients should be screened at diagnosis and during follow-up for specific features, such as PTH resistance, TSH resistance, growth hormone deficiency, hypogonadism, skeletal deformities, oral health, weight gain, glucose intolerance or type 2 diabetes mellitus, and hypertension, as well as subcutaneous and/or deeper ectopic ossifications and neurocognitive impairment. Overall, a coordinated and multidisciplinary approach from infancy through adulthood, including a transition programme, should help us to improve the care of patients affected by these disorders.
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Affiliation(s)
- Giovanna Mantovani
- Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Endocrinology Unit, Department of Clinical Sciences and Community Health, University of Milan, Milan, Italy
| | - Murat Bastepe
- Endocrine Unit, Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - David Monk
- Imprinting and Cancer Group, Cancer Epigenetic and Biology Program (PEBC), Institut d'Investigació Biomedica de Bellvitge (IDIBELL), Barcelona, Spain
| | - Luisa de Sanctis
- Pediatric Endocrinology Unit, Department of Public Health and Pediatric Sciences, University of Torino, Turin, Italy
| | - Susanne Thiele
- Division of Pediatric Endocrinology and Diabetes, Department of Pediatrics, University of Lübeck, Lübeck, Germany
| | - Alessia Usardi
- APHP, Reference Center for Rare Disorders of Calcium and Phosphate Metabolism, Platform of Expertise Paris-Sud for Rare Diseases and Filière OSCAR, Bicêtre Paris Sud Hospital (HUPS), Le Kremlin-Bicêtre, France
- APHP, Endocrinology and diabetes for children, Bicêtre Paris Sud Hospital (HUPS), Le Kremlin-Bicêtre, France
| | - S Faisal Ahmed
- Developmental Endocrinology Research Group, School of Medicine, Dentistry and Nursing, University of Glasgow, Glasgow, UK
| | - Roberto Bufo
- IPOHA, Italian Progressive Osseous Heteroplasia Association, Cerignola, Foggia, Italy
| | - Timothée Choplin
- K20, French PHP and related disorders patient association, Jouars Pontchartrain, France
| | - Gianpaolo De Filippo
- APHP, Department of medicine for adolescents, Bicêtre Paris Sud Hospital (HUPS), Le Kremlin-Bicêtre, France
| | - Guillemette Devernois
- K20, French PHP and related disorders patient association, Jouars Pontchartrain, France
| | - Thomas Eggermann
- Institute of Human Genetics, Medical Faculty, RWTH Aachen University, Aachen, Germany
| | - Francesca M Elli
- Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Endocrinology Unit, Department of Clinical Sciences and Community Health, University of Milan, Milan, Italy
| | - Kathleen Freson
- Department of Cardiovascular Sciences, Center for Molecular and Vascular Biology, Gasthuisberg, University of Leuven, Leuven, Belgium
| | - Aurora García Ramirez
- AEPHP, Spanish PHP and related disorders patient association, Huércal-Overa, Almería, Spain
| | - Emily L Germain-Lee
- Albright Center & Center for Rare Bone Disorders, Division of Pediatric Endocrinology & Diabetes, Connecticut Children's Medical Center, Farmington, CT, USA
- Department of Pediatrics, University of Connecticut School of Medicine, Farmington, CT, USA
| | - Lionel Groussin
- APHP, Department of Endocrinology, Cochin Hospital (HUPC), Paris, France
- University of Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Neveen Hamdy
- Department of Medicine, Division of Endocrinology and Centre for Bone Quality, Leiden University Medical Center, Leiden, Netherlands
| | - Patrick Hanna
- INSERM U1169, Bicêtre Paris Sud, Paris Sud - Paris Saclay University, Le Kremlin-Bicêtre, France
| | - Olaf Hiort
- Division of Pediatric Endocrinology and Diabetes, Department of Pediatrics, University of Lübeck, Lübeck, Germany
| | - Harald Jüppner
- Endocrine Unit, Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Peter Kamenický
- APHP, Reference Center for Rare Disorders of Calcium and Phosphate Metabolism, Platform of Expertise Paris-Sud for Rare Diseases and Filière OSCAR, Bicêtre Paris Sud Hospital (HUPS), Le Kremlin-Bicêtre, France
- APHP, Department of Endocrinology and Reproductive Diseases, Bicêtre Paris Sud Hospital (HUPS), Le Kremlin-Bicêtre, France
- INSERM U1185, Paris Sud - Paris Saclay University, Le Kremlin-Bicêtre, France
| | - Nina Knight
- UK acrodysostosis patients' group, London, UK
| | - Marie-Laure Kottler
- Department of Genetics, Reference Centre for Rare Disorders of Calcium and Phosphate Metabolism, Caen University Hospital, Caen, France
- BIOTARGEN, UNICAEN, Normandie University, Caen, France
| | - Elvire Le Norcy
- University of Paris Descartes, Sorbonne Paris Cité, Paris, France
- APHP, Department of Odontology, Bretonneau Hospital (PNVS), Paris, France
| | - Beatriz Lecumberri
- Department of Endocrinology and Nutrition, La Paz University Hospital, Madrid, Spain
- Department of Medicine, Autonomous University of Madrid (UAM), Madrid, Spain
- Endocrine Diseases Research Group, Hospital La Paz Institute for Health Research (IdiPAZ), Madrid, Spain
| | - Michael A Levine
- Division of Endocrinology and Diabetes and Center for Bone Health, Children's Hospital of Philadelphia and Department of Pediatrics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Outi Mäkitie
- Children's Hospital, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - Regina Martin
- Osteometabolic Disorders Unit, Hormone and Molecular Genetics Laboratory (LIM/42), Endocrinology Division, Hospital das Clínicas HCFMUSP, Faculty of Medicine, University of Sao Paulo, Sao Paulo, Brazil
| | - Gabriel Ángel Martos-Moreno
- Department of Endocrinology, Hospital Infantil Universitario Niño Jesús, CIBERobn, ISCIII, Madrid, Spain
- Department of Pediatrics, Autonomous University of Madrid (UAM), Madrid, Spain
- Endocrine Diseases Research Group, Hospital La Princesa Institute for Health Research (IIS La Princesa), Madrid, Spain
| | | | - Philip Murray
- Department of Paediatric Endocrinology, Royal Manchester Children's Hospital, Manchester University NHS Foundation Trust, Manchester, UK
| | - Arrate Pereda
- Molecular (Epi)Genetics Laboratory, BioAraba National Health Institute, Hospital Universitario Araba-Txagorritxu, Vitoria-Gasteiz, Alava, Spain
| | | | - Lars Rejnmark
- Department of Endocrinology and Internal Medicine, Aarhus University Hospital, Aarhus, Denmark
| | - Rebecca Rodado
- AEPHP, Spanish PHP and related disorders patient association, Huércal-Overa, Almería, Spain
| | - Anya Rothenbuhler
- APHP, Reference Center for Rare Disorders of Calcium and Phosphate Metabolism, Platform of Expertise Paris-Sud for Rare Diseases and Filière OSCAR, Bicêtre Paris Sud Hospital (HUPS), Le Kremlin-Bicêtre, France
- APHP, Endocrinology and diabetes for children, Bicêtre Paris Sud Hospital (HUPS), Le Kremlin-Bicêtre, France
| | - Vrinda Saraff
- Department of Endocrinology and Diabetes, Birmingham Children's Hospital, Birmingham, UK
| | - Ashley H Shoemaker
- Pediatric Endocrinology and Diabetes, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Eileen M Shore
- Departments of Orthopaedic Surgery and Genetics, Center for Research in FOP and Related Disorders, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Caroline Silve
- APHP, Service de Biochimie et Génétique Moléculaires, Hôpital Cochin, Paris, France
| | - Serap Turan
- Department of Pediatrics, Division of Endocrinology and Diabetes, Marmara University, Istanbul, Turkey
| | | | - M Carola Zillikens
- Department of Internal Medicine, Bone Center Erasmus MC - University Medical Center Rotterdam, Rotterdam, Netherlands
| | - Guiomar Perez de Nanclares
- Molecular (Epi)Genetics Laboratory, BioAraba National Health Institute, Hospital Universitario Araba-Txagorritxu, Vitoria-Gasteiz, Alava, Spain.
| | - Agnès Linglart
- APHP, Reference Center for Rare Disorders of Calcium and Phosphate Metabolism, Platform of Expertise Paris-Sud for Rare Diseases and Filière OSCAR, Bicêtre Paris Sud Hospital (HUPS), Le Kremlin-Bicêtre, France.
- APHP, Endocrinology and diabetes for children, Bicêtre Paris Sud Hospital (HUPS), Le Kremlin-Bicêtre, France.
- INSERM U1169, Bicêtre Paris Sud, Paris Sud - Paris Saclay University, Le Kremlin-Bicêtre, France.
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10
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Affiliation(s)
- Morri E Markowitz
- Department of Pediatrics, Albert Einstein College of Medicine, Bronx, NY
| | - Lisa Underland
- Department of Pediatrics, Albert Einstein College of Medicine, Bronx, NY
| | - Robert Gensure
- Department of Pediatrics, Albert Einstein College of Medicine, Bronx, NY
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11
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Takatani R, Molinaro A, Grigelioniene G, Tafaj O, Watanabe T, Reyes M, Sharma A, Singhal V, Raymond FL, Linglart A, Jüppner H. Analysis of Multiple Families With Single Individuals Affected by Pseudohypoparathyroidism Type Ib (PHP1B) Reveals Only One Novel Maternally Inherited GNAS Deletion. J Bone Miner Res 2016; 31:796-805. [PMID: 26479409 PMCID: PMC4826817 DOI: 10.1002/jbmr.2731] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/03/2015] [Revised: 10/05/2015] [Accepted: 10/12/2015] [Indexed: 01/22/2023]
Abstract
Proximal tubular resistance to parathyroid hormone (PTH) resulting in hypocalcemia and hyperphosphatemia are preeminent abnormalities in pseudohypoparathyroidism type Ib (PHP1B), but resistance toward other hormones as well as variable features of Albright's Hereditary Osteodystrophy (AHO) can occur also. Genomic DNA from PHP1B patients shows epigenetic changes at one or multiple differentially methylated regions (DMRs) within GNAS, the gene encoding Gαs and splice variants thereof. In the autosomal dominant disease variant, these methylation abnormalities are caused by deletions in STX16 or GNAS on the maternal allele. The molecular defect(s) leading to sporadic PHP1B (sporPHP1B) remains in most cases unknown and we therefore analyzed 60 sporPHP1B patients and available family members by microsatellite markers, single nucleotide polymorphisms (SNPs), multiplex ligation-dependent probe amplification (MLPA), and methylation-specific MLPA (MS-MLPA). All investigated cases revealed broad GNAS methylation changes, but no evidence for inheritance of two paternal chromosome 20q alleles. Some patients with partial epigenetic modifications in DNA from peripheral blood cells showed more complete GNAS methylation changes when testing their immortalized lymphoblastoid cells. Analysis of siblings and children of sporPHP1B patients provided no evidence for an abnormal mineral ion regulation and no changes in GNAS methylation. Only one patient revealed, based on MLPA and microsatellite analyses, evidence for an allelic loss, which resulted in the discovery of two adjacent, maternally inherited deletions (37,597 and 1427 bp, respectively) that remove the area between GNAS antisense exons 3 and 5, including exon NESP. Our findings thus emphasize that the region comprising antisense exons 3 and 4 is required for establishing all maternal GNAS methylation imprints. The genetic defect(s) leading in sporPHP1B to epigenetic GNAS changes and thus PTH-resistance remains unknown, but it seems unlikely that this disease variant is caused by heterozygous inherited or de novo mutations involving GNAS.
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Affiliation(s)
- Rieko Takatani
- Endocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Angelo Molinaro
- Endocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Giedre Grigelioniene
- Endocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Olta Tafaj
- Endocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Tomoyuki Watanabe
- Endocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Monica Reyes
- Endocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Amita Sharma
- Pediatric Nephrology Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Vibha Singhal
- Pediatric Endocrinology Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - F Lucy Raymond
- Department of Medical Genetics, Cambridge Institute for Medical Research, University of Cambridge, Cambridge, UK
| | - Agnès Linglart
- Paediatric Endocrinology and Diabetology, French National Reference Centre for Rare Disorders of Mineral Metabolism, AP-HP Hôpital Bicêtre Paris Sud, le Kremlin-Bicêtre, France
- Faculté de Médecine, Université Paris Sud, le Kremlin-Bicêtre, France
| | - Harald Jüppner
- Endocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
- Pediatric Nephrology Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
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12
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Tascau L, Gardner T, Anan H, Yongpravat C, Cardozo CP, Bauman WA, Lee FY, Oh DS, Tawfeek HA. Activation of Protein Kinase A in Mature Osteoblasts Promotes a Major Bone Anabolic Response. Endocrinology 2016; 157:112-26. [PMID: 26488807 DOI: 10.1210/en.2015-1614] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Protein kinase A (PKA) regulates osteoblast cell function in vitro and is activated by important bone mass modulating agents. We determined whether PKA activation in osteoblasts is sufficient to mediate a bone anabolic response. Thus, a mouse model conditionally expressing a constitutively active PKA (CA-PKA) in osteoblasts (CA-PKA-OB mouse) was developed by crossing a 2.3-kb α1 (I)-collagen promoter-Cre mouse with a floxed-CA-PKA mouse. Primary osteoblasts from the CA-PKA-OB mice exhibited higher basal PKA activity than those from control mice. Microcomputed tomographic analysis revealed that CA-PKA-OB female mice had an 8.6-fold increase in femoral but only 1.16-fold increase in lumbar 5 vertebral bone volume/total volume. Femur cortical thickness and volume were also higher in the CA-PKA-OB mice. In contrast, alterations in many femoral microcomputed tomographic parameters in male CA-PKA-OB mice were modest. Interestingly, the 3-dimensional structure model index was substantially lower both in femur and lumbar 5 of male and female CA-PKA-OB mice, reflecting an increase in the plate to rod-like structure ratio. In agreement, femurs from female CA-PKA-OB mice had greater load to failure and were stiffer compared with those of control mice. Furthermore, the CA-PKA-OB mice had higher levels of serum bone turnover markers and increased osteoblast and osteoclast numbers per total tissue area compared with control animals. In summary, constitutive activation of PKA in osteoblasts is sufficient to increase bone mass and favorably modify bone architecture and improve mechanical properties. PKA activation in mature osteoblasts is, therefore, an important target for designing anabolic drugs for treating diseases with bone loss.
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Affiliation(s)
- Liana Tascau
- National Center for the Medical Consequences of Spinal Cord Injury (C.P.C., W.A.B., H.A.T.), James J. Peters VA Medical Center, Bronx, New York 10468; Center for Orthopaedic Research (T.G., C.Y., F.Y.L.), College of Dental Medicine (D.S.O.), and Department of Molecular Medicine (L.T.), Columbia University, and Departments of Medicine (C.P.C., W.A.B., H.A.T.), Rehabilitation Medicine (C.P.C., W.A.B.), and Pharmacology and Systems Therapeutics (C.P.C.), The Icahn School of Medicine at Mount Sinai, New York, New York 10029; and Sacred Heart Hospital/Temple University (H.A.), Allentown, Pennsylvania 16102
| | - Thomas Gardner
- National Center for the Medical Consequences of Spinal Cord Injury (C.P.C., W.A.B., H.A.T.), James J. Peters VA Medical Center, Bronx, New York 10468; Center for Orthopaedic Research (T.G., C.Y., F.Y.L.), College of Dental Medicine (D.S.O.), and Department of Molecular Medicine (L.T.), Columbia University, and Departments of Medicine (C.P.C., W.A.B., H.A.T.), Rehabilitation Medicine (C.P.C., W.A.B.), and Pharmacology and Systems Therapeutics (C.P.C.), The Icahn School of Medicine at Mount Sinai, New York, New York 10029; and Sacred Heart Hospital/Temple University (H.A.), Allentown, Pennsylvania 16102
| | - Hussein Anan
- National Center for the Medical Consequences of Spinal Cord Injury (C.P.C., W.A.B., H.A.T.), James J. Peters VA Medical Center, Bronx, New York 10468; Center for Orthopaedic Research (T.G., C.Y., F.Y.L.), College of Dental Medicine (D.S.O.), and Department of Molecular Medicine (L.T.), Columbia University, and Departments of Medicine (C.P.C., W.A.B., H.A.T.), Rehabilitation Medicine (C.P.C., W.A.B.), and Pharmacology and Systems Therapeutics (C.P.C.), The Icahn School of Medicine at Mount Sinai, New York, New York 10029; and Sacred Heart Hospital/Temple University (H.A.), Allentown, Pennsylvania 16102
| | - Charlie Yongpravat
- National Center for the Medical Consequences of Spinal Cord Injury (C.P.C., W.A.B., H.A.T.), James J. Peters VA Medical Center, Bronx, New York 10468; Center for Orthopaedic Research (T.G., C.Y., F.Y.L.), College of Dental Medicine (D.S.O.), and Department of Molecular Medicine (L.T.), Columbia University, and Departments of Medicine (C.P.C., W.A.B., H.A.T.), Rehabilitation Medicine (C.P.C., W.A.B.), and Pharmacology and Systems Therapeutics (C.P.C.), The Icahn School of Medicine at Mount Sinai, New York, New York 10029; and Sacred Heart Hospital/Temple University (H.A.), Allentown, Pennsylvania 16102
| | - Christopher P Cardozo
- National Center for the Medical Consequences of Spinal Cord Injury (C.P.C., W.A.B., H.A.T.), James J. Peters VA Medical Center, Bronx, New York 10468; Center for Orthopaedic Research (T.G., C.Y., F.Y.L.), College of Dental Medicine (D.S.O.), and Department of Molecular Medicine (L.T.), Columbia University, and Departments of Medicine (C.P.C., W.A.B., H.A.T.), Rehabilitation Medicine (C.P.C., W.A.B.), and Pharmacology and Systems Therapeutics (C.P.C.), The Icahn School of Medicine at Mount Sinai, New York, New York 10029; and Sacred Heart Hospital/Temple University (H.A.), Allentown, Pennsylvania 16102
| | - William A Bauman
- National Center for the Medical Consequences of Spinal Cord Injury (C.P.C., W.A.B., H.A.T.), James J. Peters VA Medical Center, Bronx, New York 10468; Center for Orthopaedic Research (T.G., C.Y., F.Y.L.), College of Dental Medicine (D.S.O.), and Department of Molecular Medicine (L.T.), Columbia University, and Departments of Medicine (C.P.C., W.A.B., H.A.T.), Rehabilitation Medicine (C.P.C., W.A.B.), and Pharmacology and Systems Therapeutics (C.P.C.), The Icahn School of Medicine at Mount Sinai, New York, New York 10029; and Sacred Heart Hospital/Temple University (H.A.), Allentown, Pennsylvania 16102
| | - Francis Y Lee
- National Center for the Medical Consequences of Spinal Cord Injury (C.P.C., W.A.B., H.A.T.), James J. Peters VA Medical Center, Bronx, New York 10468; Center for Orthopaedic Research (T.G., C.Y., F.Y.L.), College of Dental Medicine (D.S.O.), and Department of Molecular Medicine (L.T.), Columbia University, and Departments of Medicine (C.P.C., W.A.B., H.A.T.), Rehabilitation Medicine (C.P.C., W.A.B.), and Pharmacology and Systems Therapeutics (C.P.C.), The Icahn School of Medicine at Mount Sinai, New York, New York 10029; and Sacred Heart Hospital/Temple University (H.A.), Allentown, Pennsylvania 16102
| | - Daniel S Oh
- National Center for the Medical Consequences of Spinal Cord Injury (C.P.C., W.A.B., H.A.T.), James J. Peters VA Medical Center, Bronx, New York 10468; Center for Orthopaedic Research (T.G., C.Y., F.Y.L.), College of Dental Medicine (D.S.O.), and Department of Molecular Medicine (L.T.), Columbia University, and Departments of Medicine (C.P.C., W.A.B., H.A.T.), Rehabilitation Medicine (C.P.C., W.A.B.), and Pharmacology and Systems Therapeutics (C.P.C.), The Icahn School of Medicine at Mount Sinai, New York, New York 10029; and Sacred Heart Hospital/Temple University (H.A.), Allentown, Pennsylvania 16102
| | - Hesham A Tawfeek
- National Center for the Medical Consequences of Spinal Cord Injury (C.P.C., W.A.B., H.A.T.), James J. Peters VA Medical Center, Bronx, New York 10468; Center for Orthopaedic Research (T.G., C.Y., F.Y.L.), College of Dental Medicine (D.S.O.), and Department of Molecular Medicine (L.T.), Columbia University, and Departments of Medicine (C.P.C., W.A.B., H.A.T.), Rehabilitation Medicine (C.P.C., W.A.B.), and Pharmacology and Systems Therapeutics (C.P.C.), The Icahn School of Medicine at Mount Sinai, New York, New York 10029; and Sacred Heart Hospital/Temple University (H.A.), Allentown, Pennsylvania 16102
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13
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Lee S, Mannstadt M, Guo J, Kim SM, Yi HS, Khatri A, Dean T, Okazaki M, Gardella TJ, Jüppner H. A Homozygous [Cys25]PTH(1-84) Mutation That Impairs PTH/PTHrP Receptor Activation Defines a Novel Form of Hypoparathyroidism. J Bone Miner Res 2015; 30:1803-13. [PMID: 25891861 PMCID: PMC4580526 DOI: 10.1002/jbmr.2532] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/05/2015] [Revised: 03/30/2015] [Accepted: 04/13/2015] [Indexed: 11/10/2022]
Abstract
Hypocalcemia and hyperphosphatemia are encountered in idiopathic hypoparathyroidism (IHP) and pseudohypoparathyroidism type Ib (PHP1B). In contrast to PHP1B, which is caused by resistance toward parathyroid hormone (PTH), the genetic defects leading to IHP impair production of this important regulator of mineral ion homeostasis. So far, only five PTH mutations were shown to cause IHP, each of which is located in the hormone's pre-pro leader segment and thus impair hormone secretion. In three siblings affected by IHP, we now identified a homozygous arginine-to-cysteine mutation at position 25 (R25C) of the mature PTH(1-84) polypeptide; heterozygous family members are healthy. Depending on the assay used for evaluating these patients, plasma PTH levels were either low or profoundly elevated, thus leading to ambiguities regarding the underlying diagnosis, namely IHP or PHP1B. Consistent with increased PTH levels, recombinant [Cys25]PTH(1-84) and wild-type PTH(1-84) were secreted equally well by transfected COS-7 cells. However, synthetic [Cys25]PTH(1-34) was found to have a lower binding affinity for the PTH receptor type-1 (PTH1R) than PTH(1-34) and consequently a lower efficiency for stimulating cAMP formation in cells expressing this receptor. Consistent with these in vitro findings, long-term infusion of [Cys25]PTH(1-34) resulted only in minimal calcemic and phosphaturic responses, despite readily detectable levels of [Cys25]PTH(1-34) in plasma. The mineral ion abnormalities observed in the three IHP patients are thus most likely caused by the inherited homozygous missense PTH mutation, which reduces bioactivity of the secreted hormone. Based on these findings, screening for PTH(1-84) mutations should be considered when clinical and laboratory findings are consistent with PHP1B, but GNAS methylation changes have been excluded. Differentiating between IHP and PHP1B has considerable implications for genetic counseling, therapy, and long-term outcome because treatment of IHP patients with inappropriately high doses of active vitamin D and calcium can contribute to development of nephrocalcinosis and chronic kidney disease.
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Affiliation(s)
- Sihoon Lee
- Department of Internal Medicine and Laboratory of Molecular Endocrinology, Gachon University School of Medicine, Incheon, South Korea
| | - Michael Mannstadt
- Endocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Jun Guo
- Endocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Seul Min Kim
- Department of Internal Medicine and Laboratory of Molecular Endocrinology, Gachon University School of Medicine, Incheon, South Korea
| | - Hyon-Seung Yi
- Department of Internal Medicine and Laboratory of Molecular Endocrinology, Gachon University School of Medicine, Incheon, South Korea
| | - Ashok Khatri
- Endocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Thomas Dean
- Endocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Makoto Okazaki
- Endocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Thomas J Gardella
- Endocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Harald Jüppner
- Endocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA.,Pediatric Nephrology Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
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14
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Abstract
The GNAS complex locus encodes the alpha-subunit of the stimulatory G protein (Gsα), a ubiquitous signaling protein mediating the actions of many hormones, neurotransmitters, and paracrine/autocrine factors via generation of the second messenger cAMP. GNAS gives rise to other gene products, most of which exhibit exclusively monoallelic expression. In contrast, Gsα is expressed biallelically in most tissues; however, paternal Gsα expression is silenced in a small number of tissues through as-yet-poorly understood mechanisms that involve differential methylation within GNAS. Gsα-coding GNAS mutations that lead to diminished Gsα expression and/or function result in Albright's hereditary osteodystrophy (AHO) with or without hormone resistance, i.e., pseudohypoparathyroidism type-Ia/Ic and pseudo-pseudohypoparathyroidism, respectively. Microdeletions that alter GNAS methylation and, thereby, diminish Gsα expression in tissues in which the paternal Gsα allele is normally silenced also cause hormone resistance, which occurs typically in the absence of AHO, a disorder termed pseudohypoparathyroidism type-Ib. Mutations of GNAS that cause constitutive Gsα signaling are found in patients with McCune-Albright syndrome, fibrous dysplasia of bone, and different endocrine and non-endocrine tumors. Clinical features of these diseases depend significantly on the parental allelic origin of the GNAS mutation, reflecting the tissue-specific paternal Gsα silencing. In this article, we review the pathogenesis and the phenotypes of these human diseases.
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Affiliation(s)
- Serap Turan
- Pediatric Endocrinology, Marmara University School of Medicine Hospital, Istanbul, Turkey;
| | - Murat Bastepe
- Endocrine Unit, Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114;
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15
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Molinaro A, Tiosano D, Takatani R, Chrysis D, Russell W, Koscielniak N, Kottler ML, Agretti P, De Marco G, Ahtiainen P, Christov M, Mäkitie O, Tonacchera M, Jüppner H. TSH elevations as the first laboratory evidence for pseudohypoparathyroidism type Ib (PHP-Ib). J Bone Miner Res 2015; 30:906-12. [PMID: 25403028 PMCID: PMC4401615 DOI: 10.1002/jbmr.2408] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/25/2014] [Revised: 11/05/2014] [Accepted: 11/10/2014] [Indexed: 01/21/2023]
Abstract
Hypocalcemia and hyperphosphatemia because of resistance toward parathyroid hormone (PTH) in the proximal renal tubules are the most prominent abnormalities in patients affected by pseudohypoparathyroidism type Ib (PHP-Ib). In this rare disorder, which is caused by GNAS methylation changes, resistance can occur toward other hormones, such as thyroid-stimulating hormone (TSH), that mediate their actions through G protein-coupled receptors. However, these additional laboratory abnormalities are usually not recognized until PTH-resistant hypocalcemia becomes clinically apparent. We now describe four pediatric patients, first diagnosed with subclinical or overt hypothyroidism between the ages of 0.2 and 15 years, who developed overt PTH-resistance 3 to 20 years later. Although anti-thyroperoxidase (anti-TPO) antibodies provided a plausible explanation for hypothyroidism in one of these patients, this and two other patients revealed broad epigenetic GNAS abnormalities, which included loss of methylation (LOM) at exons AS, XL, and A/B, and gain of methylation at exon NESP55; ie, findings consistent with PHP-Ib. LOM at GNAS exon A/B alone led in the fourth patient to the identification of a maternally inherited 3-kb STX16 deletion, a well-established cause of autosomal dominant PHP-Ib. Although GNAS methylation changes were not detected in additional pediatric and adult patients with subclinical hypothyroidism (23 pediatric and 39 adult cases), hypothyroidism can obviously be the initial finding in PHP-Ib patients. One should therefore consider measuring PTH, along with calcium and phosphate, in patients with unexplained hypothyroidism for extended periods of time to avoid hypocalcemia and associated clinical complications.
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Affiliation(s)
- Angelo Molinaro
- Endocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
- Endocrinology Unit, Department of Clinical and Experimental Medicine, University of Pisa, University Hospital of Pisa, Pisa, Italy
| | - Dov Tiosano
- Division of Pediatric Endocrinology, Meyer Children's Hospital, Rambam Health Care Campus, Haifa, Israel
| | - Rieko Takatani
- Endocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Dionisios Chrysis
- Department of Pediatrics, Medical School, University of Patras, Patras, Greece
| | - William Russell
- Division of Pediatric Endocrinology and Diabetes, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Nikolas Koscielniak
- Program in Occupational Therapy, Washington University School of Medicine, St. Louis, MO, USA
| | - Marie-Laure Kottler
- Centre Hospitalier Universitaire de Caen, Department of Genetics, Reference Centre for Rare Disorders of Calcium and Phosphorus Metabolism, F-14000 Caen, France
| | - Patrizia Agretti
- Endocrinology Unit, Department of Clinical and Experimental Medicine, University of Pisa, University Hospital of Pisa, Pisa, Italy
| | - Giuseppina De Marco
- Endocrinology Unit, Department of Clinical and Experimental Medicine, University of Pisa, University Hospital of Pisa, Pisa, Italy
| | - Petteri Ahtiainen
- Central Finland Central Hospital, Jyväskylä, and Kuopio University Hospital, Kuopio, Finland
| | - Marta Christov
- Endocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Outi Mäkitie
- Hospital for Children and Adolescents, University of Helsinki, and Folkhälsan Institute of Genetics, Helsinki, Finland
| | - Massimo Tonacchera
- Endocrinology Unit, Department of Clinical and Experimental Medicine, University of Pisa, University Hospital of Pisa, Pisa, Italy
| | - Harald Jüppner
- Endocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
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Perez-Nanclares G, Velayos T, Vela A, Muñoz-Torres M, Castaño L. Pseudohypoparathyroidism type Ib associated with novel duplications in the GNAS locus. PLoS One 2015; 10:e0117691. [PMID: 25710380 PMCID: PMC4339194 DOI: 10.1371/journal.pone.0117691] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2014] [Accepted: 12/30/2014] [Indexed: 12/18/2022] Open
Abstract
Context Pseudohypoparathyroidism type 1b (PHP-Ib) is characterized by renal resistance to PTH (and, sometimes, a mild resistance to TSH) and absence of any features of Albright's hereditary osteodystrophy. Patients with PHP-Ib suffer of defects in the methylation pattern of the complex GNAS locus. PHP-Ib can be either sporadic or inherited in an autosomal dominant pattern. Whereas familial PHP-Ib is well characterized at the molecular level, the genetic cause of sporadic PHP-Ib cases remains elusive, although some molecular mechanisms have been associated with this subtype. Objective The aim of the study was to investigate the molecular and imprinting defects in the GNAS locus in two unrelated patients with PHP-Ib. Design We have analyzed the GNAS locus by direct sequencing, Methylation-Specific Multiplex Ligation-dependent Probe Amplification, microsatellites, Quantitative Multiplex PCR of Short Fluorescent fragments and array-Comparative Genomic Hybridization studies in order to characterize two unrelated families with clinical features of PHP-Ib. Results We identified two duplications in the GNAS region in two patients with PHP-Ib: one of them, comprising ∼320 kb, occurred ‘de novo’ in the patient, whereas the other one, of ∼179 kb in length, was inherited from the maternal allele. In both cases, no other known genetic cause was observed. Conclusion In this article, we describe the to-our-knowledge biggest duplications reported so far in the GNAS region. Both are associated to PHP-Ib, one of them occurring ‘de novo’ and the other one being maternally inherited.
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Affiliation(s)
- Gustavo Perez-Nanclares
- Endocrinology and Diabetes Research Group, Hospital Universitario Cruces, BioCruces, CIBERER, CIBERDEM, UPV-EHU, Barakaldo, Basque Country, Spain
| | - Teresa Velayos
- Endocrinology and Diabetes Research Group, Hospital Universitario Cruces, BioCruces, CIBERER, CIBERDEM, UPV-EHU, Barakaldo, Basque Country, Spain
| | - Amaya Vela
- Endocrinology and Diabetes Research Group, Hospital Universitario Cruces, BioCruces, CIBERER, CIBERDEM, UPV-EHU, Barakaldo, Basque Country, Spain
| | - Manuel Muñoz-Torres
- Clinical Management Unit of Endocrinology and Nutrition, Hospital Universitario San Cecilio, Instituto de Investigacion Biosanitaria de Granada, Granada, Spain
| | - Luis Castaño
- Endocrinology and Diabetes Research Group, Hospital Universitario Cruces, BioCruces, CIBERER, CIBERDEM, UPV-EHU, Barakaldo, Basque Country, Spain
- * E-mail:
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17
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Mutations in pseudohypoparathyroidism 1a and pseudopseudohypoparathyroidism in ethnic Chinese. PLoS One 2014; 9:e90640. [PMID: 24651309 PMCID: PMC3961212 DOI: 10.1371/journal.pone.0090640] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2013] [Accepted: 02/03/2014] [Indexed: 11/30/2022] Open
Abstract
An inactivating mutation in the GNAS gene causes either pseudohypoparathyroidism 1a (PHP1A) when it is maternally inherited or pseudopseudohypoparathyroidism (PPHP) when it is paternally inherited. We investigated clinical manifestations and mutations of the GNAS gene in ethnic Chinese patients with PHP1A or PPHP. Seven patients from 5 families including 4 girls and 2 boys with PHP1A and 1 girl with PPHP were studied. All PHP1A patients had mental retardation. They were treated with calcitriol and CaCO3 with regular monitoring of serum Ca levels, urinary Ca/Cr ratios, and renal sonography. Among them, 5 patients also had primary hypothyroidism suggesting TSH resistance. One female patient had a renal stone which was treated with extracorporeal shockwave lithotripsy. She had an increased urinary Ca/Cr ratio of 0.481 mg/mg when the stone was detected. We detected mutations using PCR and sequencing as well as analysed a splice acceptor site mutation using RT-PCR, sequencing, and minigene construct. We detected 5 mutations: c.85C>T (Q29*), c.103C>T (Q35*), c.840-2A>G (R280Sfs*21), c.1027_1028delGA (D343*), and c.1174G>A (E392K). Mutations c.840-2A>G and c.1027_1028delGA were novel. The c.840-2A>G mutation at the splice acceptor site of intron 10 caused retention of intron 10 in the minigene construct but skipping of exon 11 in the peripheral blood cells. The latter was the most probable mechanism which caused a frameshift, changing Arg to Ser at residue 280 and invoking a premature termination of translation at codon 300 (R280Sfs*21). Five GNAS mutations in ethnic Chinese with PHP1A and PPHP were reported. Two of them were novel. Mutation c.840-2A>G destroyed a spice acceptor site and caused exon skipping. Regular monitoring and adjustment in therapy are mandatory to achieve optimal therapeutic effects and avoid nephrolithiasis in patients with PHP1A.
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Maupetit-Méhouas S, Azzi S, Steunou V, Sakakini N, Silve C, Reynes C, Perez de Nanclares G, Keren B, Chantot S, Barlier A, Linglart A, Netchine I. Simultaneous Hyper- and Hypomethylation at Imprinted Loci in a Subset of Patients withGNASEpimutations Underlies a Complex and Different Mechanism of Multilocus Methylation Defect in Pseudohypoparathyroidism Type 1b. Hum Mutat 2013; 34:1172-80. [DOI: 10.1002/humu.22352] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2013] [Accepted: 04/29/2013] [Indexed: 12/31/2022]
Affiliation(s)
- Stéphanie Maupetit-Méhouas
- Inserm U986, Hôpital Bicêtre-Paris-Sud; Le Kremlin-Bicêtre; France
- Center of reference for rare disorders of the calcium and phosphorus metabolism; Hôpital Bicêtre-Paris-Sud; Le Kremlin-Bicêtre France
| | - Salah Azzi
- Saint Antoine research center INSERM UMR-S938 Yves Le Bouc team, Pierre & Marie Curie-Paris 6 University, Endocrine Laboratory of functional Explorations, APHP; Armand Trousseau Hospital; Paris France
| | - Virginie Steunou
- Saint Antoine research center INSERM UMR-S938 Yves Le Bouc team, Pierre & Marie Curie-Paris 6 University, Endocrine Laboratory of functional Explorations, APHP; Armand Trousseau Hospital; Paris France
| | - Nathalie Sakakini
- Laboratory of Molecular Biology; University Hospital of Marseille - AP-HM - Conception; Marseille France
- CRN2M; UMR7286-CNRS, Aix-Marseille University, Marseille Cedex 15; Marseille France
| | - Caroline Silve
- Inserm U986, Hôpital Bicêtre-Paris-Sud; Le Kremlin-Bicêtre; France
- Center of reference for rare disorders of the calcium and phosphorus metabolism; Hôpital Bicêtre-Paris-Sud; Le Kremlin-Bicêtre France
| | - Christelle Reynes
- Laboratoire de Physique Industrielle et Traitement de l'Information; EA 2415, UFR Pharmacie-Univ. Montpellier 1, Montpellier Cedex 5; France
| | | | - Boris Keren
- Department of Genetics, APHP; CRicm UPMC Inserm UMRS975/CNRS UMR7225, Pitié-Salpêtrière Hospital; Paris France
| | - Sandra Chantot
- Laboratoire de génétique moléculaire, APHP; Hôpital Armand Trousseau; Paris France
| | - Anne Barlier
- Laboratory of Molecular Biology; University Hospital of Marseille - AP-HM - Conception; Marseille France
- CRN2M; UMR7286-CNRS, Aix-Marseille University, Marseille Cedex 15; Marseille France
| | - Agnès Linglart
- Inserm U986, Hôpital Bicêtre-Paris-Sud; Le Kremlin-Bicêtre; France
- Center of reference for rare disorders of the calcium and phosphorus metabolism; Hôpital Bicêtre-Paris-Sud; Le Kremlin-Bicêtre France
- Endocrinology and Diabetology for Children; APHP, Hôpital Bicêtre-Paris-Sud, University Paris 11; Le Kremlin-Bicêtre France
| | - Irène Netchine
- Saint Antoine research center INSERM UMR-S938 Yves Le Bouc team, Pierre & Marie Curie-Paris 6 University, Endocrine Laboratory of functional Explorations, APHP; Armand Trousseau Hospital; Paris France
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Fernández-Rebollo E, Lecumberri B, Gaztambide S, Martinez-Indart L, Perez de Nanclares G, Castaño L. Endocrine profile and phenotype-(epi)genotype correlation in Spanish patients with pseudohypoparathyroidism. J Clin Endocrinol Metab 2013; 98:E996-1006. [PMID: 23533243 DOI: 10.1210/jc.2012-4164] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
CONTEXT Recent advances in genetics and epigenetics have revealed an overlap between molecular and clinical features of pseudohypoparathyroidism (PHP) subtypes, broadening the previous spectrum of PHP genotype-phenotype correlations and indicating limitations of the current classification of the disease. OBJECTIVES The aim of the study was to screen patients with clinical diagnoses of PHP type I or pseudo-PHP for underlying molecular defects and explore possible correlations between molecular findings and clinical features. PATIENTS AND METHODS We investigated the GNAS locus at the molecular level in 72 affected patients (46 women and 26 men) from 56 nonrelated families. Clinical data were obtained for 63 of these patients (38 women and 25 men). RESULTS The molecular analysis showed that 35 patients carried structural mutations, 32 had loss of methylation, and 2 had a 2q37 deletion but did not reveal any (epi)mutation for 3 patients. Comparing these results and the clinical data, we observed that a younger age at diagnosis was associated with structural defects at the GNAS gene and epigenetic defects with a diagnosis later in life (9.19 ± 1.64 vs 24.57 ± 2.28 years, P < .0001). CONCLUSIONS This first global review of PHP in Spain highlights the importance of a detailed clinical and genetic study of each patient and the integrated analysis of the findings from the two approaches. It may also help geneticists and clinicians to raise the suspicion of PHP earlier, reach more accurate diagnoses, and provide patients with PHP and their families with useful genetic information and counseling, thereby improving outcomes and quality of life.
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Affiliation(s)
- Eduardo Fernández-Rebollo
- Endocrinology and Diabetes Research Group, Hospital Universitario de Cruces, Universidad del País Vasco-Euskal Herriko Unibertsitatea, 48903 Barakaldo, Spain
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Turan S, Bastepe M. The GNAS complex locus and human diseases associated with loss-of-function mutations or epimutations within this imprinted gene. Horm Res Paediatr 2013; 80:229-41. [PMID: 24107509 PMCID: PMC3874326 DOI: 10.1159/000355384] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/21/2012] [Accepted: 08/29/2013] [Indexed: 12/14/2022] Open
Abstract
GNAS is a complex imprinted locus leading to several different gene products that show exclusive monoallelic expression. GNAS also encodes the α-subunit of the stimulatory G protein (Gsα), a ubiquitously expressed signaling protein that is essential for the actions of many hormones and other endogenous molecules. Gsα is expressed biallelically in most tissues but its expression is silenced from the paternal allele in a small number of tissues. The tissue-specific paternal silencing of Gsα results in different parent-of-origin-specific phenotypes in patients who carry inactivating GNAS mutations. In this paper, we review the GNAS complex locus and discuss how disruption of Gsα expression and the expression of other GNAS products shape the phenotypes of human disorders caused by mutations in this gene.
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Affiliation(s)
- Serap Turan
- Pediatric Endocrinology, Marmara University School of Medicine Hospital, Istanbul, Turkey
| | - Murat Bastepe
- Endocrine Unit, Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, MA
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Abstract
PURPOSE OF REVIEW To provide the reader with a review of contemporary literature describing the evolving understanding of the molecular pathobiology of pseudohypoparathyroidism (PHP). RECENT FINDINGS The features of PHP type 1 reflect imprinting of the GNAS gene, which encodes the α subunit of the heterotrimeric G protein (Gα(s)) that couples heptahelical receptors to activation of adenylyl cyclase. Transcription of Gα(s) is biallelic in most cells, but is primarily from the maternal allele in some tissues (e.g. proximal renal tubules, thyroid, pituitary somatotropes, gonads). Patients with PHP 1a have heterozygous mutations within the exons of the maternal GNAS allele that encode Gα(s), whereas patients with PHP 1b have methylation defects in the GNAS locus that reduce transcription of Gα(s) from the maternal allele. In both PHP 1a and PHP 1b, paternal imprinting of Gα(s) leads to resistance to parathyroid hormone and TSH. Although brachydactyly is characteristic of PHP 1a, it is sometimes present in patients with PHP 1b. SUMMARY Molecular studies enable a distinction between PHP 1a and PHP 1b, with different mechanisms accounting for Gα(s) deficiency. Clinical overlap between these two forms of PHP type 1 is likely due to the variable levels of Gα(s) activity expressed in specific cell types.
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Affiliation(s)
- Michael A Levine
- Department of Pediatrics, Division of Endocrinology and Diabetes, Children's Hospital of Philadelphia, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania 19104, USA.
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Turan S, Ignatius J, Moilanen JS, Kuismin O, Stewart H, Mann NP, Linglart A, Bastepe M, Jüppner H. De novo STX16 deletions: an infrequent cause of pseudohypoparathyroidism type Ib that should be excluded in sporadic cases. J Clin Endocrinol Metab 2012; 97:E2314-9. [PMID: 23087324 PMCID: PMC3513531 DOI: 10.1210/jc.2012-2920] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/29/2012] [Accepted: 09/24/2012] [Indexed: 01/18/2023]
Abstract
CONTEXT Maternally inherited 3-kb STX16 deletions cause autosomal dominant pseudohypoparathyroidism type Ib (PHP-Ib) characterized by PTH resistance with loss of methylation restricted to the GNAS exon A/B. OBJECTIVE The objective of the study was to search for the 3-kb STX16 deletion and to establish haplotypes for the GNAS region for two PHP-Ib patients and their families. SETTING The study was conducted at a research laboratory and tertiary care hospitals. PATIENTS The index cases presented at the ages 8 and 9.5 yr, respectively, with hypocalcemia, hyperphosphatemia, and elevated PTH. INTERVENTIONS There were no interventions. RESULTS DNA analyses of the index cases revealed an isolated loss of the GNAS exon A/B methylation and the 3-kb STX16 deletion. In the first family, the patient's healthy mother and sister showed no genetic or epigenetic abnormality, yet microsatellite analysis of the GNAS region indicated that both siblings share the same maternal allele, with the exception of an allelic loss for marker 261P9-CA1 (located within STX16), leading to the conclusion that a de novo mutation had occurred on the maternal allele. In the second family, three siblings of the index case are also affected, and an analysis of their DNA revealed the 3-kb STX16 deletion, which was also found in the healthy mother and a maternal uncle. Analysis of the siblings of the deceased maternal grandfather and some of their descendants excluded the 3-kb STX16 deletion, but haplotype analysis of the GNAS region suggested that he had acquired the mutation de novo. CONCLUSIONS De novo 3-kb STX16 deletions, reported only once previously, are infrequent but should be excluded in all cases of PHP-Ib, even when the family history is negative for an inherited form of this disorder.
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Affiliation(s)
- Serap Turan
- Endocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114, USA
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Plagge A. Non-Coding RNAs at the Gnas and Snrpn-Ube3a Imprinted Gene Loci and Their Involvement in Hereditary Disorders. Front Genet 2012; 3:264. [PMID: 23226156 PMCID: PMC3509947 DOI: 10.3389/fgene.2012.00264] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2012] [Accepted: 11/05/2012] [Indexed: 12/02/2022] Open
Abstract
Non-coding RNAs (ncRNAs) have long been recognized at imprinted gene loci and provided early paradigms to investigate their functions and molecular mechanisms of action. The characteristic feature of imprinted genes, their monoallelic, parental-origin-dependent expression, is achieved through complex epigenetic regulation, which is modulated by ncRNAs. This minireview focuses on two imprinted gene clusters, in which changes in ncRNA expression contribute to human disorders. At the GNAS locus loss of NESP RNA can cause autosomal dominant Pseudohypoparathyroidism type 1b (AD-PHP-Ib), while at the SNRPN-UBE3A locus a long ncRNA and processed snoRNAs play a role in Angelman-Syndrome (AS) and Prader–Willi-Syndrome (PWS). The ncRNAs silence overlapping protein-coding transcripts in sense or anti-sense orientation through changes in histone modifications as well as DNA methylation at CpG-rich sequence motifs. Their epigenetic modulatory functions are required in early development in the pre-implantation embryo or already in the parental germ cells. However, it remains unclear whether the sequence homology-carrying ncRNA itself is required, or whether the process of its transcription through other promoters causes the silencing effect.
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Affiliation(s)
- Antonius Plagge
- Department of Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool Liverpool, UK
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Izzi B, Francois I, Labarque V, Thys C, Wittevrongel C, Devriendt K, Legius E, Van den Bruel A, D'Hooghe M, Lambrechts D, de Zegher F, Van Geet C, Freson K. Methylation defect in imprinted genes detected in patients with an Albright's hereditary osteodystrophy like phenotype and platelet Gs hypofunction. PLoS One 2012; 7:e38579. [PMID: 22679513 PMCID: PMC3367970 DOI: 10.1371/journal.pone.0038579] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2011] [Accepted: 05/07/2012] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND Pseudohypoparathyroidism (PHP) indicates a group of heterogeneous disorders whose common feature is represented by impaired signaling of hormones that activate Gsalpha, encoded by the imprinted GNAS gene. PHP-Ib patients have isolated Parathormone (PTH) resistance and GNAS epigenetic defects while PHP-Ia cases present with hormone resistance and characteristic features jointly termed as Albright's Hereditary Osteodystrophy (AHO) due to maternally inherited GNAS mutations or similar epigenetic defects as found for PHP-Ib. Pseudopseudohypoparathyroidism (PPHP) patients with an AHO phenotype and no hormone resistance and progressive osseous heteroplasia (POH) cases have inactivating paternally inherited GNAS mutations. METHODOLOGY/PRINCIPAL FINDINGS We here describe 17 subjects with an AHO-like phenotype that could be compatible with having PPHP but none of them carried Gsalpha mutations. Functional platelet studies however showed an obvious Gs hypofunction in the 13 patients that were available for testing. Methylation for the three differentially methylated GNAS regions was quantified via the Sequenom EpiTYPER. Patients showed significant hypermethylation of the XL amplicon compared to controls (36 ± 3 vs. 29 ± 3%; p<0.001); a pattern that is reversed to XL hypomethylation found in PHPIb. Interestingly, XL hypermethylation was associated with reduced XLalphaS protein levels in the patients' platelets. Methylation for NESP and ExonA/B was significantly different for some but not all patients, though most patients have site-specific CpG methylation abnormalities in these amplicons. Since some AHO features are present in other imprinting disorders, the methylation of IGF2, H19, SNURF and GRB10 was quantified. Surprisingly, significant IGF2 hypermethylation (20 ± 10 vs. 14 ± 7%; p<0.05) and SNURF hypomethylation (23 ± 6 vs. 32 6%; p<0.001) was found in patients vs. controls, while H19 and GRB10 methylation was normal. CONCLUSION/SIGNIFICANCE In conclusion, this is the first report of methylation defects including GNAS in patients with an AHO-like phenotype without endocrinological abnormalities. Additional studies are still needed to correlate the methylation defect with the clinical phenotype.
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Affiliation(s)
- Benedetta Izzi
- Center for Molecular and Vascular Biology, University of Leuven, Leuven, Belgium
| | - Inge Francois
- Departement of Pediatrics, University of Leuven, Leuven, Belgium
| | - Veerle Labarque
- Departement of Pediatrics, University of Leuven, Leuven, Belgium
| | - Chantal Thys
- Center for Molecular and Vascular Biology, University of Leuven, Leuven, Belgium
| | | | - Koen Devriendt
- Center for Human Genetics, University of Leuven, Leuven, Belgium
| | - Eric Legius
- Center for Human Genetics, University of Leuven, Leuven, Belgium
| | | | | | | | | | - Chris Van Geet
- Center for Molecular and Vascular Biology, University of Leuven, Leuven, Belgium
- Departement of Pediatrics, University of Leuven, Leuven, Belgium
| | - Kathleen Freson
- Center for Molecular and Vascular Biology, University of Leuven, Leuven, Belgium
- * E-mail:
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