1
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Witkowski L, Dillon MW, Murphy E, S Lebo M, Mason-Suares H. Expanding the Noonan spectrum/RASopathy NGS panel: Benefits of adding NF1 and SPRED1. Mol Genet Genomic Med 2020; 8:e1180. [PMID: 32107864 PMCID: PMC7196473 DOI: 10.1002/mgg3.1180] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Revised: 12/28/2019] [Accepted: 01/30/2020] [Indexed: 01/13/2023] Open
Abstract
Background RASopathies are a group of disorders caused by disruptions to the RAS‒MAPK pathway. Despite being in the same pathway, Neurofibromatosis Type 1 (NF1) and Legius syndrome (LS) typically present with phenotypes distinct from Noonan spectrum disorders (NSDs). However, some NF1/LS individuals also exhibit NSD phenotypes, often referred to as Neurofibromatosis‐Noonan syndrome (NFNS), and may be mistakenly evaluated for NSDs, delaying diagnosis, and affecting patient management. Methods A derivation cohort of 28 patients with a prior negative NSD panel and either NFNS or a suspicion of NSD and café‐au‐lait spots underwent NF1 and SPRED1 sequencing. To further determine the utility and burden of adding these genes, a validation cohort of 505 patients with a suspected RASopathy were tested on a 14‐gene RASopathy‐associated panel. Results In the derivation cohort, six (21%) patients had disease‐causing NF1 or SPRED1 variants. In the validation cohort, 11 (2%) patients had disease‐causing variants and 15 (3%) had variants of uncertain significance in NF1 or SPRED1. Of those with disease‐causing variants, 5/17 only had an NSD diagnosis. Conclusions Adding NF1 and SPRED1 to RASopathy panels can speed diagnosis and improve patient management, without significantly increasing the burden of inconclusive results.
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Affiliation(s)
- Leora Witkowski
- Departments of Pathology, Harvard Medical School and Brigham and Women's Hospital, Boston, MA, USA.,Laboratory for Molecular Medicine, Partners HealthCare Personalized Medicine, Cambridge, MA, USA
| | - Mitchell W Dillon
- Laboratory for Molecular Medicine, Partners HealthCare Personalized Medicine, Cambridge, MA, USA
| | - Elissa Murphy
- Laboratory for Molecular Medicine, Partners HealthCare Personalized Medicine, Cambridge, MA, USA
| | - Matthew S Lebo
- Departments of Pathology, Harvard Medical School and Brigham and Women's Hospital, Boston, MA, USA.,Laboratory for Molecular Medicine, Partners HealthCare Personalized Medicine, Cambridge, MA, USA
| | - Heather Mason-Suares
- Departments of Pathology, Harvard Medical School and Brigham and Women's Hospital, Boston, MA, USA.,Laboratory for Molecular Medicine, Partners HealthCare Personalized Medicine, Cambridge, MA, USA
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2
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Pinna V, Daniele P, Calcagni G, Mariniello L, Criscione R, Giardina C, Lepri FR, Hozhabri H, Alberico A, Cavone S, Morella AT, Mandile R, Annunziata F, Di Giosaffatte N, D'Asdia MC, Versacci P, Capolino R, Strisciuglio P, Giustini S, Melis D, Digilio MC, Tartaglia M, Marino B, De Luca A. Prevalence, Type, and Molecular Spectrum of NF1 Mutations in Patients with Neurofibromatosis Type 1 and Congenital Heart Disease. Genes (Basel) 2019; 10:E675. [PMID: 31487937 PMCID: PMC6770533 DOI: 10.3390/genes10090675] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2019] [Revised: 08/30/2019] [Accepted: 09/01/2019] [Indexed: 02/05/2023] Open
Abstract
The aim of this study was to assess the prevalence and type of congenital heart disease (CHD) and the associated mutation spectrum in a large series of patients with neurofibromatosis type 1 (NF1), and correlate the mutation type with the presence and subgroups of cardiac defects. The study cohort included 493 individuals with molecularly confirmed diagnosis of NF1 for whom cardiac evaluation data were available. CHD was reported in 62/493 (12.6%) patients. Among these patients, 23/62 (37.1%) had pulmonary valve stenosis/dysplasia, 20/62 (32.3%) had mitral valve anomalies, and 10/62 (16.1%) had septal defects. Other defects occurred as rare events. In this NF1 subcohort, three subjects carried a whole-gene deletion, while 59 were heterozygous for an intragenic mutation. A significantly increased prevalence of non-truncating intragenic mutations was either observed in individuals with CHD (22/59, 37.3%) or with pulmonary valve stenosis (13/20, 65.0%), when compared to individuals without CHD (89/420, 21.2%) (p = 0.038) or pulmonary valve stenosis (98/459, 21.4%) (p = 0.002). Similarly, patients with non-truncating NF1 mutations displayed two- and six-fold higher risk of developing CHD (odds ratio = 1.9713, 95% confidence interval (CI): 1.1162-3.4814, p = 0.0193) and pulmonary valve stenosis (odds ratio = 6.8411, 95% CI: 2.6574-17.6114, p = 0.0001), respectively. Noteworthy, all but one patient (19/20, 95.0%) with pulmonary valve stenosis, and 18/35 (51.4%) patients with other CHDs displayed Noonan syndrome (NS)-like features. Present data confirm the significant frequency of CHD in patients with NF1, and provide further evidence for a higher than expected prevalence of NF1 in-frame variants and NS-like characteristics in NF1 patients with CHD, particularly with pulmonary valve stenosis.
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Affiliation(s)
- Valentina Pinna
- UOS Diagnosi Genetica Molecolare, Fondazione IRCCS Casa Sollievo della Sofferenza, 71013 San Giovanni Rotondo (FG), Italy.
| | - Paola Daniele
- UOS Diagnosi Genetica Molecolare, Fondazione IRCCS Casa Sollievo della Sofferenza, 71013 San Giovanni Rotondo (FG), Italy.
| | - Giulio Calcagni
- Department of Pediatric Cardiology and Cardiac Surgery, Bambino Gesù Pediatric Hospital and Research Institute, 00165 Rome, Italy.
| | - Lucio Mariniello
- Department of Translational Medical Science, Section of Pediatrics, Federico II University, 80100 Naples, Italy.
| | - Roberta Criscione
- UOS Diagnosi Genetica Molecolare, Fondazione IRCCS Casa Sollievo della Sofferenza, 71013 San Giovanni Rotondo (FG), Italy.
- Department of Pediatrics, Sapienza University of Rome, 00161 Rome, Italy.
| | - Chiara Giardina
- UOS Diagnosi Genetica Molecolare, Fondazione IRCCS Casa Sollievo della Sofferenza, 71013 San Giovanni Rotondo (FG), Italy.
- Department of Pediatrics, Sapienza University of Rome, 00161 Rome, Italy.
| | - Francesca Romana Lepri
- Genetics and Rare Diseases Research Division, Ospedale Pediatrico Bambino Gesù, IRCCS, 00146 Rome, Italy.
| | - Hossein Hozhabri
- UOS Diagnosi Genetica Molecolare, Fondazione IRCCS Casa Sollievo della Sofferenza, 71013 San Giovanni Rotondo (FG), Italy.
| | - Angela Alberico
- UOS Diagnosi Genetica Molecolare, Fondazione IRCCS Casa Sollievo della Sofferenza, 71013 San Giovanni Rotondo (FG), Italy.
| | - Stefania Cavone
- UOS Diagnosi Genetica Molecolare, Fondazione IRCCS Casa Sollievo della Sofferenza, 71013 San Giovanni Rotondo (FG), Italy.
| | - Annunziata Tina Morella
- UOS Diagnosi Genetica Molecolare, Fondazione IRCCS Casa Sollievo della Sofferenza, 71013 San Giovanni Rotondo (FG), Italy.
| | - Roberta Mandile
- Department of Translational Medical Science, Section of Pediatrics, Federico II University, 80100 Naples, Italy.
| | - Francesca Annunziata
- UOS Diagnosi Genetica Molecolare, Fondazione IRCCS Casa Sollievo della Sofferenza, 71013 San Giovanni Rotondo (FG), Italy.
| | - Niccolò Di Giosaffatte
- UOS Diagnosi Genetica Molecolare, Fondazione IRCCS Casa Sollievo della Sofferenza, 71013 San Giovanni Rotondo (FG), Italy.
| | - Maria Cecilia D'Asdia
- UOS Diagnosi Genetica Molecolare, Fondazione IRCCS Casa Sollievo della Sofferenza, 71013 San Giovanni Rotondo (FG), Italy.
| | - Paolo Versacci
- Department of Pediatrics, Sapienza University of Rome, 00161 Rome, Italy.
| | - Rossella Capolino
- Genetics and Rare Diseases Research Division, Ospedale Pediatrico Bambino Gesù, IRCCS, 00146 Rome, Italy.
| | - Pietro Strisciuglio
- Department of Translational Medical Science, Section of Pediatrics, Federico II University, 80100 Naples, Italy.
| | - Sandra Giustini
- Department of Dermatology and Venereology, Sapienza University of Rome, Policlinico Umberto I, 00161 Rome, Italy.
| | - Daniela Melis
- Department of Translational Medical Science, Section of Pediatrics, Federico II University, 80100 Naples, Italy.
| | - Maria Cristina Digilio
- Genetics and Rare Diseases Research Division, Ospedale Pediatrico Bambino Gesù, IRCCS, 00146 Rome, Italy.
| | - Marco Tartaglia
- Genetics and Rare Diseases Research Division, Ospedale Pediatrico Bambino Gesù, IRCCS, 00146 Rome, Italy.
| | - Bruno Marino
- Department of Pediatrics, Sapienza University of Rome, 00161 Rome, Italy
| | - Alessandro De Luca
- UOS Diagnosi Genetica Molecolare, Fondazione IRCCS Casa Sollievo della Sofferenza, 71013 San Giovanni Rotondo (FG), Italy.
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3
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Trevisson E, Morbidoni V, Forzan M, Daolio C, Fumini V, Parrozzani R, Cassina M, Midena E, Salviati L, Clementi M. The Arg1038Gly missense variant in the NF1 gene causes a mild phenotype without neurofibromas. Mol Genet Genomic Med 2019; 7:e616. [PMID: 30843352 PMCID: PMC6503065 DOI: 10.1002/mgg3.616] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Revised: 01/16/2019] [Accepted: 02/11/2019] [Indexed: 01/08/2023] Open
Abstract
Background Neurofibromatosis type 1 (NF1) is an autosomal dominant condition caused by inactivating mutations of the NF1 gene. The wide allelic heterogeneity of this condition, with more than 3,000 pathogenic variants reported so far, is paralleled by its high clinical variability, which is observed even within the same family. The definition of genotype–phenotype correlations has been hampered by the complexity of the NF1 gene and, although a few exceptions have been recognized, the clinical course remains unpredictable in most patients. Methods Sequencing of NF1 in patients with cafè‐au‐lait spots identified the c.3112A>G variant. RNA analysis and a minigene assay were employed to investigate splicing. Results Here we report a novel genotype–phenotype correlation in NF1: the identification of the missense variant NM_000267.3:c.3112A>G p.(Arg1038Gly) in seven individuals from two unrelated families with a mild phenotype. All the patients manifest cafè‐au‐lait spots without neurofibromas or other NF1–associated complications, and Noonan syndrome features in most cases. The missense variant was not previously reported in available databases, segregates with the phenotype and involves a highly conserved residue. Both a minigene assay and patient's RNA analysis excluded an effect on splicing. Conclusion Our data support the correlation of the p.Arg1038Gly missense substitution with the cutaneous phenotype without neurofibromas or other complications. This finding may have relevant implications for patients and genetic counseling, but also to get insights into the function of neurofibromin.
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Affiliation(s)
- Eva Trevisson
- Department of Women's and Children's Health, Clinical Genetics Unit, University of Padova, Padova, Italy.,Laboratorio di Genetica Clinica ed Epidemiologica, Istituto di Ricerca Pediatrica, IRP, Padova, Italy
| | - Valeria Morbidoni
- Department of Women's and Children's Health, Clinical Genetics Unit, University of Padova, Padova, Italy.,Laboratorio di Genetica Clinica ed Epidemiologica, Istituto di Ricerca Pediatrica, IRP, Padova, Italy
| | - Monica Forzan
- Department of Women's and Children's Health, Clinical Genetics Unit, University of Padova, Padova, Italy.,Laboratorio di Genetica Clinica ed Epidemiologica, Istituto di Ricerca Pediatrica, IRP, Padova, Italy
| | | | - Valentina Fumini
- Department of Women's and Children's Health, Clinical Genetics Unit, University of Padova, Padova, Italy
| | | | - Matteo Cassina
- Department of Women's and Children's Health, Clinical Genetics Unit, University of Padova, Padova, Italy
| | - Edoardo Midena
- Department of Neurosciences, University of Padova, Padova, Italy.,IRCCS-Fondazione Bietti, Rome, Italy
| | - Leonardo Salviati
- Department of Women's and Children's Health, Clinical Genetics Unit, University of Padova, Padova, Italy.,Laboratorio di Genetica Clinica ed Epidemiologica, Istituto di Ricerca Pediatrica, IRP, Padova, Italy
| | - Maurizio Clementi
- Department of Women's and Children's Health, Clinical Genetics Unit, University of Padova, Padova, Italy.,Laboratorio di Genetica Clinica ed Epidemiologica, Istituto di Ricerca Pediatrica, IRP, Padova, Italy
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4
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Santoro C, Pacileo G, Limongelli G, Scianguetta S, Giugliano T, Piluso G, Ragione FD, Cirillo M, Mirone G, Perrotta S. LEOPARD syndrome: clinical dilemmas in differential diagnosis of RASopathies. BMC MEDICAL GENETICS 2014; 15:44. [PMID: 24767283 PMCID: PMC4005403 DOI: 10.1186/1471-2350-15-44] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/16/2014] [Accepted: 04/22/2014] [Indexed: 11/10/2022]
Abstract
Background Diagnosis within RASopathies still represents a challenge. Nevertheless, many efforts have been made by clinicians to identify specific clinical features which might help in differentiating one disorder from another. Here, we describe a child initially diagnosed with Neurofibromatosis-Noonan syndrome. The follow-up of the proband, the clinical evaluation of his father together with a gene-by-gene testing approach led us to the proper diagnosis. Case presentation We report a 8-year-old male with multiple café-au-lait macules, several lentigines and dysmorphic features that suggest Noonan syndrome initially diagnosed with Neurofibromatosis-Noonan syndrome. However, after a few years of clinical and ophthalmological follow-up, the absence of typical features of Neurofibromatosis type 1 and the lack of NF1 mutation led us to reconsider the original diagnosis. A new examination of the patient and his similarly affected father, who was initially referred as healthy, led us to suspect LEOPARD syndrome, The diagnosis was then confirmed by the occurrence in both patients of a heterozygous mutation c.1403 C > T, p.(Thr468Met), of PTPN11. Subsequently, the proband was also found to have type-1 Arnold-Chiari malformation in association with syringomyelia. Conclusion Our experience suggests that differential clinical diagnosis among RASopathies remains ambiguous and raises doubts on the current diagnostic clinical criteria. In some cases, genetic tests represent the only conclusive proof for a correct diagnosis and, consequently, for establishing individual prognosis and providing adequate follow-up. Thus, molecular testing represents an essential tool in differential diagnosis of RASophaties. This view is further strengthened by the increasing accessibility of new sequencing techniques. Finally, to our knowledge, the described case represents the third report of the occurrence of Arnold Chiari malformation and the second description of syringomyelia with LEOPARD syndrome.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | - Silverio Perrotta
- Dipartimento della Donna, del Bambino e di Chirurgia Generale e Specialistica, Second University of Naples, Via Luigi De Crecchio, 4, Naples 80138, Italy.
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5
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Carcavilla A, Pinto I, Muñoz-Pacheco R, Barrio R, Martin-Frías M, Ezquieta B. LEOPARD syndrome (PTPN11, T468M) in three boys fulfilling neurofibromatosis type 1 clinical criteria. Eur J Pediatr 2011; 170:1069-74. [PMID: 21365175 DOI: 10.1007/s00431-011-1418-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/23/2010] [Accepted: 02/03/2011] [Indexed: 01/20/2023]
Abstract
Noonan syndrome (NS) and neurofibromatosis type 1 (NF1) are well-defined entities. The association of both disorders is called neurofibromatosis-Noonan syndrome (NFNS), a disorder that has been related to mutations in the NF1 gene. Both NS and NFNS display phenotypic overlapping with LEOPARD syndrome (LS), and differential diagnosis between these two entities often represents a challenge for clinicians. We report on three patients (two brothers and a not-related patient) diagnosed as having NFNS. They fulfilled NF1 diagnostic criteria and had some features of NS. The three of them had hypertophic cardiomyopathy while neurofibromas, Lisch nodules, and unidentified bright objects on MRI were absent. PTPN11 gene assays revealed a T468M mutation, typical of LS. Thorough clinical examinations of the patients revealed multiple lentigines, which were considered to be freckling in the initial evaluation. We conclude that NF1 clinical criteria should be used with caution in patients with features of NS. Patients with hyperpigmented cutaneous spots associated with cardiac anomalies, even if fulfilling the minimal NF1 criteria for diagnosis, should be strongly considered for LS diagnosis.
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6
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Stratakis CA. Genetics of Carney Complex and Related Familial Lentiginoses, and other Multiple Tumor Syndromes. ACTA ACUST UNITED AC 2010. [DOI: 10.1080/15513810009168808] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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7
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LEOPARD syndrome with recurrent PTPN11 mutation Y279C and different cutaneous manifestations: two case reports and a review of the literature. Eur J Pediatr 2010; 169:469-73. [PMID: 19768645 DOI: 10.1007/s00431-009-1058-1] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/15/2009] [Accepted: 08/27/2009] [Indexed: 02/07/2023]
Abstract
LEOPARD syndrome (LS) is a heterogeneous disease characterised mainly by cutaneous manifestations. LEOPARD is the acronym for its major features-multiple lentigines, electrocardiographic conduction defects, ocular hypertelorism, pulmonary stenosis, abnormalities of (male) genitalia, retardation of growth and sensorineural deafness. As clinical manifestations are variable, molecular testing is supportive in the diagnosis of LS. We describe two unrelated LS cases with a common PTPN11 mutation Y279C and with completely different clinical features including distinct changes in skin pigmentation. In patient 1, the first complaint was hyperactive behaviour. First lentigines were presented at birth, but intensive growth began at the age of 2-4 years. Multiple dark lentigines were located mainly on the face and the upper part of the trunk, but the oral mucosa was spared. Patient 2 was born from induced labour due to polyhydramnion, and in the second week of life, mitral valve insufficiency and hypertrophic cardiomyopathy were diagnosed. Rapid growth of lentigines began at the age of 3 years. These are mostly located in the joint areas in the lower extremities; the face and upper trunk are spared from lentigines. In both cases, the rapid growth of lentigines made it possible to shift the diagnosis towards LS. Clinicians should give more consideration to rare genetic syndromes, especially in the case of symptoms from different clinical areas.
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8
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Denayer E, Brems H, de Cock P, Evans GD, Van Calenbergh F, Bowers N, Sciot R, Debiec-Rychter M, Vermeesch JV, Fryns JP, Legius E. Pathogenesis of vestibular schwannoma in ring chromosome 22. BMC MEDICAL GENETICS 2009; 10:97. [PMID: 19772601 PMCID: PMC2758865 DOI: 10.1186/1471-2350-10-97] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/15/2009] [Accepted: 09/22/2009] [Indexed: 12/05/2022]
Abstract
Background Ring chromosome 22 is a rare human constitutional cytogenetic abnormality. Clinical features of neurofibromatosis type 1 and 2 as well as different tumour types have been reported in patients with ring chromosome 22. The pathogenesis of these tumours is not always clear yet. Methods We report on a female patient with a ring chromosome 22 presenting with severe mental retardation, autistic behaviour, café-au-lait macules and facial dysmorphism. Peripheral blood lymphocytes were karyotyped and array CGH was performed on extracted DNA. At the age of 20 years she was diagnosed with a unilateral vestibular schwannoma. Tumour cells were analyzed by karyotyping, array CGH and NF2 mutation analysis. Results Karyotype on peripheral blood lymphocytes revealed a ring chromosome 22 in all analyzed cells. A 1 Mb array CGH experiment on peripheral blood DNA showed a deletion of 5 terminal clones on the long arm of chromosome 22. Genetic analysis of vestibular schwannoma tissue revealed loss of the ring chromosome 22 and a somatic second hit in the NF2 gene on the remaining chromosome 22. Conclusion We conclude that tumours can arise by the combination of loss of the ring chromosome and a pathogenic NF2 mutation on the remaining chromosome 22 in patients with ring chromosome 22. Our findings indicate that patients with a ring 22 should be monitored for NF2-related tumours starting in adolescence.
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Affiliation(s)
- Ellen Denayer
- Department of human genetics, University Hospital Gasthuisberg, Leuven, Belgium.
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9
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Sarkozy A, Schirinzi A, Lepri F, Bottillo I, De Luca A, Pizzuti A, Tartaglia M, Digilio MC, Dallapiccola B. Clinical lumping and molecular splitting of LEOPARD and NF1/NF1-Noonan syndromes. Am J Med Genet A 2007; 143A:1009-11. [PMID: 17366582 DOI: 10.1002/ajmg.a.31666] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Affiliation(s)
- Anna Sarkozy
- IRCCS-CSS, San Giovanni Rotondo and CSS-Mendel Institute, Rome, Italy.
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10
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Walker JA, Tchoudakova AV, McKenney PT, Brill S, Wu D, Cowley GS, Hariharan IK, Bernards A. Reduced growth of Drosophila neurofibromatosis 1 mutants reflects a non-cell-autonomous requirement for GTPase-Activating Protein activity in larval neurons. Genes Dev 2006; 20:3311-23. [PMID: 17114577 PMCID: PMC1686607 DOI: 10.1101/gad.1466806] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Neurofibromatosis type 1 (NF1) is among the most common genetic disorders of humans and is caused by loss of neurofibromin, a large and highly conserved protein whose only known function is to serve as a GTPase-Activating Protein (GAP) for Ras. However, most Drosophila NF1 mutant phenotypes, including an overall growth deficiency, are not readily modified by manipulating Ras signaling strength, but are rescued by increasing signaling through the cAMP-dependent protein kinase A pathway. This has led to suggestions that NF1 has distinct Ras- and cAMP-related functions. Here we report that the Drosophila NF1 growth defect reflects a non-cell-autonomous requirement for NF1 in larval neurons that express the R-Ras ortholog Ras2, that NF1 is a GAP for Ras1 and Ras2, and that a functional NF1-GAP catalytic domain is both necessary and sufficient for rescue. Moreover, a Drosophila p120RasGAP ortholog, when expressed in the appropriate cells, can substitute for NF1 in growth regulation. Our results show that loss of NF1 can give rise to non-cell-autonomous developmental defects, implicate aberrant Ras-mediated signaling in larval neurons as the primary cause of the NF1 growth deficiency, and argue against the notion that neurofibromin has separable Ras- and cAMP-related functions.
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Affiliation(s)
- James A Walker
- Massachusetts General Hospital Center for Cancer Research and Harvard Medical School, Charlestown, Massachusetts 02129, USA
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11
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Stevenson DA, Viskochil DH, Rope AF, Carey JC. Clinical and molecular aspects of an informative family with neurofibromatosis type 1 and Noonan phenotype. Clin Genet 2006; 69:246-53. [PMID: 16542390 PMCID: PMC3243644 DOI: 10.1111/j.1399-0004.2006.00576.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Neurofibromatosis-Noonan syndrome (NFNS) has been described as a unique phenotype, combining manifestations of neurofibromatosis type 1 (NF1) and Noonan syndrome, which are separate syndromes. Potential etiologies of NFNS include a discrete syndrome of distinct etiology, co-segregation of two mutated common genes, variable clinical expressivity of NF1, and/or allelic heterogeneity. We present an informative family with an unusual NF1 mutation with variable features of NF1 and Noonan syndrome. We hypothesize that an NF1 mutant allele can lead to diagnostic manifestations of Noonan syndrome, supporting the hypothesis that NF1 allelic heterogeneity causes NFNS.
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Affiliation(s)
- D A Stevenson
- Department of Pediatrics, Division of Medical Genetics, University of Utah, Salt Lake City, UT 84132, USA
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12
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Hüffmeier U, Zenker M, Hoyer J, Fahsold R, Rauch A. A variable combination of features of Noonan syndrome and neurofibromatosis type I are caused by mutations in theNF1 gene. Am J Med Genet A 2006; 140:2749-56. [PMID: 17103458 DOI: 10.1002/ajmg.a.31547] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Signs of neurofibromatosis type 1 (NF1) and Noonan syndrome (NS), two distinct autosomal dominant disorders, occur together in patients reported as Watson syndrome (WS), neurofibromatosis-Noonan syndrome (NFNS), partial LEOPARD syndrome, NS with features of NF1, and NF1 with Noonan-like features. The molecular basis of these combined phenotypes was poorly understood and controversially discussed over several decades. Only recently, there is increasing evidence for WS and NFNS being allelic to NF1 in the majority of patients. In this study we describe seven novel patients from five unrelated families with variable phenotypes of the NF1-NS spectrum which were systematically analyzed for mutations in the disease-causing genes NF1 for NF1 and PTPN11 for NS. Heterozygous mutations or deletions of NF1 were identified in all patients, while no PTPN11 mutation was found. The NF1 mutation segregated with the phenotype in both familial cases. These results support the hypothesis that variable phenotypes of the NF1-NS spectrum represent variants of NF1 in the majority of cases. Constitutive deregulation of the Ras pathway either through activating mutations of PTPN11 or through haploinsufficiency of neurofibromin, which acts as a Ras-inactivating GTP-ase, is probably the common pathogenetic mechanism explaining the phenotypic overlap of NS and NF1.
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Affiliation(s)
- Ulrike Hüffmeier
- Institute of Human Genetics, University Erlangen-Nuremberg, Erlangen, Germany
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13
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Digilio MC, Capolino R, Marino B, Sarkozy A, Dallapiccola B. Congenital intrahepatic portosystemic venous shunt: an unusual feature in LEOPARD syndrome and in neurofibromatosis type 1. Am J Med Genet A 2005; 134:457-8. [PMID: 15669093 DOI: 10.1002/ajmg.a.30582] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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14
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Pinson S, Wolkenstein P. La neurofibromatose 1 (NF1) ou maladie de Von Recklinghausen. Rev Med Interne 2005; 26:196-215. [PMID: 15777582 DOI: 10.1016/j.revmed.2004.06.011] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2003] [Accepted: 06/20/2004] [Indexed: 10/26/2022]
Abstract
OBJECTIVES Neurofibromatosis 1(NF1) is one of the most common genetic diseases. NF1 is an autosomal dominant genetic disorder and half of affected individuals have NF1 as the result of a new gene NF1 mutation. The offspring of an affected individual have a 50% risk of inheriting the altered NF1 gene. The disease manifestations are extremely variable, even within a family. NF1 is characterized by multiple cafe au lait spots, axillary and inguinal freckling, multiple discrete dermal neurofibromas, and iris Lisch nodules. Learning disabilities are frequent. Less common but potentially more serious manifestations include plexiform neurofibromas, optic and other central nervous system gliomas, malignant peripheral nerve sheath tumors, vasculopathy, and osseous lesions. CURRENT KNOWLEDGES AND KEY POINTS Since the original National Institutes of Health consensus Development Conference in 1987, there have been significant progress toward a more complete understanding of the molecular-bases for neurofibromatosis 1 and the routine follow-up for the care of the NF1 patients. The authors review the present data on the clinical and molecular aspects of the neurofibromatosis 1. FUTURE PROSPECTS AND PROJECTS NF1 requires life-long management adapted to age and multidisciplinary structures are particularly well adapted to the diversity of the manifestations of this pathology. The French NF-France Network has been created in 2001 to federate the French multidisciplinary structures for neurofibromatosis and harmonize the follow-up of NF1 patients in France.
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Affiliation(s)
- S Pinson
- Laboratoire de génétique moléculaire, bâtiment E, hôpital Edouard-Hérriot, 5, place d'Arsonval, 69437 Lyon, France.
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Baralle D, Mattocks C, Kalidas K, Elmslie F, Whittaker J, Lees M, Ragge N, Patton MA, Winter RM, ffrench-Constant C. Different mutations in the NF1 gene are associated with Neurofibromatosis-Noonan syndrome (NFNS). Am J Med Genet A 2003; 119A:1-8. [PMID: 12707950 DOI: 10.1002/ajmg.a.20023] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The association of the Noonan phenotype with neurofibromatosis type 1 (NF1) was first noted by Allanson et al. [Am J Med Genet 1985;21:457-462.] and 30 further cases have subsequently been reported. It has been suggested that this phenotype is more common than previously appreciated, as Colley et al. [Clin Genet 1996;49:59-64.] examined 94 sequentially identified patients with NF1 from their genetic register and found Noonan features in 12. A 3-bp deletion of exon 17 of the NF1 neurofibromin gene was described in one family by Carey et al. [Proc Greenwood Genet Center 1997;17:52-53]. However, it remains unclear whether Neurofibromatosis-Noonan syndrome (NFNS) represents a form of NF1 (with mutations in the NF1 neurofibromin gene) or a separate syndrome. We have used a new, rapid sequence analysis technique-comparative sequence analysis (CSA)-to examine the NF1 gene in six patients with NFNS. None of the six patients had the previously identified mutation, nor did we observe other mutations within this exon. However, two other mutations were found: in exon 25, a 3-bp deletion 4312 del GAA, and in exon 23-2, a 2-bp insertion 4095 ins TG. The PTPN11 gene, now known to cause over 50% of Noonan syndrome was also examined in four cases of NFNS, and no mutations were found. These results show that NFNS can in some cases result from different mutations in the NF1 gene and therefore represents a variant form of NF1.
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Affiliation(s)
- Diana Baralle
- Department of Medical Genetics, Addenbrooke's Hospital, Cambridge, United Kingdom.
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Digilio MC, Conti E, Sarkozy A, Mingarelli R, Dottorini T, Marino B, Pizzuti A, Dallapiccola B. Grouping of multiple-lentigines/LEOPARD and Noonan syndromes on the PTPN11 gene. Am J Hum Genet 2002; 71:389-94. [PMID: 12058348 PMCID: PMC379170 DOI: 10.1086/341528] [Citation(s) in RCA: 267] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2002] [Accepted: 04/30/2002] [Indexed: 01/08/2023] Open
Abstract
Multiple-lentigines (ML)/LEOPARD (multiple lentigines, electrocardiographic-conduction abnormalities, ocular hypertelorism, pulmonary stenosis, abnormal genitalia, retardation of growth, and sensorineural deafness) syndrome is an autosomal dominant condition--characterized by lentigines and café au lait spots, facial anomalies, cardiac defects--that shares several clinical features with Noonan syndrome (NS). We screened nine patients with ML/LEOPARD syndrome (including a mother-daughter pair) and two children with NS who had multiple café au lait spots, for mutations in the NS gene, PTPN11, and found, in 10 of 11 patients, one of two new missense mutations, in exon 7 or exon 12. Both mutations affect the PTPN11 phosphotyrosine phosphatase domain, which is involved in <30% of the NS PTPN11 mutations. The study demonstrates that ML/LEOPARD syndrome and NS are allelic disorders. The detected mutations suggest that distinct molecular and pathogenetic mechanisms cause the peculiar cutaneous manifestations of the ML/LEOPARD-syndrome subtype of NS.
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Affiliation(s)
- Maria Cristina Digilio
- Division of Medical Genetics, Bambino Gesù Hospital, Istituto di Ricovero e Cura a Carattere Scientifico, Casa Sollievo della Sofferenza Hospital, Istituto di Ricovero e Cura a Carattere Scientifico, San Giovanni Rotondo and Casa Sollievo della Sofferenza–Mendel Institute, Section of Medical Genetics, Department of Experimental Medicine and Pathology, and Division of Pediatric Cardiology, Institute of Pediatrics, University “La Sapienza,” Rome
| | - Emanuela Conti
- Division of Medical Genetics, Bambino Gesù Hospital, Istituto di Ricovero e Cura a Carattere Scientifico, Casa Sollievo della Sofferenza Hospital, Istituto di Ricovero e Cura a Carattere Scientifico, San Giovanni Rotondo and Casa Sollievo della Sofferenza–Mendel Institute, Section of Medical Genetics, Department of Experimental Medicine and Pathology, and Division of Pediatric Cardiology, Institute of Pediatrics, University “La Sapienza,” Rome
| | - Anna Sarkozy
- Division of Medical Genetics, Bambino Gesù Hospital, Istituto di Ricovero e Cura a Carattere Scientifico, Casa Sollievo della Sofferenza Hospital, Istituto di Ricovero e Cura a Carattere Scientifico, San Giovanni Rotondo and Casa Sollievo della Sofferenza–Mendel Institute, Section of Medical Genetics, Department of Experimental Medicine and Pathology, and Division of Pediatric Cardiology, Institute of Pediatrics, University “La Sapienza,” Rome
| | - Rita Mingarelli
- Division of Medical Genetics, Bambino Gesù Hospital, Istituto di Ricovero e Cura a Carattere Scientifico, Casa Sollievo della Sofferenza Hospital, Istituto di Ricovero e Cura a Carattere Scientifico, San Giovanni Rotondo and Casa Sollievo della Sofferenza–Mendel Institute, Section of Medical Genetics, Department of Experimental Medicine and Pathology, and Division of Pediatric Cardiology, Institute of Pediatrics, University “La Sapienza,” Rome
| | - Tania Dottorini
- Division of Medical Genetics, Bambino Gesù Hospital, Istituto di Ricovero e Cura a Carattere Scientifico, Casa Sollievo della Sofferenza Hospital, Istituto di Ricovero e Cura a Carattere Scientifico, San Giovanni Rotondo and Casa Sollievo della Sofferenza–Mendel Institute, Section of Medical Genetics, Department of Experimental Medicine and Pathology, and Division of Pediatric Cardiology, Institute of Pediatrics, University “La Sapienza,” Rome
| | - Bruno Marino
- Division of Medical Genetics, Bambino Gesù Hospital, Istituto di Ricovero e Cura a Carattere Scientifico, Casa Sollievo della Sofferenza Hospital, Istituto di Ricovero e Cura a Carattere Scientifico, San Giovanni Rotondo and Casa Sollievo della Sofferenza–Mendel Institute, Section of Medical Genetics, Department of Experimental Medicine and Pathology, and Division of Pediatric Cardiology, Institute of Pediatrics, University “La Sapienza,” Rome
| | - Antonio Pizzuti
- Division of Medical Genetics, Bambino Gesù Hospital, Istituto di Ricovero e Cura a Carattere Scientifico, Casa Sollievo della Sofferenza Hospital, Istituto di Ricovero e Cura a Carattere Scientifico, San Giovanni Rotondo and Casa Sollievo della Sofferenza–Mendel Institute, Section of Medical Genetics, Department of Experimental Medicine and Pathology, and Division of Pediatric Cardiology, Institute of Pediatrics, University “La Sapienza,” Rome
| | - Bruno Dallapiccola
- Division of Medical Genetics, Bambino Gesù Hospital, Istituto di Ricovero e Cura a Carattere Scientifico, Casa Sollievo della Sofferenza Hospital, Istituto di Ricovero e Cura a Carattere Scientifico, San Giovanni Rotondo and Casa Sollievo della Sofferenza–Mendel Institute, Section of Medical Genetics, Department of Experimental Medicine and Pathology, and Division of Pediatric Cardiology, Institute of Pediatrics, University “La Sapienza,” Rome
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Abstract
Neurofibromatosis 1 is a progressive autosomal dominant condition caused by mutations in the NF1 gene on chromosome 17. The condition shows clinical variable expressivity, with varying features even between family members who share the same mutation. Furthermore, it is impossible to precisely predict the severity and course of the condition, a source of frustration for families and physicians. Neurofibromatosis 1 is also heterogeneous at the mutation level, with more than 300 independent mutations having been reported in this gene. The mutation data have accumulated slowly owing to the variability of the mutation types and the size and complexity of the gene. This is also reflected in the lack of a simple, inexpensive, highly accurate DNA-based test for neurofibromatosis 1 at present. This article reviews current NF1 mutation spectrum and testing, discussing and illustrating mutation mechanisms and pathogenetic effects, as well as factors affecting DNA testing and interpretation/diagnosis.
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Affiliation(s)
- Susanne A M Thomson
- Department of Molecular Genetics, University of Florida College of Medicine, Gainesville 32610-0266, USA
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Pacheco TR, Bellus GA, Oreskovich NM, Talbert J, Old W, Fain PR. Exclusion of candidate genes and loci for multiple lentigines syndrome. J Invest Dermatol 2002; 119:535-8. [PMID: 12190883 DOI: 10.1046/j.1523-1747.2002.18203.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Ars E, Kruyer H, Gaona A, Casquero P, Rosell J, Volpini V, Serra E, Lázaro C, Estivill X. A clinical variant of neurofibromatosis type 1: familial spinal neurofibromatosis with a frameshift mutation in the NF1 gene. Am J Hum Genet 1998; 62:834-41. [PMID: 9529361 PMCID: PMC1377042 DOI: 10.1086/301803] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Spinal neurofibromatosis (SNF) has been considered to be an alternative form of neurofibromatosis in which spinal cord tumors are the main clinical characteristic. Familial SNF has been reported, elsewhere, in three families-two linked to markers within the gene for neurofibromatosis type 1 (NF1) and the other not linked to NF1-but no molecular alterations have been described in these families. We describe a three-generation family that includes five members affected by SNF. All the affected members presented multiple spinal neurofibromas and café au lait spots, one member had cutaneous neurofibromas, and some members had other signs of NF1. Genetic analysis, performed with markers within and flanking the NF1 gene, showed segregation with the NF1 locus. Mutation analysis, performed with the protein-truncation test and SSCP/heteroduplex analysis of the whole coding region of the NF1 gene, identified a frameshift mutation (8042insA) in exon 46, which should result in a truncated NF1 protein. The 8042insA mutation was detected in all five family members with the SNF/NF1 phenotype. To our knowledge, this is the first time that a mutation in the NF1 gene has been associated with SNF. The clinical homogeneity in the severity of the disease among the affected members of the family, which is unusual in NF1, suggests that a particular property of the NF1 mutation described here, a gene closely linked to NF1, or posttranscriptional events are involved in this severe neurological phenotype.
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Affiliation(s)
- E Ars
- Medical and Molecular Genetics Center-IRO, Hospital Duran i Reynals, Barcelona, Catalonia, Spain
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Coppin BD, Temple IK. Multiple lentigines syndrome (LEOPARD syndrome or progressive cardiomyopathic lentiginosis). J Med Genet 1997; 34:582-6. [PMID: 9222968 PMCID: PMC1051000 DOI: 10.1136/jmg.34.7.582] [Citation(s) in RCA: 86] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The multiple lentigines syndrome is an autosomal dominant condition which has many similarities to Noonan syndrome, except in the most striking feature from which its name is derived. The less neutral but very apt mnemonic, LEOPARD syndrome, was first used by Gorlin et al to whom the major debt in the definition of this syndrome lies, that is, Lentigines, ECG abnormalities, Ocular hypertelorism/Obstructive cardiomyopathy, Pulmonary valve stenosis, Abnormalities of genitalia in males, Retardation of growth, and Deafness. Not previously included in the mnemonic is cardiomyopathy which is an important feature because it is associated with significant mortality.
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Affiliation(s)
- B D Coppin
- Wessex Clinical Genetics Service, Princess Anne Hospital, Southampton, UK
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