1
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Guo XH, Jin X, Wang B, Wang ZY. Identifying a novel frameshift pathogenic variant in a Chinese family with neurofibromatosis type 1 and review of literature. Int J Ophthalmol 2023; 16:47-52. [PMID: 36659944 PMCID: PMC9815979 DOI: 10.18240/ijo.2023.01.07] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Accepted: 11/03/2022] [Indexed: 12/30/2022] Open
Abstract
AIM To detect the pathogenic gene variant in a family with neurofibromatosis type 1 (NF1). METHODS This patient with NF1 was sequenced using target sequence capture and high-throughput sequencing technology. After detecting the suspicious pathogenic variant type, the pathogenic variant sites of the patient and the patient's family members were verified by multiple ligation dependent probe amplification and Sanger sequencing. Sift, polyphen-2, Mutation Taster and GERP++ software were used to predict the pathogenicity of the unknown loci. The clinical data, diagnosis and treatment process of the patients were reviewed. Using the keyword "NF1; frameshift pathogenic variant", relevant literature was gathered for analysis from Chinese and international databases, with articles dating from the establishment of each database to April 2022. RESULTS A heterozygous frameshift pathogenic variant of NF1 in exon 33 was detected in the patient. The insertion of adenine in coding region 4486 resulted in the replacement of isoleucine with asparagine in protein 1497. Sanger sequencing validation and segregation analysis were performed, which demonstrated that the NF1 gene was cosegregated with the disease phenotype in this family. This study identified a novel NF1 heterozygous frameshift mutation c.4486dupA (p.I1497Nfs*12). Relevant literature retrieval found 7 Chinese articles and 12 foreign articles. With NF1 gene mutation, mutation types are diverse, including point mutation, frameshift mutation, splice site mutation, exon mutation, chimeric mutation and de novo mutation. Foreign reports are based on autosomal dominant inheritance. CONCLUSION This study's results demonstrate that a novel deletion in exon 33 caused NF1 in this Chinese family, expanding the mutational spectrum of the NF1 gene.
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Affiliation(s)
- Xiao-Hui Guo
- Senior Department of Ophthalmology, the Third Medical Center of PLA General Hospital, Beijing 100039, China
| | - Xin Jin
- Senior Department of Ophthalmology, the Third Medical Center of PLA General Hospital, Beijing 100039, China
| | - Bin Wang
- Department of Otolaryngology, Peking Union Medical College Hospital, Beijing 100730, China
| | - Zhao-Yan Wang
- Senior Department of Ophthalmology, the Third Medical Center of PLA General Hospital, Beijing 100039, China
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2
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Stella A, Lastella P, Viggiano L, Bagnulo R, Resta N. Clinical presentation and genetic analyses of neurofibromatosis type 1 in independent patients with monoallelic double de novo closely spaced mutations in the NF1 gene. Hum Mutat 2022; 43:1354-1360. [PMID: 35723633 PMCID: PMC9540858 DOI: 10.1002/humu.24423] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2022] [Revised: 06/14/2022] [Accepted: 06/15/2022] [Indexed: 12/15/2022]
Abstract
Neurofibromatosis type 1 (NF1) belongs to RASopathies, a group of syndromes caused by germline mutations in Ras/MAPK pathway genes. Most NF1 patients exhibit single inactivating pathogenic variants within the NF1 gene. We performed extensive genetic analyses in two NF1 families disclosing the first two cases of double de novo monoallelic NF1 variants. Both index patients described in this study had classical NF1. Probands were born from fathers in their late 30s and presented closely spaced double mutations (<100 bp) in NF1 regions showing an excess of somatic mutations. Closely spaced multiple mutations have been reported in RAS/MAPK signaling genes but never in NF1. Mutagenesis is a quasi-random process in humans, therefore two causative variants in the same gene, moreover in the same allele are exceptional. Here, we discuss possible mechanisms for this ultrarare event. Our findings confirm the possibility of a higher risk of concurrent de novo variants in NF1.
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Affiliation(s)
- Alessandro Stella
- Department of Biomedical Sciences and Human OncologyLaboratory of Medical Genetics, Università di Bari Aldo MoroBariItaly
| | - Patrizia Lastella
- Rare Disease CenterInternal MedicineUnit ‘C. Frugoni’, AOU Policlinico di BariBariItaly
| | - Luigi Viggiano
- Department of BiologyUniversity of Bari Aldo MoroBariItaly
| | - Rosanna Bagnulo
- Department of Biomedical Sciences and Human OncologyLaboratory of Medical Genetics, Università di Bari Aldo MoroBariItaly
| | - Nicoletta Resta
- Department of Biomedical Sciences and Human OncologyLaboratory of Medical Genetics, Università di Bari Aldo MoroBariItaly
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3
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Garcia B, Catasus N, Ros A, Rosas I, Negro A, Guerrero-Murillo M, Valero AM, Duat-Rodriguez A, Becerra JL, Bonache S, Lázaro Garcia C, Comas C, Bielsa I, Serra E, Hernández-Chico C, Martin Y, Castellanos E, Blanco I. Neurofibromatosis type 1 families with first-degree relatives harbouring distinct NF1 pathogenic variants. Genetic counselling and familial diagnosis: what should be offered? J Med Genet 2022; 59:1017-1023. [PMID: 35121649 DOI: 10.1136/jmedgenet-2021-108301] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2021] [Accepted: 01/09/2022] [Indexed: 11/03/2022]
Abstract
Neurofibromatosis type 1 (NF1) is an autosomal dominant disorder caused by pathogenic variants in NF1 Recently, NF1 testing has been included as a clinical criterion for NF1 diagnosis. Additionally, preconception genetic counselling in patients with NF1 focuses on a 50% risk of transmitting the familial variant as the risk of having a sporadic NF1 is considered the same as the general population. METHODS 829 individuals, 583 NF1 sporadic cases and 246 patients with NF1 with documented family history, underwent genetic testing for NF1. Genotyping and segregation analysis of NF1 familial variants was determined by microsatellite analysis and NF1 sequencing. RESULTS The mutational analysis of NF1 in 154 families with two or more affected cases studied showed the co-occurrence of two different NF1 germline pathogenic variants in four families. The estimated mutation rate in those families was 3.89×10-3, 20 times higher than the NF1 mutation rate (~2×10-4) (p=0.0008). Furthermore, the co-occurrence of two different NF1 germline pathogenic variants in these families was 1:39, 60 times the frequency of sporadic NF1 (1:2500) (p=0.003). In all cases, the de novo NF1 pathogenic variant was present in a descendant of an affected male. In two cases, variants were detected in the inherited paternal wild-type allele. CONCLUSIONS Our results, together with previous cases reported, suggest that the offspring of male patients with NF1 could have an increased risk of experiencing de novo NF1 pathogenic variants. This observation, if confirmed in additional cohorts, could have relevant implications for NF1 genetic counselling, family planning and NF1 genetic testing.
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Affiliation(s)
- Belen Garcia
- Genetic Counseling Unit, Clinical Genetics Service, Northern Metropolitan Clinical Laboratory, Hospital Universitari Germans Trias i Pujol, Badalona, Spain.,Clinical Genomics Research Unit, Foundation Institute of Research in Health Sciences Germans Trias i Pujol, Badalona, Spain
| | - Nuria Catasus
- Clinical Genomics Research Unit, Foundation Institute of Research in Health Sciences Germans Trias i Pujol, Badalona, Spain
| | - Andrea Ros
- Genetic Counseling Unit, Clinical Genetics Service, Northern Metropolitan Clinical Laboratory, Hospital Universitari Germans Trias i Pujol, Badalona, Spain.,Clinical Genomics Research Unit, Foundation Institute of Research in Health Sciences Germans Trias i Pujol, Badalona, Spain
| | - Inma Rosas
- Clinical Genomics Research Unit, Foundation Institute of Research in Health Sciences Germans Trias i Pujol, Badalona, Spain.,Clinical Genomics Unit-Genetics Service, Hospital Universitari Germans Trias i Pujol, Badalona, Spain
| | - Alejandro Negro
- Clinical Genomics Research Unit, Foundation Institute of Research in Health Sciences Germans Trias i Pujol, Badalona, Spain.,Clinical Genomics Unit-Genetics Service, Hospital Universitari Germans Trias i Pujol, Badalona, Spain
| | - Mercedes Guerrero-Murillo
- Clinical Genomics Research Unit, Foundation Institute of Research in Health Sciences Germans Trias i Pujol, Badalona, Spain.,Clinical Genomics Unit-Genetics Service, Hospital Universitari Germans Trias i Pujol, Badalona, Spain
| | - Ana Maria Valero
- Servicio de Genética, Hospital Universitario Ramon y Cajal, Madrid, Spain
| | - Anna Duat-Rodriguez
- Neurology Service, Hospital Infantil Universitario Niño Jesús, Madrid, Spain
| | - Juan Luis Becerra
- Neurology, Hospital Universitari Germans Trias i Pujol, Badalona, Spain
| | - Sandra Bonache
- Clinical Genomics Research Unit, Foundation Institute of Research in Health Sciences Germans Trias i Pujol, Badalona, Spain.,Clinical Genomics Unit-Genetics Service, Hospital Universitari Germans Trias i Pujol, Badalona, Spain
| | - Conxi Lázaro Garcia
- Hereditary Cancer Program, Program in Molecular Mechanisms and Experimental Therapy in Oncology (Oncobell), IDIBELL, Catalan Institute of Oncology, L'Hospitalet de Llobregat, Spain.,Centro de Investigación Biomédica en Red de Cáncer, CIBERONC, Madrid, Spain
| | - Carmina Comas
- Department of Obstetrics, Hospital Universitari Germans Trias i Pujol, Badalona, Spain
| | - Isabel Bielsa
- Dermatology, Hospital Universitari Germans Trias i Pujol, Badalona, Spain
| | - Eduard Serra
- Centro de Investigación Biomédica en Red de Cáncer, CIBERONC, Madrid, Spain.,Hereditary Cancer Group, Fundació Institut d'Investigació en Ciències de la Salut Germans Trias i Pujol, Badalona, Spain
| | - Concepción Hernández-Chico
- Servicio de Genética, IRYCIS, Hospital Universitario Ramon y Cajal, Madrid, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Raras, CIBERER, Valencia, Spain
| | - Yolanda Martin
- Servicio de Genética, IRYCIS, Hospital Universitario Ramon y Cajal, Madrid, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Raras, CIBERER, Valencia, Spain
| | - Elisabeth Castellanos
- Clinical Genomics Research Unit, Foundation Institute of Research in Health Sciences Germans Trias i Pujol, Badalona, Spain .,Clinical Genomics Unit-Genetics Service, Hospital Universitari Germans Trias i Pujol, Badalona, Spain
| | - Ignacio Blanco
- Genetic Counseling Unit, Clinical Genetics Service, Northern Metropolitan Clinical Laboratory, Hospital Universitari Germans Trias i Pujol, Badalona, Spain.,Clinical Genomics Research Unit, Foundation Institute of Research in Health Sciences Germans Trias i Pujol, Badalona, Spain
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4
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Pinti E, Nemeth K, Staub K, Lengyel A, Fekete G, Haltrich I. Diagnostic difficulties and possibilities of NF1-like syndromes in childhood. BMC Pediatr 2021; 21:331. [PMID: 34325699 PMCID: PMC8320045 DOI: 10.1186/s12887-021-02791-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/03/2021] [Accepted: 06/30/2021] [Indexed: 12/28/2022] Open
Abstract
BACKGROUND Neurofibromatosis type 1 (NF1), which is caused by heterozygous inactivating pathogenic variants in the NF1, has poor phenotypic expressivity in the early years of life and there are numerous conditions, including many other tumor predisposition syndromes, that can mimic its appearance. These are collectively termed NF1-like syndromes and are also connected by their genetic background. Therefore, the NF1's clinical diagnostic efficiency in childhood could be difficult and commonly should be completed with genetic testing. METHODS To estimate the number of syndromes/conditions that could mimic NF1, we compiled them through an extensive search of the scientific literature. To test the utility of NF1's National Institutes of Health (NIH) clinical diagnostic criteria, which have been in use for a long time, we analyzed the data of a 40-member pediatric cohort with symptoms of the NF1-like syndromes' overlapping phenotype and performed NF1 genetic test, and established the average age when diagnostic suspicion arises. To facilitate timely identification, we compiled strongly suggestive phenotypic features and anamnestic data. RESULTS In our cohort the utility of NF1's clinical diagnostic criteria were very limited (sensitivity: 80%, specificity: 30%). Only 53% of children with clinically diagnosed NF1 had a detectable NF1 pathogenic variation, whereas 40% of patients without fulfilled clinical criteria tested positive. The average age at first genetic counseling was 9 years, and 40% of children were referred after at least one tumor had already been diagnosed. These results highlight the need to improve NF1-like syndromes' diagnostic efficiency in childhood. We collected the most extensive spectrum of NF1-like syndromes to help the physicians in differential diagnosis. We recommend the detailed, non-invasive clinical evaluation of patients before referring them to a clinical geneticist. CONCLUSIONS Early diagnosis of NF1-like syndromes can help to prevent severe complications by appropriate monitoring and management. We propose a potential screening, diagnostic and management strategy based on our findings and recent scientific knowledge.
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Affiliation(s)
- Eva Pinti
- II. Department of Pediatrics, Semmelweis University, Tuzolto utca 7-9, Budapest, 1094, Hungary.
| | - Krisztina Nemeth
- II. Department of Pediatrics, Semmelweis University, Tuzolto utca 7-9, Budapest, 1094, Hungary
| | - Krisztina Staub
- II. Department of Pediatrics, Semmelweis University, Tuzolto utca 7-9, Budapest, 1094, Hungary
| | - Anna Lengyel
- II. Department of Pediatrics, Semmelweis University, Tuzolto utca 7-9, Budapest, 1094, Hungary
| | - Gyorgy Fekete
- II. Department of Pediatrics, Semmelweis University, Tuzolto utca 7-9, Budapest, 1094, Hungary
| | - Iren Haltrich
- II. Department of Pediatrics, Semmelweis University, Tuzolto utca 7-9, Budapest, 1094, Hungary
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5
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Bianchessi D, Ibba MC, Saletti V, Blasa S, Langella T, Paterra R, Cagnoli GA, Melloni G, Scuvera G, Natacci F, Cesaretti C, Finocchiaro G, Eoli M. Simultaneous Detection of NF1, SPRED1, LZTR1, and NF2 Gene Mutations by Targeted NGS in an Italian Cohort of Suspected NF1 Patients. Genes (Basel) 2020; 11:genes11060671. [PMID: 32575496 PMCID: PMC7349720 DOI: 10.3390/genes11060671] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2020] [Revised: 06/12/2020] [Accepted: 06/16/2020] [Indexed: 12/30/2022] Open
Abstract
Neurofibromatosis type 1 (NF1) displays overlapping phenotypes with other neurocutaneous diseases such as Legius Syndrome. Here, we present results obtained using a next generation sequencing (NGS) panel including NF1, NF2, SPRED1, SMARCB1, and LZTR1 genes on Ion Torrent. Together with NGS, the Multiplex Ligation-Dependent Probe Amplification Analysis (MLPA) method was performed to rule out large deletions/duplications in NF1 gene; we validated the MLPA/NGS approach using Sanger sequencing on DNA or RNA of both positive and negative samples. In our cohort, a pathogenic variant was found in 175 patients; the pathogenic variant was observed in NF1 gene in 168 cases. A SPRED1 pathogenic variant was also found in one child and in a one year old boy, both NF2 and LZTR1 pathogenic variants were observed; in addition, we identified five LZTR1 pathogenic variants in three children and two adults. Six NF1 pathogenic variants, that the NGS analysis failed to identify, were detected on RNA by Sanger. NGS allows the identification of novel mutations in five genes in the same sequencing run, permitting unambiguous recognition of disorders with overlapping phenotypes with NF1 and facilitating genetic counseling and a personalized follow-up.
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Affiliation(s)
- Donatella Bianchessi
- Molecular Neuro-Oncology Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta, via Celoria 11, 20133 Milan, Italy; (D.B.); (M.C.I.); (S.B.); (T.L.); (R.P.); (G.F.)
| | - Maria Cristina Ibba
- Molecular Neuro-Oncology Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta, via Celoria 11, 20133 Milan, Italy; (D.B.); (M.C.I.); (S.B.); (T.L.); (R.P.); (G.F.)
| | - Veronica Saletti
- Developmental Neurology Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta, via Celoria 11, 20133 Milan, Italy; (V.S.); (G.M.)
| | - Stefania Blasa
- Molecular Neuro-Oncology Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta, via Celoria 11, 20133 Milan, Italy; (D.B.); (M.C.I.); (S.B.); (T.L.); (R.P.); (G.F.)
- Department of Biotechnology and Biosciences, University of Milano-Bicocca, Piazza dell’Ateneo Nuovo, 1, 20126 Milan, Italy
| | - Tiziana Langella
- Molecular Neuro-Oncology Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta, via Celoria 11, 20133 Milan, Italy; (D.B.); (M.C.I.); (S.B.); (T.L.); (R.P.); (G.F.)
- Molecular Immunology Unit, Department of Research, Fondazione IRCCS Istituto Nazionale dei Tumori, Via Venezian, 20133 Milan, Italy
| | - Rosina Paterra
- Molecular Neuro-Oncology Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta, via Celoria 11, 20133 Milan, Italy; (D.B.); (M.C.I.); (S.B.); (T.L.); (R.P.); (G.F.)
| | - Giulia Anna Cagnoli
- Medical Genetics Unit, Woman-Child-Newborn Department, Fondazione IRCCS Ca’ Granda-Ospedale Maggiore Policlinico, via Francesco Sforza 28, 20122 Milan, Italy; (G.A.C.); (F.N.); (C.C.)
| | - Giulia Melloni
- Developmental Neurology Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta, via Celoria 11, 20133 Milan, Italy; (V.S.); (G.M.)
| | - Giulietta Scuvera
- Pediatric Highly Intensive Care Unit, Università degli Studi di Milano, Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico, via Francesco Sforza 28, 20122 Milan, Italy;
| | - Federica Natacci
- Medical Genetics Unit, Woman-Child-Newborn Department, Fondazione IRCCS Ca’ Granda-Ospedale Maggiore Policlinico, via Francesco Sforza 28, 20122 Milan, Italy; (G.A.C.); (F.N.); (C.C.)
| | - Claudia Cesaretti
- Medical Genetics Unit, Woman-Child-Newborn Department, Fondazione IRCCS Ca’ Granda-Ospedale Maggiore Policlinico, via Francesco Sforza 28, 20122 Milan, Italy; (G.A.C.); (F.N.); (C.C.)
| | - Gaetano Finocchiaro
- Molecular Neuro-Oncology Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta, via Celoria 11, 20133 Milan, Italy; (D.B.); (M.C.I.); (S.B.); (T.L.); (R.P.); (G.F.)
| | - Marica Eoli
- Molecular Neuro-Oncology Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta, via Celoria 11, 20133 Milan, Italy; (D.B.); (M.C.I.); (S.B.); (T.L.); (R.P.); (G.F.)
- Correspondence:
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