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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] [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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2
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N Abdel-Aziz N, Y El-Kamah G, A Khairat R, R Mohamed H, Z Gad Y, El-Ghor AM, Amr KS. Mutational spectrum of NF1 gene in 24 unrelated Egyptian families with neurofibromatosis type 1. Mol Genet Genomic Med 2021; 9:e1631. [PMID: 34080803 PMCID: PMC8683698 DOI: 10.1002/mgg3.1631] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Revised: 09/19/2020] [Accepted: 02/09/2021] [Indexed: 11/25/2022] Open
Abstract
Background Neurofibromatosis 1 (NF1; OMIM# 162200) is a common autosomal dominant genetic disease [incidence: ~1:3500]. In 95% of cases, clinical diagnosis of the disease is based on the presence of at least two of the seven National Institute of Health diagnostic criteria. The molecular pathology underlying this disorder entails mutation in the NF1 gene. The aim of this study was to investigate clinical and molecular characteristics of a cohort of Egyptian NF1 patients. Method This study included 35 clinically diagnosed NF1 patients descending from 25 unrelated families. Patients had ≥2 NIH diagnostic criteria. Examination of NF1 gene was done through direct cDNA sequencing of multiple overlapping fragments. This was supplemented by NF1 multiple ligation dependent probe amplification (MLPA) analysis of leucocytic DNA. Results The clinical presentations encompassed, café‐au‐lait spots in 100% of probands, freckling (52%), neurofibromas (20%), Lisch nodules of the iris (12%), optic pathway glioma (8%), typical skeletal disorders (20%), and positive family history (32%). Mutations could be detected in 24 families (96%). Eight mutations (33%) were novel. Conclusion This study illustrates the underlying molecular pathology among Egyptian NF1 patients for the first time. It also reports on 8 novel mutation expanding pathogenic mutational spectra in the NF1 gene.
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Affiliation(s)
- Nahla N Abdel-Aziz
- Medical Molecular Genetics Department, Human Genetics and Genome Research Division, National Research Centre, Cairo, Egypt
| | - Ghada Y El-Kamah
- Clinical Genetics Department, Human Genetics and Genome Research Division, National Research Centre, Cairo, Egypt
| | - Rabab A Khairat
- Medical Molecular Genetics Department, Human Genetics and Genome Research Division, National Research Centre, Cairo, Egypt
| | - Hanan R Mohamed
- Zoology Department, Faculty of Science, Cairo University, Cairo, Egypt
| | - Yehia Z Gad
- Medical Molecular Genetics Department, Human Genetics and Genome Research Division, National Research Centre, Cairo, Egypt
| | - Akmal M El-Ghor
- Zoology Department, Faculty of Science, Cairo University, Cairo, Egypt
| | - Khalda S Amr
- Medical Molecular Genetics Department, Human Genetics and Genome Research Division, National Research Centre, Cairo, Egypt
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3
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Biotteau M, Déjean S, Lelong S, Iannuzzi S, Faure-Marie N, Castelnau P, Rivier F, Lauwers-Cancès V, Baudou E, Chaix Y. Sporadic and Familial Variants in NF1: An Explanation of the Wide Variability in Neurocognitive Phenotype? Front Neurol 2020; 11:368. [PMID: 32431664 PMCID: PMC7214842 DOI: 10.3389/fneur.2020.00368] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Accepted: 04/14/2020] [Indexed: 12/15/2022] Open
Abstract
Background: Cognitive impairment is the most common neurological manifestation in NF1 and occurs in 30–70% of NF1 cases. The onset and severity of each specific cognitive deficit varies greatly from child to child, with no apparent external causes. The wide variability of phenotype is the most complex aspect in terms of management and care. Despite multiple research, the mechanism underlying the high heterogeneity in NF1 has not yet been elucidated. While many studies have focused on the effects of specific and precise genetic mutations on the NF1 phenotype, little has been done on the impact of NF1 transmission (sporadic vs. familial cases). We used a complete neuropsychological evaluation designed to assess five large cognitive areas: general cognitive functions (WISC-IV and EVIP); reading skills (“L'Alouette,” ODEDYS-2 and Lobrot French reading tests); phonological process (ODEDYS-2 test); visual perceptual skills (JLO, Thurstone and Corsi block tests) and attention (CPT-II), as well as psychosocial adjustments (CBCL) to explore the impact of NF1 transmission on cognitive disease manifestation in 96 children affected by NF1 [55 sporadic cases (29♀, 26♂); 41 familial cases (24♀, 17♂)]. Results: Familial and Sporadic form of NF1 only differ in IQ expression. The families' socioeconomic status (SES) impacts IQ performance but not differently between sporadic and familial variants. However, SES is lower in familial variants than in the sporadic variant of NF1. No other cognitive differences emerge between sporadic and familial NF1. Conclusions: Inheritance in NF1 failed to explain the phenotype variability in its entirety. IQ differences between groups seems in part linked to the environment where the child grows up. Children with NF1, and especially those that have early diagnoses (most often in inherited cases), must obtain careful monitoring from their early childhood, at home to strengthen investment in education and in school to early detect emerging academic problems and to quickly place them into care. Trial Registration: IDRCB, IDRCB2008-A01444-51. Registered 19 January 2009.
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Affiliation(s)
- Maëlle Biotteau
- ToNIC, Toulouse NeuroImaging Center, University of Toulouse, Inserm, UPS, Toulouse, France.,Children's Hospital, Toulouse-Purpan University Hospital, Toulouse, France
| | - Sébastien Déjean
- Institut de Mathématiques de Toulouse, UMR5219 Université de Toulouse, CNRS UPS, Toulouse, France
| | - Sandrine Lelong
- Children's Hospital, Toulouse-Purpan University Hospital, Toulouse, France
| | - Stéphanie Iannuzzi
- Children's Hospital, Toulouse-Purpan University Hospital, Toulouse, France
| | | | - Pierre Castelnau
- UMR 1253, iBrain, University of Tours, INSERM, Tours, France.,Department of Medicine, University of Tours Francois Rabelais, Tours, France.,Pediatric Neurology, Clocheville Children's Hospital, Tours University Hospital, Tours, France
| | - François Rivier
- Department of Pediatric Neurology and Reference Center for Language Disabilities, CHU Montpellier, PhyMedExp, University of Montpellier, INSERM, CNRS, Montpellier, France
| | | | - Eloïse Baudou
- ToNIC, Toulouse NeuroImaging Center, University of Toulouse, Inserm, UPS, Toulouse, France.,Children's Hospital, Toulouse-Purpan University Hospital, Toulouse, France
| | - Yves Chaix
- ToNIC, Toulouse NeuroImaging Center, University of Toulouse, Inserm, UPS, Toulouse, France.,Children's Hospital, Toulouse-Purpan University Hospital, Toulouse, France
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4
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Pacot L, Burin des Roziers C, Laurendeau I, Briand-Suleau A, Coustier A, Mayard T, Tlemsani C, Faivre L, Thomas Q, Rodriguez D, Blesson S, Dollfus H, Muller YG, Parfait B, Vidaud M, Gilbert-Dussardier B, Yardin C, Dauriat B, Derancourt C, Vidaud D, Pasmant E. One NF1 Mutation may Conceal Another. Genes (Basel) 2019; 10:genes10090633. [PMID: 31443423 PMCID: PMC6769760 DOI: 10.3390/genes10090633] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Revised: 08/10/2019] [Accepted: 08/20/2019] [Indexed: 01/01/2023] Open
Abstract
Neurofibromatosis type 1 (NF1) is an autosomal dominant disease with complete penetrance but high variable expressivity. NF1 is caused by loss-of-function mutations in the NF1 gene, a negative regulator of the RAS-MAPK pathway. The NF1 gene has one of the highest mutation rates in human disorders, which may explain the outbreak of independent de novo variants in the same family. Here, we report the co-occurrence of pathogenic variants in the NF1 and SPRED1 genes in six families with NF1 and Legius syndrome, using next-generation sequencing. In five of these families, we observed the co-occurrence of two independent NF1 variants. All NF1 variants were classified as pathogenic, according to the American College of Medical Genetics and Genomics and the Association for Molecular Pathology (ACMG-AMP) guidelines. In the sixth family, one sibling inherited a complete deletion of the NF1 gene from her mother and carried a variant of unknown significance in the SPRED1 gene. This variant was also present in her brother, who was diagnosed with Legius syndrome, a differential diagnosis of NF1. This work illustrates the complexity of molecular diagnosis in a not-so-rare genetic disease.
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Affiliation(s)
- Laurence Pacot
- Service de Génétique et Biologie Moléculaires, Hôpital Cochin, HUPC, Assistance Publique-Hôpitaux de Paris, 75014 Paris, France
- Institut Cochin, INSERM U1016, Université Paris Descartes, 75014 Paris, France
| | - Cyril Burin des Roziers
- Service de Génétique et Biologie Moléculaires, Hôpital Cochin, HUPC, Assistance Publique-Hôpitaux de Paris, 75014 Paris, France
- Institut Cochin, INSERM U1016, Université Paris Descartes, 75014 Paris, France
| | - Ingrid Laurendeau
- Institut Cochin, INSERM U1016, Université Paris Descartes, 75014 Paris, France
| | - Audrey Briand-Suleau
- Service de Génétique et Biologie Moléculaires, Hôpital Cochin, HUPC, Assistance Publique-Hôpitaux de Paris, 75014 Paris, France
- Institut Cochin, INSERM U1016, Université Paris Descartes, 75014 Paris, France
| | - Audrey Coustier
- Service de Génétique et Biologie Moléculaires, Hôpital Cochin, HUPC, Assistance Publique-Hôpitaux de Paris, 75014 Paris, France
| | - Théodora Mayard
- Service de Génétique et Biologie Moléculaires, Hôpital Cochin, HUPC, Assistance Publique-Hôpitaux de Paris, 75014 Paris, France
| | - Camille Tlemsani
- Service de Génétique et Biologie Moléculaires, Hôpital Cochin, HUPC, Assistance Publique-Hôpitaux de Paris, 75014 Paris, France
- Institut Cochin, INSERM U1016, Université Paris Descartes, 75014 Paris, France
| | - Laurence Faivre
- Inserm, UMR 1231, Génétique des Anomalies du Développement, Université de Bourgogne, 21079 Dijon, France
- Centre de Référence Anomalies du Développement et Syndromes Malformatifs, Hôpital d'Enfants, 21079 Dijon, France
| | - Quentin Thomas
- Inserm, UMR 1231, Génétique des Anomalies du Développement, Université de Bourgogne, 21079 Dijon, France
- Centre de Référence Anomalies du Développement et Syndromes Malformatifs, Hôpital d'Enfants, 21079 Dijon, France
| | - Diana Rodriguez
- Department of Child Neurology and National Reference Center for Neurogenetic Disorders, Armand Trousseau Hospital, GHUEP, AP-HP, INSERM U1141, 75012 Paris, France
- GRC n°19 ConCer-LD, Sorbonne Université, 75012 Paris, France
| | - Sophie Blesson
- Service de Génétique, CHRU de Tours, 37044 Tours, France
| | - Hélène Dollfus
- Centre de référence pour les Affections Rares en Génétique Ophtalmologique (CARGO), Hôpital Civil, 67091 Strasbourg, France
- Service de Génétique Médicale, Hôpital de Hautepierre, 67200 Strasbourg, France
- Laboratoire de Génétique Médicale, INSERM U1112, 67000 Strasbourg, France
| | | | - Béatrice Parfait
- Service de Génétique et Biologie Moléculaires, Hôpital Cochin, HUPC, Assistance Publique-Hôpitaux de Paris, 75014 Paris, France
- Institut Cochin, INSERM U1016, Université Paris Descartes, 75014 Paris, France
| | - Michel Vidaud
- Service de Génétique et Biologie Moléculaires, Hôpital Cochin, HUPC, Assistance Publique-Hôpitaux de Paris, 75014 Paris, France
- Institut Cochin, INSERM U1016, Université Paris Descartes, 75014 Paris, France
| | | | - Catherine Yardin
- Department of Cytogenetics and clinical genetics, Limoges University Hospital, 87042 Limoges, France
- UMR 7252, Limoges University, CNRS, XLIM, 87000 Limoges, France
| | - Benjamin Dauriat
- Department of Cytogenetics and clinical genetics, Limoges University Hospital, 87042 Limoges, France
| | - Christian Derancourt
- EA 4537, Antilles University, 97261 Fort-de-France, Martinique, France
- DRCI, Martinique University Hospital, 97261 Fort-de-France, Martinique, France
| | - Dominique Vidaud
- Service de Génétique et Biologie Moléculaires, Hôpital Cochin, HUPC, Assistance Publique-Hôpitaux de Paris, 75014 Paris, France
- Institut Cochin, INSERM U1016, Université Paris Descartes, 75014 Paris, France
| | - Eric Pasmant
- Service de Génétique et Biologie Moléculaires, Hôpital Cochin, HUPC, Assistance Publique-Hôpitaux de Paris, 75014 Paris, France.
- Institut Cochin, INSERM U1016, Université Paris Descartes, 75014 Paris, France.
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5
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Wang W, Qin W, Ge H, Kong X, Xie C, Tang Y, Li M. Clinical and molecular characteristics of thirty NF1 variants in Chinese patients with neurofibromatosis type 1. Mol Biol Rep 2019; 46:4349-4359. [PMID: 31201679 DOI: 10.1007/s11033-019-04888-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Accepted: 05/15/2019] [Indexed: 01/29/2023]
Abstract
Neurofibromatosis type 1 (NF1) is a common autosomal dominant tumor-predisposition disorder that mainly impacts the nervous system and skin. Since the full clinical presentation of NF1 depends on age, it can be difficult to make an early and definite diagnosis in paediatric patients without family history who only exhibited multiple cafè-au-lait spots, highlighting the need for mutational analysis. A combination of techniques was conducted in 30 families with NF1, including multi-gene panels, direct sequencing, cDNA sequencing and multiplex ligation-dependent probe amplification. Thirty variants were identified in 36 patients from the 30 families, among which ten variants were novel. As a result, we confirmed that the combination of techniques were highly accurate and sensitive for identifying pathogenic variants in patients clinically suspected of having NF1, in particular, for patients who only present with multiple cafè-au-lait spots.
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Affiliation(s)
- Wen Wang
- Departments of Dermatology and Venereology, The Fourth Affiliated Hospital of Anhui Medical University, Hefei, Anhui, China
| | - Weibing Qin
- NHC Key Laboratory of Male Reproduction and Genetics, Family Planning Research Institute of Guangdong Province, Guangzhou, China
| | - Hongsong Ge
- Departments of Dermatology, Anhui Provincial Children's Hospital, Hefei, Anhui, China
| | | | - Chao Xie
- Department of Paediatrics, The First People's Hospital of Hefei, Hefei, Anhui, China
| | - Yunge Tang
- NHC Key Laboratory of Male Reproduction and Genetics, Family Planning Research Institute of Guangdong Province, Guangzhou, China.
| | - Ming Li
- Departments of Dermatology, Xin Hua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China.
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6
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Sharafi P, Anlar B, Ersoy-Evans S, Varan A, Yılmaz OF, Turan M, Ayter S. The effect of parental age on NF1 patients in Turkey. J Community Genet 2017; 9:227-232. [PMID: 29143198 DOI: 10.1007/s12687-017-0346-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2017] [Accepted: 11/07/2017] [Indexed: 10/18/2022] Open
Abstract
Neurofibromatosis type 1 (NF1) is the most common neurogenetic disorder worldwide, and its clinical presentations are highly variable. NF1 is caused by mutations in the NF1 gene, and 50% of NF1 cases are sporadic, which occur in the absence of a family history of the disease and usually result from a new mutation in the germline of a parent. Advanced paternal age may increase the risk for germinal NF1 mutations; however, some dominant conditions, including neurofibromatosis, have shown a lesser association with paternal age, although there are conflicting reports in the literature. We investigated the effects of paternal and maternal age in 241 NF1 patients (121 sporadic and 120 familial cases) who were seen in Hacettepe hospital, a reference center for genetic diseases in Turkey. For statistical analysis, Spearman's and Chi-square tests were used. In this study, we evaluated paternal and maternal age at birth in sporadic and familial cases of NF1. We also compared the effect of parental age on the appearance and coexistence of various NF1 symptoms. There were no significant statistical differences between paternal age and coexistence of the NF1 symptoms. However, a slightly negative correlation was observed between paternal age and the coexistence of NF1 symptoms in familial cases (p < 0.05). We did not find strong evidence for the effect of parental age on the clinical severity of NF1.
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Affiliation(s)
- P Sharafi
- Department of Medical Biology, TOBB University of Economics and Technology, Faculty of Medicine, Ankara, Turkey
| | - B Anlar
- Department of Pediatrics, Pediatric Neurology, Hacettepe University, School of Medicine, Ankara, Turkey
| | - S Ersoy-Evans
- Department of Dermatology, Hacettepe University, School of Medicine, Ankara, Turkey
| | - A Varan
- Department of Pediatrics, Pediatric Oncology, Hacettepe University, School of Medicine, Ankara, Turkey
| | - O F Yılmaz
- Faculty of Medicine, TOBB University of Economics and Technology, Ankara, Turkey
| | - M Turan
- Faculty of Medicine, TOBB University of Economics and Technology, Ankara, Turkey
| | - S Ayter
- Department of Medical Biology, TOBB University of Economics and Technology, Faculty of Medicine, Ankara, Turkey.
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7
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Yapijakis C, Pachis N, Voumvourakis C. Neurofibromatosis-Noonan Syndrome: A Possible Paradigm of the Combination of Genetic and Epigenetic Factors. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 987:151-159. [PMID: 28971455 DOI: 10.1007/978-3-319-57379-3_14] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Neurofibromatosis-Noonan syndrome (NFNS) is a clinical entity possessing traits of autosomal dominant disorders neurofibromatosis type 1 (NF1) and Noonan syndrome (NS). Germline mutations that disrupt the RAS/MAPK pathway are involved in the pathogenesis of both NS and NF1. In light of a studied Greek family, a new theory for etiological pathogenesis of NFNS is suggested. The NFNS phenotype may be the final result of a combination of a genetic factor (a mutation in the NF1 gene) and an environmental factor with the epigenetic effects of muscle hypotonia (such as hydantoin in the reported Greek family), causing hypoplasia of the face and micrognathia.
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Affiliation(s)
- Christos Yapijakis
- Department of Oral and Maxillofacial Surgery, School of Medicine, University of Athens, Attikon Hospital, Athens, Greece. .,"Cephalogenetics" Genetic Center, Athens, Greece. .,Department of Neurology, School of Medicine, University of Athens, Eginition Hospital, Athens, Greece.
| | - Nikos Pachis
- "Cephalogenetics" Genetic Center, Athens, Greece
| | - Costas Voumvourakis
- 2nd Department of Neurology, School of Medicine, University of Athens, Attikon Hospital, Athens, Greece
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8
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Intra-individual plasticity of the TAZ gene leading to different heritable mutations in siblings with Barth syndrome. Eur J Hum Genet 2015; 23:1708-12. [PMID: 25782672 DOI: 10.1038/ejhg.2015.50] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2014] [Revised: 02/06/2015] [Accepted: 02/17/2015] [Indexed: 02/06/2023] Open
Abstract
Infantile-onset skeletal myopathy Barth syndrome (OMIM #302060) is caused by mutations in the X-linked TAZ gene and hence usually manifests itself only in hemizygous males. Confirmatory testing is provided by mutational analysis of the TAZ gene and/or by biochemical dosage of the monolysocardiolipin/tetralinoleoyl cardiolipin ratio. Heterozygous females do not usually display a clinical phenotype but may undergo molecular genetic prenatal diagnosis during pregnancy. We characterized two novel and non-identical TAZ gene rearrangements in the offspring of a single female carrier of Barth syndrome. The hg19chrX:g.153634427_153644361delinsKP_123427.1 TAZ gene rearrangement was identified in her affected son, whereas the NM_000116.3(TAZ)c.-72_109+51del TAZ gene deletion was identified in a male foetus during a subsequent pregnancy. The unaffected mother was surprisingly found to harbour both variants in addition to a wild-type TAZ allele. A combination of breakpoint junction sequencing, linkage analysis and assessment of allelic dosage revealed that the two variants had originated independently from an apparently unstable/mutable TAZ maternal allele albeit via different mutational mechanisms. We conclude that molecular prenatal diagnosis in Barth syndrome families with probands carrying TAZ gene rearrangements should include investigation of the entire coding region of the TAZ gene. The identification of the breakpoint junctions of such gross gene rearrangements is important to ensure accurate ascertainment of carriership with a view to providing appropriate genetic counselling.
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9
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Sabbagh A, Pasmant E, Imbard A, Luscan A, Soares M, Blanché H, Laurendeau I, Ferkal S, Vidaud M, Pinson S, Bellanné-Chantelot C, Vidaud D, Parfait B, Wolkenstein P. NF1 molecular characterization and neurofibromatosis type I genotype-phenotype correlation: the French experience. Hum Mutat 2013; 34:1510-8. [PMID: 23913538 DOI: 10.1002/humu.22392] [Citation(s) in RCA: 116] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2013] [Accepted: 07/25/2013] [Indexed: 12/20/2022]
Abstract
Neurofibromatosis type 1 (NF1) affects about one in 3,500 people in all ethnic groups. Most NF1 patients have private loss-of-function mutations scattered along the NF1 gene. Here, we present an original NF1 investigation strategy and report a comprehensive mutation analysis of 565 unrelated patients from the NF-France Network. A NF1 mutation was identified in 546 of the 565 patients, giving a mutation detection rate of 97%. The combined cDNA/DNA approach showed that a significant proportion of NF1 missense mutations (30%) were deleterious by affecting pre-mRNA splicing. Multiplex ligation-dependent probe amplification allowed the identification of restricted rearrangements that would have been missed if only sequencing or microsatellite analysis had been performed. In four unrelated families, we identified two distinct NF1 mutations within the same family. This fortuitous association points out the need to perform an exhaustive NF1 screening in the case of molecular discordant-related patients. A genotype-phenotype study was performed in patients harboring a truncating (N = 368), in-frame splicing (N = 36), or missense (N = 35) mutation. The association analysis of these mutation types with 12 common NF1 clinical features confirmed a weak contribution of the allelic heterogeneity of the NF1 mutation to the NF1 variable expressivity.
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Affiliation(s)
- Audrey Sabbagh
- UMR745 INSERM, PRES Sorbonne Paris Cité, Université Paris Descartes, Faculté des Sciences Pharmaceutiques et Biologiques, Paris, France; IRD, UMR216, Mère et enfant face aux infections tropicales, Paris, France; PRES Sorbonne Paris Cité, Université Paris Descartes, Faculté des Sciences Pharmaceutiques et Biologiques, Paris, France
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10
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Trevisson E, Forzan M, Salviati L, Clementi M. Neurofibromatosis type 1 in two siblings due to maternal germline mosaicism. Clin Genet 2013; 85:386-9. [PMID: 23621909 DOI: 10.1111/cge.12177] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2013] [Revised: 04/18/2013] [Accepted: 04/18/2013] [Indexed: 11/30/2022]
Abstract
Neurofibromatosis type 1 (NF1) is caused by loss of function mutations of the NF1 gene, which are de novo in 50% of cases. Although this gene shows one of the highest mutation rates in the human genome, germline mosaicism is very rare in this condition. We describe the molecular analysis of a family in which neurofibromatosis type 1 occurred in two out of four siblings born to unaffected parents. Molecular analysis of the NF1 gene identified in both patients the same splicing mutation c.1392+1G>A, which was absent in parental lymphocytes. Microsatellite analysis showed that the two affected siblings shared the same maternal allele, however a specific PCR-RFLP assay excluded the presence of the NF1 splicing mutation in multiple maternal tissues. Our molecular and clinical findings are consistent with a germline mosaicism for the NF1 splicing mutation. This is the first case of maternal germline mosaicism for a NF1 mutation characterized so far at the molecular level. Our data confirm that germline mosaicism is rare in neurofibromatosis 1, but it has important implications for genetic counseling.
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Affiliation(s)
- E Trevisson
- Clinical Genetics Unit, Department of Woman and Child Health, University of Padova, Padova, Italy
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11
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Snajderova M, Riccardi VM, Petrak B, Zemkova D, Zapletalova J, Mardesic T, Petrakova A, Lanska V, Marikova T, Bendova S, Havlovicova M, Kaluzova M. The importance of advanced parental age in the origin of neurofibromatosis type 1. Am J Med Genet A 2012; 158A:519-23. [DOI: 10.1002/ajmg.a.34413] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2011] [Accepted: 11/09/2011] [Indexed: 11/10/2022]
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12
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Bottillo I, Torrente I, Lanari V, Pinna V, Giustini S, Divona L, De Luca A, Dallapiccola B. Germline mosaicism in neurofibromatosis type 1 due to a paternally derived multi-exon deletion. Am J Med Genet A 2010; 152A:1467-73. [PMID: 20503322 DOI: 10.1002/ajmg.a.33386] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
We report on the clinical and molecular features of a family in which neurofibromatosis type 1 (NF1) occurred in two of three siblings born to unaffected parents and in one granddaughter. Linkage analysis showed that the two affected siblings and the daughter of one of them shared the same paternal allele, whereas they had inherited different maternal alleles. We detected a disease-causing deletion (c.4773-3622-?_5749+?del) encompassing three NF1 gene exons in affected individuals. This mutation occurred on the paternally derived allele, arguing for a germline mosaicism in the probands' father. Real-time PCR showed that the mutation was present in about 10-17% of the paternal sperms. Current results confirm that germline mosaicism can explain the recurrence of NF1 in offspring of unaffected parents.
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Affiliation(s)
- Irene Bottillo
- IRCCS, Casa Sollievo della Sofferenza Hospital, San Giovanni Rotondo, Italy
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13
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14
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Rosser LG, McKee S, Millar DS, Archer H, Hughes J, Butler R, Chuzhanova N, Cooper DN, Lazarou LP. Two sisters with Rett syndrome and non-identical paternally-derived microdeletions in the MECP2 gene. Genomic Med 2008; 2:77-81. [PMID: 18810657 DOI: 10.1007/s11568-008-9026-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2008] [Revised: 08/26/2008] [Accepted: 08/27/2008] [Indexed: 11/29/2022] Open
Abstract
The unique case of two sisters with symptoms of RTT and two quite distinct, novel, and apparently de novo microdeletions of the MECP2 gene is described. One sister possessed an 18 base-pair (bp) deletion (c.1155_1172del18) within the deletion hotspot region of exon 4, whereas the other sister exhibited a 43 bp deletion at a different location in the same exon (c.1448_1461del14+29). Although these lesions occurred on the same paternally-derived X chromosome, this is probably due to chance co-occurrence owing to the relatively high mutation rate of the MECP2 gene rather than to a constitutional mutator phenotype.
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Affiliation(s)
- Lyndon G Rosser
- Institute of Medical Genetics, Cardiff and Vale NHS Trust, University Hospital of Wales, Heath Park, Cardiff, CF14 4XW, UK
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15
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Upadhyaya M, Huson SM, Davies M, Thomas N, Chuzhanova N, Giovannini S, Evans DG, Howard E, Kerr B, Griffiths S, Consoli C, Side L, Adams D, Pierpont M, Hachen R, Barnicoat A, Li H, Wallace P, Van Biervliet JP, Stevenson D, Viskochil D, Baralle D, Haan E, Riccardi V, Turnpenny P, Lazaro C, Messiaen L. An absence of cutaneous neurofibromas associated with a 3-bp inframe deletion in exon 17 of the NF1 gene (c.2970-2972 delAAT): evidence of a clinically significant NF1 genotype-phenotype correlation. Am J Hum Genet 2007; 80:140-51. [PMID: 17160901 PMCID: PMC1785321 DOI: 10.1086/510781] [Citation(s) in RCA: 232] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2006] [Accepted: 11/07/2006] [Indexed: 01/23/2023] Open
Abstract
Neurofibromatosis type 1 (NF1) is characterized by cafe-au-lait spots, skinfold freckling, and cutaneous neurofibromas. No obvious relationships between small mutations (<20 bp) of the NF1 gene and a specific phenotype have previously been demonstrated, which suggests that interaction with either unlinked modifying genes and/or the normal NF1 allele may be involved in the development of the particular clinical features associated with NF1. We identified 21 unrelated probands with NF1 (14 familial and 7 sporadic cases) who were all found to have the same c.2970-2972 delAAT (p.990delM) mutation but no cutaneous neurofibromas or clinically obvious plexiform neurofibromas. Molecular analysis identified the same 3-bp inframe deletion (c.2970-2972 delAAT) in exon 17 of the NF1 gene in all affected subjects. The Delta AAT mutation is predicted to result in the loss of one of two adjacent methionines (codon 991 or 992) ( Delta Met991), in conjunction with silent ACA-->ACG change of codon 990. These two methionine residues are located in a highly conserved region of neurofibromin and are expected, therefore, to have a functional role in the protein. Our data represent results from the first study to correlate a specific small mutation of the NF1 gene to the expression of a particular clinical phenotype. The biological mechanism that relates this specific mutation to the suppression of cutaneous neurofibroma development is unknown.
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Affiliation(s)
- M Upadhyaya
- Institute of Medical Genetics, Cardiff University, Cardiff, CF14 4XN, UK.
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16
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Fahsold R, Hoffmeyer S, Mischung C, Gille C, Ehlers C, Kücükceylan N, Abdel-Nour M, Gewies A, Peters H, Kaufmann D, Buske A, Tinschert S, Nürnberg P. Minor lesion mutational spectrum of the entire NF1 gene does not explain its high mutability but points to a functional domain upstream of the GAP-related domain. Am J Hum Genet 2000; 66:790-818. [PMID: 10712197 PMCID: PMC1288164 DOI: 10.1086/302809] [Citation(s) in RCA: 204] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/1999] [Accepted: 10/14/1999] [Indexed: 11/03/2022] Open
Abstract
More than 500 unrelated patients with neurofibromatosis type 1 (NF1) were screened for mutations in the NF1 gene. For each patient, the whole coding sequence and all splice sites were studied for aberrations, either by the protein truncation test (PTT), temperature-gradient gel electrophoresis (TGGE) of genomic PCR products, or, most often, by direct genomic sequencing (DGS) of all individual exons. A total of 301 sequence variants, including 278 bona fide pathogenic mutations, were identified. As many as 216 or 183 of the genuine mutations, comprising 179 or 161 different ones, can be considered novel when compared to the recent findings of Upadhyaya and Cooper, or to the NNFF mutation database. Mutation-detection efficiencies of the various screening methods were similar: 47.1% for PTT, 53.7% for TGGE, and 54.9% for DGS. Some 224 mutations (80.2%) yielded directly or indirectly premature termination codons. These mutations showed even distribution over the whole gene from exon 1 to exon 47. Of all sequence variants determined in our study, <20% represent C-->T or G-->A transitions within a CpG dinucleotide, and only six different mutations also occur in NF1 pseudogenes, with five being typical C-->T transitions in a CpG. Thus, neither frequent deamination of 5-methylcytosines nor interchromosomal gene conversion may account for the high mutation rate of the NF1 gene. As opposed to the truncating mutations, the 28 (10.1%) missense or single-amino-acid-deletion mutations identified clustered in two distinct regions, the GAP-related domain (GRD) and an upstream gene segment comprising exons 11-17. The latter forms a so-called cysteine/serine-rich domain with three cysteine pairs suggestive of ATP binding, as well as three potential cAMP-dependent protein kinase (PKA) recognition sites obviously phosphorylated by PKA. Coincidence of mutated amino acids and those conserved between human and Drosophila strongly suggest significant functional relevance of this region, with major roles played by exons 12a and 15 and part of exon 16.
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Affiliation(s)
- Raimund Fahsold
- Gemeinschaftspraxis B. Prager & A. Junge, Dresden; Epidauros AG, Bernried; Institut für Medizinische Genetik, Universitätsklinikum Charité, Berlin; Institut für Biochemie, Universitätsklinikum Charité, Berlin; Abteilung Humangenetik, Universität Ulm, Ulm
| | - Sven Hoffmeyer
- Gemeinschaftspraxis B. Prager & A. Junge, Dresden; Epidauros AG, Bernried; Institut für Medizinische Genetik, Universitätsklinikum Charité, Berlin; Institut für Biochemie, Universitätsklinikum Charité, Berlin; Abteilung Humangenetik, Universität Ulm, Ulm
| | - Claudia Mischung
- Gemeinschaftspraxis B. Prager & A. Junge, Dresden; Epidauros AG, Bernried; Institut für Medizinische Genetik, Universitätsklinikum Charité, Berlin; Institut für Biochemie, Universitätsklinikum Charité, Berlin; Abteilung Humangenetik, Universität Ulm, Ulm
| | - Christoph Gille
- Gemeinschaftspraxis B. Prager & A. Junge, Dresden; Epidauros AG, Bernried; Institut für Medizinische Genetik, Universitätsklinikum Charité, Berlin; Institut für Biochemie, Universitätsklinikum Charité, Berlin; Abteilung Humangenetik, Universität Ulm, Ulm
| | - Christian Ehlers
- Gemeinschaftspraxis B. Prager & A. Junge, Dresden; Epidauros AG, Bernried; Institut für Medizinische Genetik, Universitätsklinikum Charité, Berlin; Institut für Biochemie, Universitätsklinikum Charité, Berlin; Abteilung Humangenetik, Universität Ulm, Ulm
| | - Nazan Kücükceylan
- Gemeinschaftspraxis B. Prager & A. Junge, Dresden; Epidauros AG, Bernried; Institut für Medizinische Genetik, Universitätsklinikum Charité, Berlin; Institut für Biochemie, Universitätsklinikum Charité, Berlin; Abteilung Humangenetik, Universität Ulm, Ulm
| | - Maher Abdel-Nour
- Gemeinschaftspraxis B. Prager & A. Junge, Dresden; Epidauros AG, Bernried; Institut für Medizinische Genetik, Universitätsklinikum Charité, Berlin; Institut für Biochemie, Universitätsklinikum Charité, Berlin; Abteilung Humangenetik, Universität Ulm, Ulm
| | - Andreas Gewies
- Gemeinschaftspraxis B. Prager & A. Junge, Dresden; Epidauros AG, Bernried; Institut für Medizinische Genetik, Universitätsklinikum Charité, Berlin; Institut für Biochemie, Universitätsklinikum Charité, Berlin; Abteilung Humangenetik, Universität Ulm, Ulm
| | - Hartmut Peters
- Gemeinschaftspraxis B. Prager & A. Junge, Dresden; Epidauros AG, Bernried; Institut für Medizinische Genetik, Universitätsklinikum Charité, Berlin; Institut für Biochemie, Universitätsklinikum Charité, Berlin; Abteilung Humangenetik, Universität Ulm, Ulm
| | - Dieter Kaufmann
- Gemeinschaftspraxis B. Prager & A. Junge, Dresden; Epidauros AG, Bernried; Institut für Medizinische Genetik, Universitätsklinikum Charité, Berlin; Institut für Biochemie, Universitätsklinikum Charité, Berlin; Abteilung Humangenetik, Universität Ulm, Ulm
| | - Annegret Buske
- Gemeinschaftspraxis B. Prager & A. Junge, Dresden; Epidauros AG, Bernried; Institut für Medizinische Genetik, Universitätsklinikum Charité, Berlin; Institut für Biochemie, Universitätsklinikum Charité, Berlin; Abteilung Humangenetik, Universität Ulm, Ulm
| | - Sigrid Tinschert
- Gemeinschaftspraxis B. Prager & A. Junge, Dresden; Epidauros AG, Bernried; Institut für Medizinische Genetik, Universitätsklinikum Charité, Berlin; Institut für Biochemie, Universitätsklinikum Charité, Berlin; Abteilung Humangenetik, Universität Ulm, Ulm
| | - Peter Nürnberg
- Gemeinschaftspraxis B. Prager & A. Junge, Dresden; Epidauros AG, Bernried; Institut für Medizinische Genetik, Universitätsklinikum Charité, Berlin; Institut für Biochemie, Universitätsklinikum Charité, Berlin; Abteilung Humangenetik, Universität Ulm, Ulm
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Toliat MR, Erdogan F, Gewies A, Fahsold R, Buske A, Tinschert S, Nürnberg P. Analysis of the NF1 gene by temperature gradient gel electrophoresis reveals a high incidence of mutations in exon 4b. Electrophoresis 2000; 21:541-4. [PMID: 10726756 DOI: 10.1002/(sici)1522-2683(20000201)21:3<541::aid-elps541>3.0.co;2-l] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
A total of 196 unrelated patients with neurofibromatosis type 1 (NF1) was screened for mutations in exons 4a-c of the NF1 gene by temperature gradient gel electrophoresis (TGGE) of polymerase chain reaction (PCR)-amplified genomic DNA fragments using intron-based primers. DNA samples with abnormal TGGE band patterns were subjected to sequence analysis. Sequence alterations were identified in ten patients (5.1%): 496delGT (1), 499delTGTT (4), T528A = D176E (2), T539A = L180X (1), 540insA (1), C574T = R192X (1). Thus, a total of six different mutations was identified in exon 4b but none in exons 4a and 4c. Only the missense mutation D176E, which we assume to be a nonpathogenic polymorphism, and the 4-base pair (bp) deletion 499delTGTT have been described before. The reason for the high incidence of mutations in exon 4b is obviously a tetranucleotide tandem repeat comprising nucleotides 495-502 (TGTTTGTT) that may give rise to slipped mispairing and subsequent deletion of one repeat unit during replication. Additionally, the recurrent 4 bp deletion was found as a second hit in a malignant schwannoma of a further NF1 patient, suggesting that microlesions may be as frequent among somatic as among germline mutations. This is the first report of a systematic study of NF1 exons 4a-c in a large group of NF1 patients.
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Affiliation(s)
- M R Toliat
- Institut für Medizinische Genetik, Universitätsklinikum Charité, Berlin, Germany
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18
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