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Thiele S, Werner R, Grötzinger J, Brix B, Staedt P, Struve D, Reiz B, Farida J, Hiort O. A positive genotype-phenotype correlation in a large cohort of patients with Pseudohypoparathyroidism Type Ia and Pseudo-pseudohypoparathyroidism and 33 newly identified mutations in the GNAS gene. Mol Genet Genomic Med 2014; 3:111-20. [PMID: 25802881 PMCID: PMC4367083 DOI: 10.1002/mgg3.117] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2014] [Revised: 09/21/2014] [Accepted: 09/23/2014] [Indexed: 12/17/2022] Open
Abstract
Maternally inherited inactivating GNAS mutations are the most common cause of parathyroid hormone (PTH) resistance and Albright hereditary osteodystrophy (AHO) leading to pseudohypoparathyroidism type Ia (PHPIa) due to Gsα deficiency. Paternally inherited inactivating mutations lead to isolated AHO signs characterizing pseudo-pseudohypoparathyroidism (PPHP). Mutations are distributed throughout the Gsα coding exons of GNAS and there is a lack of genotype–phenotype correlation. In this study, we sequenced exon 1–13 of GNAS in a large cohort of PHPIa- and PPHP patients and identified 58 different mutations in 88 patients and 27 relatives. Thirty-three mutations including 15 missense mutations were newly discovered. Furthermore, we found three hot spots: a known hotspot (p.D190MfsX14), a second at codon 166 (p.R166C), and a third at the exon 5 acceptor splice site (c.435 + 1G>A), found in 15, 5, and 4 unrelated patients, respectively. Comparing the clinical features to the molecular genetic data, a significantly higher occurrence of subcutaneous calcifications in patients harboring truncating versus missense mutations was demonstrated. Thus, in the largest cohort of PHPIa patients described to date, we extend the spectrum of known GNAS mutations and hot spots and demonstrate for the first time a correlation between the genetic defects and the expression of a clinical AHO-feature.
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Affiliation(s)
- Susanne Thiele
- Division of Experimental Paediatric Endocrinology and Diabetes, Department of Paediatrics, University of Lübeck Lübeck, Germany
| | - Ralf Werner
- Division of Experimental Paediatric Endocrinology and Diabetes, Department of Paediatrics, University of Lübeck Lübeck, Germany
| | - Joachim Grötzinger
- Institute of Biochemistry, Christian-Albrechts-University of Kiel Kiel, Germany
| | - Bettina Brix
- Division of Experimental Paediatric Endocrinology and Diabetes, Department of Paediatrics, University of Lübeck Lübeck, Germany
| | - Pia Staedt
- Division of Experimental Paediatric Endocrinology and Diabetes, Department of Paediatrics, University of Lübeck Lübeck, Germany
| | - Dagmar Struve
- Division of Experimental Paediatric Endocrinology and Diabetes, Department of Paediatrics, University of Lübeck Lübeck, Germany
| | - Benedikt Reiz
- Institute for Integrative and Experimental Genomics, University of Lübeck Lübeck, Germany
| | - Jennane Farida
- Service de Pédiatrie 2 unité, Hôpital universitaire Abderrahim Harouchi Chu ibn Rochd Casablanca, Morocco
| | - Olaf Hiort
- Division of Experimental Paediatric Endocrinology and Diabetes, Department of Paediatrics, University of Lübeck Lübeck, Germany
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Brix B, Werner R, Staedt P, Struve D, Hiort O, Thiele S. Different pattern of epigenetic changes of the GNAS gene locus in patients with pseudohypoparathyroidism type Ic confirm the heterogeneity of underlying pathomechanisms in this subgroup of pseudohypoparathyroidism and the demand for a new classification of GNAS-related disorders. J Clin Endocrinol Metab 2014; 99:E1564-70. [PMID: 24878042 DOI: 10.1210/jc.2013-4477] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
CONTEXT Disorders characterized by PTH resistance are grouped within the term pseudohypoparathyroidism type I (PHPI). Most subtypes of this disease are caused by genetic or epigenetic changes of the GNAS locus leading to deficiency of the α-subunit of stimulatory G proteins (Gsα). Because the in vitro measured Gsα protein activity is normal in pseudohypoparathyroidism Ic (PHPIc), it had previously been postulated that this subtype is caused by impairment of distinct components of the G protein-signaling pathway. However, recently, pathogenic GNAS mutations in a subset of PHPIc patients were found. OBJECTIVE To clarify the underlying pathogenic mechanism of GNAS exon 1-13 mutation-negative PHPIc cases by investigating the differentially methylated regions of GNAS for epigenetic abnormalities. PATIENTS AND METHODS The methylation pattern of GNAS exons A/B, AS, XL, and NESP from blood-derived leukocytes of 26 PHPIc patients was assessed by pyrosequencing of bisulfite-converted DNA. RESULTS Six patients presented with three different patterns of epigenetic changes. One patient had an exclusive loss of methylation of exon A/B associated with a STX16 deletion; four patients had an additional loss of methylation in XL and AS and a gain of methylation in NESP; and one patient presented with partial GNAS methylation changes concerning all differentially methylated regions. CONCLUSIONS Our results confirm that PHPIc is a heterogeneous entity caused in part by impaired Gsα function, not only due to mutations, but also due to abnormal imprinting of GNAS. However, in the majority of cases of PHPIc, the underlying etiopathogenesis remains elusive.
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Affiliation(s)
- Bettina Brix
- Division of Experimental Paediatric Endocrinology and Diabetes, Department of Paediatrics, University of Lübeck, 23538 Lübeck, Germany
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Leyme A, Marivin A, Casler J, Nguyen LT, Garcia-Marcos M. Different biochemical properties explain why two equivalent Gα subunit mutants cause unrelated diseases. J Biol Chem 2014; 289:21818-27. [PMID: 24982418 DOI: 10.1074/jbc.m114.549790] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
There is an increasing number of disease-associated Gα mutations identified from genome-wide sequencing campaigns or targeted efforts. Albright's Hereditary Osteodystrophy (AHO) was the first inherited disease associated with loss-of-function mutations in a G protein (Gαs) and other studies revealed gain-of-function Gα mutations in cancer. Here we attempted to solve the apparent quandary posed by the fact that the same mutation in two different G proteins appeared associated with both AHO and cancer. We first confirmed the presence of an inherited Gαs-R265H mutation from a previously described clinical case report of AHO. This mutation is structurally analogous to Gαo-R243H, an oncogenic mutant with increased activity in vitro and in cells due to rapid nucleotide exchange. We found that, contrary to Gαo-R243H, Gαs-R265H activity is compromised due to greatly impaired nucleotide binding in vitro and in cells. We obtained equivalent results when comparing another AHO mutation in Gαs (D173N) with a counterpart cancer mutation in Gαo (D151N). Gαo-R243H binds nucleotides efficiently under steady-state conditions but releases GDP much faster than the WT protein, suggesting diminished affinity for the nucleotide. These results indicate that the same disease-linked mutation in two different G proteins affects a common biochemical feature (nucleotide affinity) but to a different grade depending on the G protein (mild decrease for Gαo and severe for Gαs). We conclude that Gαs-R265H has dramatically impaired nucleotide affinity leading to the loss-of-function in AHO whereas Gαo-R243H has a mild decrease in nucleotide affinity that causes rapid nucleotide turnover and subsequent hyperactivity in cancer.
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Affiliation(s)
- Anthony Leyme
- From the Department of Biochemistry, Boston University School of Medicine, Boston, Massachusetts 02118
| | - Arthur Marivin
- From the Department of Biochemistry, Boston University School of Medicine, Boston, Massachusetts 02118
| | - Jason Casler
- From the Department of Biochemistry, Boston University School of Medicine, Boston, Massachusetts 02118
| | - Lien T Nguyen
- From the Department of Biochemistry, Boston University School of Medicine, Boston, Massachusetts 02118
| | - Mikel Garcia-Marcos
- From the Department of Biochemistry, Boston University School of Medicine, Boston, Massachusetts 02118
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Hasani-Ranjbar S, Jouyandeh Z, Amoli MM, Soltani A, Arzaghi SM. A patient with features of albright hereditory osteodystrophy and unusual neuropsychiatric findings without coding Gsalpha mutations. J Diabetes Metab Disord 2014; 13:56. [PMID: 24959527 PMCID: PMC4067066 DOI: 10.1186/2251-6581-13-56] [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: 08/27/2013] [Accepted: 04/10/2014] [Indexed: 11/10/2022]
Abstract
BACKGROUND Pseudohypoparathyroidism(PHP) is a heterogeneous group of rare metabolic disorders characterized by hypocalcemia and hyperphosphatemia resulting from PTH resistance. Different forms of PHP have been reported based on biochemical and clinical manifestation and genetic findings. Most of these forms are caused by defects in GNAS, an imprinted gene locus with multiple subunits. We reported a 12- year- old girl with unusual clinical manifestations of Pseudopseudohypoparathyroidism(PPHP). METHODS After clinical and biochemical evaluations, the patients' genomic DNA was isolated from peripheral blood leukocytes using salting out method. The whole coding sequences of GNAS gene including 13 exons were amplified by PCR. Quantitative PCR reactions were performed too. FINDINGS We described a 12- year- old girl with Albright Hereditory osteodystrophy (AHO) phenotype, poor school performance, some abnormal movements, TSH resistance with normal serum calcium and phosphorus levels and normal Gsα bioactivity with no mutation in GNAS exons. Unusual neuropsychiatric findings in this patient were compatible with Asperger syndrome. CONCLUSIONS According to our findings this patient could not be categorized in any of PHP subgroups. Identifying of such individuals may be useful to discover different genetic patterns in pseudohypoparathyroidism and pseudopseudohypoparathyroidism. It is important to identify patients in whom PHP is caused by novel GNAS mutations, as careful investigations of these findings will likely further our knowledge of this complex and this unique disorder. In addition this case presented with unusual neuropsychiatric findings which has not been reported up to now.
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Affiliation(s)
- Shirin Hasani-Ranjbar
- Obesity & Eating Habits Research Center, Endocrinology and metabolism Cellular & Molecular Science Institute, Endocrinology & Metabolism research institute, Tehran University of Medical Sciences, Tehran, Iran ; Endocrinology and Metabolism Research center, Endocrinology & Metabolism research institute, Tehran University of Medical Sciences, Tehran, Iran ; Endocrinology & Metabolism Research Institute, 5th Floor, Shariati Hospital, North Kargar Ave., Tehran 14114, Iran
| | - Zahra Jouyandeh
- Endocrinology and Metabolism Research center, Endocrinology & Metabolism research institute, Tehran University of Medical Sciences, Tehran, Iran
| | - Mahsa Mohammad Amoli
- Endocrinology and Metabolism Research center, Endocrinology & Metabolism research institute, Tehran University of Medical Sciences, Tehran, Iran
| | - Akbar Soltani
- Endocrinology and Metabolism Research center, Endocrinology & Metabolism research institute, Tehran University of Medical Sciences, Tehran, Iran
| | - Seyed Masoud Arzaghi
- Endocrinology and Metabolism Research center, Endocrinology & Metabolism research institute, Tehran University of Medical Sciences, Tehran, Iran
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Todorova-Koteva K, Wood K, Imam S, Jaume JC. Screening for parathyroid hormone resistance in patients with nonphenotypically evident pseudohypoparathyroidism. Endocr Pract 2013; 18:864-9. [PMID: 22784837 DOI: 10.4158/ep12007.or] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
OBJECTIVE Hypocalcemia and hyperphosphatemia in the setting of elevated parathyroid hormone (PTH) and normal vitamin D metabolites, raises the possibility of PTH resistance. The idiopathic and inherited forms of PTH resistance are referred to as pseudohypoparathyroidism. Nonphenotypically evident pseudohypoparathyroidism can go undiagnosed for decades. We have designed a new test to diagnose PTH resistance and confirmed its clinical utility in the diagnosis of pseudohypoparathyroidism. METHODS Our test consists of a subcutaneous injection of commercially available recombinant PTH and concomitant measurement of cyclic adenosine monophosphate in urine. We implemented the test in 2 patients with recalcitrant hypocalcemia and a healthy control subject. RESULTS Our test unequivocally demonstrated PTH resistance in both patients. One of the patients had phenotypically evident pseudohypoparathyroidism type-1a hence, PTH resistance was suspected. The other patient with nonphenotypically evident disease, also showed PTH resistance and was later demonstrated to have pseudohypoparathyroidism type-1b at the genomic level and confirmed to be of familial type. CONCLUSION Our results show for the first time the implementation of a simple new diagnostic tool designed to check for PTH resistance. This new test has already proven to be useful in few occasions at our institution. Larger populations, however, should be tested before implementation of such a test is considered a standard of care.
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Affiliation(s)
- Kristina Todorova-Koteva
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, School of Medicine and Veterans Affairs Medical Center, University of Wisconsin-Madison, Madison, Wisconsin 53792-5148, USA
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Fernández-Rebollo E, Lecumberri B, Gaztambide S, Martinez-Indart L, Perez de Nanclares G, Castaño L. Endocrine profile and phenotype-(epi)genotype correlation in Spanish patients with pseudohypoparathyroidism. J Clin Endocrinol Metab 2013; 98:E996-1006. [PMID: 23533243 DOI: 10.1210/jc.2012-4164] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
CONTEXT Recent advances in genetics and epigenetics have revealed an overlap between molecular and clinical features of pseudohypoparathyroidism (PHP) subtypes, broadening the previous spectrum of PHP genotype-phenotype correlations and indicating limitations of the current classification of the disease. OBJECTIVES The aim of the study was to screen patients with clinical diagnoses of PHP type I or pseudo-PHP for underlying molecular defects and explore possible correlations between molecular findings and clinical features. PATIENTS AND METHODS We investigated the GNAS locus at the molecular level in 72 affected patients (46 women and 26 men) from 56 nonrelated families. Clinical data were obtained for 63 of these patients (38 women and 25 men). RESULTS The molecular analysis showed that 35 patients carried structural mutations, 32 had loss of methylation, and 2 had a 2q37 deletion but did not reveal any (epi)mutation for 3 patients. Comparing these results and the clinical data, we observed that a younger age at diagnosis was associated with structural defects at the GNAS gene and epigenetic defects with a diagnosis later in life (9.19 ± 1.64 vs 24.57 ± 2.28 years, P < .0001). CONCLUSIONS This first global review of PHP in Spain highlights the importance of a detailed clinical and genetic study of each patient and the integrated analysis of the findings from the two approaches. It may also help geneticists and clinicians to raise the suspicion of PHP earlier, reach more accurate diagnoses, and provide patients with PHP and their families with useful genetic information and counseling, thereby improving outcomes and quality of life.
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Affiliation(s)
- Eduardo Fernández-Rebollo
- Endocrinology and Diabetes Research Group, Hospital Universitario de Cruces, Universidad del País Vasco-Euskal Herriko Unibertsitatea, 48903 Barakaldo, Spain
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Thiele S, de Sanctis L, Werner R, Grötzinger J, Aydin C, Jüppner H, Bastepe M, Hiort O. Functional characterization of GNAS mutations found in patients with pseudohypoparathyroidism type Ic defines a new subgroup of pseudohypoparathyroidism affecting selectively Gsα-receptor interaction. Hum Mutat 2011; 32:653-60. [PMID: 21488135 DOI: 10.1002/humu.21489] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2010] [Accepted: 02/09/2011] [Indexed: 01/09/2023]
Abstract
Pseudohypoparathyroidism type Ia (PHPIa) is caused by GNAS mutations leading to deficiency of the α-subunit of stimulatory G proteins (Gsα) that mediate signal transduction of G protein-coupled receptors via cAMP. PHP type Ic (PHPIc) and PHPIa share clinical features of Albright hereditary osteodystrophy (AHO); however, in vitro activity of solubilized Gsα protein is normal in PHPIc but reduced in PHPIa. We screened 32 patients classified as PHPIc for GNAS mutations and identified three mutations (p.E392K, p.E392X, p.L388R) in four unrelated families. These and one novel mutation associated with PHPIa (p.L388P) were introduced into a pcDNA3.1(-) expression vector encoding Gsα wild-type and expressed in a Gsα-null cell line (Gnas(E2-/E2-) ). To investigate receptor-mediated cAMP accumulation, we stimulated the endogenous expressed β(2) -adrenergic receptor, or the coexpressed PTH or TSH receptors, and measured the synthesized cAMP by RIA. The results were compared to receptor-independent cholera toxin-induced cAMP accumulation. Each of the mutants associated with PHPIc significantly reduced or completely disrupted receptor-mediated activation, but displayed normal receptor-independent activation. In contrast, PHPIa associated p.L388P disrupted both receptor-mediated activation and receptor-independent activation. We present a new subgroup of PHP that is caused by Gsα deficiency and selectively affects receptor coupling functions of Gsα.
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Affiliation(s)
- Susanne Thiele
- Department of Pediatrics and Adolescent Medicine, University of Lübeck, Germany.
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Makita N, Sato J, Rondard P, Fukamachi H, Yuasa Y, Aldred MA, Hashimoto M, Fujita T, Iiri T. Human G(salpha) mutant causes pseudohypoparathyroidism type Ia/neonatal diarrhea, a potential cell-specific role of the palmitoylation cycle. Proc Natl Acad Sci U S A 2007; 104:17424-9. [PMID: 17962410 PMCID: PMC2077272 DOI: 10.1073/pnas.0708561104] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2007] [Indexed: 01/08/2023] Open
Abstract
Pseudohypoparathyroidism type Ia (PHP-Ia) results from the loss of one allele of G(salpha), causing resistance to parathyroid hormone and other hormones that transduce signals via G(s). Most G(salpha)mutations cause the complete loss of protein expression, but some cause loss of function only, and these have provided valuable insights into the normal function of G proteins. Here we have analyzed a mutant G(salpha) (alphas-AVDT) harboring AVDT amino acid repeats within its GDP/GTP binding site, which was identified in unique patients with PHP-Ia accompanied by neonatal diarrhea. Biochemical and intact cell analyses showed that alphas-AVDT is unstable but constitutively active as a result of rapid GDP release and reduced GTP hydrolysis. This instability underlies the PHP-Ia phenotype. alphas-AVDT is predominantly localized in the cytosol, but in rat and mouse small intestine epithelial cells (IEC-6 and DIF-12 cells) alphas-AVDT was found to be localized predominantly in the membrane where adenylyl cyclase is present and constitutive increases in cAMP accumulation occur in parallel. The likely cause of this membrane localization is the inhibition of an activation-dependent decrease in alphas palmitoylation. Upon the overexpression of acyl-protein thioesterase 1, however, alphas-AVDT translocates from the membrane to the cytosol, and the constitutive accumulation of cAMP becomes attenuated. These results suggest that PHP-Ia results from the instability of alphas-AVDT and that the accompanying neonatal diarrhea may result from its enhanced constitutive activity in the intestine. Hence, palmitoylation may control the activity and localization of G(salpha) in a cell-specific manner.
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Affiliation(s)
- Noriko Makita
- *Department of Endocrinology and Nephrology, University of Tokyo School of Medicine, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-8655, Japan
| | - Junichiro Sato
- *Department of Endocrinology and Nephrology, University of Tokyo School of Medicine, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-8655, Japan
| | - Philippe Rondard
- Institut de Génomique Fonctionnelle, 141 Rue de la Cardonille, 34094 Montpellier Cedex 5, France
| | - Hiroshi Fukamachi
- Department of Molecular Oncology, Graduate School of Medicine and Dentistry, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8549, Japan; and
| | - Yasuhito Yuasa
- Department of Molecular Oncology, Graduate School of Medicine and Dentistry, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8549, Japan; and
| | - Micheala A. Aldred
- Division of Medical Genetics, University of Leicester and Leicestershire Genetics Service, University Hospitals of Leicester NHS Trust, Leicester, United Kingdom
| | - Makiko Hashimoto
- *Department of Endocrinology and Nephrology, University of Tokyo School of Medicine, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-8655, Japan
| | - Toshiro Fujita
- *Department of Endocrinology and Nephrology, University of Tokyo School of Medicine, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-8655, Japan
| | - Taroh Iiri
- *Department of Endocrinology and Nephrology, University of Tokyo School of Medicine, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-8655, Japan
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