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Urakawa T, Sano S, Kawashima S, Nakamura A, Shima H, Ohta M, Yamada Y, Nishida A, Narusawa H, Ohtsu Y, Matsubara K, Dateki S, Maruo Y, Fukami M, Ogata T, Kagami M. (Epi)genetic and clinical characteristics in 84 patients with pseudohypoparathyroidism type 1B. Eur J Endocrinol 2023; 189:590-600. [PMID: 38039118 DOI: 10.1093/ejendo/lvad163] [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: 07/25/2023] [Revised: 10/20/2023] [Accepted: 10/23/2023] [Indexed: 12/03/2023]
Abstract
OBJECTIVE Pseudohypoparathyroidism type 1B (PHP1B) caused by methylation defects of differentially methylated regions (DMRs) on the GNAS locus can be categorized into groups according to etiologies and methylation defect patterns of the DMRs. The aim of this study was to clarify the clinical characteristics of each group. DESIGN Comprehensive molecular analyses consisting of methylation, copy number, and microsatellite analyses. METHODS Eighty-four patients with PHP1B were included in this study. We classified them into 5 groups, namely, autosomal dominant inheritance-PHP1B (Group 1, G1), sporadic-PHP1B (G2), and atypical-PHP1B (G3-G5), based on the methylation defect patterns in 4 DMRs on the GNAS locus and etiologies and evaluated the clinical findings in each group and compared them among the groups. RESULTS G2 had the youngest age and the highest serum intact parathyroid hormone levels among the 5 groups at the time of diagnosis. The most common symptoms at the time of diagnosis were tetany in G1, and seizures or loss of consciousness in G2. Albright's hereditary osteodystrophy and PHP-suggestive features were most frequently observed in the G2 proband. Nine patients had neurodevelopmental disorders (NDs) consisting of mild to borderline intellectual disability and/or developmental delay. There were no significant correlations between the average methylation ratios of 7 CpG sites in the GNAS-A/B:TSS-DMR and hormonal and biochemical findings. CONCLUSION This study revealed the differences in some clinical characteristics, particularly clinical features, and ages at the time of diagnosis between G2 and other groups and detailed NDs observed in some patients with PHP1B.
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Affiliation(s)
- Tatsuki Urakawa
- Department of Molecular Endocrinology, National Research Institute for Child Health and Development, Tokyo 157-8535, Japan
- Department of Pediatrics, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki 852-8102, Japan
| | - Shinichiro Sano
- Department of Molecular Endocrinology, National Research Institute for Child Health and Development, Tokyo 157-8535, Japan
- Department of Endocrinology and Metabolism, Shizuoka Children's Hospital, Shizuoka 420-8660, Japan
| | - Sayaka Kawashima
- Department of Molecular Endocrinology, National Research Institute for Child Health and Development, Tokyo 157-8535, Japan
- Department of Pediatrics, Tohoku University Graduate School of Medicine, Sendai 980-8574, Japan
| | - Akie Nakamura
- Department of Molecular Endocrinology, National Research Institute for Child Health and Development, Tokyo 157-8535, Japan
- Department of Pediatrics, Hokkaido University Graduate School of Medicine, Sapporo 060-8648, Japan
| | - Hirohito Shima
- Department of Pediatrics, Tohoku University Graduate School of Medicine, Sendai 980-8574, Japan
| | - Motoki Ohta
- Department of Pediatrics, Saiseikai Shigaken Hospital, Ritto 520-3046, Japan
| | - Yuki Yamada
- Division of Pediatric Endocrinology and Metabolism, Children's Medical Center, Osaka City General Hospital, Osaka 534-0021, Japan
| | - Ai Nishida
- Diabetes and Endocrinology, Kameda Medical Center, Kamogawa 296-0041, Japan
| | - Hiromune Narusawa
- Department of Molecular Endocrinology, National Research Institute for Child Health and Development, Tokyo 157-8535, Japan
| | - Yoshiaki Ohtsu
- Department of Pediatrics, Gunma University Graduate School of Medicine, Maebashi 371-0034, Japan
| | - Keiko Matsubara
- Department of Molecular Endocrinology, National Research Institute for Child Health and Development, Tokyo 157-8535, Japan
| | - Sumito Dateki
- Department of Pediatrics, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki 852-8102, Japan
| | - Yoshihiro Maruo
- Department of Pediatrics, Shiga University of Medical Sciences, Otsu 520-2192, Japan
| | - Maki Fukami
- Department of Molecular Endocrinology, National Research Institute for Child Health and Development, Tokyo 157-8535, Japan
| | - Tsutomu Ogata
- Department of Molecular Endocrinology, National Research Institute for Child Health and Development, Tokyo 157-8535, Japan
- Department of Biochemistry, Hamamatsu University School of Medicine, Hamamatsu 431-3192, Japan
- Department of Pediatrics, Hamamatsu Medical Center, Hamamatsu 432-8580, Japan
| | - Masayo Kagami
- Department of Molecular Endocrinology, National Research Institute for Child Health and Development, Tokyo 157-8535, Japan
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Iwasaki Y, Aksu C, Reyes M, Ay B, He Q, Bastepe M. The long-range interaction between two GNAS imprinting control regions delineates pseudohypoparathyroidism type 1B pathogenesis. J Clin Invest 2023; 133:e167953. [PMID: 36853809 PMCID: PMC10104902 DOI: 10.1172/jci167953] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Accepted: 02/21/2023] [Indexed: 03/01/2023] Open
Abstract
Genetic defects of GNAS, the imprinted gene encoding the stimulatory G protein α-subunit, are responsible for multiple diseases. Abnormal GNAS imprinting causes pseudohypoparathyroidism type 1B (PHP1B), a prototype of mammalian end-organ hormone resistance. Hypomethylation at the maternally methylated GNAS A/B region is the only shared defect in patients with PHP1B. In autosomal dominant (AD) PHP1B kindreds, A/B hypomethylation is associated with maternal microdeletions at either the GNAS NESP55 differentially methylated region or the STX16 gene located approximately 170 kb upstream. Functional evidence is meager regarding the causality of these microdeletions. Moreover, the mechanisms linking A/B methylation and the putative imprinting control regions (ICRs) NESP-ICR and STX16-ICR remain unknown. Here, we generated a human embryonic stem cell model of AD-PHP1B by introducing ICR deletions using CRISPR/Cas9. With this model, we showed that the NESP-ICR is required for methylation and transcriptional silencing of A/B on the maternal allele. We also found that the SXT16-ICR is a long-range enhancer of NESP55 transcription, which originates from the maternal NESP-ICR. Furthermore, we demonstrated that the STX16-ICR is an embryonic stage-specific enhancer enabled by the direct binding of pluripotency factors. Our findings uncover an essential GNAS imprinting control mechanism and advance the molecular understanding of PHP1B pathogenesis.
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Affiliation(s)
- Yorihiro Iwasaki
- Endocrine Unit, Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, USA
- Tazuke Kofukai Medical Research Institute, Kitano Hospital, Osaka, Japan
| | - Cagri Aksu
- Endocrine Unit, Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, USA
| | - Monica Reyes
- Endocrine Unit, Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, USA
| | - Birol Ay
- Endocrine Unit, Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, USA
| | - Qing He
- Endocrine Unit, Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, USA
- The State Key Laboratory Breeding Base of Basic Science of Stomatology and Key Laboratory for Oral Biomedicine of the Ministry of Education, School and Hospital of Stomatology, Wuhan University, Wuhan, China
| | - Murat Bastepe
- Endocrine Unit, Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, USA
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Miller DE, Hanna P, Galey M, Reyes M, Linglart A, Eichler EE, Jüppner H. Targeted Long-Read Sequencing Identifies a Retrotransposon Insertion as a Cause of Altered GNAS Exon A/B Methylation in a Family With Autosomal Dominant Pseudohypoparathyroidism Type 1b (PHP1B). J Bone Miner Res 2022; 37:1711-1719. [PMID: 35811283 PMCID: PMC9474630 DOI: 10.1002/jbmr.4647] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Revised: 06/14/2022] [Accepted: 07/01/2022] [Indexed: 11/09/2022]
Abstract
Pseudohypoparathyroidism type Ib (PHP1B) is characterized predominantly by resistance to parathyroid hormone (PTH) leading to hypocalcemia and hyperphosphatemia. These laboratory abnormalities are caused by maternal loss-of-methylation (LOM) at GNAS exon A/B, which reduces in cis expression of the stimulatory G protein α-subunit (Gsα). Paternal Gsα expression in proximal renal tubules is silenced through unknown mechanisms, hence LOM at exon A/B reduces further Gsα protein in this kidney portion, leading to PTH resistance. In a previously reported PHP1B family, affected members showed variable LOM at exon A/B, yet no genetic defect was found by whole-genome sequencing despite linkage to GNAS. Using targeted long-read sequencing (T-LRS), we discovered an approximately 2800-bp maternally inherited retrotransposon insertion nearly 1200 bp downstream of exon XL not found in public databases or in 13,675 DNA samples analyzed by short-read whole-genome sequencing. T-LRS data furthermore confirmed normal methylation at exons XL, AS, and NESP and showed that LOM comprising exon A/B is broader than previously thought. The retrotransposon most likely causes the observed epigenetic defect by impairing function of a maternally derived NESP transcript, consistent with findings in mice lacking full-length NESP mRNA and in PHP1B patients with deletion of exon NESP and adjacent intronic sequences. In addition to demonstrating that T-LRS is an effective strategy for identifying a small disease-causing variant that abolishes or severely reduces exon A/B methylation, our data demonstrate that this sequencing technology has major advantages for simultaneously identifying structural defects and altered methylation. © 2022 American Society for Bone and Mineral Research (ASBMR).
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Affiliation(s)
- Danny E. Miller
- Division of Genetic Medicine, Department of Pediatrics, University of Washington and Seattle Children’s Hospital, Seattle, WA
- Department of Genome Sciences, University of Washington School of Medicine, Seattle, WA
| | - Patrick Hanna
- Endocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Miranda Galey
- Department of Genome Sciences, University of Washington School of Medicine, Seattle, WA
| | - Monica Reyes
- Endocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Agnès Linglart
- Université Paris-Saclay, Inserm, Physiologie et physiopathologie endocrinienne; AP-HP, Department of molecular genetics, Bicêtre Paris-Saclay hospital, Le Kremlin Bicêtre, France
| | - Evan E. Eichler
- Department of Genome Sciences, University of Washington School of Medicine, Seattle, WA
- Howard Hughes Medical Institute, University of Washington, Seattle, WA
- Brotman Baty Institute for Precision Medicine, University of Washington, Seattle, WA
| | - 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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Campbell D, Reyes M, Kaygusuz SB, Abali S, Guran T, Bereket A, Kagami M, Turan S, Jüppner H. A novel deletion involving the first GNAS exon encoding Gsα causes PHP1A without methylation changes at exon A/B. Bone 2022; 157:116344. [PMID: 35104666 PMCID: PMC9301885 DOI: 10.1016/j.bone.2022.116344] [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: 12/19/2021] [Revised: 01/17/2022] [Accepted: 01/25/2022] [Indexed: 11/20/2022]
Abstract
Individuals affected by pseudohypoparathyroidism type 1A (PHP1A) display hyperphosphatemia and hypocalcemia despite elevated PTH levels, as well as features of Albright Hereditary Osteodystrophy (AHO). PHP1A is caused by variants involving the maternal GNAS exons 1-13 encoding the stimulatory G protein α-subunit (Gsα). MLPA and aCGH analysis led in a male PHP1A patient to identification of a de novo 1284-bp deletion involving GNAS exon 1. This novel variant overlaps with a previously identified 1438-bp deletion in another PHP1A patient (ref. Li et al. (2020) [13], patient 2) that extends from the exon 1 promoter into the up-stream intronic region. This latter deletion is associated with reduced methylation at GNAS exon A/B, i.e. the differentially methylated region (DMR) that is demethylated in most pseudohypoparathyroidism type 1B (PHP1B) patients. In contrast, genomic DNA from our patient revealed no evidence for an epigenetic GNAS defect as determined by MS-MLPA and pyrosequencing. These findings thus reduce the region, which, in addition to other nucleotide sequences telomeric of exon A/B, may undergo histone modifications or interacts with transcription factors and possibly as-yet unknown proteins that are required for establishing the maternal methylation imprints at this site. Taken together, nucleotide deletions or changes within an approximately 1300-bp region telomeric of exon A/B could be a cause of PHP1B variants with complete or incomplete loss-of-methylation at the exon A/B DMR. In addition, when investigating patients with suspected PHP1A, MLPA should be considered to search for structural abnormalities within this difficult to analyze genomic region comprising GNAS exon 1.
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Affiliation(s)
- Devon Campbell
- 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
| | - Sare Betul Kaygusuz
- Department of Pediatric Endocrinology, Marmara University School of Medicine, Istanbul, Turkey
| | - Saygın Abali
- Department of Pediatric Endocrinology, Acibadem Mehmet Ali Aydinlar University School of Medicine, Istanbul, Turkey
| | - Tulay Guran
- Department of Pediatric Endocrinology, Marmara University School of Medicine, Istanbul, Turkey
| | - Abdullah Bereket
- Department of Pediatric Endocrinology, Marmara University School of Medicine, Istanbul, Turkey
| | - Masayo Kagami
- Department of Molecular Endocrinology, National Research Institute for Child Health and Development, Tokyo 157-8535, Japan
| | - Serap Turan
- Department of Pediatric Endocrinology, Marmara University School of Medicine, Istanbul, Turkey
| | - 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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Januś D, Roztoczyńska D, Janeczko M, Starzyk JB. New insights into thyroid dysfunction in patients with inactivating parathyroid hormone/parathyroid hormone-related protein signalling disorder (the hormonal and ultrasound aspects): One-centre preliminary results. Front Endocrinol (Lausanne) 2022; 13:1012658. [PMID: 36213284 PMCID: PMC9539917 DOI: 10.3389/fendo.2022.1012658] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Accepted: 09/08/2022] [Indexed: 11/18/2022] Open
Abstract
OBJECTIVE This study aimed to present the spectrum of thyroid dysfunction, including hormonal and ultrasound aspects, in a cohort of paediatric and adult patients diagnosed with inactivating parathyroid hormone (PTH)/PTH-related protein signalling disorders 2 and 3 (iPPSD). METHODS The medical records of 31 patients from 14 families diagnosed with iPPSD between 1980 and 2021 in a single tertiary unit were retrospectively analysed. Biochemical, hormonal, molecular, and ultrasonographic parameters were assessed. RESULTS In total, 28 patients from 13 families were diagnosed with iPPSD2 (previously pseudohypoparathyroidism [PHP], PHP1A, and pseudo-PHP) at a mean age of 12.2 years (ranging from infancy to 48 years), and three patients from one family were diagnosed with iPPSD3 (PHP1B). Thyroid dysfunction was diagnosed in 21 of the 28 (75%) patients with iPPSD2. Neonatal screening detected congenital hypothyroidism (CH) in 4 of the 20 (20%) newborns. The spectrum of thyroid dysfunction included: CH, 3/21 (14.2%); CH and autoimmune thyroiditis with nodular goitre, 1/21 (4.8%); subclinical hypothyroidism, 10/21 (47.6%); subclinical hypothyroidism and nodular goitre, 1/21 (4.8%); primary hypothyroidism, 4/21 (19%); and autoimmune thyroiditis (Hashimoto and Graves' disease), 2/21 (9.6%). Thyroid function was normal in 7 of the 28 (25%) patients with iPPSD2 and in all patients with iPPSD3. Ultrasound evaluation of the thyroid gland revealed markedly inhomogeneous echogenicity and structure in all patients with thyroid dysfunction. Goitre was found in three patients. CONCLUSION The spectrum of thyroid dysfunction in iPPSD ranges from CH to autoimmune thyroiditis and nodular goitre. Ultrasonography of the thyroid gland may reveal an abnormal thyroid parenchyma.
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Affiliation(s)
- Dominika Januś
- Department of Paediatric and Adolescent Endocrinology, Chair of Paediatrics, Institute of Paediatrics, Jagiellonian University Medical College, Krakow, Poland
- Department of Paediatric and Adolescent Endocrinology, University Children’s Hospital, Krakow, Poland
- *Correspondence: Dominika Januś,
| | - Dorota Roztoczyńska
- Department of Paediatric and Adolescent Endocrinology, University Children’s Hospital, Krakow, Poland
| | - Magdalena Janeczko
- Department of Genetics, Chair of Paediatrics, University Children’s Hospital, Krakow, Poland
| | - Jerzy B. Starzyk
- Department of Paediatric and Adolescent Endocrinology, Chair of Paediatrics, Institute of Paediatrics, Jagiellonian University Medical College, Krakow, Poland
- Department of Paediatric and Adolescent Endocrinology, University Children’s Hospital, Krakow, Poland
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Antoun J, Williamson D, Hubler M, Shoemaker AH. Calcitriol and Levothyroxine Dosing for Patients With Pseudohypoparathyroidism. J Endocr Soc 2021; 5:bvab161. [PMID: 34765856 PMCID: PMC8579912 DOI: 10.1210/jendso/bvab161] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Indexed: 11/29/2022] Open
Abstract
Pseudohypoparathyroidism (PHP) is a rare hormone resistance syndrome caused by mutations in GNAS. This cross-sectional study investigated whether PHP patients with parathyroid hormone (PTH), thyrotropin (thyroid stimulating hormone; TSH), and free thyroxine (T4) levels at goal required higher doses of levothyroxine and calcitriol than recommended by current guidelines to overcome mineral ion abnormalities due to hormone resistance. Baseline demographic and clinical data of participants enrolled in PHP research studies between 2012-2021 were collected via retrospective chart review. Longitudinally, data were recorded at a maximum frequency of once a year starting at 1 year of age. The PTH at goal (PAG) group was defined as PTH < 150 pg/mL and calcium ≥ 8.4 mg/dL, and the TSH and free T4 at goal (TAG) group was defined as TSH < 5 mIU/L and free T4 ≥ 0.8 ng/dL. The PAG group (n = 74) was prescribed higher calcitriol doses than the PTH not at goal (PNAG) group (n = 50) (0.9 ± 1.1 vs 0.5 ± 0.9 mcg/day, P = 0.04) and 21% of individual patients were prescribed ≥ 1.5 mcg of calcitriol daily. This remained true after normalization for body weight (0.013 ± 0.015 vs 0.0067 ± 0.0095 mcg/kg/day, P = 0.008). There was no statistically significant difference in levothyroxine dosing between the TAG group (n = 122) and TSH and free T4 not at goal (TNAG) group (n = 45) when normalized for weight (2.0 ± 0.7 vs 1.8 ± 0.7 mcg/kg/day, P = 0.2). More than one-third of patients with PHP had PTH levels not at goal and some patients required calcitriol doses ≥ 1.5 mcg/day to meet current treatment goals.
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Affiliation(s)
| | - Dylan Williamson
- Division of Pediatric Endocrinology, Vanderbilt University Medical Center, Nashville, TN 37212, USA
| | - Merla Hubler
- Department of Pediatrics, University of Tennessee Health Science Center, Chattanooga, TN 37403, USA
| | - Ashley H Shoemaker
- Division of Pediatric Endocrinology, Vanderbilt University Medical Center, Nashville, TN 37212, USA
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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
Parathyroid hormone (PTH), which is primarily regulated by extracellular calcium changes, controls calcium and phosphate homeostasis. Different diseases are derived from PTH deficiency (hypoparathyroidism), excess (hyperparathyroidism) and resistance (pseudohypoparathyroidism, PHP). Pseudohypoparathyroidism was historically classified into subtypes according to the presence or not of inherited PTH resistance associated or not with features of Albright's hereditary osteodystrophy and deep and progressive ectopic ossifications. The growing knowledge on the PTH/PTHrP signaling pathway showed that molecular defects affecting different members of this pathway determined distinct, yet clinically related disorders, leading to the proposal of a new nomenclature and classification encompassing all disorders, collectively termed inactivating PTH/PTHrP signaling disorders (iPPSD).
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Affiliation(s)
- Giovanna Mantovani
- University of Milan, Dept. Clinical Sciences and Commmunity Health, Via Lamarmora 5, Milan, Italy; Fondazione IRCCS Cà Granda Ospedale Maggiore Policlinico, Endocrinology Unit, Via Lamarmora 5, 20122, Milan, Italy.
| | - Francesca Marta Elli
- Fondazione IRCCS Cà Granda Ospedale Maggiore Policlinico, Endocrinology Unit, Via Lamarmora 5, 20122, Milan, Italy.
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Elli FM, Mantovani G. Pseudohypoparathyroidism, acrodysostosis, progressive osseous heteroplasia: different names for the same spectrum of diseases? Endocrine 2021; 72:611-618. [PMID: 33179219 PMCID: PMC8159830 DOI: 10.1007/s12020-020-02533-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Accepted: 10/24/2020] [Indexed: 12/27/2022]
Abstract
Pseudohypoparathyroidism (PHP), the first known post-receptorial hormone resistance, derives from a partial deficiency of the α subunit of the stimulatory G protein (Gsα), a key component of the PTH/PTHrP signaling pathway. Since its first description, different studies unveiled, beside the molecular basis for PHP, the existence of different subtypes and of diseases in differential diagnosis associated with genetic alterations in other genes of the PTH/PTHrP pathway. The clinical and molecular overlap among PHP subtypes and with different but related disorders make both differential diagnosis and genetic counseling challenging. Recently, a proposal to group all these conditions under the novel term "inactivating PTH/PTHrP signaling disorders (iPPSD)" was promoted and, soon afterwards, the first international consensus statement on the diagnosis and management of these disorders has been published. This review will focus on the major and minor features characterizing PHP/iPPSDs as a group and on the specificities as well as the overlap associated with the most frequent subtypes.
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Affiliation(s)
- Francesca Marta Elli
- Endocrinology Unit, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Giovanna Mantovani
- Endocrinology Unit, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy.
- Department of Clinical Sciences and Community Health, University of Milan, Milan, Italy.
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Zervas A, Chrousos G, Livadas S. Snow White and the Seven Dwarfs: a fairytale for endocrinologists. Endocr Connect 2021; 10:R189-R199. [PMID: 33878729 PMCID: PMC8183629 DOI: 10.1530/ec-20-0615] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Accepted: 04/16/2021] [Indexed: 11/16/2022]
Abstract
'Snow White and the Seven Dwarfs', a fairytale that is widely known across the Western world, was originally written by the Brothers Grimm, and published in 1812 as 'Snow White'. Though each dwarf was first given an individual name in the 1912 Broadway play, in Walt Disney's 1937 film 'Snow White and the Seven Dwarfs', they were renamed, and the dwarfs have become household names. It is well known that myths, fables, and fairytales, though appearing to be merely children's tales about fictional magical beings and places, have, more often than not, originated from real facts. Therefore, the presence of the seven brothers with short stature in the story is, from an endocrinological point of view, highly intriguing, in fact, thrilling. The diversity of the phenotypes among the seven dwarfs is also stimulating, although puzzling. We undertook a differential diagnosis of their common underlying disorder based on the original Disney production's drawings and the unique characteristics of these little gentlemen, while we additionally evaluated several causes of short stature and, focusing on endocrine disorders that could lead to these clinical features among siblings, we have, we believe, been able to reveal the underlying disease depicted in this archetypal tale.
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Affiliation(s)
| | - George Chrousos
- Division of Endocrinology, Metabolism and Diabetes, First Department of Pediatrics, University Research Institute of Maternal and Child Health and Precision Medicine, and UNESCO Chair on Adolescent Health Care, National and Kapodistrian University of Athens, Athens, Greece
- National and Kapodistrian University of Athens Medical School, ‘Aghia Sophia’ Children’s Hospital, Athens, Greece
| | - Sarantis Livadas
- Endocrine Unit, Athens Medical Centre, Athens, Greece
- Correspondence should be addressed to S Livadas:
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11
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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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12
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Reyes M, Kagami M, Kawashima S, Pallotta J, Schnabel D, Fukami M, Jüppner H. A Novel GNAS Duplication Associated With Loss-of-Methylation Restricted to Exon A/B Causes Pseudohypoparathyroidism Type Ib (PHP1B). J Bone Miner Res 2021; 36:546-552. [PMID: 33180333 PMCID: PMC8048081 DOI: 10.1002/jbmr.4209] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Revised: 10/03/2020] [Accepted: 11/01/2020] [Indexed: 11/09/2022]
Abstract
Pseudohypoparathyroidism type Ib (PHP1B) is characterized by resistance to parathyroid hormone (PTH) leading to hypocalcemia and hyperphosphatemia, and in some cases resistance toward additional hormones. Patients affected by this disorder all share a loss-of-methylation (LOM) at the differentially methylated GNAS exon A/B, which reduces expression of the stimulatory G protein α-subunit (Gsα) from the maternal allele. This leads in the proximal renal tubules, where the paternal GNAS allele does not contribute much to expression of this signaling protein, to little or no Gsα expression thereby causing PTH resistance. We now describe a PHP1B patient with a de novo genomic GNAS duplication of approximately 88 kb, which is associated with LOM restricted to exon A/B alone. Multiplex ligation-dependent probe amplification (MLPA), comparative genomic hybridization (CGH), and whole-genome sequencing (WGS) established that the duplicated DNA fragment extends from GNAS exon AS1 (telomeric breakpoint) to a small region between two imperfect repeats just upstream of LOC105372695 (centromeric breakpoint). Our novel duplication is considerably shorter than previously described duplications/triplications in that portion of chromosome 20q13 and it does not affect methylation at exons AS and XL. Based on these and previous findings, it appears plausible that the identified genomic abnormality disrupts in cis the actions of a transcript that is required for establishing or maintaining exon A/B methylation. Our findings extend the molecular causes of PHP1B and provide additional insights into structural GNAS features that are required for maintaining maternal Gsα expression and for preventing PTH-resistance. © 2020 American Society for Bone and Mineral Research (ASBMR).
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Affiliation(s)
- Monica Reyes
- Endocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Masayo Kagami
- Department of Molecular Endocrinology, National Research Institute for Child Health and Development, Tokyo, Japan
| | - Sayaka Kawashima
- Department of Molecular Endocrinology, National Research Institute for Child Health and Development, Tokyo, Japan
| | - Johanna Pallotta
- Pediatric Nephrology Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Dirk Schnabel
- Center for Chronically Sick Children, Pediatric Endocrinology, Charité University Medicine, Berlin, Germany
| | - Maki Fukami
- Department of Molecular Endocrinology, National Research Institute for Child Health and Development, Tokyo, Japan
| | - 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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13
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Hungry Bone Syndrome Secondary to Subtotal Thyroidectomy in A Patient With Thyrotoxicosis. Am J Med Sci 2021; 362:314-320. [PMID: 33582155 DOI: 10.1016/j.amjms.2021.02.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Revised: 12/23/2020] [Accepted: 02/08/2021] [Indexed: 11/23/2022]
Abstract
Patients with thyrotoxicosis are prone to transient hypocalcemia after thyroidectomy, which may be due in part to surgical damage to the parathyroid glands. Hungry bone syndrome (HBS) can also cause hypocalcemia after thyroidectomy. HBS is due to increased osteoblast-mediated bone formation activity and normal or decreased bone resorption activity. As HBS is uncommon in patients after thyroidectomy, we herein present a case of hypocalcemia secondary to HBS after subtotal thyroidectomy for thyrotoxicosis in a 25-year-old woman with a two-month history of tingling extremities and carpopedal spasms after subtotal thyroidectomy for thyrotoxicosis. Diagnostic tests showed hypocalcemia and hyperphosphatemia with elevated parathyroid hormone levels and moderately decreased serum 25-hydroxyvitamin D levels. In addition to thyroid hormone replacement therapy, she was given calcitriol and Caltrate D (600 mg calcium plus 125 IU cholecalciferol). After two months of treatment, she no longer had spasms and her paresthesia improved. Meanwhile, serum electrolytes and parathyroid hormone levels had almost returned to the normal ranges. This is a rare case of HBS presented as a complication of subtotal thyroidectomy in a patient with thyrotoxicosis.
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Choufani S, Ko JM, Lou Y, Shuman C, Fishman L, Weksberg R. Paternal Uniparental Disomy of the Entire Chromosome 20 in a Child with Beckwith-Wiedemann Syndrome. Genes (Basel) 2021; 12:genes12020172. [PMID: 33513760 PMCID: PMC7911624 DOI: 10.3390/genes12020172] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2020] [Revised: 01/22/2021] [Accepted: 01/25/2021] [Indexed: 12/14/2022] Open
Abstract
Epigenetic alterations at imprinted genes on different chromosomes have been linked to several imprinting disorders (IDs) such as Beckwith-Wiedemann syndrome (BWS) and pseudohypoparathyroidism type 1b (PHP1b). Here, we present a male patient with these two distinct IDs caused by two independent mechanisms-loss of methylation (LOM) at chromosome 11p15.5 associated with multi-locus imprinting disturbances (MLID and paternal uniparental disomy of chromosome 20 (patUPD20). A clinical diagnosis of BWS was made based on the clinical features of macrosomia, macroglossia, and umbilical hernia. The diagnosis of PHP1b was supported by the presence of reduced growth velocity and mild learning disability as well as hypocalcemia and hyperphosphatemia at 14 years of age. Molecular analyses, including genome-wide DNA methylation (Illumina 450k array), bisulfite pyrosequencing, single nucleotide polymorphism (SNP) array and microsatellite analysis, demonstrated loss of methylation (LOM) at IC2 on chromosome 11p15.5, and paternal isodisomy of the entire chromosome 20. In addition, imprinting disturbances were noted at the differentially methylated regions (DMRs) associated with DIRAS3 on chromosome 1 and PLAGL1 on chromosome 6. This is the first case report of PHP1b due to patUPD20 diagnosed in a BWS patient with LOM at IC2 demonstrating etiologic heterogeneity for multiple imprinting disorders in a single individual.
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Affiliation(s)
- Sanaa Choufani
- Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada; (S.C.); (J.M.K.); (Y.L.)
| | - Jung Min Ko
- Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada; (S.C.); (J.M.K.); (Y.L.)
- Department of Pediatrics, Seoul National University Children’s Hospital, Seoul National University College of Medicine, Seoul 03080, Korea
| | - Youliang Lou
- Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada; (S.C.); (J.M.K.); (Y.L.)
| | - Cheryl Shuman
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5G 1X8, Canada;
| | - Leona Fishman
- Division of Clinical and Metabolic Genetics, The Hospital for Sick Children, Toronto, ON M5G 1X8, Canada;
- Department of Pediatrics, University of Toronto, Toronto, ON M5S 1A1, Canada
| | - Rosanna Weksberg
- Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada; (S.C.); (J.M.K.); (Y.L.)
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5G 1X8, Canada;
- Division of Clinical and Metabolic Genetics, The Hospital for Sick Children, Toronto, ON M5G 1X8, Canada;
- Department of Pediatrics, University of Toronto, Toronto, ON M5S 1A1, Canada
- Correspondence:
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15
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Vlachopapadopoulou EA, Anagnostou E, Dikaiakou E, Hanna P, Tsolia M, Michalacos S, Linglart A, Karavanaki K. Pseudohypoparathyroidism type 1B (PHP1B), a rare disorder encountered in adolescence. J Pediatr Endocrinol Metab 2020; 33:1475-1479. [PMID: 33027051 DOI: 10.1515/jpem-2020-0192] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Accepted: 08/31/2020] [Indexed: 11/15/2022]
Abstract
Objectives The objective of this paper is to report a peculiar case of a patient with pseudohypoparathyroidism type 1b (PHP1B). Pseudohypoparathyroidism (PHP) refers to a group of disorders characterized by hypocalcemia, hyperphosphatemia, and elevated parathyroid hormone (PTH) concentrations as the result of end-organ unresponsiveness to PTH. Case presentation We present a 14-year-old boy, who was admitted with severe symptomatic hypocalcaemia, absence of dysmorphic features and Albright's hereditary osteodystrophy features. Laboratory investigations revealed markedly low serum calcium, high phosphate, markedly elevated PTH levels and vitamin D insufficiency, while magnesium, albumin, ALP and TSH were normal. The clinical and laboratory findings were consistent with PHP1B. Molecular analysis revealed loss of methylation at the AB DMR of the GNAS locus, confirming the diagnosis. Yet no STX16 deletion was detected. Conclusions It is possible that delSTX16- patients carry a defect in an element that controls the methylation both at the GNAS-A/B DMR and at the GNAS-AS2. This rare case emphasizes the need of individualized molecular analysis in PHP1B patients in order to elucidate the possible molecular defect.
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Affiliation(s)
| | - Elli Anagnostou
- Department of Endocrinology-Growth and Development, Children's Hospital "P. & A. Kyriakou", Athens, Greece
| | - Eirini Dikaiakou
- Department of Endocrinology-Growth and Development, Children's Hospital "P. & A. Kyriakou", Athens, Greece
| | - Patrick Hanna
- INSERM U1169, Bicêtre Hospital, Paris Sud University, Paris, France
| | - Maria Tsolia
- 2nd Department of Paediatrics, University of Athens, "P & A Kyriakou" Children's Hospital, Athens, Greece
| | - Stefanos Michalacos
- Department of Endocrinology-Growth and Development, Children's Hospital "P. & A. Kyriakou", Athens, Greece
| | - Agnès Linglart
- APHP Reference Center for rare disorders of the Calcium and Phosphate, Bicêtre Hospital, Paris Sud University, Paris, France
| | - Kyriaki Karavanaki
- 2nd Department of Paediatrics, University of Athens, "P & A Kyriakou" Children's Hospital, Athens, Greece
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16
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Li D, Bupp C, March ME, Hakonarson H, Levine MA. Intragenic Deletions of GNAS in Pseudohypoparathyroidism Type 1A Identify a New Region Affecting Methylation of Exon A/B. J Clin Endocrinol Metab 2020; 105:5841615. [PMID: 32436958 PMCID: PMC7947960 DOI: 10.1210/clinem/dgaa286] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Accepted: 05/15/2020] [Indexed: 12/13/2022]
Abstract
CONTEXT Pseudohypoparathyroidism type 1A (PHP1A) and pseudopseudohypoparathyroidism (PPHP) are caused by inactivating mutations in the exons of GNAS that encode the alpha-subunit of the stimulatory G protein (Gsα). In some cases abnormal methylation of exon A/B of GNAS, a hallmark of PHP1B, has been reported. OBJECTIVE To identify the underlying genetic basis for PHP1A/PPHP in patients in whom molecular defects were not detected by GNAS sequencing and microarray-based analysis of copy number variations. METHODS Whole genome sequencing (WGS) and pyrosequencing of differentially methylated regions (DMRs) of GNAS using genomic deoxyribonucleic acid from affected patients. RESULTS We identified 2 novel heterozygous GNAS deletions: a 6.4 kb deletion that includes exon 2 of GNAS in the first proband that was associated with normal methylation (57%) of exon A/B DMR, and a 1438 bp deletion in a second PHP1A patient that encompasses the promoter region and 5' untranslated region of Gsα transcripts, which was inherited from his mother with PPHP. This deletion was associated with reduced methylation (32%) of exon A/B DMR. CONCLUSIONS WGS can detect exonic and intronic mutations, including deletions that are too small to be identified by microarray analysis, and therefore is more sensitive than other techniques for molecular analysis of PHP1A/PPHP. One of the deletions we identified led to reduced methylation of exon A/B DMR, further refining a region needed for normal imprinting of this DMR. We propose that deletion of this region can explain why some PHP1A patients have reduced of methylation of the exon A/B DMR.
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Affiliation(s)
- Dong Li
- Center for Applied Genomics, The Children’s Hospital of Philadelphia, Philadelphia, PA
| | | | - Michael E March
- Center for Applied Genomics, The Children’s Hospital of Philadelphia, Philadelphia, PA
| | - Hakon Hakonarson
- Center for Applied Genomics, The Children’s Hospital of Philadelphia, Philadelphia, PA
- Department of Pediatrics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA
| | - Michael A Levine
- Department of Pediatrics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA
- Division of Endocrinology and Diabetes, The Children’s Hospital of Philadelphia, Philadelphia, PA
- Correspondence and Reprint Requests: Michael A. Levine, MD, Division of Endocrinology and Diabetes, The Children’s Hospital of Philadelphia, Abramson Research Center, Room 510A, 3615 Civic Center Boulevard, Philadelphia, PA 19104. E-mail:
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17
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Impaired iloprost-induced platelet inhibition and phosphoproteome changes in patients with confirmed pseudohypoparathyroidism type Ia, linked to genetic mutations in GNAS. Sci Rep 2020; 10:11389. [PMID: 32647264 PMCID: PMC7347634 DOI: 10.1038/s41598-020-68379-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2020] [Accepted: 06/22/2020] [Indexed: 11/16/2022] Open
Abstract
Patients diagnosed with pseudohypoparathyroidism type Ia (PHP Ia) suffer from hormonal resistance and abnormal postural features, in a condition classified as Albright hereditary osteodystrophy (AHO) syndrome. This syndrome is linked to a maternally inherited mutation in the GNAS complex locus, encoding for the GTPase subunit Gsα. Here, we investigated how platelet phenotype and omics analysis can assist in the often difficult diagnosis. By coupling to the IP receptor, Gsα induces platelet inhibition via adenylyl cyclase and cAMP-dependent protein kinase A (PKA). In platelets from seven patients with suspected AHO, one of the largest cohorts examined, we studied the PKA-induced phenotypic changes. Five patients with a confirmed GNAS mutation, displayed impairments in Gsα-dependent VASP phosphorylation, aggregation, and microfluidic thrombus formation. Analysis of the platelet phosphoproteome revealed 2,516 phosphorylation sites, of which 453 were regulated by Gsα-PKA. Common changes in the patients were: (1) a joint panel of upregulated and downregulated phosphopeptides; (2) overall PKA dependency of the upregulated phosphopeptides; (3) links to key platelet function pathways. In one patient with GNAS mutation, diagnosed as non-AHO, the changes in platelet phosphoproteome were reversed. This combined approach thus revealed multiple phenotypic and molecular biomarkers to assist in the diagnosis of suspected PHP Ia.
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18
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Snanoudj S, Molin A, Colson C, Coudray N, Paulien S, Mittre H, Gérard M, Schaefer E, Goldenberg A, Bacchetta J, Odent S, Naudion S, Demeer B, Faivre L, Gruchy N, Kottler ML, Richard N. Maternal Transmission Ratio Distortion of GNAS Loss-of-Function Mutations. J Bone Miner Res 2020; 35:913-919. [PMID: 31886927 DOI: 10.1002/jbmr.3948] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Revised: 12/09/2019] [Accepted: 12/14/2019] [Indexed: 12/14/2022]
Abstract
Pseudohypoparathyroidism type 1A (PHP1A) and pseudopseudohypoparathyroidism (PPHP) are two rare autosomal dominant disorders caused by loss-of-function mutations in the imprinted Guanine Nucleotide Binding Protein, Alpha Stimulating Activity (GNAS) gene, coding Gs α. PHP1A is caused by mutations in the maternal allele and results in Albright's hereditary osteodystrophy (AHO) and hormonal resistance, mainly to the parathormone (PTH), whereas PPHP, with AHO features and no hormonal resistance, is linked to mutations in the paternal allele. This study sought to investigate parental transmission of GNAS mutations. We conducted a retrospective study in a population of 204 families with 361 patients harboring GNAS mutations. To prevent ascertainment bias toward a higher proportion of affected children due to the way in which data were collected, we excluded from transmission analysis all probands in the ascertained sibships. After bias correction, the distribution ratio of the mutated alleles was calculated from the observed genotypes of the offspring of nuclear families and was compared to the expected ratio of 50% according to Mendelian inheritance (one-sample Z-test). Sex ratio, phenotype of the transmitting parent, and transmission depending on the severity of the mutation were also analyzed. Transmission analysis was performed in 114 nuclear families and included 250 descendants. The fertility rates were similar between male and female patients. We showed an excess of transmission from mother to offspring of mutated alleles (59%, p = .022), which was greater when the mutations were severe (61.7%, p = .023). Similarly, an excess of transmission was found when the mother had a PHP1A phenotype (64.7%, p = .036). By contrast, a Mendelian distribution was observed when the mutations were paternally inherited. Higher numbers of females within the carriers, but not in noncarriers, were also observed. The mother-specific transmission ratio distortion (TRD) and the sex-ratio imbalance associated to PHP1A point to a role of Gs α in oocyte biology or embryogenesis, with implications for genetic counseling. © 2019 American Society for Bone and Mineral Research.
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Affiliation(s)
- Sarah Snanoudj
- Normandie Université, UNICAEN, CHU de Caen Normandie, Department of Genetics, Reference Center for Rare Diseases of Calcium and Phosphorus Metabolism, EA7450 BioTARGen, Caen, France
| | - Arnaud Molin
- Normandie Université, UNICAEN, CHU de Caen Normandie, Department of Genetics, Reference Center for Rare Diseases of Calcium and Phosphorus Metabolism, EA7450 BioTARGen, Caen, France
| | - Cindy Colson
- Normandie Université, UNICAEN, CHU de Caen Normandie, Department of Genetics, Reference Center for Rare Diseases of Calcium and Phosphorus Metabolism, EA7450 BioTARGen, Caen, France
| | - Nadia Coudray
- Normandie Université, UNICAEN, CHU de Caen Normandie, Department of Genetics, Reference Center for Rare Diseases of Calcium and Phosphorus Metabolism, EA7450 BioTARGen, Caen, France
| | - Sylvie Paulien
- Normandie Université, UNICAEN, CHU de Caen Normandie, Department of Genetics, Reference Center for Rare Diseases of Calcium and Phosphorus Metabolism, EA7450 BioTARGen, Caen, France
| | - Hervé Mittre
- Normandie Université, UNICAEN, CHU de Caen Normandie, Department of Genetics, Reference Center for Rare Diseases of Calcium and Phosphorus Metabolism, EA7450 BioTARGen, Caen, France
| | - Marion Gérard
- Normandie Université, UNICAEN, CHU de Caen Normandie, Department of Genetics, Reference Center for Rare Diseases of Calcium and Phosphorus Metabolism, EA7450 BioTARGen, Caen, France
| | - Elise Schaefer
- Department of Genetics, CHU de Strasbourg, Strasbourg, France
| | | | - Justine Bacchetta
- Department of Pediatric Nephrology, Rheumatology and Dermatology, CHU de Lyon, Bron, France
| | - Sylvie Odent
- Department of Genetics, CHU de Rennes, Rennes, France
| | - Sophie Naudion
- Department of Genetics, CHU de Bordeaux, Bordeaux, France
| | | | | | - Nicolas Gruchy
- Normandie Université, UNICAEN, CHU de Caen Normandie, Department of Genetics, Reference Center for Rare Diseases of Calcium and Phosphorus Metabolism, EA7450 BioTARGen, Caen, France
| | - Marie-Laure Kottler
- Normandie Université, UNICAEN, CHU de Caen Normandie, Department of Genetics, Reference Center for Rare Diseases of Calcium and Phosphorus Metabolism, EA7450 BioTARGen, Caen, France
| | - Nicolas Richard
- Normandie Université, UNICAEN, CHU de Caen Normandie, Department of Genetics, Reference Center for Rare Diseases of Calcium and Phosphorus Metabolism, EA7450 BioTARGen, Caen, France
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19
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Elli FM, deSanctis L, Maffini MA, Bordogna P, Tessaris D, Pirelli A, Arosio M, Linglart A, Mantovani G. Association of GNAS imprinting defects and deletions of chromosome 2 in two patients: clues explaining phenotypic heterogeneity in pseudohypoparathyroidism type 1B/iPPSD3. Clin Epigenetics 2019; 11:3. [PMID: 30616679 PMCID: PMC6322333 DOI: 10.1186/s13148-018-0607-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Accepted: 12/26/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The term pseudohypoparathyroidism (PHP) describes disorders derived from resistance to the parathyroid hormone. Albright hereditary osteodystrophy (AHO) is a disorder with several physical features that can occur alone or in association with PHP. The subtype 1B, classically associated with resistance to PTH and TSH, derives from the epigenetic dysregulation of the GNAS locus. Patients showing features of AHO were described, but no explanation for such phenotypic heterogeneity is available. An AHO-like phenotype was associated with the loss of genetic information stored in chromosome 2q37, making this genomic region an interesting object of study as it could contain modifier genes involved in the development of AHO features in patients with GNAS imprinting defects. The present study aimed to screen a series of 65 patients affected with GNAS imprinting defects, with or without signs of AHO, for the presence of 2q37 deletions in order to find genes involved in the clinical variability. RESULTS The molecular investigations performed on our cohort of patients with GNAS imprinting defects identified two overlapping terminal deletions of the long arm of chromosome 2. The smaller deletion was of approximately 3 Mb and contained 38 genes, one or more of which is potentially involved in the clinical presentation. Patients with the deletions were both affected by a combination of the most pathognomic AHO-like features, brachydactyly, cognitive impairment and/or behavioural defects. Our results support the hypothesis that additional genetic factors besides GNAS methylation defects are involved in the development of a complex phenotype in the subgroup of patients showing signs of AHO. CONCLUSIONS For the first time, the present work describes PHP patients with hormone resistance and AHO signs simultaneously affected by GNAS imprinting defects and 2q37 deletions. Although further studies are needed to confirm the cause of these two rare molecular alterations and to identify candidate genes, this finding provides novel interesting clues for the identification of factors involved in the still unexplained clinical variability observed in PHP1B.
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Affiliation(s)
- F M Elli
- Department of Clinical Sciences and Community Health, University of Milan, Milan, Italy.
| | - L deSanctis
- Department of Public Health and Paediatric Sciences, University of Torino, Turin, Italy
| | - M A Maffini
- Department of Clinical Sciences and Community Health, University of Milan, Milan, Italy
| | - P Bordogna
- Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Endocrinology Unit, Milan, Italy
| | - D Tessaris
- Department of Public Health and Paediatric Sciences, University of Torino, Turin, Italy
| | - A Pirelli
- Department of Clinical Sciences and Community Health, University of Milan, Milan, Italy
| | - M Arosio
- Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Endocrinology Unit, Milan, Italy
- Department of Clinical Sciences and Community Health, University of Milan, Milan, Italy
| | - A Linglart
- APHP, Paediatric Endocrinology and Diabetology for Children, Reference Centre for Rare Disorders of Calcium and Phosphate Metabolism, Platform of Expertise Paris-Sud for Rare Diseases and Filière OSCAR, Bicêtre Paris-Sud Hospital, 94270, Le Kremlin-Bicêtre, France
- APHP, Department of Endocrinology and Diabetology, Reference Centre for Rare Disorders of Calcium and Phosphate Metabolism, 94270, Le Kremlin-Bicêtre, France
| | - G Mantovani
- Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Endocrinology Unit, Milan, Italy
- Department of Clinical Sciences and Community Health, University of Milan, Milan, Italy
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20
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Elli FM, de Sanctis L, Madeo B, Maffini MA, Bordogna P, Pirelli A, Arosio M, Mantovani G. 2q37 Deletions in Patients With an Albright Hereditary Osteodystrophy Phenotype and PTH Resistance. Front Endocrinol (Lausanne) 2019; 10:604. [PMID: 31555217 PMCID: PMC6727065 DOI: 10.3389/fendo.2019.00604] [Citation(s) in RCA: 3] [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] [Received: 05/28/2019] [Accepted: 08/19/2019] [Indexed: 12/12/2022] Open
Abstract
Pseudohypoparathyroidism (PHP) is a rare endocrine disorder derived from the defective activation of the cAMP pathway by the parathyroid hormone secondary to GNAS molecular defects. PHP subtypes are defined by the presence/absence of specific clinical/biochemical features. PHP1A is characterized by resistance to multiple hormones with features of Albright hereditary osteodystrophy (AHO), while pseudopseudohypoparathyroidism (PPHP) is characterized by AHO in the absence of PTH resistance. Small subsets of PHP and PPHP patients without known molecular defects have been re-diagnosed as being affected by the brachydactyly-mental retardation syndrome (BDMR), also known as the AHO-like syndrome. This study aimed to analyse 24 PHP1A and 51 PPHP patients without a molecular diagnosis for the presence of BDMR-associated 2q37 deletions to improve the differential diagnosis and to identify features that might help to avoid a misdiagnosis. Molecular investigations identified 4 deletions in 4 unrelated patients. The affected patients showed a combination of the most pathognomonic AHO features. Of note, 3 of the patients also displayed mild PTH resistance, and none of the patients developed ectopic ossifications. Our work confirmed the rarity of the misdiagnosis of BDMR in PHP patients through the identification of 4 patients bearing a 2q37 deletion in a cohort of 73 PHP patients (5.3%). Three patients with the deletion presented a PHP1A phenotype in the absence of any BDMR-specific findings. Further studies on larger case series are needed to elucidate the overlap between these clinical entities and to allow the early identification of patients.
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Affiliation(s)
- Francesca Marta Elli
- Department of Clinical Sciences and Community Health, University of Milan, Milan, Italy
| | - Luisa de Sanctis
- Department of Public Health and Pediatric Sciences, Regina Margherita Children's Hospital-AOU Città della Salute e della Scienza, University of Torino, Turin, Italy
| | - Bruno Madeo
- Unit of Endocrinology, Department of Medical Specialties, Ospedale Civile di Baggiovara, Azienda Ospedaliero-Universitaria di Modena, Modena, Italy
| | - Maria A. Maffini
- Department of Clinical Sciences and Community Health, University of Milan, Milan, Italy
| | - Paolo Bordogna
- Endocrinology Unit, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Arianna Pirelli
- Department of Clinical Sciences and Community Health, University of Milan, Milan, Italy
| | - Maura Arosio
- Department of Clinical Sciences and Community Health, University of Milan, Milan, Italy
- Endocrinology Unit, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Giovanna Mantovani
- Department of Clinical Sciences and Community Health, University of Milan, Milan, Italy
- Endocrinology Unit, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
- *Correspondence: Giovanna Mantovani
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Perez KM, Curley KL, Slaughter JC, Shoemaker AH. Glucose Homeostasis and Energy Balance in Children With Pseudohypoparathyroidism. J Clin Endocrinol Metab 2018; 103:4265-4274. [PMID: 30085125 PMCID: PMC6194807 DOI: 10.1210/jc.2018-01067] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Accepted: 07/31/2018] [Indexed: 01/20/2023]
Abstract
CONTEXT Pseudohypoparathyroidism (PHP) is a rare genetic disorder characterized by early-onset obesity and multihormone resistance. To treat abnormal weight gain and prevent complications such as diabetes, we must understand energy balance and glucose homeostasis in PHP types 1A and 1B. OBJECTIVE The aim of this study was to evaluate food intake, energy expenditure, and glucose homeostasis in children with PHP. DESIGN Assessments included resting energy expenditure (REE), physical activity, food intake, sucrose preference, questionnaires, endocrine status, and auxological status. All patients underwent an oral glucose tolerance test (OGTT). SETTING Vanderbilt University Medical Center. PATIENTS We assessed 16 children with PHP1A, three with PHP1B, and 15 healthy controls. MAIN OUTCOME MEASURES Food intake during an ad lib buffet meal and glucose at five time points during OGTT. RESULTS PHP1A and control groups were well matched. Participants with PHP1A had significantly lower REE without concomitant change in food intake or physical activity. At baseline, participants with PHP1A had significantly lower fasting glucose and insulin resistance. During OGTT, participants with PHP1A had significantly delayed peak glucose and a slower rate of glucose decline despite similar oral glucose insulin sensitivity. Participants with PHP1A had 0.46% lower HbA1c levels than controls from a clinic database after adjustment for OGTT 2-hour glucose. The PHP1B group was similar to the PHP1A group. CONCLUSIONS In contrast to other monogenic obesity syndromes, our results support reduced energy expenditure, not severe hyperphagia, as the primary cause of abnormal weight gain in PHP. Patients with PHP are at high risk for dysglycemia without reduced insulin sensitivity.
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Affiliation(s)
- Katia M Perez
- Wake Forest University School of Medicine, Winston-Salem, North Carolina
| | - Kathleen L Curley
- The George Washington University School of Medicine and Health Sciences, Washington, DC
| | - James C Slaughter
- Department of Biostatistics, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Ashley H Shoemaker
- Department of Pediatrics, Division of Pediatric Endocrinology, Vanderbilt University Medical Center, Nashville, Tennessee
- Correspondence and Reprint Requests: Ashley H. Shoemaker, MD, Department of Pediatrics, Division of Pediatric Endocrinology, Vanderbilt University Medical Center, 1500 21st Avenue South Street, Suite 1514, Nashville, Tennessee 37212. E-mail:
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22
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Leclercq V, Benoit V, Lederer D, Delaunoy M, Ruiz M, de Halleux C, Robaux O, Wanty C, Maystadt I. Case report: An infantile lethal form of Albright hereditary osteodystrophy due to a GNAS mutation. Clin Case Rep 2018; 6:1933-1940. [PMID: 30349702 PMCID: PMC6186887 DOI: 10.1002/ccr3.1739] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Revised: 06/11/2018] [Accepted: 07/08/2018] [Indexed: 12/25/2022] Open
Abstract
Germline loss-of-function GNAS mutations are associated with multiple phenotypes, depending on the parental origin of the mutant allele. Here, we describe an infantile lethal form of atypical pseudohypoparathyroidism type 1a or 1c with severe Albright's hereditary osteodystrophy phenotype, underlying the extremely variable expressivity of this syndrome.
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Affiliation(s)
- Valérie Leclercq
- Centre de Génétique HumaineInstitut de Pathologie et de GénétiqueGosseliesBelgium
| | - Valérie Benoit
- Centre de Génétique HumaineInstitut de Pathologie et de GénétiqueGosseliesBelgium
| | - Damien Lederer
- Centre de Génétique HumaineInstitut de Pathologie et de GénétiqueGosseliesBelgium
| | | | - Marcela Ruiz
- Département de PédiatrieGrand Hôpital de CharleroiCharleroiBelgium
| | | | - Olivier Robaux
- Département de PédiatrieGrand Hôpital de CharleroiCharleroiBelgium
| | - Catherine Wanty
- Département de PédiatrieGrand Hôpital de CharleroiCharleroiBelgium
| | - Isabelle Maystadt
- Centre de Génétique HumaineInstitut de Pathologie et de GénétiqueGosseliesBelgium
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23
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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: 181] [Impact Index Per Article: 30.2] [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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24
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Shim JO, Yang HR, Moon JS, Chang JY, Ko JS, Park SS, Seo JK. Multiplex Ligation-dependent Probe Amplification Analysis Subsequent to Direct DNA Full Sequencing for Identifying ATP7B Mutations and Phenotype Correlations in Children with Wilson Disease. J Korean Med Sci 2018; 33:e177. [PMID: 29930488 PMCID: PMC6010744 DOI: 10.3346/jkms.2018.33.e177] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Accepted: 04/17/2018] [Indexed: 11/20/2022] Open
Abstract
BACKGROUND Mutations in ATP7B cause Wilson disease (WD). However, direct DNA full sequencing cannot detect all mutations in patients with WD. Multiplex ligation-dependent probe amplification (MLPA) analysis is reportedly useful in increasing the diagnostic yield in other genetic disorders with large deletions or insertions. The aim of this study was to evaluate whether the detection rate of ATP7B mutations can be increased by using MLPA. METHODS We enrolled 114 children with WD from 104 unrelated families based on biochemical tests and direct DNA full sequencing. The patients with one or zero mutant allele were investigated using MLPA. We analyzed phenotypic correlations. RESULTS Total allele frequency by full sequencing was 87.5%. Full sequencing revealed two mutant alleles in 80 of 104 unrelated children. One mutant allele was detected in 22 children, and no mutations were found in two children. Novel mutations including small deletions with frameshift mutations were identified by DNA sequencing. MLPA revealed no gross deletion or duplication in 24 children with one or zero mutant alleles. The number of detected mutations was not associated with hepatic manifestation, age of onset, Kayser-Fleischer ring, ceruloplasmin, and urinary Cu concentrations. CONCLUSION MLPA showed a limited role to increase the mutation detection rate in children who do not receive a definite genetic diagnosis of WD through DNA full sequencing. This finding suggests that large deletions or duplications might be extremely rare in WD. Further development is needed to improve the genetic diagnosis of WD.
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Affiliation(s)
- Jung Ok Shim
- Department of Pediatrics, Seoul National University College of Medicine, Seoul, Korea
- Department of Pediatrics, Korea University College of Medicine, Seoul, Korea
| | - Hye Ran Yang
- Department of Pediatrics, Seoul National University College of Medicine, Seoul, Korea
| | - Jin Soo Moon
- Department of Pediatrics, Seoul National University College of Medicine, Seoul, Korea
| | - Ju Young Chang
- Department of Pediatrics, Seoul National University College of Medicine, Seoul, Korea
| | - Jae Sung Ko
- Department of Pediatrics, Seoul National University College of Medicine, Seoul, Korea
| | - Sung Sup Park
- Department of Laboratory Medicine, Seoul National University College of Medicine, Seoul, Korea
| | - Jeong Kee Seo
- Department of Pediatrics, Seoul National University College of Medicine, Seoul, Korea
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25
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Elli FM, Bordogna P, Arosio M, Spada A, Mantovani G. Mosaicism for GNAS methylation defects associated with pseudohypoparathyroidism type 1B arose in early post-zygotic phases. Clin Epigenetics 2018; 10:16. [PMID: 29445425 PMCID: PMC5801752 DOI: 10.1186/s13148-018-0449-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2017] [Accepted: 01/30/2018] [Indexed: 11/10/2022] Open
Abstract
Background Pseudohypoparathyroidism type 1B (PHP1B; MIM#603233) is a rare imprinting disorder (ID), associated with the GNAS locus, characterized by parathyroid hormone (PTH) resistance in the absence of other endocrine or physical abnormalities. Sporadic PHP1B cases, with no known underlying primary genetic lesions, could represent true stochastic errors in early embryonic maintenance of methylation. Previous data confirmed the existence of different degrees of methylation defects associated with PHP1B and suggested the presence of mosaicism, a phenomenon already described in the context of other IDs. Results With respect to mosaic conditions, the study of multiple tissues is a necessary approach; thus, we investigated somatic cell lines (peripheral blood and buccal epithelium and cells from the urine sediment) descending from different germ layers from 19 PHP patients (11 spor-PHP1B, 4 GNAS mutated PHP1A, and 4 PHP with no GNAS (epi)genetic defects) and 5 healthy controls. We identified 11 patients with epigenetic defects, further subdivided in groups with complete or partial methylation defects. The recurrence of specific patterns of partial methylation defects limited to specific CpGs was confirmed by checking methylation profiles of spor-PHP1B patients diagnosed in our lab (n = 56). Underlying primary genetic defects, such as uniparental disomy or deletion, potentially causative for the detected partial methylation were excluded in all samples. Conclusions Our data showed no differences of methylation levels between organs and tissues from the same patient, so we concluded that the epimutation occurred in early post-zygotic phases and that the partial defects were mosaics. The number of patients with no detectable (epi)genetic GNAS defects was too small to exclude epimutations occurring in later post-zygotic phases, affecting only selected tissues different from blood, thus leading to underdiagnosis during routine molecular diagnosis. Finally, we found no correlation between methylation ratios, representing the proportion of epimutated cells, and the clinical presentation, further confirming the hypothesis of a threshold effect of the GNAS loss of imprinting leading to an "all-or-none" phenotype.
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Affiliation(s)
- Francesca Marta Elli
- Endocrinology Unit, Department of Clinical Sciences and Community Health, University of Milan, Via Francesco Sforza, 35-20122 Milan, Italy
| | - Paolo Bordogna
- Endocrinology and Metabolic Diseases Unit, Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Maura Arosio
- Endocrinology Unit, Department of Clinical Sciences and Community Health, University of Milan, Via Francesco Sforza, 35-20122 Milan, Italy
- Endocrinology and Metabolic Diseases Unit, Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Anna Spada
- Endocrinology Unit, Department of Clinical Sciences and Community Health, University of Milan, Via Francesco Sforza, 35-20122 Milan, Italy
- Endocrinology and Metabolic Diseases Unit, Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Giovanna Mantovani
- Endocrinology Unit, Department of Clinical Sciences and Community Health, University of Milan, Via Francesco Sforza, 35-20122 Milan, Italy
- Endocrinology and Metabolic Diseases Unit, Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico, Milan, Italy
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26
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Reyes M, Karaca A, Bastepe M, Gulcelik NE, Jüppner H. A novel deletion involving GNAS exon 1 causes PHP1A and further refines the region required for normal methylation at exon A/B. Bone 2017; 103:281-286. [PMID: 28711660 PMCID: PMC5943703 DOI: 10.1016/j.bone.2017.07.013] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/02/2017] [Revised: 06/20/2017] [Accepted: 07/11/2017] [Indexed: 11/25/2022]
Abstract
GNAS exons 1-13 encode the biallelically expressed alpha-subunit of the stimulatory G protein (Gαs). Additional transcripts derived from this locus use alternative first exons that undergo parent-specific methylation, thus allowing transcription only from the non-modified allele. Pseudohypoparathyroidism type Ia (PHP1A) is characterized by Albright's Hereditary Osteodystrophy (AHO) and resistance to multiple hormones; this disorder is caused by maternal inactivating mutations involving Gαs exons. In contrast, pseudohypoparathyroidism type Ib (PHP1B) is characterized mostly by resistance to PTH and often mild TSH resistance, usually without AHO features. The autosomal dominant variant of PHP1B (AD-PHP1B) is caused by maternal deletions in GNAS or STX16 that reduce Gαs expression through loss-of-methylation at GNAS exon A/B alone or at multiple differentially methylated regions (DMR). Several large maternal deletions involve not only GNAS exons 1-13, but also one or several GNAS DMRs, thus causing PHP1A combined with apparent GNAS epigenetic changes that are indistinguishable from those observed in PHP1B. Some of these deletions include a large CpG island extending from exon A/B to the intron between GNAS exons 1 and 2, but there is no evidence for parent-specific exon 1 methylation. We now describe a family in which the female proband and her daughter presented with hypocalcemia, elevated PTH levels, shortened metacarpals, and obesity, but without obvious neurocognitive abnormalities. A maternally inherited 2015-bp deletion that includes GNAS exon 1 was identified thereby establishing the diagnosis of PHP1A. The centromeric deletion breakpoint is located 178bp upstream of exon 1, yet no methylation changes were observed at exon A/B. This novel deletion therefore refines further the region between exon A/B and exon 1 that is critical for establishing or maintaining normal methylation at GNAS exon A/B.
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Affiliation(s)
- Monica Reyes
- Endocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Anara Karaca
- Ankara Training and Research Hospital, Endocrinology and Metabolism, Ankara, Turkey
| | - Murat Bastepe
- Endocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Nese Ersoz Gulcelik
- Ankara Training and Research Hospital, Endocrinology and Metabolism, Ankara, Turkey
| | - 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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27
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Elli FM, Boldrin V, Pirelli A, Spada A, Mantovani G. The Complex GNAS Imprinted Locus and Mesenchymal Stem Cells Differentiation. Horm Metab Res 2017; 49:250-258. [PMID: 27756094 DOI: 10.1055/s-0042-115305] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
All tissues and organs derive from stem cells, which are undifferentiated cells able to differentiate into specialized cells and self-renewal. In mammals, there are embryonic stem cells that generate germ layers, and adult stem cells, which act as a repair system for the body and maintain the normal turnover of regenerative organs. Mesenchymal stem cells (MSCs) are nonhematopoietic adult multipotent cells, which reside in virtually all postnatal organs and tissues, and, under appropriate in vitro conditions, are capable to differentiate into osteogenic, adipogenic, chondrogenic, myogenic, and neurogenic lineages. Their commitment and differentiation depend on several interacting signaling pathways and transcription factors. Most GNAS-based disorders have the common feature of episodic de novo formation of islands of extraskeletal, qualitatively normal, bone in skin and subcutaneous fat. The tissue distribution of these lesions suggests that pathogenesis involves abnormal differentiation of MSCs and/or more committed precursor cells that are present in subcutaneous tissues. Data coming from transgenic mice support the concept that GNAS is a key factor in the regulation of lineage switching between osteoblast and adipocyte fates, and that its role may be to prevent bone formation in tissues where bone should not form. Despite the growing knowledge about the process of heterotopic ossification in rare genetic disorders, the pathophysiological mechanisms by which alterations of cAMP signaling lead to ectopic bone formation in the context of mesenchymal tissues is not fully understood.
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Affiliation(s)
- F M Elli
- Department of Clinical Sciences and Community Health, Endocrinology and Diabetology Unit, University of Milan, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - V Boldrin
- Department of Clinical Sciences and Community Health, Endocrinology and Diabetology Unit, University of Milan, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - A Pirelli
- Department of Clinical Sciences and Community Health, Endocrinology and Diabetology Unit, University of Milan, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - A Spada
- Department of Clinical Sciences and Community Health, Endocrinology and Diabetology Unit, University of Milan, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - G Mantovani
- Department of Clinical Sciences and Community Health, Endocrinology and Diabetology Unit, University of Milan, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
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Grigelioniene G, Nevalainen PI, Reyes M, Thiele S, Tafaj O, Molinaro A, Takatani R, Ala-Houhala M, Nilsson D, Eisfeldt J, Lindstrand A, Kottler ML, Mäkitie O, Jüppner H. A Large Inversion Involving GNAS Exon A/B and All Exons Encoding Gsα Is Associated With Autosomal Dominant Pseudohypoparathyroidism Type Ib (PHP1B). J Bone Miner Res 2017; 32:776-783. [PMID: 28084650 PMCID: PMC5395346 DOI: 10.1002/jbmr.3083] [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: 10/05/2016] [Revised: 12/31/2016] [Accepted: 01/11/2017] [Indexed: 01/08/2023]
Abstract
Pseudohypoparathyroidism type Ib (PHP1B) is characterized primarily by resistance to parathyroid hormone (PTH) and thus hypocalcemia and hyperphosphatemia, in most cases without evidence for Albright hereditary osteodystrophy (AHO). PHP1B is associated with epigenetic changes at one or several differentially-methylated regions (DMRs) within GNAS, which encodes the α-subunit of the stimulatory G protein (Gsα) and splice variants thereof. Heterozygous, maternally inherited STX16 or GNAS deletions leading to isolated loss-of-methylation (LOM) at exon A/B alone or at all maternal DMRs are the cause of autosomal dominant PHP1B (AD-PHP1B). In this study, we analyzed three affected individuals, the female proband and her two sons. All three revealed isolated LOM at GNAS exon A/B, whereas the proband's healthy maternal grandmother and uncle showed normal methylation at this locus. Haplotype analysis was consistent with linkage to the STX16/GNAS region, yet no deletion could be identified. Whole-genome sequencing of one of the patients revealed a large heterozygous inversion (1,882,433 bp). The centromeric breakpoint of the inversion is located 7,225 bp downstream of GNAS exon XL, but its DMR showed no methylation abnormality, raising the possibility that the inversion disrupts a regulatory element required only for establishing or maintaining exon A/B methylation. Because our three patients presented phenotypes consistent with PHP1B, and not with PHP1A, the Gsα promoter is probably unaffected by the inversion. Our findings expand the spectrum of genetic mutations that lead to LOM at exon A/B alone and thus biallelic expression of the transcript derived from this alternative first GNAS exon. © 2017 American Society for Bone and Mineral Research.
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Affiliation(s)
- Giedre Grigelioniene
- Endocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
- Department of Clinical Genetics, Karolinska University Hospital Stockholm, Stockholm, Sweden
| | - Pasi I Nevalainen
- Endocrine Unit, Department of Internal Medicine, Tampere University Hospital, Tampere, Finland
| | - Monica Reyes
- Endocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Susanne Thiele
- 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
| | - Angelo Molinaro
- Endocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Rieko Takatani
- Endocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Marja Ala-Houhala
- Department of Pediatrics, Tampere University Hospital, Tampere, Finland
| | - Daniel Nilsson
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
- Department of Clinical Genetics, Karolinska University Hospital Stockholm, Stockholm, Sweden
- Science for Life Laboratory, Karolinska Institutet Science Park, Solna, Sweden
| | - Jesper Eisfeldt
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
- Science for Life Laboratory, Karolinska Institutet Science Park, Solna, Sweden
| | - Anna Lindstrand
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
- Department of Clinical Genetics, Karolinska University Hospital Stockholm, Stockholm, Sweden
| | - Marie-Laure Kottler
- Centre Hospitalier Universitaire de Caen, Department of Genetics, Reference Centre for Rare Disorders of Calcium and Phosphorus Metabolism, Caen, France
| | - Outi Mäkitie
- Children's Hospital, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
- Folkhälsan Institute of Genetics, Helsinki, Finland
| | - 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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Abstract
PURPOSE OF REVIEW To provide readers with a review of contemporary literature describing the evolving understanding of the pseudohypoparathyroidism type 1A (PHP1A) phenotype. RECENT FINDINGS The classic features of PHP1A include multihormone resistance and the Albright Hereditary Osteodystrophy phenotype (round facies, short stature, subcutaneous ossifications, brachydactyly, and early-onset obesity. Obesity may be because of a decrease in resting energy expenditure because most patients do not report significant hyperphagia. Patients with PHP1A have an increased risk of type 2 diabetes. In addition to brachydactyly and short stature, orthopedic complications can include spinal stenosis and carpal tunnel syndrome. Hearing loss, both sensorineural and conductive, has been reported in PHP1A. In addition, ear-nose-throat findings include decreased olfaction and frequent otitis media requiring tympanostomy tubes. Sleep apnea was shown to be 4.4-fold more common in children with PHP1A compared with other obese children; furthermore, asthma-like symptoms have been reported. These new findings are likely multifactorial and further research is needed to better understand these nonclassic features of PHP1A. SUMMARY Along with the Albright Hereditary Osteodystrophy phenotype and hormone resistance, patients with PHP1A may have additional skeletal, metabolic, ear-nose-throat, and pulmonary complications. Understanding these nonclassic features will help improve clinical care of patients with PHP1A.
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Affiliation(s)
- Ashley H Shoemaker
- aDivision of Pediatric Endocrinology, Vanderbilt University, Nashville, TN bEndocrine Unit and Pediatric Nephrology Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
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Kayemba-Kay’s S, Tripon C, Heron A, Hindmarsh P. Pseudohypoparathyroidism Type 1A-Subclinical Hypothyroidism and Rapid Weight Gain as Early Clinical Signs: A Clinical Review of 10 Cases. J Clin Res Pediatr Endocrinol 2016; 8:432-438. [PMID: 27467896 PMCID: PMC5198002 DOI: 10.4274/jcrpe.2743] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
OBJECTIVE To evaluate the clinical signs and symptoms that would help clinicians to consider pseudohypoparathyroidism (PHP) type 1A as a diagnosis in a child. METHODS A retrospective review of the medical records of children diagnosed by erythrocyte Gsα activity and/or GNAS1 gene study and followed-up for PHP type 1A. Clinical and biochemical parameters along with epidemiological data were extracted and analyzed. Weight gain during infancy and early childhood was calculated as change in weight standard deviation score (SDS), using the French growth reference values. An upward gain in weight ≥0.67 SDS during these periods was considered indicative of overweight and/or obesity. RESULTS Ten cases of PHP type 1A were identified (mean age 41.1 months, range from 4 to 156 months). In children aged ≤2 years, the commonest clinical features were round lunar face, obesity (70%), and subcutaneous ossifications (60%). In older children, brachydactyly was present in 60% of cases. Seizures occurred in older children (3 cases). Short stature was common at all ages. Subclinical hypothyroidism was present in 70%, increased parathormone (PTH) in 83%, and hyperphosphatemia in 50%. Only one case presented with hypocalcemia. Erythrocyte Gsα activity tested in seven children was reduced; GNAS1 gene testing was performed in 9 children. Maternal transmission was the most common (six patients). In three other cases, the mutations were de novo, c.585delGACT in exon 8 (case 2) and c.344C>TP115L in exon 5 (cases 6&7). CONCLUSION Based on our results, PHP type 1A should be considered in toddlers presenting with round face, rapid weight gain, subcutaneous ossifications, and subclinical hypothyroidism. In older children, moderate mental retardation, brachydactyly, afebrile seizures, short stature, and thyroid-stimulating hormone resistance are the most suggestive features.
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Affiliation(s)
- Simon Kayemba-Kay’s
- Victor Jousselin Hospital, Clinic of Pediatrics and Neonatal Medicine, Pediatric Endocrinology Unit, Dreux, France
,
Victor Jousselin Hospital, Clinical Research Unit, Dreux, France
,
University College London and Institute of Child Health, Developmental Endocrinology Research Group, London, United Kingdom
,* Address for Correspondence: Victor Jousselin Hospital, Clinic of Pediatrics and Neonatal Medicine, Pediatric Endocrinology Unit, Dreux, France Phone: +33 2 37 51 53 13 E-mail:
| | - Cedric Tripon
- Poitiers University Hospital, Clinic of Pediatrics, Poitiers, France
| | - Anne Heron
- Victor Jousselin Hospital, Clinical Research Unit, Dreux, France
| | - Peter Hindmarsh
- University College London and Institute of Child Health, Developmental Endocrinology Research Group, London, United Kingdom
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31
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Elli FM, Linglart A, Garin I, de Sanctis L, Bordogna P, Grybek V, Pereda A, Giachero F, Verrua E, Hanna P, Mantovani G, Perez de Nanclares G. The Prevalence of GNAS Deficiency-Related Diseases in a Large Cohort of Patients Characterized by the EuroPHP Network. J Clin Endocrinol Metab 2016; 101:3657-3668. [PMID: 27428667 DOI: 10.1210/jc.2015-4310] [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] [Indexed: 12/30/2022]
Abstract
CONTEXT The term pseudohypoparathyroidism (PHP) was coined to describe the clinical condition resulting from end-organ resistance to parathormone (rPTH), caused by genetic and/or epigenetic alterations within or upstream of GNAS. Although knowledge about PHP is growing, there are few data on the prevalence of underlying molecular defects. OBJECTIVE The purpose of our study was to ascertain the relative prevalence of PHP-associated molecular defects. DESIGN With a specially designed questionnaire, we collected data from all patients (n = 407) clinically and molecularly characterized to date by expert referral centers in France, Italy, and Spain. RESULTS Isolated rPTH (126/407, 31%) was caused only by epigenetic defects, 70% of patients showing loss of imprinting affecting all four GNAS differentially methylated regions and 30% loss of methylation restricted to the GNAS A/B:TSS-DMR. Multihormone resistance with no Albright's hereditary osteodystrophy (AHO) signs (61/407, 15%) was essentially due to epigenetic defects, although 10% of patients had point mutations. In patients with rPTH and AHO (40/407, 10%), the rate of point mutations was higher (28%) and methylation defects lower (about 70%). In patients with multihormone resistance and AHO (155/407, 38%), all types of molecular defects appeared with different frequencies. Finally, isolated AHO (18/407, 4%) and progressive osseous heteroplasia (7/407, 2%) were exclusively caused by point mutations. CONCLUSION With European data, we have established the prevalence of various genetic and epigenetic lesions in PHP-affected patients. Using these findings, we will develop objective criteria to guide cost-effective strategies for genetic testing and explore the implications for management and prognosis.
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Affiliation(s)
- Francesca Marta Elli
- Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico (F.M.E., E.V., P.B., G.M.), Department of Clinical Sciences and Community Health, University of Milan, Endocrinology and Diabetology Unit, Milan, Italy; APHP (A.L., V.G., P.H.), Reference Center for Rare Disorders of the Mineral Metabolism and Plateforme d'expertise Paris Sud Maladies Rares, Le Kremlin Bicêtre, France; INSERM U1169 (A.L., V.G., P.H.), Hôpital Bicêtre, Le Kremlin Bicêtre, et Université Paris-Saclay, France; Molecular (Epi)Genetics Laboratory (I.G., A.P., G.P.d.N.), BioAraba National Health Institute, Hospital Universitario Araba-Txagorritxu, Vitoria-Gasteiz, Spain; Department of Public Health and Pediatrics (L.d.S., F.G.), University of Turin, Regina Margherita Children's Hospital, Health and Science City, Turin, Italy; Department of Biochemistry and Molecular Biology (A.P.), University of Basque Country, Leioa, Spain
| | - Agnès Linglart
- Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico (F.M.E., E.V., P.B., G.M.), Department of Clinical Sciences and Community Health, University of Milan, Endocrinology and Diabetology Unit, Milan, Italy; APHP (A.L., V.G., P.H.), Reference Center for Rare Disorders of the Mineral Metabolism and Plateforme d'expertise Paris Sud Maladies Rares, Le Kremlin Bicêtre, France; INSERM U1169 (A.L., V.G., P.H.), Hôpital Bicêtre, Le Kremlin Bicêtre, et Université Paris-Saclay, France; Molecular (Epi)Genetics Laboratory (I.G., A.P., G.P.d.N.), BioAraba National Health Institute, Hospital Universitario Araba-Txagorritxu, Vitoria-Gasteiz, Spain; Department of Public Health and Pediatrics (L.d.S., F.G.), University of Turin, Regina Margherita Children's Hospital, Health and Science City, Turin, Italy; Department of Biochemistry and Molecular Biology (A.P.), University of Basque Country, Leioa, Spain
| | - Intza Garin
- Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico (F.M.E., E.V., P.B., G.M.), Department of Clinical Sciences and Community Health, University of Milan, Endocrinology and Diabetology Unit, Milan, Italy; APHP (A.L., V.G., P.H.), Reference Center for Rare Disorders of the Mineral Metabolism and Plateforme d'expertise Paris Sud Maladies Rares, Le Kremlin Bicêtre, France; INSERM U1169 (A.L., V.G., P.H.), Hôpital Bicêtre, Le Kremlin Bicêtre, et Université Paris-Saclay, France; Molecular (Epi)Genetics Laboratory (I.G., A.P., G.P.d.N.), BioAraba National Health Institute, Hospital Universitario Araba-Txagorritxu, Vitoria-Gasteiz, Spain; Department of Public Health and Pediatrics (L.d.S., F.G.), University of Turin, Regina Margherita Children's Hospital, Health and Science City, Turin, Italy; Department of Biochemistry and Molecular Biology (A.P.), University of Basque Country, Leioa, Spain
| | - Luisa de Sanctis
- Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico (F.M.E., E.V., P.B., G.M.), Department of Clinical Sciences and Community Health, University of Milan, Endocrinology and Diabetology Unit, Milan, Italy; APHP (A.L., V.G., P.H.), Reference Center for Rare Disorders of the Mineral Metabolism and Plateforme d'expertise Paris Sud Maladies Rares, Le Kremlin Bicêtre, France; INSERM U1169 (A.L., V.G., P.H.), Hôpital Bicêtre, Le Kremlin Bicêtre, et Université Paris-Saclay, France; Molecular (Epi)Genetics Laboratory (I.G., A.P., G.P.d.N.), BioAraba National Health Institute, Hospital Universitario Araba-Txagorritxu, Vitoria-Gasteiz, Spain; Department of Public Health and Pediatrics (L.d.S., F.G.), University of Turin, Regina Margherita Children's Hospital, Health and Science City, Turin, Italy; Department of Biochemistry and Molecular Biology (A.P.), University of Basque Country, Leioa, Spain
| | - Paolo Bordogna
- Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico (F.M.E., E.V., P.B., G.M.), Department of Clinical Sciences and Community Health, University of Milan, Endocrinology and Diabetology Unit, Milan, Italy; APHP (A.L., V.G., P.H.), Reference Center for Rare Disorders of the Mineral Metabolism and Plateforme d'expertise Paris Sud Maladies Rares, Le Kremlin Bicêtre, France; INSERM U1169 (A.L., V.G., P.H.), Hôpital Bicêtre, Le Kremlin Bicêtre, et Université Paris-Saclay, France; Molecular (Epi)Genetics Laboratory (I.G., A.P., G.P.d.N.), BioAraba National Health Institute, Hospital Universitario Araba-Txagorritxu, Vitoria-Gasteiz, Spain; Department of Public Health and Pediatrics (L.d.S., F.G.), University of Turin, Regina Margherita Children's Hospital, Health and Science City, Turin, Italy; Department of Biochemistry and Molecular Biology (A.P.), University of Basque Country, Leioa, Spain
| | - Virginie Grybek
- Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico (F.M.E., E.V., P.B., G.M.), Department of Clinical Sciences and Community Health, University of Milan, Endocrinology and Diabetology Unit, Milan, Italy; APHP (A.L., V.G., P.H.), Reference Center for Rare Disorders of the Mineral Metabolism and Plateforme d'expertise Paris Sud Maladies Rares, Le Kremlin Bicêtre, France; INSERM U1169 (A.L., V.G., P.H.), Hôpital Bicêtre, Le Kremlin Bicêtre, et Université Paris-Saclay, France; Molecular (Epi)Genetics Laboratory (I.G., A.P., G.P.d.N.), BioAraba National Health Institute, Hospital Universitario Araba-Txagorritxu, Vitoria-Gasteiz, Spain; Department of Public Health and Pediatrics (L.d.S., F.G.), University of Turin, Regina Margherita Children's Hospital, Health and Science City, Turin, Italy; Department of Biochemistry and Molecular Biology (A.P.), University of Basque Country, Leioa, Spain
| | - Arrate Pereda
- Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico (F.M.E., E.V., P.B., G.M.), Department of Clinical Sciences and Community Health, University of Milan, Endocrinology and Diabetology Unit, Milan, Italy; APHP (A.L., V.G., P.H.), Reference Center for Rare Disorders of the Mineral Metabolism and Plateforme d'expertise Paris Sud Maladies Rares, Le Kremlin Bicêtre, France; INSERM U1169 (A.L., V.G., P.H.), Hôpital Bicêtre, Le Kremlin Bicêtre, et Université Paris-Saclay, France; Molecular (Epi)Genetics Laboratory (I.G., A.P., G.P.d.N.), BioAraba National Health Institute, Hospital Universitario Araba-Txagorritxu, Vitoria-Gasteiz, Spain; Department of Public Health and Pediatrics (L.d.S., F.G.), University of Turin, Regina Margherita Children's Hospital, Health and Science City, Turin, Italy; Department of Biochemistry and Molecular Biology (A.P.), University of Basque Country, Leioa, Spain
| | - Federica Giachero
- Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico (F.M.E., E.V., P.B., G.M.), Department of Clinical Sciences and Community Health, University of Milan, Endocrinology and Diabetology Unit, Milan, Italy; APHP (A.L., V.G., P.H.), Reference Center for Rare Disorders of the Mineral Metabolism and Plateforme d'expertise Paris Sud Maladies Rares, Le Kremlin Bicêtre, France; INSERM U1169 (A.L., V.G., P.H.), Hôpital Bicêtre, Le Kremlin Bicêtre, et Université Paris-Saclay, France; Molecular (Epi)Genetics Laboratory (I.G., A.P., G.P.d.N.), BioAraba National Health Institute, Hospital Universitario Araba-Txagorritxu, Vitoria-Gasteiz, Spain; Department of Public Health and Pediatrics (L.d.S., F.G.), University of Turin, Regina Margherita Children's Hospital, Health and Science City, Turin, Italy; Department of Biochemistry and Molecular Biology (A.P.), University of Basque Country, Leioa, Spain
| | - Elisa Verrua
- Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico (F.M.E., E.V., P.B., G.M.), Department of Clinical Sciences and Community Health, University of Milan, Endocrinology and Diabetology Unit, Milan, Italy; APHP (A.L., V.G., P.H.), Reference Center for Rare Disorders of the Mineral Metabolism and Plateforme d'expertise Paris Sud Maladies Rares, Le Kremlin Bicêtre, France; INSERM U1169 (A.L., V.G., P.H.), Hôpital Bicêtre, Le Kremlin Bicêtre, et Université Paris-Saclay, France; Molecular (Epi)Genetics Laboratory (I.G., A.P., G.P.d.N.), BioAraba National Health Institute, Hospital Universitario Araba-Txagorritxu, Vitoria-Gasteiz, Spain; Department of Public Health and Pediatrics (L.d.S., F.G.), University of Turin, Regina Margherita Children's Hospital, Health and Science City, Turin, Italy; Department of Biochemistry and Molecular Biology (A.P.), University of Basque Country, Leioa, Spain
| | - Patrick Hanna
- Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico (F.M.E., E.V., P.B., G.M.), Department of Clinical Sciences and Community Health, University of Milan, Endocrinology and Diabetology Unit, Milan, Italy; APHP (A.L., V.G., P.H.), Reference Center for Rare Disorders of the Mineral Metabolism and Plateforme d'expertise Paris Sud Maladies Rares, Le Kremlin Bicêtre, France; INSERM U1169 (A.L., V.G., P.H.), Hôpital Bicêtre, Le Kremlin Bicêtre, et Université Paris-Saclay, France; Molecular (Epi)Genetics Laboratory (I.G., A.P., G.P.d.N.), BioAraba National Health Institute, Hospital Universitario Araba-Txagorritxu, Vitoria-Gasteiz, Spain; Department of Public Health and Pediatrics (L.d.S., F.G.), University of Turin, Regina Margherita Children's Hospital, Health and Science City, Turin, Italy; Department of Biochemistry and Molecular Biology (A.P.), University of Basque Country, Leioa, Spain
| | - Giovanna Mantovani
- Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico (F.M.E., E.V., P.B., G.M.), Department of Clinical Sciences and Community Health, University of Milan, Endocrinology and Diabetology Unit, Milan, Italy; APHP (A.L., V.G., P.H.), Reference Center for Rare Disorders of the Mineral Metabolism and Plateforme d'expertise Paris Sud Maladies Rares, Le Kremlin Bicêtre, France; INSERM U1169 (A.L., V.G., P.H.), Hôpital Bicêtre, Le Kremlin Bicêtre, et Université Paris-Saclay, France; Molecular (Epi)Genetics Laboratory (I.G., A.P., G.P.d.N.), BioAraba National Health Institute, Hospital Universitario Araba-Txagorritxu, Vitoria-Gasteiz, Spain; Department of Public Health and Pediatrics (L.d.S., F.G.), University of Turin, Regina Margherita Children's Hospital, Health and Science City, Turin, Italy; Department of Biochemistry and Molecular Biology (A.P.), University of Basque Country, Leioa, Spain
| | - Guiomar Perez de Nanclares
- Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico (F.M.E., E.V., P.B., G.M.), Department of Clinical Sciences and Community Health, University of Milan, Endocrinology and Diabetology Unit, Milan, Italy; APHP (A.L., V.G., P.H.), Reference Center for Rare Disorders of the Mineral Metabolism and Plateforme d'expertise Paris Sud Maladies Rares, Le Kremlin Bicêtre, France; INSERM U1169 (A.L., V.G., P.H.), Hôpital Bicêtre, Le Kremlin Bicêtre, et Université Paris-Saclay, France; Molecular (Epi)Genetics Laboratory (I.G., A.P., G.P.d.N.), BioAraba National Health Institute, Hospital Universitario Araba-Txagorritxu, Vitoria-Gasteiz, Spain; Department of Public Health and Pediatrics (L.d.S., F.G.), University of Turin, Regina Margherita Children's Hospital, Health and Science City, Turin, Italy; Department of Biochemistry and Molecular Biology (A.P.), University of Basque Country, Leioa, Spain
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de Lange IM, Verrijn Stuart AA, van der Luijt RB, Ploos van Amstel HK, van Haelst MM. Macrosomia, obesity, and macrocephaly as first clinical presentation of PHP1b caused by STX16 deletion. Am J Med Genet A 2016; 170:2431-5. [PMID: 27338644 DOI: 10.1002/ajmg.a.37818] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2015] [Accepted: 06/12/2016] [Indexed: 01/21/2023]
Abstract
Pseudohypoparathyroidism (PHP) is a genetic disorder with resistance to parathyroid hormone (PTH) as most important feature. Main subtypes of the disease are pseudohypoparathyroidism 1b (PHP1b) and pseudohypoparathyroidism 1a (PHP1a). PHP1b is characterized by PTH resistance of the renal cortex due to reduced activity of the stimulatory G protein α subunit (Gsα) of the PTH receptor. In addition to resistance to PTH, PHP1a patients also lack sensitivity for other hormones that signal their actions through G protein-coupled receptors and display physical features of Albright hereditary osteodystrophy (AHO), which is not classically seen in PHP1b patients. PHP1a is caused by heterozygous loss-of-function mutations in maternally inherited GNAS exons 1-13, which encode Gsα. PHP1b is often caused by deletion of the STX16 gene, which is thought to have an important role in controlling the methylation and thus imprinting at part of the GNAS locus. Here we present a patient with PHP1b caused by the previously described recurrent 3-kb STX16 deletion. The patient's first symptoms were macrosomia, early onset obesity, and macrocephaly. Since this is an atypical but previously described rare presentation of PHP1b, we reemphasize STX16 deletions and PHP1b as a rare cause for early onset obesity and macrosomia. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Iris M de Lange
- Department of Medical Genetics, University Medical Centre, Utrecht, The Netherlands
| | | | - Rob B van der Luijt
- Department of Medical Genetics, University Medical Centre, Utrecht, The Netherlands
| | | | - Mieke M van Haelst
- Department of Medical Genetics, University Medical Centre, Utrecht, The Netherlands
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Mantovani G, Spada A, Elli FM. Pseudohypoparathyroidism and Gsα-cAMP-linked disorders: current view and open issues. Nat Rev Endocrinol 2016; 12:347-56. [PMID: 27109785 DOI: 10.1038/nrendo.2016.52] [Citation(s) in RCA: 64] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Pseudohypoparathyroidism exemplifies an unusual form of hormone resistance as the underlying molecular defect is a partial deficiency of the α subunit of the stimulatory G protein (Gsα), a key regulator of the cAMP signalling pathway, rather than of the parathyroid hormone (PTH) receptor itself. Despite the first description of this disorder dating back to 1942, later findings have unveiled complex epigenetic alterations in addition to classic mutations in GNAS underpining the molecular basis of the main subtypes of pseudohypoparathyroidism. Moreover, mutations in PRKAR1A and PDE4D, which encode proteins crucial for Gsα-cAMP-mediated signalling, have been found in patients with acrodysostosis. As acrodysostosis, a disease characterized by skeletal malformations and endocrine disturbances, shares clinical and molecular characteristics with pseudohypoparathyroidism, making a differential diagnosis and providing genetic counselling to patients and families is a challenge for endocrinologists. Accumulating data on the genetic and clinical aspects of this group of diseases highlight the limitation of the current classification system and prompt the need for a new definition as well as for new diagnostic and/or therapeutic algorithms. This Review discusses both the current understanding and future challenges for the clinical and molecular diagnosis, classification and treatment of pseudohypoparathyroidism.
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MESH Headings
- Bone Diseases, Metabolic/diagnosis
- Bone Diseases, Metabolic/genetics
- Chromogranins/genetics
- Chromosome Deletion
- Chromosomes, Human, Pair 2/genetics
- Cyclic AMP
- Cyclic AMP-Dependent Protein Kinase RIalpha Subunit/genetics
- Cyclic Nucleotide Phosphodiesterases, Type 4/genetics
- Diagnosis, Differential
- Dysostoses/diagnosis
- Dysostoses/genetics
- Epigenesis, Genetic/genetics
- GTP-Binding Protein alpha Subunits, Gs/genetics
- Humans
- Intellectual Disability/diagnosis
- Intellectual Disability/genetics
- Ossification, Heterotopic/diagnosis
- Ossification, Heterotopic/genetics
- Osteochondrodysplasias/diagnosis
- Osteochondrodysplasias/genetics
- Pseudohypoparathyroidism/classification
- Pseudohypoparathyroidism/diagnosis
- Pseudohypoparathyroidism/genetics
- Signal Transduction
- Skin Diseases, Genetic/diagnosis
- Skin Diseases, Genetic/genetics
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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, Via Francesco Sforza 35, Milan 20122, Italy
| | - Anna Spada
- Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Endocrinology Unit, Department of Clinical Sciences and Community Health, University of Milan, Via Francesco Sforza 35, Milan 20122, Italy
| | - Francesca Marta Elli
- Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Endocrinology Unit, Department of Clinical Sciences and Community Health, University of Milan, Via Francesco Sforza 35, Milan 20122, Italy
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Elli FM, Bordogna P, de Sanctis L, Giachero F, Verrua E, Segni M, Mazzanti L, Boldrin V, Toromanovic A, Spada A, Mantovani G. Screening of PRKAR1A and PDE4D in a Large Italian Series of Patients Clinically Diagnosed With Albright Hereditary Osteodystrophy and/or Pseudohypoparathyroidism. J Bone Miner Res 2016; 31:1215-24. [PMID: 26763073 DOI: 10.1002/jbmr.2785] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/16/2015] [Revised: 12/20/2015] [Accepted: 01/11/2016] [Indexed: 01/10/2023]
Abstract
The cyclic adenosine monophosphate (cAMP) intracellular signaling pathway mediates the physiological effects of several hormones and neurotransmitters, acting by the activation of G-protein coupled receptors (GPCRs) and several downstream intracellular effectors, including the heterotrimeric stimulatory G-protein (Gs), the cAMP-dependent protein kinase A (PKA), and cAMP-specific phosphodiesterases (PDEs). Defective G-protein-mediated signaling has been associated with an increasing number of disorders, including Albright hereditary osteodistrophy (AHO) and pseudohypoparathyroidism (PHP), a heterogeneous group of rare genetic metabolic disorders resulting from molecular defects at the GNAS locus. Moreover, mutations in PRKAR1A and PDE4D genes have been recently detected in patients with acrodysostosis (ACRDYS), showing a skeletal and endocrinological phenotype partially overlapping with AHO/PHP. Despite the high detection rate of molecular defects by currently available molecular approaches, about 30% of AHO/PHP patients still lack a molecular diagnosis, hence the need to screen patients negative for GNAS epi/genetic defects also for chromosomal regions and genes associated with diseases that undergo differential diagnosis with PHP. According to the growing knowledge on Gsα-cAMP signaling-linked disorders, we investigated our series of patients (n = 81) with a clinical diagnosis of PHP/AHO but negative for GNAS anomalies for the presence of novel genetic variants at PRKAR1A and PDE4D genes. Our work allowed the detection of 8 novel missense variants affecting genes so far associated with ACRDYS in 9 patients. Our data further confirm the molecular and clinical overlap among these disorders. We present the data collected from a large series of patients and a brief review of the literature in order to compare our findings with already published data; to look for PRKAR1A/PDE4D mutation spectrum, recurrent mutations, and mutation hot spots; and to identify specific clinical features associated with ACRDYS that deserve surveillance during follow-up. © 2016 American Society for Bone and Mineral Research.
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Affiliation(s)
- Francesca Marta Elli
- Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Endocrinology Unit, Department of Clinical Sciences and Community Health, University of Milan, Milan, Italy
| | - Paolo Bordogna
- Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Endocrinology Unit, Department of Clinical Sciences and Community Health, University of Milan, Milan, Italy
| | - Luisa de Sanctis
- Department of Public Health and Pediatrics, University of Turin and Regina Margherita Children's Hospital, Turin, Italy
| | - Federica Giachero
- Department of Public Health and Pediatrics, University of Turin and Regina Margherita Children's Hospital, Turin, Italy
| | - Elisa Verrua
- Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Endocrinology Unit, Department of Clinical Sciences and Community Health, University of Milan, Milan, Italy
| | - Maria Segni
- Department of Pediatrics and Child Neuropsychiatry, Sapienza University, Rome, Italy
| | - Laura Mazzanti
- Pediatrics Endocrinology and Rare Diseases, Pediatrics Unit, AOU S. Orsola-Malpighi, University of Bologna, Bologna, Italy
| | - Valentina Boldrin
- Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Endocrinology Unit, Department of Clinical Sciences and Community Health, University of Milan, Milan, Italy
| | - Alma Toromanovic
- Department of Pediatrics, University Clinical Center Tuzla, Tuzla, Bosnia and Herzegovina
| | - Anna Spada
- Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Endocrinology Unit, Department of Clinical Sciences and Community Health, University of Milan, Milan, Italy
| | - Giovanna Mantovani
- Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Endocrinology Unit, Department of Clinical Sciences and Community Health, University of Milan, Milan, Italy
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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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Roca-Rodríguez MDM, Cornejo-Pareja I, Mancha-Doblas I, Tinahones FJ. [STX16 deletion associated to pseudohypoparathyroidism]. Med Clin (Barc) 2016; 146:e33-4. [PMID: 26654555 DOI: 10.1016/j.medcli.2015.10.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Revised: 10/06/2015] [Accepted: 10/08/2015] [Indexed: 01/03/2023]
Affiliation(s)
- María Del Mar Roca-Rodríguez
- Unidad de Gestión Clínica de Endocrinología y Nutrición, Hospital Clínico, Málaga, España; Unidad de Gestión Clínica de Endocrinología y Nutrición, Hospital Regional, Málaga, España.
| | - Isabel Cornejo-Pareja
- Unidad de Gestión Clínica de Endocrinología y Nutrición, Hospital Clínico, Málaga, España
| | - Isabel Mancha-Doblas
- Unidad de Gestión Clínica de Endocrinología y Nutrición, Hospital Clínico, Málaga, España
| | - Francisco J Tinahones
- Unidad de Gestión Clínica de Endocrinología y Nutrición, Hospital Clínico, Málaga, España; Unidad de Gestión Clínica de Endocrinología y Nutrición, Hospital Regional, Málaga, España
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Rochtus A, Martin-Trujillo A, Izzi B, Elli F, Garin I, Linglart A, Mantovani G, Perez de Nanclares G, Thiele S, Decallonne B, Van Geet C, Monk D, Freson K. Genome-wide DNA methylation analysis of pseudohypoparathyroidism patients with GNAS imprinting defects. Clin Epigenetics 2016; 8:10. [PMID: 26819647 PMCID: PMC4728790 DOI: 10.1186/s13148-016-0175-8] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Accepted: 01/17/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Pseudohypoparathyroidism (PHP) is caused by (epi)genetic defects in the imprinted GNAS cluster. Current classification of PHP patients is hampered by clinical and molecular diagnostic overlaps. The European Consortium for the study of PHP designed a genome-wide methylation study to improve molecular diagnosis. METHODS The HumanMethylation 450K BeadChip was used to analyze genome-wide methylation in 24 PHP patients with parathyroid hormone resistance and 20 age- and gender-matched controls. Patients were previously diagnosed with GNAS-specific differentially methylated regions (DMRs) and include 6 patients with known STX16 deletion (PHP(Δstx16)) and 18 without deletion (PHP(neg)). RESULTS The array demonstrated that PHP patients do not show DNA methylation differences at the whole-genome level. Unsupervised clustering of GNAS-specific DMRs divides PHP(Δstx16) versus PHP(neg) patients. Interestingly, in contrast to the notion that all PHP patients share methylation defects in the A/B DMR while only PHP(Δstx16) patients have normal NESP, GNAS-AS1 and XL methylation, we found a novel DMR (named GNAS-AS2) in the GNAS-AS1 region that is significantly different in both PHP(Δstx16) and PHP(neg), as validated by Sequenom EpiTYPER in a larger PHP cohort. The analysis of 58 DMRs revealed that 8/18 PHP(neg) and 1/6 PHP(Δstx16) patients have multi-locus methylation defects. Validation was performed for FANCC and SVOPL DMRs. CONCLUSIONS This is the first genome-wide methylation study for PHP patients that confirmed that GNAS is the most significant DMR, and the presence of STX16 deletion divides PHP patients in two groups. Moreover, a novel GNAS-AS2 DMR affects all PHP patients, and PHP patients seem sensitive to multi-locus methylation defects.
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Affiliation(s)
- Anne Rochtus
- Department of Cardiovascular Sciences, Center for Molecular and Vascular Biology, University of Leuven, Campus Gasthuisberg, O&N1, Herestraat 49, Box 911, 3000 Leuven, Belgium ; Department of Pediatrics, University Hospitals Leuven, 3000 Leuven, Belgium
| | | | - Benedetta Izzi
- Department of Cardiovascular Sciences, Center for Molecular and Vascular Biology, University of Leuven, Campus Gasthuisberg, O&N1, Herestraat 49, Box 911, 3000 Leuven, Belgium
| | - Francesca Elli
- Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Endocrinology and Diabetology Unit, Department of Clinical Sciences and Community Health, University of Milan, 20122, Milan, Italy
| | - Intza Garin
- Molecular (Epi)Genetics Laboratory, BioAraba National Health Institute, Hospital Universitario Araba-Txagorritxu, 01009 Vitoria-Gasteiz, Spain
| | - Agnes Linglart
- Department of Pediatric Endocrinology and Diabetology for Children, APHP, Bicêtre Paris Sud, 94275 Le Kremlin Bicêtre, France ; Reference Center for Rare Disorders of the Mineral Metabolism and Plateforme d'Expertise Paris Sud, APHP, 94275 Le Kremlin Bicêtre, France
| | - Giovanna Mantovani
- Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Endocrinology and Diabetology Unit, Department of Clinical Sciences and Community Health, University of Milan, 20122, Milan, Italy
| | - Guiomar Perez de Nanclares
- Molecular (Epi)Genetics Laboratory, BioAraba National Health Institute, Hospital Universitario Araba-Txagorritxu, 01009 Vitoria-Gasteiz, Spain
| | - Suzanne Thiele
- Division of Experimental Paediatric Endocrinology and Diabetes, Department of Paediatrics, University of Luebeck, 23560 Luebeck, Germany
| | - Brigitte Decallonne
- Department of Clinical and Experimental Endocrinology, University of Leuven, 3000 Leuven, Belgium
| | - Chris Van Geet
- Department of Pediatrics, University Hospitals Leuven, 3000 Leuven, Belgium
| | - David Monk
- Laboratory of Genomic Imprinting and Cancer, IDIBELL, 08908 Barcelona, Spain
| | - Kathleen Freson
- Department of Cardiovascular Sciences, Center for Molecular and Vascular Biology, University of Leuven, Campus Gasthuisberg, O&N1, Herestraat 49, Box 911, 3000 Leuven, Belgium
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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: 52] [Impact Index Per Article: 5.8] [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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Mantovani G, Elli FM. Pseudohypoparathyroidism type Ib in 2015. ANNALES D'ENDOCRINOLOGIE 2015; 76:101-4. [PMID: 25910998 DOI: 10.1016/j.ando.2015.03.028] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2015] [Accepted: 03/11/2015] [Indexed: 10/23/2022]
Abstract
The term pseudohypoparathryoidism (PHP) refers to a group of rare genetic and epigenetic disorders characterized by resistance to the action of parathyroid hormone (PTH) that activates cAMP signaling in target cells. Together with pseudohypoparathyroidism, Albright hereditary osteodystrophy (AHO) and progressive osseous heteroplasia (POH) represent rare, related and deeply impairing disorders encompassing heterogeneous features, such as brachydactyly, ectopic ossifications, short stature, mental retardation and endocrine deficiencies due to resistance to the action of different hormones. The two main subtypes, PHP-Ia and PHP-Ib, are caused by mutations in GNAS exons 1-13 and methylation defects in the imprinted GNAS cluster respectively, while mutations in the PRKAR1A and PDE4D genes (also involved in mediating cAMP signalling) have been demonstrated in patients with acrodysostosis, a disease of bone formation with characteristics similar to AHO. The molecular overlap among these disorders indicates the need for different classification models and seriously alters our understanding of the mechanisms through which GNAS defects, together with the new recently described defects involving other components of the cAMP signalling cascade, cause AHO-related disorders.
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Affiliation(s)
- Giovanna Mantovani
- Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Endocrinology and Diabetology Unit, Department of Clinical Sciences and Community Health, University of Milan, Via F. Sforza, 35, 20122 Milan, Italy.
| | - Francesca M Elli
- Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Endocrinology and Diabetology Unit, Department of Clinical Sciences and Community Health, University of Milan, Via F. Sforza, 35, 20122 Milan, Italy
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Sano S, Iwata H, Matsubara K, Fukami M, Kagami M, Ogata T. Growth hormone deficiency in monozygotic twins with autosomal dominant pseudohypoparathyroidism type Ib. Endocr J 2015; 62:523-9. [PMID: 25843330 DOI: 10.1507/endocrj.ej15-0033] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Pseudohypoparathyroidism (PHP) is associated with compromised signal transductions via PTH receptor (PTH-R) and other G-protein-coupled receptors including GHRH-R. To date, while GH deficiency (GHD) has been reported in multiple patients with PHP-Ia caused by mutations on the maternally expressed GNAS coding regions and in two patients with sporadic form of PHP-Ib accompanied by broad methylation defects of maternally derived GNAS differentially methylated regions (DMRs), it has not been identified in a patient with an autosomal dominant form of PHP-Ib (AD-PHP-Ib) accompanied by an STX16 microdeletion and an isolated loss of methylation (LOM) at exon A/B-DMR. We studied 5 4/12-year-old monozygotic twins with short stature (both -3.4 SD) and GHD (peak GH values, <6.0 μg/L after arginine and clonidine stimulations). Molecular studies revealed maternally derived STX16 microdeletions and isolated LOMs at exon A/B-DMR in the twins, confirming the diagnosis of AD-PHP-Ib. GNAS mutation was not identified, and neither mutation nor copy number variation was detected in GH1, POU1F1, PROP1, GHRHR, LHX3, LHX4, and HESX1 in the twins. The results, in conjunction with the previous finding that GNAS shows maternal expression in the pituitary, suggest that GHD of the twins is primarily ascribed to compromised GHRH-R signaling caused by AD-PTH-Ib. Thus, resistance to multiple hormones including GHRH should be considered in AD-PHP-Ib.
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Affiliation(s)
- Shinichiro Sano
- Department of Molecular Endocrinology, National Research Institute for Child Health and Development, Tokyo 157-8535, Japan
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Lemos MC, Thakker RV. GNAS mutations in Pseudohypoparathyroidism type 1a and related disorders. Hum Mutat 2014; 36:11-9. [PMID: 25219572 PMCID: PMC4309471 DOI: 10.1002/humu.22696] [Citation(s) in RCA: 87] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2014] [Accepted: 09/02/2014] [Indexed: 12/13/2022]
Abstract
Pseudohypoparathyroidism type 1a (PHP1a) is characterized by hypocalcaemia and hyperphosphatemia due to parathyroid hormone resistance, in association with the features of Albright's hereditary osteodystrophy (AHO). PHP1a is caused by maternally inherited inactivating mutations of Gs-alpha, which is encoded by a complex imprinted locus termed GNAS. Paternally inherited mutations can lead either to pseudopseudohypoparathyroidism (PPHP) characterized by AHO alone, or to progressive osseous heteroplasia (POH), characterized by severe heterotopic ossification. The clinical aspects and molecular genetics of PHP1a and its related disorders are reviewed together with the 343 kindreds with Gs-alpha germline mutations reported so far in the literature. These 343 (176 different) mutations are scattered throughout the 13 exons that encode Gs-alpha and consist of 44.9% frameshift, 28.0% missense, 14.0% nonsense, and 9.0% splice-site mutations, 3.2% in-frame deletions or insertions, and 0.9% whole or partial gene deletions. Frameshift and other highly disruptive mutations were more frequent in the reported 37 POH kindreds than in PHP1a/PPHP kindreds (97.3% vs. 68.7%, P < 0.0001). This mutation update and respective genotype-phenotype data may be of use for diagnostic and research purposes and contribute to a better understanding of these complex disorders.
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Affiliation(s)
- Manuel C Lemos
- CICS-UBI, Health Sciences Research Centre, Faculty of Health Sciences, University of Beira Interior, Covilhã 6200-506, Portugal
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