1
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Liu L, Hu C, Chen Z, Zhu S, Zhu L. Co-Occurring Thrombotic Thrombocytopenic Purpura and Autoimmune Hemolytic Anemia in a Child Carrying the Pathogenic SHOC2 c.4A>G (p.Ser2Gly) Variant. AMERICAN JOURNAL OF CASE REPORTS 2023; 24:e942377. [PMID: 38019730 PMCID: PMC10697549 DOI: 10.12659/ajcr.942377] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Revised: 11/21/2023] [Accepted: 11/11/2023] [Indexed: 12/01/2023]
Abstract
BACKGROUND RASopathies involve mutations in genes that encode proteins participating in the RAS-mitogen-activated protein kinase pathway and are a collection of multisystem disorders that clinically overlap. Variants in the SHOC2 gene have been reported in Noonan-like syndrome, which include distinct facial features, short stature, congenital cardiac defects, developmental delays, bleeding disorders, and loose anagen hair. This report is of a 7-year-old girl with the c.4A>G (p.Ser2Gly) variant of the SHOC2 gene, consistent with Noonan-like syndrome, with loose anagen hair, presenting with thrombotic thrombocytopenic purpura and autoimmune hemolytic anemia. CASE REPORT The child had a medical history of 7 hospitalizations at our institution. At the age of 2 months, she underwent surgical correction for ventricular and atrial septal defects. At the age of 2 years, tonsil and adenoid removal surgery was performed, followed by surgery for otitis media at age 5 years. At 7 years, she was hospitalized for the simultaneous occurrence of thrombotic thrombocytopenic purpura and autoimmune hemolytic anemia. The patient displayed short stature and mild intellectual disability. Notable facial features included sparse hair, mild frontal bossing, and low-set ears. Antinuclear antibody levels demonstrated a significant gradual shift. Through trio whole-exome sequencing, a c.4A>G (p.Ser2Gly) variation in the SHOC2 gene was identified. CONCLUSIONS Given the clinical information and genetic testing results, the patient's condition appeared to closely be a type of RASopathy. This report has highlighted the importance of physical, developmental, and genetic testing in children presenting with dysmorphism, developmental delay, and hematological abnormalities.
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Affiliation(s)
- Lijun Liu
- Department of Pediatric Intensive Care Unit, Children’s Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, PR China
| | - Chanchan Hu
- Department of Pediatric Intensive Care Unit, Children’s Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, PR China
| | - Zhenjie Chen
- Department of Pediatric Intensive Care Unit, Children’s Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, PR China
| | - Shuzhen Zhu
- Department of Emergency, Children’s Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, Hangzhou, Zhejiang, PR China
| | - Lvchang Zhu
- Department of Pediatric Intensive Care Unit, Children’s Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, PR China
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2
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Campbell L, Fredericks J, Mathivha K, Moshesh P, Coovadia A, Chirwa P, Dillon B, Ghoor A, Lawrence D, Nair L, Mabaso N, Mokwele D, Novellie M, Krause A, Carstens N. The implementation and utility of clinical exome sequencing in a South African infant cohort. Front Genet 2023; 14:1277948. [PMID: 38028619 PMCID: PMC10665497 DOI: 10.3389/fgene.2023.1277948] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2023] [Accepted: 10/23/2023] [Indexed: 12/01/2023] Open
Abstract
Genetic disorders are significant contributors to infant hospitalization and mortality globally. The early diagnosis of these conditions in infants remains a considerable challenge. Clinical exome sequencing (CES) has shown to be a successful tool for the early diagnosis of genetic conditions, however, its utility in African infant populations has not been investigated. The impact of the under-representation of African genomic data, the cost of testing, and genomic workforce shortages, need to be investigated and evidence-based implementation strategies accounting for locally available genetics expertise and diagnostic infrastructure need to be developed. We evaluated the diagnostic utility of singleton CES in a cohort of 32 ill, South African infants from two State hospitals in Johannesburg, South Africa. We analysed the data using a series of filtering approaches, including a curated virtual gene panel consisting of genes implicated in neonatal-and early childhood-onset conditions and genes with known founder and common variants in African populations. We reported a diagnostic yield of 22% and identified seven pathogenic variants in the NPHS1, COL2A1, OCRL, SHOC2, TPRV4, MTM1 and STAC3 genes. This study demonstrates the utility value of CES in the South African State healthcare setting, providing a diagnosis to patients who would otherwise not receive one and allowing for directed management. We anticipate an increase in the diagnostic yield of our workflow with further refinement of the study inclusion criteria. This study highlights important considerations for the implementation of genomic medicine in under-resourced settings and in under-represented African populations where variant interpretation remains a challenge.
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Affiliation(s)
- L. Campbell
- Division of Human Genetics, National Health Laboratory Service andSchool of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - J. Fredericks
- Department of Paediatrics and Child Health, School of Clinical Medicine, Rahima Moosa Mother and Child Hospital, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - K. Mathivha
- Department of Paediatrics and Child Health, School of Clinical Medicine, Nelson Mandela Children’s Hospital, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - P. Moshesh
- Department of Paediatrics and Child Health, School of Clinical Medicine, Nelson Mandela Children’s Hospital, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - A. Coovadia
- Department of Paediatrics and Child Health, School of Clinical Medicine, Rahima Moosa Mother and Child Hospital, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - P. Chirwa
- Nelson Mandela Children’s Hospital, Johannesburg, South Africa
| | - B. Dillon
- Division of Human Genetics, National Health Laboratory Service andSchool of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - A. Ghoor
- Department of Paediatrics and Child Health, School of Clinical Medicine, Rahima Moosa Mother and Child Hospital, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - D. Lawrence
- Department of Paediatrics and Child Health, School of Clinical Medicine, Rahima Moosa Mother and Child Hospital, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - L. Nair
- Department of Paediatrics and Child Health, School of Clinical Medicine, Rahima Moosa Mother and Child Hospital, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - N. Mabaso
- Division of Human Genetics, National Health Laboratory Service andSchool of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - D. Mokwele
- Division of Human Genetics, National Health Laboratory Service andSchool of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - M. Novellie
- Division of Human Genetics, National Health Laboratory Service andSchool of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - A. Krause
- Division of Human Genetics, National Health Laboratory Service andSchool of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - N. Carstens
- Division of Human Genetics, National Health Laboratory Service andSchool of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
- Genomics Platform, South African Medical Research Council, Cape Town, South Africa
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3
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Frey T, Ivanovski I, Bahr A, Zweier M, Laube J, Luchsinger I, Steindl K, Rauch A. A very mild phenotype in six individuals of a three-generation family with the novel HRAS variant c.176C > G p.(Ala59Gly): Emergence of a new HRAS-related RASopathy distinct from Costello syndrome. Am J Med Genet A 2023; 191:2074-2082. [PMID: 37194190 DOI: 10.1002/ajmg.a.63240] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Revised: 04/26/2023] [Accepted: 04/29/2023] [Indexed: 05/18/2023]
Abstract
Costello syndrome is a clinically recognizable, severe neurodevelopmental disorder caused by heterozygous activating variants in HRAS. The vast majority of affected patients share recurring variants affecting HRAS codons 12 and 13 and a relatively uniform phenotype. Here, we report the unique and attenuated phenotype of six individuals of an extended family affected by the HRAS variant c.176C>T p.(Ala59Gly), which, to our knowledge, has never been reported as a germline variant in patients so far. HRAS Alanine 59 has been previously functionally investigated as an oncogenic hotspot and the p.Ala59Gly substitution was shown to impair intrinsic GTP hydrolysis. All six individuals we report share a phenotype of ectodermal anomalies and mild features suggestive of a RASopathy, reminiscent of patients with Noonan syndrome-like disorder with loose anagen hair. All six are of normal intelligence, none have a history of failure to thrive or malignancy, and they have no known cardiac or neurologic pathologies. Our report adds to the previous reports of patients with rare variants affecting amino acids located in the SWITCH II/G3 region of HRAS and suggests a consistent, attenuated phenotype distinct from classical Costello syndrome. We propose the definition of a new distinct HRAS-related RASopathy for patients carrying HRAS variants affecting codons 58, 59, 60.
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Affiliation(s)
- Tanja Frey
- Institute of Medical Genetics, University of Zurich, Zurich, Switzerland
| | - Ivan Ivanovski
- Institute of Medical Genetics, University of Zurich, Zurich, Switzerland
| | - Angela Bahr
- Institute of Medical Genetics, University of Zurich, Zurich, Switzerland
| | - Markus Zweier
- Institute of Medical Genetics, University of Zurich, Zurich, Switzerland
| | - Julia Laube
- Institute of Medical Genetics, University of Zurich, Zurich, Switzerland
| | - Isabelle Luchsinger
- Department of Dermatology, Pediatric Skin Center, University Children's Hospital Zurich, Zurich, Switzerland
| | - Katharina Steindl
- Institute of Medical Genetics, University of Zurich, Zurich, Switzerland
| | - Anita Rauch
- Institute of Medical Genetics, University of Zurich, Zurich, Switzerland
- University Children's Hospital Zurich, Zurich, Switzerland
- University of Zurich Research Priority Program ITINERARE: Innovative Therapies in Rare Diseases, Zurich, Switzerland
- University of Zurich Research Priority Program AdaBD: Adaptive Brain Circuits in Development and Learning, Zurich, Switzerland
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4
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Ayaz E, Yıldırım R, Çelebi C, Ozalkak S. Noonan syndrome: Neuroimaging findings and morphometric analysis of the cranium base and posterior fossa in children. J Neuroimaging 2023; 33:318-327. [PMID: 36480458 DOI: 10.1111/jon.13075] [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: 09/14/2022] [Revised: 10/28/2022] [Accepted: 11/23/2022] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND AND PURPOSE There are a few studies regarding intracranial findings in neonates with Noonan syndrome (NS); however, there are no quantitative analyses in a pediatric population. The aim of this study was to find characteristic intracranial abnormalities and to quantitatively analyze the posterior fossa and cranium base in children with NS. METHODS A total of 30 patients (11 females and 19 males, mean age 13.1 ± 4.3 years) were retrospectively identified between July 2017 and June 2022. Twenty-one patients had MRI. Age at MRI examination, sex, genetic mutations, and clinical findings were noted. In patients with MRI, the presence of white matter lesions, basal ganglia lesions, corpus callosum abnormalities, sellar/parasellar lesions, and tonsillar ectopia was noted. For morphometric analysis, cerebellar diameter, vermis and clivus heights, cranial base, tentorial and infratentorial angles, and McRae's and Twining's lines were each measured twice by two radiologists individually. RESULTS The most common lesions were focal white matter lesions, followed by abnormalities of the splenium of the corpus callosum. The cerebellar diameter, vermis and clivus heights, Twining's line, and infratentorial angle were significantly smaller; cranial base angle and tentorial angle were significantly larger in NS (p < .05). Interrater and intrarater agreements were the highest for cerebellar diameter and the lowest for tentorial angle measurements. CONCLUSION Children with NS had characteristic callosal and tentorial findings and neuroimaging findings similar to other RASopathies. This study also shows that a small posterior fossa and flattening of the cranial base are present in children with NS, which may aid in diagnosis.
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Affiliation(s)
- Ercan Ayaz
- Department of Radiology, Diyarbakir Children's Hospital, Diyarbakir, Turkey
| | - Ruken Yıldırım
- Department of Pediatric Endocrinology, Diyarbakir Children's Hospital, Diyarbakir, Turkey
| | - Canan Çelebi
- Department of Radiology, Diyarbakir Children's Hospital, Diyarbakir, Turkey
| | - Servan Ozalkak
- Department of Pediatric Endocrinology, Diyarbakir Children's Hospital, Diyarbakir, Turkey
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5
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Wang Q, Cheng S, Fu Y, Yuan H. Case report: A de novo RASopathy-causing SHOC2 variant in a Chinese girl with noonan syndrome-like with loose anagen hair. Front Genet 2022; 13:1040124. [PMID: 36579329 PMCID: PMC9792188 DOI: 10.3389/fgene.2022.1040124] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2022] [Accepted: 11/28/2022] [Indexed: 12/14/2022] Open
Abstract
Pathogenic variants in the RASopathy-causing SHOC2 gene have been suggested to cause Noonan syndrome-like with loose anagen hair (NS/LAH). This condition is characterized by facial features resembling Noonan syndrome (NS), short stature, growth hormone deficiency (GHD), cognitive deficits, cardiac defects, and ectodermal abnormalities, including easily pluckable, sparse, thin, slow-growing hair, hyperpigmented skin and hypernasal voice. The mutation spectrum of SHOC2 is narrow, and only 8 pathogenic variants have been identified. Here, we report a 5-year-3-month-old Chinese female who displays characteristics typical of NS and has normal neurodevelopment. Trio-based whole-exome sequencing (WES) revealed a de novo variant (c.1231A>G, p.Thr411Ala) in SHOC2. This variant has been recently reported in one subject in the literature who displayed facial features typical of NS and also presented with significant speech delays, moderate intellectual disabilities, epilepsy, bilateral sensorineural deafness and renal dysplasia. The differential phenotypes between these subjects deserve to be further investigated. Next, we reviewed the clinical pictures of NS/LAH and noticed that a recurrent SHOC2 Ser2Gly variant was more likely to result in delayed neurodevelopment and short stature, compared to other SHOC2 variants. And growth hormone (GH) therapy could improve height prognosis. It was noticed that the slight sleep problems and friendly and relatively mature personality observed in our patient may be a novel phenotype of NS/LAH. Our study reconfirms the pathogenic nature of the SHOC2 Thr411Ala variant. It also provides insights into the genotype-phenotype relationship in NS/LAH and a foundation for its genetic counseling, diagnosis and treatment.
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Affiliation(s)
- Qingming Wang
- Dongguan Maternal and Child Healthcare Hospital, Dongguan, China,Dongguan Institute of Reproductive and Genetic Research, Dongguan, China
| | - Shuangxi Cheng
- Dongguan Maternal and Child Healthcare Hospital, Dongguan, China
| | - Youqing Fu
- Dongguan Maternal and Child Healthcare Hospital, Dongguan, China
| | - Haiming Yuan
- Dongguan Maternal and Child Healthcare Hospital, Dongguan, China,Dongguan Institute of Reproductive and Genetic Research, Dongguan, China,*Correspondence: Haiming Yuan,
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6
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Wingbermühle E, Roelofs RL, Oomens W, Kramer J, Draaisma JMT, Leenders E, Kleefstra T, Kessels RPC, Egger JIM. Cognitive Phenotype and Psychopathology in Noonan Syndrome Spectrum Disorders through Various Ras/MAPK Pathway Associated Gene Variants. J Clin Med 2022; 11:jcm11164735. [PMID: 36012976 PMCID: PMC9410383 DOI: 10.3390/jcm11164735] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Revised: 08/01/2022] [Accepted: 08/11/2022] [Indexed: 12/02/2022] Open
Abstract
Cognitive difficulties are argued to be common in patients with Noonan syndrome spectrum disorders (NSSDs), but findings are based on studies in which patients with variants in PTPN11 (prevalence ~50%) were overrepresented. The current study, using a structured clinical approach, describes the cognitive phenotype and psychopathology of 100 patients (aged 6 to 61 years) with nine different gene variants in the Ras/MAPK pathway underlying NSSDs (PTPN11n = 61, PTPN11 Noonan syndrome with multiple lentigines n = 3, SOS1n = 14, KRASn = 7, LZTR1n = 5, RAF1n = 4, SHOC2n = 2, CBLn = 2, SOS2n = 2). After weighted assessment and bootstrapping of the results of individual neuropsychological assessments and measures of psychopathology, cognitive performances in most variant groups were within the ranges of expectation. IQs were significantly lower in patients with variants in PTPN11, KRAS, RAF1, and SHOC2, but no specific cognitive impairments were found. The performances of younger participants (<16 years of age) did not differ from those of adults. Alexithymia and internalizing problems were more frequent in patients with variants in PTPN11 and SOS1, while PTPN11 patients also showed higher levels of externalizing problems. These results stress the need to take intelligence into account when interpreting lower cognitive performances in individual neuropsychological assessments, which is crucial for an adequate understanding and guidance of patients with NSSDs.
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Affiliation(s)
- Ellen Wingbermühle
- Center of Excellence for Neuropsychiatry, Vincent van Gogh Institute for Psychiatry, 5803 DM Venray, The Netherlands
- Donders Institute for Brain, Cognition and Behaviour, Radboud University, 6525 GD Nijmegen, The Netherlands
- Department of Human Genetics, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands
- Correspondence:
| | - Renée L. Roelofs
- Center of Excellence for Neuropsychiatry, Vincent van Gogh Institute for Psychiatry, 5803 DM Venray, The Netherlands
- Department of Human Genetics, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands
| | - Wouter Oomens
- Center of Excellence for Neuropsychiatry, Vincent van Gogh Institute for Psychiatry, 5803 DM Venray, The Netherlands
- Donders Institute for Brain, Cognition and Behaviour, Radboud University, 6525 GD Nijmegen, The Netherlands
| | - Jennifer Kramer
- Center of Excellence for Neuropsychiatry, Vincent van Gogh Institute for Psychiatry, 5803 DM Venray, The Netherlands
| | - Jos M. T. Draaisma
- Department of Pediatrics, Amalia Children’s Hospital, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands
| | - Erika Leenders
- Department of Human Genetics, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands
| | - Tjitske Kleefstra
- Center of Excellence for Neuropsychiatry, Vincent van Gogh Institute for Psychiatry, 5803 DM Venray, The Netherlands
- Donders Institute for Brain, Cognition and Behaviour, Radboud University, 6525 GD Nijmegen, The Netherlands
- Department of Human Genetics, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands
| | - Roy P. C. Kessels
- Donders Institute for Brain, Cognition and Behaviour, Radboud University, 6525 GD Nijmegen, The Netherlands
- Center of Excellence for Korsakoff and Alcohol-Related Cognitive Disorders, Vincent van Gogh Institute for Psychiatry, 5803 DN Venray, The Netherlands
- Department of Medical Psychology and Radboudumc Alzheimer Center, Radboud University Medical Center, 6500 HB Nijmegen, The Netherlands
| | - Jos I. M. Egger
- Center of Excellence for Neuropsychiatry, Vincent van Gogh Institute for Psychiatry, 5803 DM Venray, The Netherlands
- Donders Institute for Brain, Cognition and Behaviour, Radboud University, 6525 GD Nijmegen, The Netherlands
- Department of Human Genetics, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands
- Center of Excellence for Korsakoff and Alcohol-Related Cognitive Disorders, Vincent van Gogh Institute for Psychiatry, 5803 DN Venray, The Netherlands
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7
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Beltrami B, Cerasani J, Consales A, Villa R, Resta N, Loconte DC, Boito S, Caschera L, Bassi L, Colombo L, Iascone M, Bedeschi MF. Prenatal overgrowth and polydramnios: Would you think about Noonan syndrome? Clin Case Rep 2022; 10:e6256. [PMID: 36017115 PMCID: PMC9393876 DOI: 10.1002/ccr3.6256] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Revised: 06/17/2022] [Accepted: 07/21/2022] [Indexed: 11/08/2022] Open
Abstract
We report on a child with prenatal findings of increased nuchal translucency, polydramnios, ascites, and overgrowth. At birth, she presented length >97° centile, minor facial anomalies, megalencephaly, and Wolff–Parkinson–White syndrome. Whole‐exome sequencing showed a pathogenic variant in the NRAS gene, but no mutations were found in PI3K/AKT/mTOR pathway genes.
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Affiliation(s)
- Benedetta Beltrami
- Medical Genetics Unit Fondazione IRCCS Ca'Granda Ospedale Maggiore Policlinico Milan Italy
| | - Jacopo Cerasani
- Neonatal Intensive Care Unit (NICU), Department of Clinical Science and Community Health Università degli Studi di Milano and Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico Milan Italy
| | - Alessandra Consales
- Neonatal Intensive Care Unit (NICU), Department of Clinical Science and Community Health Università degli Studi di Milano and Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico Milan Italy
| | - Roberta Villa
- Medical Genetics Unit Fondazione IRCCS Ca'Granda Ospedale Maggiore Policlinico Milan Italy
| | - Nicoletta Resta
- Department of Biomedical Sciences and Human Oncology (DIMO), Medical Genetics University of Bari “Aldo Moro” Bari Italy
| | - Daria Carmela Loconte
- Department of Biomedical Sciences and Human Oncology (DIMO), Medical Genetics University of Bari “Aldo Moro” Bari Italy
| | - Simona Boito
- Fetal Medicine and Surgery Service Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico Milan Italy
| | - Luca Caschera
- Neuroradiology Unit Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico Milan Italy
| | - Laura Bassi
- Neonatal Intensive Care Unit (NICU), Department of Clinical Science and Community Health Università degli Studi di Milano and Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico Milan Italy
| | - Lorenzo Colombo
- Neonatal Intensive Care Unit (NICU), Department of Clinical Science and Community Health Università degli Studi di Milano and Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico Milan Italy
| | - Maria Iascone
- Laboratory of Medical Genetics Ospedale Papa Giovanni XXIII Bergamo Italy
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8
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Clinical report of a brain magnetic resonance imaging finding in Noonan syndrome. Childs Nerv Syst 2021; 37:3963-3966. [PMID: 33811550 DOI: 10.1007/s00381-021-05149-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Accepted: 03/24/2021] [Indexed: 10/21/2022]
Abstract
Noonan syndrome (NS) is an autosomal dominant disease caused by aberrant up-regulated signaling through RAS GTPase. It is characterized by facial dysmorphisms, short stature, congenital heart defects, malformations of rib cage bones, bleeding problems, learning difficulties, or mild intellectual disability. Additional intracranial findings in NS patients include tumors, midline anomalies, and malformations of cortical development. In this report, we present the case of a young female patient, with a known diagnosis of Noonan syndrome that in complete well being developed two brain lesions, in the right nucleus pallidus and in the left cerebellar hemisphere respectively, whose location and signal on MRI looked similar to neurofibromatosis type 1 unidentified bright objects (UBOs), and whose spectroscopic characteristics excluded neoplasms.
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9
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Leoni C, Blandino R, Delogu AB, De Rosa G, Onesimo R, Verusio V, Marino MV, Lanza GA, Rigante D, Tartaglia M, Zampino G. Genotype-cardiac phenotype correlations in a large single-center cohort of patients affected by RASopathies: Clinical implications and literature review. Am J Med Genet A 2021; 188:431-445. [PMID: 34643321 DOI: 10.1002/ajmg.a.62529] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Revised: 08/11/2021] [Accepted: 09/21/2021] [Indexed: 11/07/2022]
Abstract
Congenital heart disease (CHD) and hypertrophic cardiomyopathy (HCM) are common features in patients affected by RASopathies. The aim of this study was to assess genotype- phenotype correlations, focusing on the cardiac features and outcomes of interventions for cardiac conditions, in a single-center cohort of 116 patients with molecularly confirmed diagnosis of RASopathy, and compare these findings with previously published data. All enrolled patients underwent a comprehensive echocardiographic examination. Relevant information was also retrospectively collected through the analysis of clinical records. As expected, significant associations were found between PTPN11 mutations and pulmonary stenosis (both valvular and supravalvular) and pulmonary valve dysplasia, and between SOS1 mutations and valvular defects. Similarly, HRAS mutations were significantly associated with HCM. Potential associations between less prevalent mutations and cardiac defects were also observed, including RIT1 mutations and HCM, SOS2 mutations and septal defects, and SHOC2 mutations and septal and valve abnormalities. Patients with PTPN11 mutations were the most likely to require both a primary treatment (transcatheter or surgical) and surgical reintervention. Other cardiac anomalies less reported until recently in this population, such as isolated functional and structural mitral valve diseases, as well as a sigmoid-shaped interventricular septum in the absence of HCM, were also reported. In conclusion, our study confirms previous data but also provides new insights on cardiac involvement in RASopathies. Further research concerning genotype/phenotype associations in RASopathies could lead to a more rational approach to surgery and the consideration of drug therapy in patients at higher risk due to age, severity, anatomy, and comorbidities.
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Affiliation(s)
- Chiara Leoni
- Center for Rare Diseases and Birth Defects, Department of Woman and Child Health and Public Health, Fondazione Policlinico Universitario A. Gemelli, Rome, Italy
| | - Rita Blandino
- Unit of Pediatrics, Pediatric Cardiology, Department of Woman and Child Health and Public Health, Fondazione Policlinico Universitario A. Gemelli IRCCS, Rome, Italy
| | - Angelica Bibiana Delogu
- Unit of Pediatrics, Pediatric Cardiology, Department of Woman and Child Health and Public Health, Fondazione Policlinico Universitario A. Gemelli IRCCS, Rome, Italy.,Università Cattolica del Sacro Cuore, Rome, Italy
| | - Gabriella De Rosa
- Unit of Pediatrics, Pediatric Cardiology, Department of Woman and Child Health and Public Health, Fondazione Policlinico Universitario A. Gemelli IRCCS, Rome, Italy.,Università Cattolica del Sacro Cuore, Rome, Italy
| | - Roberta Onesimo
- Center for Rare Diseases and Birth Defects, Department of Woman and Child Health and Public Health, Fondazione Policlinico Universitario A. Gemelli, Rome, Italy
| | - Valeria Verusio
- Unit of Pediatrics, Pediatric Cardiology, Department of Woman and Child Health and Public Health, Fondazione Policlinico Universitario A. Gemelli IRCCS, Rome, Italy
| | - Maria Vittoria Marino
- Unit of Pediatrics, Pediatric Cardiology, Department of Woman and Child Health and Public Health, Fondazione Policlinico Universitario A. Gemelli IRCCS, Rome, Italy
| | - Gaetano Antonio Lanza
- Università Cattolica del Sacro Cuore, Rome, Italy.,Department of Cardiovascular and Thoracic Sciences, Fondazione Policlinico Universitario A. Gemelli IRCSS, Rome, Italy
| | - Donato Rigante
- Center for Rare Diseases and Birth Defects, Department of Woman and Child Health and Public Health, Fondazione Policlinico Universitario A. Gemelli, Rome, Italy.,Università Cattolica del Sacro Cuore, Rome, Italy
| | - Marco Tartaglia
- Genetics and Rare Diseases Research Division, Ospedale Pediatrico Bambino Gesù, IRCCS, Rome, Italy
| | - Giuseppe Zampino
- Center for Rare Diseases and Birth Defects, Department of Woman and Child Health and Public Health, Fondazione Policlinico Universitario A. Gemelli, Rome, Italy.,Università Cattolica del Sacro Cuore, Rome, Italy
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10
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Soetens E, Ballegeer M, Saelens X. An Inside Job: Applications of Intracellular Single Domain Antibodies. Biomolecules 2020; 10:biom10121663. [PMID: 33322697 PMCID: PMC7764588 DOI: 10.3390/biom10121663] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Revised: 12/09/2020] [Accepted: 12/10/2020] [Indexed: 02/06/2023] Open
Abstract
Sera of camelid species contain a special kind of antibody that consists only of heavy chains. The variable antigen binding domain of these heavy chain antibodies can be expressed as a separate entity, called a single domain antibody that is characterized by its small size, high solubility and oftentimes exceptional stability. Because of this, most single domain antibodies fold correctly when expressed in the reducing environment of the cytoplasm, and thereby retain their antigen binding specificity. Single domain antibodies can thus be used to target a broad range of intracellular proteins. Such intracellular single domain antibodies are also known as intrabodies, and have proven to be highly useful tools for basic research by allowing visualization, disruption and even targeted degradation of intracellular proteins. Furthermore, intrabodies can be used to uncover prospective new therapeutic targets and have the potential to be applied in therapeutic settings in the future. In this review we provide a brief overview of recent advances in the field of intracellular single domain antibodies, focusing on their use as research tools and potential therapeutic applications. Special attention is given to the available methods that allow delivery of single domain antibodies into cells.
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Affiliation(s)
- Eline Soetens
- VIB-UGent Center for Medical Biotechnology, VIB, B-9052 Ghent, Belgium; (E.S.); (M.B.)
- Department of Biochemistry and Microbiology, Ghent University, B-9000 Ghent, Belgium
| | - Marlies Ballegeer
- VIB-UGent Center for Medical Biotechnology, VIB, B-9052 Ghent, Belgium; (E.S.); (M.B.)
- Department of Biochemistry and Microbiology, Ghent University, B-9000 Ghent, Belgium
| | - Xavier Saelens
- VIB-UGent Center for Medical Biotechnology, VIB, B-9052 Ghent, Belgium; (E.S.); (M.B.)
- Department of Biochemistry and Microbiology, Ghent University, B-9000 Ghent, Belgium
- Correspondence:
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11
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Jang H, Stevens P, Gao T, Galperin E. The leucine-rich repeat signaling scaffolds Shoc2 and Erbin: cellular mechanism and role in disease. FEBS J 2020; 288:721-739. [PMID: 32558243 DOI: 10.1111/febs.15450] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Revised: 05/28/2020] [Accepted: 06/10/2020] [Indexed: 12/12/2022]
Abstract
Leucine-rich repeat-containing proteins (LRR proteins) are involved in supporting a large number of cellular functions. In this review, we summarize recent advancements in understanding functions of the LRR proteins as signaling scaffolds. In particular, we explore what we have learned about the mechanisms of action of the LRR scaffolds Shoc2 and Erbin and their roles in normal development and disease. We discuss Shoc2 and Erbin in the context of their multiple known interacting partners in various cellular processes and summarize often unexpected functions of these proteins through analysis of their roles in human pathologies. We also review these LRR scaffold proteins as promising therapeutic targets and biomarkers with potential application across various pathologies.
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Affiliation(s)
- HyeIn Jang
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, KY, USA
| | - Payton Stevens
- Center for Cancer and Cell Biology, Van Andel Institute, Grand Rapids, MI, USA
| | - Tianyan Gao
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, KY, USA.,Markey Cancer Center, University of Kentucky, Lexington, KY, USA
| | - Emilia Galperin
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, KY, USA
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12
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Patterson VL, Burdine RD. Swimming toward solutions: Using fish and frogs as models for understanding RASopathies. Birth Defects Res 2020; 112:749-765. [PMID: 32506834 DOI: 10.1002/bdr2.1707] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Accepted: 04/25/2020] [Indexed: 12/16/2022]
Abstract
The RAS signaling pathway regulates cell growth, survival, and differentiation, and its inappropriate activation is associated with disease in humans. The RASopathies, a set of developmental syndromes, arise when the pathway is overactive during development. Patients share a core set of symptoms, including congenital heart disease, craniofacial anomalies, and neurocognitive delay. Due to the conserved nature of the pathway, animal models are highly informative for understanding disease etiology, and zebrafish and Xenopus are emerging as advantageous model systems. Here we discuss these aquatic models of RASopathies, which recapitulate many of the core symptoms observed in patients. Craniofacial structures become dysmorphic upon expression of disease-associated mutations, resulting in wider heads. Heart defects manifest as delays in cardiac development and changes in heart size, and behavioral deficits are beginning to be explored. Furthermore, early convergence and extension defects cause elongation of developing embryos: this phenotype can be quantitatively assayed as a readout of mutation strength, raising interesting questions regarding the relationship between pathway activation and disease. Additionally, the observation that RAS signaling may be simultaneously hyperactive and attenuated suggests that downregulation of signaling may also contribute to etiology. We propose that models should be characterized using a standardized approach to allow easier comparison between models, and a better understanding of the interplay between mutation and disease presentation.
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Affiliation(s)
- Victoria L Patterson
- Department of Molecular Biology, Princeton University, Princeton, New Jersey, USA
| | - Rebecca D Burdine
- Department of Molecular Biology, Princeton University, Princeton, New Jersey, USA
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13
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Alkhunaizi E, Unger S, Shannon P, Nishimura G, Blaser S, Chitayat D. Maternal SLE and brachytelephalangic chondrodysplasia punctata in a patient with unrelated de novo RAF1 and SIX2 variants. Am J Med Genet A 2020; 182:1807-1811. [PMID: 32506814 DOI: 10.1002/ajmg.a.61621] [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: 07/09/2019] [Revised: 02/29/2020] [Accepted: 03/16/2020] [Indexed: 11/07/2022]
Abstract
Our improved tools to identify the aetiologies in patients with multiple abnormalities resulted in the finding that some patients have more than a single genetic condition and that some of the diagnoses made in the past are acquired rather than inherited. However, limited knowledge has been accumulated regarding the phenotypic outcome of the interaction between different genetic conditions identified in the same patients. We report a newborn girl with brachytelephalangic chondrodysplasia punctata (BCDP) as well as frontonasal dysplasia, ptosis, bilateral hearing loss, vertebral anomalies, and pulmonary hypoplasia who was found, by whole exome sequencing, to have a de novo pathogenic variant in RAF1 (c.770C>T, [p.Ser257Leu]) and a likely pathogenic variant in SIX2 (c.760G>A [p.A254T]), as well as maternal systemic lupus erythematosus (SLE). This case shows that BCDP is most probably not a diagnostic entity and can be associated with various conditions associated with CDP including maternal SLE.
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Affiliation(s)
- Ebba Alkhunaizi
- Genetics Program, North York General Hospital, University of Toronto, Toronto, Ontario, Canada
| | - Sharon Unger
- Department of Pediatrics, Mount Sinai Hospital, University of Toronto, Toronto, Ontario, Canada
| | - Patrick Shannon
- Department of Pathology and Laboratory Medicine, Mount Sinai Hospital, University of Toronto, Toronto, Ontario, Canada
| | - Gen Nishimura
- Center for Intractable Diseases, Saitama Medical University Hospital, Saitama, Japan
| | - Susan Blaser
- Department of Diagnostic Imaging, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - David Chitayat
- The Prenatal Diagnosis and Medical Genetics Program, Department of Obstetrics and Gynecology, Mount Sinai Hospital, University of Toronto, Toronto, Ontario, Canada.,Division of Clinical and Metabolic Genetics, Department of Pediatrics, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
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14
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Jang H, Oakley E, Forbes-Osborne M, Kesler MV, Norcross R, Morris AC, Galperin E. Hematopoietic and neural crest defects in zebrafish shoc2 mutants: a novel vertebrate model for Noonan-like syndrome. Hum Mol Genet 2019; 28:501-514. [PMID: 30329053 DOI: 10.1093/hmg/ddy366] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Accepted: 10/12/2018] [Indexed: 12/15/2022] Open
Abstract
The extracellular signal-related kinase 1 and 2 (ERK1/2) pathway is a highly conserved signaling cascade with numerous essential functions in development. The scaffold protein Shoc2 amplifies the activity of the ERK1/2 pathway and is an essential modulator of a variety of signaling inputs. Germline mutations in Shoc2 are associated with the human developmental disease known as the Noonan-like syndrome with loose anagen hair. Clinical manifestations of this disease include congenital heart defects, developmental delays, distinctive facial abnormalities, reduced growth and cognitive deficits along with hair anomalies. The many molecular details of pathogenesis of the Noonan-like syndrome and related developmental disorders, cumulatively called RASopathies, remain poorly understood. Mouse knockouts for Shoc2 are embryonic lethal, emphasizing the need for additional animal models to study the role of Shoc2 in embryonic development. Here, we characterize a zebrafish shoc2 mutant, and show that Shoc2 is essential for development, and that its loss is detrimental for the development of the neural crest and for hematopoiesis. The zebrafish model of the Noonan-like syndrome described here provides a novel system for the study of structure-function analyses and for genetic screens in a tractable vertebrate system.
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Affiliation(s)
- HyeIn Jang
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, KY, USA
| | - Erin Oakley
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, KY, USA
| | | | - Melissa V Kesler
- Division of Pathology and Laboratory Medicine, University of Kentucky, Lexington, KY, USA
| | - Rebecca Norcross
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, KY, USA
| | - Ann C Morris
- Department of Biology, University of Kentucky, Lexington, KY, USA
| | - Emilia Galperin
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, KY, USA
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15
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Cizmeci MN, Lequin M, Lichtenbelt KD, Chitayat D, Kannu P, James AG, Groenendaal F, Chakkarapani E, Blaser S, de Vries LS. Characteristic MR Imaging Findings of the Neonatal Brain in RASopathies. AJNR Am J Neuroradiol 2018; 39:1146-1152. [PMID: 29622558 DOI: 10.3174/ajnr.a5611] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2017] [Accepted: 02/05/2018] [Indexed: 12/12/2022]
Abstract
BACKGROUND AND PURPOSE Neuroimaging features in neonates with RASopathies are rarely reported, and to date, there are no neuroimaging studies conducted in this population. Our aim was to investigate the occurrence of supratentorial and posterior fossa abnormalities on brain MRIs of neonates with a RASopathy. MATERIALS AND METHODS An observational case-control study of neonates with a confirmed RASopathy was conducted. The presence of an intraventricular and/or parenchymal hemorrhage and punctate white matter lesions and assessments of the splenium of the corpus callosum, gyrification of the cortical gray matter, and enlargement of the extracerebral space were noted. The vermis height, transverse cerebellar diameter, cranial base angle, tentorial angle, and infratentorial angle were measured. RESULTS We reviewed 48 brain MR studies performed at 3 academic centers in 3 countries between 2009 and 2017. Sixteen of these infants had a genetically confirmed RASopathy (group 1), and 32 healthy infants were enrolled as the control group (group 2). An increased rate of white matter lesions, extracerebral space enlargement, simplification of the cortical gyrification, and white matter abnormalities were seen in group 1 (P < .001, for each). The vermis height of patients was significantly lower, and tentorial and infratentorial angles were significantly higher in group 1 (P = .01, P < .001, and P = .001, respectively). CONCLUSIONS Neonates with a RASopathy had characteristic structural and acquired abnormalities in the cortical gray matter, white matter, corpus callosum, cerebellum, and posterior fossa. This study provides novel neuroimaging findings on supratentorial and posterior fossa abnormalities in neonates with a RASopathy.
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Affiliation(s)
- M N Cizmeci
- From the Departments of Neonatology (M.N.C., F.G., L.S.d.V.).,Brain Center Rudolf Magnus (M.N.C., F.G., L.S.d.V.)
| | - M Lequin
- Pediatric Radiology (M.L.), Wilhelmina Children's Hospital, University Medical Center Utrecht, Utrecht, the Netherlands
| | - K D Lichtenbelt
- Department of Medical Genetics (K.D.L.), University Medical Center Utrecht, Utrecht, the Netherlands
| | - D Chitayat
- Divisions of Clinical and Metabolic Genetics (D.C., P.K.).,Departments of Obstetrics and Gynecology, Laboratory Medicine, Pathobiology and Molecular Genetics (D.C.), University of Toronto, Toronto, Canada
| | - P Kannu
- Divisions of Clinical and Metabolic Genetics (D.C., P.K.)
| | | | - F Groenendaal
- From the Departments of Neonatology (M.N.C., F.G., L.S.d.V.).,Brain Center Rudolf Magnus (M.N.C., F.G., L.S.d.V.)
| | - E Chakkarapani
- Division of Neonatology (E.C.), School of Clinical Sciences, St Michael's Hospital, University of Bristol, Bristol, UK
| | - S Blaser
- Neuroradiology (S.B.), Department of Diagnostic Imaging, The Hospital for Sick Children and Department of Paediatrics, University of Toronto, Toronto, Canada
| | - L S de Vries
- From the Departments of Neonatology (M.N.C., F.G., L.S.d.V.) .,Brain Center Rudolf Magnus (M.N.C., F.G., L.S.d.V.)
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16
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Green T, Naylor PE, Davies W. Attention deficit hyperactivity disorder (ADHD) in phenotypically similar neurogenetic conditions: Turner syndrome and the RASopathies. J Neurodev Disord 2017; 9:25. [PMID: 28694877 PMCID: PMC5502326 DOI: 10.1186/s11689-017-9205-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Accepted: 05/18/2017] [Indexed: 11/17/2022] Open
Abstract
Background ADHD (attention deficit hyperactivity disorder) is a common neurodevelopmental disorder. There has been extensive clinical and basic research in the field of ADHD over the past 20 years, but the mechanisms underlying ADHD risk are multifactorial, complex and heterogeneous and, as yet, are poorly defined. In this review, we argue that one approach to address this challenge is to study well-defined disorders to provide insights into potential biological pathways that may be involved in idiopathic ADHD. Main body To address this premise, we selected two neurogenetic conditions that are associated with significantly increased ADHD risk: Turner syndrome and the RASopathies (of which Noonan syndrome and neurofibromatosis type 1 are the best-defined with regard to ADHD-related phenotypes). These syndromes were chosen for two main reasons: first, because intellectual functioning is relatively preserved, and second, because they are strikingly phenotypically similar but are etiologically distinct. We review the cognitive, behavioural, neural and cellular phenotypes associated with these conditions and examine their relevance as a model for idiopathic ADHD. Conclusion We conclude by discussing current and future opportunities in the clinical and basic research of these conditions, which, in turn, may shed light upon the biological pathways underlying idiopathic ADHD.
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Affiliation(s)
- Tamar Green
- Center for Interdisciplinary Brain Sciences Research, Stanford University School of Medicine, Stanford, USA
| | - Paige E Naylor
- Department of Clinical Psychology, Palo Alto University, Palo Alto, CA USA
| | - William Davies
- Medical Research Council Centre for Neuropsychiatric Genetics and Genomics and Division of Psychological Medicine and Clinical Neurosciences, School of Medicine, Cardiff University, Cardiff, UK.,School of Psychology, Cardiff University, Tower Building, 70, Park Place, Cardiff, CF10 3AT UK.,Neuroscience and Mental Health Research Institute, Cardiff University, Cardiff, UK
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17
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Kane J, Berrebi K, McLean R, Petkiewicz S, Hay B, Martin M, Wiss K. Noonan syndrome with loose anagen hair associated with trichorrhexis nodosa and trichoptilosis. Clin Case Rep 2017; 5:1152-1154. [PMID: 28680615 PMCID: PMC5494382 DOI: 10.1002/ccr3.1011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Revised: 04/27/2017] [Accepted: 04/28/2017] [Indexed: 12/17/2022] Open
Abstract
We report a case of Noonan syndrome with loose anagen hair (NS/LAH), a rare variant of Noonan syndrome, with associated trichorrhexis nodosa and trichoptilosis. The SHOC2 mutation may be responsible for these additional hair shaft defects, revealing the importance of microscopic examination of hairs in these patients.
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Affiliation(s)
- Jennifer Kane
- Department of DermatologyUniversity of Massachusetts Medical School281 Lincoln StreetWorcester01605Massachusetts
| | - Kristen Berrebi
- Department of DermatologyUniversity of Massachusetts Medical School281 Lincoln StreetWorcester01605Massachusetts
| | - Riley McLean
- Department of DermatologyUniversity of Massachusetts Medical School281 Lincoln StreetWorcester01605Massachusetts
| | - Stephanie Petkiewicz
- Department of DermatologyUniversity of Massachusetts Medical School281 Lincoln StreetWorcester01605Massachusetts
- Department of PathologyUniversity of Massachusetts Medical School55 Lake Avenue NorthWorcester01655Massachusetts
| | - Beverly Hay
- Department of PediatricsUniversity of Massachusetts Medical School55 Lake Avenue NorthWorcester01605Massachusetts
| | - Madelena Martin
- Department of PediatricsUniversity of Massachusetts Medical School55 Lake Avenue NorthWorcester01605Massachusetts
| | - Karen Wiss
- Department of DermatologyUniversity of Massachusetts Medical School281 Lincoln StreetWorcester01605Massachusetts
- Department of PediatricsUniversity of Massachusetts Medical School55 Lake Avenue NorthWorcester01605Massachusetts
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18
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Mitra I, Lavillaureix A, Yeh E, Traglia M, Tsang K, Bearden CE, Rauen KA, Weiss LA. Reverse Pathway Genetic Approach Identifies Epistasis in Autism Spectrum Disorders. PLoS Genet 2017; 13:e1006516. [PMID: 28076348 PMCID: PMC5226683 DOI: 10.1371/journal.pgen.1006516] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Accepted: 12/01/2016] [Indexed: 02/08/2023] Open
Abstract
Although gene-gene interaction, or epistasis, plays a large role in complex traits in model organisms, genome-wide by genome-wide searches for two-way interaction have limited power in human studies. We thus used knowledge of a biological pathway in order to identify a contribution of epistasis to autism spectrum disorders (ASDs) in humans, a reverse-pathway genetic approach. Based on previous observation of increased ASD symptoms in Mendelian disorders of the Ras/MAPK pathway (RASopathies), we showed that common SNPs in RASopathy genes show enrichment for association signal in GWAS (P = 0.02). We then screened genome-wide for interactors with RASopathy gene SNPs and showed strong enrichment in ASD-affected individuals (P < 2.2 x 10-16), with a number of pairwise interactions meeting genome-wide criteria for significance. Finally, we utilized quantitative measures of ASD symptoms in RASopathy-affected individuals to perform modifier mapping via GWAS. One top region overlapped between these independent approaches, and we showed dysregulation of a gene in this region, GPR141, in a RASopathy neural cell line. We thus used orthogonal approaches to provide strong evidence for a contribution of epistasis to ASDs, confirm a role for the Ras/MAPK pathway in idiopathic ASDs, and to identify a convergent candidate gene that may interact with the Ras/MAPK pathway.
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Affiliation(s)
- Ileena Mitra
- Department of Psychiatry, University of California San Francisco, San Francisco, California, United States of America
- Institute for Human Genetics, University of California San Francisco, San Francisco, California, United States of America
| | - Alinoë Lavillaureix
- Department of Psychiatry, University of California San Francisco, San Francisco, California, United States of America
- Institute for Human Genetics, University of California San Francisco, San Francisco, California, United States of America
- Université Paris Descartes, Sorbonne Paris Cité, Faculty of Medicine, Paris, France
| | - Erika Yeh
- Department of Psychiatry, University of California San Francisco, San Francisco, California, United States of America
- Institute for Human Genetics, University of California San Francisco, San Francisco, California, United States of America
| | - Michela Traglia
- Department of Psychiatry, University of California San Francisco, San Francisco, California, United States of America
- Institute for Human Genetics, University of California San Francisco, San Francisco, California, United States of America
| | - Kathryn Tsang
- Department of Psychiatry, University of California San Francisco, San Francisco, California, United States of America
- Institute for Human Genetics, University of California San Francisco, San Francisco, California, United States of America
| | - Carrie E. Bearden
- Department of Psychiatry and Biobehavioral Sciences, Semel Institute for Neuroscience and Human Behavior, University of California Los Angeles, Los Angeles, California, United States of America
- Department of Psychology, University of California Los Angeles, Los Angeles, California, United States of America
| | - Katherine A. Rauen
- Institute for Human Genetics, University of California San Francisco, San Francisco, California, United States of America
- Department of Pediatrics, School of Medicine, University of California San Francisco, San Francisco, California, United States of America
| | - Lauren A. Weiss
- Department of Psychiatry, University of California San Francisco, San Francisco, California, United States of America
- Institute for Human Genetics, University of California San Francisco, San Francisco, California, United States of America
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19
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Ma L, Bayram Y, McLaughlin HM, Cho MT, Krokosky A, Turner CE, Lindstrom K, Bupp CP, Mayberry K, Mu W, Bodurtha J, Weinstein V, Zadeh N, Alcaraz W, Powis Z, Shao Y, Scott DA, Lewis AM, White JJ, Jhangiani SN, Gulec EY, Lalani SR, Lupski JR, Retterer K, Schnur RE, Wentzensen IM, Bale S, Chung WK. De novo missense variants in PPP1CB are associated with intellectual disability and congenital heart disease. Hum Genet 2016; 135:1399-1409. [PMID: 27681385 DOI: 10.1007/s00439-016-1731-1] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Accepted: 09/19/2016] [Indexed: 10/20/2022]
Abstract
Intellectual disabilities are genetically heterogeneous and can be associated with congenital anomalies. Using whole-exome sequencing (WES), we identified five different de novo missense variants in the protein phosphatase-1 catalytic subunit beta (PPP1CB) gene in eight unrelated individuals who share an overlapping phenotype of dysmorphic features, macrocephaly, developmental delay or intellectual disability (ID), congenital heart disease, short stature, and skeletal and connective tissue abnormalities. Protein phosphatase-1 (PP1) is a serine/threonine-specific protein phosphatase involved in the dephosphorylation of a variety of proteins. The PPP1CB gene encodes a PP1 subunit that regulates the level of protein phosphorylation. All five altered amino acids we observed are highly conserved among the PP1 subunit family, and all are predicted to disrupt PP1 subunit binding and impair dephosphorylation. Our data suggest that our heterozygous de novo PPP1CB pathogenic variants are associated with syndromic intellectual disability.
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Affiliation(s)
- Lijiang Ma
- Department of Pediatrics, Columbia University Medical Center, 1150 St. Nicholas Avenue, New York, NY, 10032, USA
| | - Yavuz Bayram
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | | | | | - Alyson Krokosky
- Walter Reed National Military Medical Center, Bethesda, MD, USA
| | | | - Kristin Lindstrom
- Division of Genetics and Metabolism, Phoenix Children's Hospital, Phoenix, AZ, USA
| | | | | | - Weiyi Mu
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University, Baltimore, MD, USA
| | - Joann Bodurtha
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University, Baltimore, MD, USA
| | - Veronique Weinstein
- Division of Genetics and Metabolism, Children's National Medical Center, Washington, DC, USA
| | | | | | - Zöe Powis
- Ambry Genetics, Aliso Viejo, CA, USA
| | - Yunru Shao
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Daryl A Scott
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA.,Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX, USA
| | - Andrea M Lewis
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Janson J White
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Shalani N Jhangiani
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA.,Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX, USA
| | - Elif Yilmaz Gulec
- Medical Genetics Section, Kanuni Sultan Suleyman Training and Research Hospital, Istanbul, Turkey
| | - Seema R Lalani
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - James R Lupski
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA.,Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX, USA.,Texas Children's Hospital, Houston, TX, USA.,Department of Pediatrics, Baylor College of Medicine, Houston, TX, USA
| | | | | | | | | | - Wendy K Chung
- Department of Pediatrics, Columbia University Medical Center, 1150 St. Nicholas Avenue, New York, NY, 10032, USA.
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20
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Gripp KW, Aldinger KA, Bennett JT, Baker L, Tusi J, Powell-Hamilton N, Stabley D, Sol-Church K, Timms AE, Dobyns WB. A novel rasopathy caused by recurrent de novo missense mutations in PPP1CB closely resembles Noonan syndrome with loose anagen hair. Am J Med Genet A 2016; 170:2237-47. [PMID: 27264673 DOI: 10.1002/ajmg.a.37781] [Citation(s) in RCA: 89] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Accepted: 05/23/2016] [Indexed: 11/10/2022]
Abstract
Noonan syndrome is a rasopathy caused by mutations in multiple genes encoding components of the RAS/MAPK pathway. Despite its variable phenotype, limited genotype-phenotype correlations exist. Noonan syndrome with loose anagen hair (NS-LAH) is characterized by its distinctive hair anomalies, developmental differences, and structural brain abnormalities and is caused by a single recurrent missense SHOC2 mutation. SHOC2 forms a complex with protein phosphatase 1 (PP1C). Protein phosphatases counterbalance kinases and control activation of signaling proteins, such as the mitogen-activated protein kinases of the RAS/MAPK pathway. Here we report four patients with de novo missense mutations in protein phosphatase one catalytic subunit beta (PPP1CB), sharing a recognizable phenotype. Three individuals had the recurrent PPP1CB c.146G>C, p.Pro49Arg mutation, the fourth had a c.166G>C, p.Ala56Pro change. All had relative or absolute macrocephaly, low-set and posteriorly angulated ears, and developmental delay. Slow growing and/or sparse hair and/or an unruly hair texture was present in all. Three individuals had feeding difficulties requiring feeding tubes. One of two males had cryptorchidism, another had pectus excavatum. Short stature was present in three. A female with the recurrent mutation had a Dandy-Walker malformation and optic nerve hypoplasia. Mild ventriculomegaly occurred in all, cerebellar tonsillar ectopia was seen in two and progressed to Chiari 1 malformation in one individual. Based on the combination of phenotypic findings and PPP1CB's effect on RAF dephosphorylation within the RAS/MAPK pathway, this novel condition can be considered a rasopathy, most similar to NS-LAH. Collectively, these mutations meet the standardized criteria for pathogenicity. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Karen W Gripp
- Division of Medical Genetics, A. I. duPont Hospital for Children, Wilmington, Delaware
| | - Kimberly A Aldinger
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, Washington
| | - James T Bennett
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, Washington.,Department of Pediatrics, University of Washington, Seattle, Washington
| | - Laura Baker
- Division of Medical Genetics, A. I. duPont Hospital for Children, Wilmington, Delaware
| | - Jessica Tusi
- Division of Medical Genetics, A. I. duPont Hospital for Children, Wilmington, Delaware
| | - Nina Powell-Hamilton
- Division of Medical Genetics, A. I. duPont Hospital for Children, Wilmington, Delaware
| | - Deborah Stabley
- Center for Applied Clinical Genomics, A. I. duPont Hospital for Children, Wilmington, Delaware
| | - Katia Sol-Church
- Center for Applied Clinical Genomics, A. I. duPont Hospital for Children, Wilmington, Delaware
| | - Andrew E Timms
- Center for Developmental Biology and Regenerative Medicine, Seattle Children's Research Institute, Seattle, Washington
| | - William B Dobyns
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, Washington
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21
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Jang ER, Galperin E. The function of Shoc2: A scaffold and beyond. Commun Integr Biol 2016; 9:e1188241. [PMID: 27574535 PMCID: PMC4988449 DOI: 10.1080/19420889.2016.1188241] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2016] [Accepted: 05/05/2016] [Indexed: 01/01/2023] Open
Abstract
The extracellular signal-regulated kinase (ERK1/2) cascade regulates a myriad of functions in multicellular organisms. Scaffold proteins provide critical spatial and temporal control over the specificity of signaling. Shoc2 is a scaffold that accelerates activity of the ERK1/2 pathway. Loss of Shoc2 expression in mice results in embryonic lethality, thus highlighting the essential role of Shoc2 in embryogenesis. In agreement, patients carrying mutated Shoc2 suffer from a wide spectrum of developmental deficiencies. Efforts to understand the mechanisms by which Shoc2 controls ERK1/2 activity revealed the intricate machinery that governs the ability of Shoc2 to transduce signals of the ERK1/2 pathway. Understanding the mechanisms by which Shoc2 contributes to a high degree of specificity of ERK1/2 signaling as well as deciphering the biological functions of Shoc2 in development and human disorders are major unresolved questions.
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Affiliation(s)
- Eun Ryoung Jang
- Department of Molecular and Cellular Biochemistry, University of Kentucky , Lexington, KY, USA
| | - Emilia Galperin
- Department of Molecular and Cellular Biochemistry, University of Kentucky , Lexington, KY, USA
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22
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Jang ER, Jang H, Shi P, Popa G, Jeoung M, Galperin E. Spatial control of Shoc2-scaffold-mediated ERK1/2 signaling requires remodeling activity of the ATPase PSMC5. J Cell Sci 2015; 128:4428-41. [PMID: 26519477 DOI: 10.1242/jcs.177543] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2015] [Accepted: 10/21/2015] [Indexed: 12/13/2022] Open
Abstract
The scaffold protein Shoc2 accelerates activity of the ERK1 and ERK2 (ERK1/2, also known as MAPK3 and MAPK1) pathway. Mutations in Shoc2 result in Noonan-like RASopathy, a developmental disorder with a wide spectrum of symptoms. The amplitude of the ERK1/2 signals transduced through the complex is fine-tuned by the HUWE1-mediated ubiquitylation of Shoc2 and its signaling partner RAF-1. Here, we provide a mechanistic basis of how ubiquitylation of Shoc2 and RAF-1 is controlled. We demonstrate that the newly identified binding partner of Shoc2, the (AAA+) ATPase PSMC5, triggers translocation of Shoc2 to endosomes. At the endosomes, PSMC5 displaces the E3 ligase HUWE1 from the scaffolding complex to attenuate ubiquitylation of Shoc2 and RAF-1. We show that a RASopathy mutation that changes the subcellular distribution of Shoc2 leads to alterations in Shoc2 ubiquitylation due to the loss of accessibility to PSMC5. In summary, our results demonstrate that PSMC5 is a new and important player involved in regulating ERK1/2 signal transmission through the remodeling of Shoc2 scaffold complex in a spatially-defined manner.
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Affiliation(s)
- Eun Ryoung Jang
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, KY 40536, USA
| | - HyeIn Jang
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, KY 40536, USA
| | - Ping Shi
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, KY 40536, USA
| | - Gabriel Popa
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, KY 40536, USA
| | - Myoungkun Jeoung
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, KY 40536, USA
| | - Emilia Galperin
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, KY 40536, USA
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23
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Gelb BD, Roberts AE, Tartaglia M. Cardiomyopathies in Noonan syndrome and the other RASopathies. PROGRESS IN PEDIATRIC CARDIOLOGY 2015; 39:13-19. [PMID: 26380542 PMCID: PMC4568836 DOI: 10.1016/j.ppedcard.2015.01.002] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Noonan syndrome and related disorders (Noonan syndrome with multiple lentigines, Costello syndrome, cardiofaciocutaneous syndrome, Noonan syndrome with loose anagen hair, and other related traits) are autosomal dominant traits. Mutations causing these disorders alter proteins relevant for signaling through RAS. Thus, these traits are now collectively called the RASopathies. While the RASopathies have pleiomorphic features, this review will focus on the hypertrophic cardiomyopathy observed in varying percentages of all of these traits. In addition, inherited abnormalities in one pathway gene, RAF1, cause pediatric-onset dilated cardiomyopathy. The pathogeneses for the RASopathy-associated cardiomyopathies are being elucidated, principally using animal models, leading to genotype-specific insights into how signal transduction is perturbed. Based on those findings, small molecule therapies seem possible for RASopathy-associated cardiomyopathies.
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Affiliation(s)
- Bruce D Gelb
- Mindich Child Health and Development Institute, Departments of Pediatrics and Genetics & Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY
| | - Amy E Roberts
- Department of Cardiology and Division of Genetics, Boston Children's Hospital, Boston, MA
| | - Marco Tartaglia
- Dipartimento di Ematologia, Oncologia e Medicina Molecolare, Istituto Superiore di Sanità, Rome, Italy
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24
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Stanco A, Pla R, Vogt D, Chen Y, Mandal S, Walker J, Hunt RF, Lindtner S, Erdman CA, Pieper AA, Hamilton SP, Xu D, Baraban SC, Rubenstein JLR. NPAS1 represses the generation of specific subtypes of cortical interneurons. Neuron 2014; 84:940-53. [PMID: 25467980 PMCID: PMC4258152 DOI: 10.1016/j.neuron.2014.10.040] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/02/2014] [Indexed: 11/29/2022]
Abstract
Little is known about genetic mechanisms that regulate the ratio of cortical excitatory and inhibitory neurons. We show that NPAS1 and NPAS3 transcription factors (TFs) are expressed in progenitor domains of the mouse basal ganglia (subpallium, MGE, and CGE). NPAS1(-/-) mutants had increased proliferation, ERK signaling, and expression of Arx in the MGE and CGE. NPAS1(-/-) mutants also had increased neocortical inhibition (sIPSC and mIPSC) and generated an excess of somatostatin(+) (SST) (MGE-derived) and vasoactive intestinal polypeptide(+) (VIP) (CGE-derived) neocortical interneurons, but had a normal density of parvalbumin(+) (PV) (MGE-derived) interneurons. In contrast, NPAS3(-/-) mutants showed decreased proliferation and ERK signaling in progenitors of the ganglionic eminences and had fewer SST(+) and VIP(+) interneurons. NPAS1 repressed activity of an Arx enhancer, and Arx overexpression resulted in increased proliferation of CGE progenitors. These results provide insights into genetic regulation of cortical interneuron numbers and cortical inhibitory tone.
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Affiliation(s)
- Amelia Stanco
- Department of Psychiatry, Neuroscience Program, and the Nina Ireland Laboratory of Developmental Neurobiology, University of California, San Francisco, San Francisco, CA 94158-2324, USA.
| | - Ramón Pla
- Department of Psychiatry, Neuroscience Program, and the Nina Ireland Laboratory of Developmental Neurobiology, University of California, San Francisco, San Francisco, CA 94158-2324, USA
| | - Daniel Vogt
- Department of Psychiatry, Neuroscience Program, and the Nina Ireland Laboratory of Developmental Neurobiology, University of California, San Francisco, San Francisco, CA 94158-2324, USA
| | - Yiran Chen
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Shyamali Mandal
- Department of Psychiatry, Neuroscience Program, and the Nina Ireland Laboratory of Developmental Neurobiology, University of California, San Francisco, San Francisco, CA 94158-2324, USA
| | - Jamie Walker
- Department of Biochemistry, UT Southwestern Medical Center, Dallas, TX 75390, USA
| | - Robert F Hunt
- Department of Neurological Surgery, Neuroscience Program, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Susan Lindtner
- Department of Psychiatry, Neuroscience Program, and the Nina Ireland Laboratory of Developmental Neurobiology, University of California, San Francisco, San Francisco, CA 94158-2324, USA
| | - Carolyn A Erdman
- Department of Psychiatry, Neuroscience Program, and the Nina Ireland Laboratory of Developmental Neurobiology, University of California, San Francisco, San Francisco, CA 94158-2324, USA
| | - Andrew A Pieper
- Department of Psychiatry and Neurology, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA
| | - Steven P Hamilton
- Department of Psychiatry, Neuroscience Program, and the Nina Ireland Laboratory of Developmental Neurobiology, University of California, San Francisco, San Francisco, CA 94158-2324, USA
| | - Duan Xu
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Scott C Baraban
- Department of Neurological Surgery, Neuroscience Program, University of California, San Francisco, San Francisco, CA 94143, USA
| | - John L R Rubenstein
- Department of Psychiatry, Neuroscience Program, and the Nina Ireland Laboratory of Developmental Neurobiology, University of California, San Francisco, San Francisco, CA 94158-2324, USA.
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25
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Hannig V, Jeoung M, Jang ER, Phillips JA, Galperin E. A Novel SHOC2 Variant in Rasopathy. Hum Mutat 2014; 35:1290-4. [PMID: 25137548 DOI: 10.1002/humu.22634] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2014] [Accepted: 08/05/2014] [Indexed: 12/26/2022]
Abstract
Rasopathies are a group of genetic disorders caused by germline mutations in multiple genes of the Extracellular signal-Regulated Kinases 1 and 2 (ERK1/2) pathway. The only previously identified missense mutation in SHOC2, a scaffold protein of the ERK1/2 pathway, led to Noonan-like syndrome with loose anagen hair. Here, we report a novel mutation in SHOC2(c.519G>A; p.M173I) that leads to a Rasopathy with clinical features partially overlapping those occurring in Noonan and cardiofaciocutaneous syndromes. Studies to clarify the significance of this SHOC2 variant revealed that the mutant protein has impaired capacity to interact with protein phosphatase 1c (PP1c), leading to insufficient activation of RAF-1 kinase. This SHOC2 variant thus is unable to fully rescue ERK1/2 activity in cells depleted of endogenous SHOC2. We conclude that SHOC2 mutations can cause a spectrum of Rasopathy phenotypes in heterozygous individuals. Importantly, our work suggests that individuals with mild Rasopathy symptoms may be underdiagnosed.
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Affiliation(s)
- Vickie Hannig
- Division of Medical Genetics and Genomic Medicine, Vanderbilt University, Nashville, Tennessee
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26
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HUWE1 is a molecular link controlling RAF-1 activity supported by the Shoc2 scaffold. Mol Cell Biol 2014; 34:3579-93. [PMID: 25022756 DOI: 10.1128/mcb.00811-14] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Scaffold proteins play a critical role in controlling the activity of the extracellular signal-regulated kinase 1/2 (ERK1/2) pathway. Shoc2 is a leucine-rich repeat scaffold protein that acts as a positive modulator of ERK1/2 signaling. However, the precise mechanism by which Shoc2 modulates the activity of the ERK1/2 pathway is unclear. Here we report the identification of the E3 ubiquitin ligase HUWE1 as a binding partner and regulator of Shoc2 function. HUWE1 mediates ubiquitination and, consequently, the levels of Shoc2. Additionally, we show that both Shoc2 and HUWE1 are necessary to control the levels and ubiquitination of the Shoc2 signaling partner, RAF-1. Depletion of HUWE1 abolishes RAF-1 ubiquitination, with corresponding changes in ERK1/2 pathway activity occurring. Our results indicate that the HUWE1-mediated ubiquitination of Shoc2 is the switch that regulates the transition from an active to an inactive state of the RAF-1 kinase. Taken together, our results demonstrate that HUWE1 is a novel player involved in regulating ERK1/2 signal transmission through the Shoc2 scaffold complex.
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