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Nguyen HTL, Kohl E, Bade J, Eng SE, Tosevska A, Al Shihabi A, Tebon PJ, Hong JJ, Dry S, Boutros PC, Panossian A, Gosline SJC, Soragni A. A platform for rapid patient-derived cutaneous neurofibroma organoid establishment and screening. CELL REPORTS METHODS 2024; 4:100772. [PMID: 38744290 PMCID: PMC11133839 DOI: 10.1016/j.crmeth.2024.100772] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2023] [Revised: 02/10/2024] [Accepted: 04/19/2024] [Indexed: 05/16/2024]
Abstract
Localized cutaneous neurofibromas (cNFs) are benign tumors that arise in the dermis of patients affected by neurofibromatosis type 1 syndrome. cNFs are benign lesions: they do not undergo malignant transformation or metastasize. Nevertheless, they can cover a significant proportion of the body, with some individuals developing hundreds to thousands of lesions. cNFs can cause pain, itching, and disfigurement resulting in substantial socio-emotional repercussions. Currently, surgery and laser desiccation are the sole treatment options but may result in scarring and potential regrowth from incomplete removal. To identify effective systemic therapies, we introduce an approach to establish and screen cNF organoids. We optimized conditions to support the ex vivo growth of genomically diverse cNFs. Patient-derived cNF organoids closely recapitulate cellular and molecular features of parental tumors as measured by immunohistopathology, methylation, RNA sequencing, and flow cytometry. Our cNF organoid platform enables rapid screening of hundreds of compounds in a patient- and tumor-specific manner.
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Affiliation(s)
- Huyen Thi Lam Nguyen
- Department of Orthopaedic Surgery, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, USA
| | - Emily Kohl
- Department of Orthopaedic Surgery, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, USA
| | - Jessica Bade
- Pacific Northwest National Laboratories, Seattle, WA, USA
| | - Stefan E Eng
- Department of Human Genetics, University of California, Los Angeles, Los Angeles, CA, USA; Institute for Precision Health, University of California, Los Angeles, Los Angeles, CA, USA; Jonsson Comprehensive Cancer Center, University of California, Los Angeles, Los Angeles, CA, USA
| | - Anela Tosevska
- Department of Molecular, Cell and Developmental Biology, University of California, Los Angeles, Los Angeles, CA, USA
| | - Ahmad Al Shihabi
- Department of Orthopaedic Surgery, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, USA; Department of Pathology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, USA
| | - Peyton J Tebon
- Department of Orthopaedic Surgery, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, USA
| | - Jenny J Hong
- Division of Hematology-Oncology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, USA
| | - Sarah Dry
- Department of Pathology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, USA
| | - Paul C Boutros
- Department of Human Genetics, University of California, Los Angeles, Los Angeles, CA, USA; Institute for Precision Health, University of California, Los Angeles, Los Angeles, CA, USA; Jonsson Comprehensive Cancer Center, University of California, Los Angeles, Los Angeles, CA, USA; Department of Urology, University of California, Los Angeles, Los Angeles, CA, USA; Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, University of California, Los Angeles, Los Angeles, CA, USA
| | | | - Sara J C Gosline
- Pacific Northwest National Laboratories, Seattle, WA, USA; Department of Biomedical Engineering, Oregon Health and Sciences University, Portland, OR, USA.
| | - Alice Soragni
- Department of Orthopaedic Surgery, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, USA; Jonsson Comprehensive Cancer Center, University of California, Los Angeles, Los Angeles, CA, USA; Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, University of California, Los Angeles, Los Angeles, CA, USA.
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Wang EHH, Lin PH, Wu PL, Kang EYC, Liu L, Yeh LK, Chen KJ, Hsiao MC, Wang NK. Genetic underpinnings explored: OPA1 deletion and complex phenotypes on chromosome 3q29. BMC Med Genomics 2024; 17:94. [PMID: 38641846 PMCID: PMC11031983 DOI: 10.1186/s12920-024-01850-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Accepted: 03/26/2024] [Indexed: 04/21/2024] Open
Abstract
BACKGROUND Copy number variations (CNVs) have emerged as significant contributors to the elusive genetic causality of inherited eye diseases. In this study, we describe a case with optic atrophy and a brain aneurysm, in which a de novo CNV 3q29 deletion was identified. CASE PRESENTATION A 40-year-old female patient was referred to our department after undergoing aneurysm transcatheter arterial embolization for a brain aneurysm. She had no history of systemic diseases, except for unsatisfactory best-corrected visual acuity (BCVA) since elementary school. Electrophysiological tests confirmed the findings in retinal images, indicating optic nerve atrophy. Chromosomal microarray analysis revealed a de novo deletion spanning 960 kb on chromosome 3q29, encompassing OPA1 and six neighboring genes. Unlike previously reported deletions in this region associated with optic atrophy, neuropsychiatric disorders, and obesity, this patient displayed a unique combination of optic atrophy and a brain aneurysm. However, there is no causal relationship between the brain aneurysm and the CNV. CONCLUSION In conclusion, the optic atrophy is conclusively attributed to the OPA1 deletion, and the aneurysm could be a coincidental association. The report emphasizes the likelihood of underestimating OPA1 deletions due to sequencing technology limitations. Recognizing these constraints, healthcare professionals must acknowledge these limitations and consistently search for OPA1 variants/deletions in Autosomal Dominant Optic Atrophy (ADOA) patients with negative sequencing results. This strategic approach ensures a more comprehensive exploration of copy-number variations, ultimately enhancing diagnostic precision in the field of genetic disorders.
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Affiliation(s)
- Ethan Hung-Hsi Wang
- Department of Ophthalmology, Edward S. Harkness Eye Institute, Columbia University, New York, NY, USA
- College of Arts and Sciences, University of Miami, Coral Gables, FL, USA
| | - Pei-Hsuan Lin
- Department of Ophthalmology, Edward S. Harkness Eye Institute, Columbia University, New York, NY, USA
- Department of Ophthalmology, National Taiwan University Yunlin Branch, Yunlin, Taiwan
| | - Pei-Liang Wu
- Department of Ophthalmology, Edward S. Harkness Eye Institute, Columbia University, New York, NY, USA
- College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Eugene Yu-Chuan Kang
- Department of Ophthalmology, Edward S. Harkness Eye Institute, Columbia University, New York, NY, USA
- College of Medicine, Chang Gung University, Taoyuan, Taiwan
- Department of Ophthalmology, Linkou Medical Center, Chang Gung Memorial Hospital, Taoyuan, Taiwan
- Graduate Institute of Clinical Medical Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Laura Liu
- Department of Ophthalmology, Linkou Medical Center, Chang Gung Memorial Hospital, Taoyuan, Taiwan
- School of Traditional Chinese Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Lung-Kun Yeh
- College of Medicine, Chang Gung University, Taoyuan, Taiwan
- Department of Ophthalmology, Linkou Medical Center, Chang Gung Memorial Hospital, Taoyuan, Taiwan
| | - Kuan-Jen Chen
- College of Medicine, Chang Gung University, Taoyuan, Taiwan
- Department of Ophthalmology, Linkou Medical Center, Chang Gung Memorial Hospital, Taoyuan, Taiwan
| | - Meng-Chang Hsiao
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, USA
| | - Nan-Kai Wang
- Department of Ophthalmology, Edward S. Harkness Eye Institute, Columbia University, New York, NY, USA.
- College of Medicine, Chang Gung University, Taoyuan, Taiwan.
- Department of Ophthalmology, Linkou Medical Center, Chang Gung Memorial Hospital, Taoyuan, Taiwan.
- Vagelos College of Physicians and Surgeons, Columbia University, New York, USA.
- Edward S. Harkness Eye Institute, Columbia University Irving Medical Center, Hammer Health Sciences Building, 701 W. 168th St, 10032, New York, NY, USA.
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Pacot L, Masliah-Planchon J, Petcu A, Terris B, Gauthier Villars M, Lespinasse J, Wolkenstein P, Vincent-Salomon A, Vidaud D, Pasmant E. Breast cancer risk in NF1-deleted patients. J Med Genet 2024; 61:428-429. [PMID: 38154814 DOI: 10.1136/jmg-2023-109682] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2023] [Accepted: 12/05/2023] [Indexed: 12/30/2023]
Affiliation(s)
- Laurence Pacot
- Institut Cochin, Inserm U1016, CNRS UMR8104, Université Paris Cité, CARPEM, Paris, France
- Department of genetics, Fédération de Génétique et Médecine Génomique, Hôpital Cochin, DMU BioPhyGen, AP-HP.Centre-Université Paris Cité, Paris, France
| | | | - Adina Petcu
- Department of Pathology, Centre Hospitalier Métropole Savoie, Chambery, France
| | - Benoit Terris
- Department of Pathology, Hôpital Cochin, Assistance Publique-Hopitaux de Paris, Paris, France
| | | | - James Lespinasse
- Unité de Génétique médicale, Centre Hospitalier Métropole Savoie, Chambéry, France
| | - Pierre Wolkenstein
- Department of Dermatology, Hôpital Henri Mondor, Assistance Publique-Hôpitaux de Paris, Créteil, France
- Centre d'Investigation Clinique 1430, INSERM, Hôpital Henri-Mondor, Assistance Publique-Hôpitaux de Paris, Referral Center of Neurofibromatosis, Créteil, France
| | - Anne Vincent-Salomon
- Department of Pathology, Curie Institute Hospital Group, Paris, Île-de-France, France
| | - Dominique Vidaud
- Institut Cochin, Inserm U1016, CNRS UMR8104, Université Paris Cité, CARPEM, Paris, France
- Department of genetics, Fédération de Génétique et Médecine Génomique, Hôpital Cochin, DMU BioPhyGen, AP-HP.Centre-Université Paris Cité, Paris, France
| | - Eric Pasmant
- Institut Cochin, Inserm U1016, CNRS UMR8104, Université Paris Cité, CARPEM, Paris, France
- Department of genetics, Fédération de Génétique et Médecine Génomique, Hôpital Cochin, DMU BioPhyGen, AP-HP.Centre-Université Paris Cité, Paris, France
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Mudau MM, Dillon B, Smal C, Feben C, Honey E, Carstens N, Krause A. Mutation analysis and clinical profile of South African patients with Neurofibromatosis type 1 (NF1) phenotype. Front Genet 2024; 15:1331278. [PMID: 38596211 PMCID: PMC11002079 DOI: 10.3389/fgene.2024.1331278] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Accepted: 03/11/2024] [Indexed: 04/11/2024] Open
Abstract
Neurofibromatosis type 1 (NF1) is an autosomal dominant genetic condition with complete age-dependent penetrance, variable expressivity and a global prevalence of ∼1/3,000. It is characteriszed by numerous café-au-lait macules, skin freckling in the inguinal or axillary regions, Lisch nodules of the iris, optic gliomas, neurofibromas, and tumour predisposition. The diagnostic testing strategy for NF1 includes testing for DNA single nucleotide variants (SNVs), copy number variants (CNVs) as well as RNA analysis for deep intronic and splice variants, which can cumulatively identify the causative variant in 95% of patients. In the present study, NF1 patients were screened using a next-generation sequencing (NGS) assay targeting NF1 exons and intron/exon boundaries for SNV and NF1 multiple ligation-dependent probe amplification (MLPA) analysis for CNV detection. Twenty-six unrelated Southern African patients clinically suspected of having NF1, based on the clinical diagnostic criteria developed by the National Institute of Health (NIH), were included in the current study. A detection rate of 58% (15/26) was obtained, with SNVs identified in 80% (12/15) using a targeted gene panel and NF1 gene deletion in 20% (3/15) identified using MLPA. Ten patients (38%) had no variants identified, although they met NF1 diagnostic criteria. One VUS was identified in this study in a patient that met NF1 diagnostic criteria, however there was no sufficient information to classify variant as pathogenic. The clinical features of Southern African patients with NF1 are similar to that of the known NF1 phenotype, with the exception of a lower frequency of plexiform neurofibromas and a higher frequency of developmental/intellectual disability compared to other cohorts. This is the first clinical and molecular characterisation of a Southern African ancestry NF1 cohort using both next-generation sequencing and MLPA analysis. A significant number of patients remained without a diagnosis following DNA-level testing. The current study offers a potential molecular testing strategy for our low resource environment that could benefit a significant proportion of patients who previously only received a clinical diagnosis without molecular confirmation.
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Affiliation(s)
- Maria Mabyalwa Mudau
- Division of Human Genetics, National Health Laboratory Service and School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Bronwyn Dillon
- Division of Human Genetics, National Health Laboratory Service and School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Clarice Smal
- Division of Human Genetics, National Health Laboratory Service and School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Candice Feben
- Division of Human Genetics, National Health Laboratory Service and School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Engela Honey
- Department of Biochemistry, Genetics and Microbiology, Faculty of Natural and Agricultural Sciences, University of Pretoria, Pretoria, South Africa
| | - Nadia Carstens
- Division of Human Genetics, National Health Laboratory Service and School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
- Genomics Platform, South African Medical Research Council, Cape Town, South Africa
| | - Amanda Krause
- Division of Human Genetics, National Health Laboratory Service and School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
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Pacot L, Girish M, Knight S, Spurlock G, Varghese V, Ye M, Thomas N, Pasmant E, Upadhyaya M. Correlation between large rearrangements and patient phenotypes in NF1 deletion syndrome: an update and review. BMC Med Genomics 2024; 17:73. [PMID: 38448973 PMCID: PMC10919053 DOI: 10.1186/s12920-024-01843-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Accepted: 03/01/2024] [Indexed: 03/08/2024] Open
Abstract
About 5-10% of neurofibromatosis type 1 (NF1) patients exhibit large genomic germline deletions that remove the NF1 gene and its flanking regions. The most frequent NF1 large deletion is 1.4 Mb, resulting from homologous recombination between two low copy repeats. This "type-1" deletion is associated with a severe clinical phenotype in NF1 patients, with several phenotypic manifestations including learning disability, a much earlier development of cutaneous neurofibromas, an increased tumour risk, and cardiovascular malformations. NF1 adjacent co-deleted genes could act as modifier loci for the specific clinical manifestations observed in deleted NF1 patients. Furthermore, other genetic modifiers (such as CNVs) not located at the NF1 locus could also modulate the phenotype observed in patients with large deletions. In this study, we analysed 22 NF1 deletion patients by genome-wide array-CGH with the aim (1) to correlate deletion length to observed phenotypic features and their severity in NF1 deletion syndrome, and (2) to identify whether the deletion phenotype could also be modulated by copy number variations elsewhere in the genome. We then review the role of co-deleted genes in the 1.4 Mb interval of type-1 deletions, and their possible implication in the main clinical features observed in this high-risk group of NF1 patients.
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Affiliation(s)
- Laurence Pacot
- Fédération de Génétique et Médecine Génomique, Hôpital Cochin, DMU BioPhyGen, AP-HP, Centre-Université Paris Cité, Paris, France
- Institut Cochin, Inserm U1016, CNRS UMR8104, Université Paris Cité, CARPEM, Paris, France
| | - Milind Girish
- School of Clinical Medicine, University of Cambridge, Cambridge, UK
| | - Samantha Knight
- School of Clinical Medicine, University of Cambridge, Cambridge, UK
| | | | - Vinod Varghese
- All Wales Medical Genomics Service, Cardiff, Great Britain
| | - Manuela Ye
- Institut Cochin, Inserm U1016, CNRS UMR8104, Université Paris Cité, CARPEM, Paris, France
| | - Nick Thomas
- School of Clinical Medicine, University of Cambridge, Cambridge, UK
| | - Eric Pasmant
- Fédération de Génétique et Médecine Génomique, Hôpital Cochin, DMU BioPhyGen, AP-HP, Centre-Université Paris Cité, Paris, France.
- Institut Cochin, Inserm U1016, CNRS UMR8104, Université Paris Cité, CARPEM, Paris, France.
| | - Meena Upadhyaya
- Division of Cancer and Genetics, Institute of Medical Genetics, Cardiff University, Heath Park, CF14 4XN, Cardiff, UK
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Pacot L, Ye M, Nectoux J, Laurendeau I, Briand-Suleau A, Coustier A, Maillard T, Barbance C, Orhant L, Vaucouleur N, Blanché H, Parfait B, Wolkenstein P, Vidaud M, Vidaud D, Pasmant E. Droplet Digital PCR for Fast and Accurate Characterization of NF1 Locus Deletions: Confirmation of the Predominant Maternal Origin of Type-1 Deletions. J Mol Diagn 2024; 26:150-157. [PMID: 38008284 DOI: 10.1016/j.jmoldx.2023.11.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2023] [Revised: 10/09/2023] [Accepted: 11/07/2023] [Indexed: 11/28/2023] Open
Abstract
Neurofibromatosis type-1 is a genetic disorder caused by loss-of-function variants in the tumor-suppressor NF1. Approximately 4% to 11% of neurofibromatosis type-1 patients have a NF1 locus complete deletion resulting from nonallelic homologous recombination between low copy repeats. Codeleted genes probably account for the more severe phenotype observed in NF1-deleted patients. This genotype-phenotype correlation highlights the need for a detailed molecular description. A droplet digital PCR (ddPCR) set along the NF1 locus was designed to delimitate the three recurrent NF1 deletion breakpoints. The ddPCR was tested in 121 samples from nonrelated NF1-deleted patients. Classification based on ddPCR versus multiplex ligation-dependent probe amplification (MLPA) was compared. In addition, microsatellites were analyzed to identify parental origin of deletions. ddPCR identified 77 type-1 (64%), 20 type-2 (16%), 7 type-3 (6%), and 17 atypical deletions (14%). The results were comparable with MLPA, except for three atypical deletions misclassified as type-2 using MLPA, for which the SUZ12 gene was not deleted. A significant maternal bias (25 of 30) in the origin of deletions was identified. This study proposes a fast and efficient ddPCR quantification to allow fine NF1 deletion classification. It indicates that ddPCR can be implemented easily into routine diagnosis to complement the techniques dedicated to NF1 point variant identification. This new tool may help unravel the genetic basis conditioning phenotypic variability in NF1-deleted patients and offer tailored genetic counseling.
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Affiliation(s)
- Laurence Pacot
- Institut Cochin, INSERM U1016, CNRS UMR8104, Université Paris Cité, CARPEM, Paris, France; Fédération de Génétique et Médecine Génomique, DMU BioPhyGen, Assistance Publique-Hôpital Paris, Centre-Université Paris Cité, Hôpital Cochin, Paris, France
| | - Manuela Ye
- Institut Cochin, INSERM U1016, CNRS UMR8104, Université Paris Cité, CARPEM, Paris, France
| | - Juliette Nectoux
- Fédération de Génétique et Médecine Génomique, DMU BioPhyGen, Assistance Publique-Hôpital Paris, Centre-Université Paris Cité, Hôpital Cochin, Paris, France
| | - Ingrid Laurendeau
- Fédération de Génétique et Médecine Génomique, DMU BioPhyGen, Assistance Publique-Hôpital Paris, Centre-Université Paris Cité, Hôpital Cochin, Paris, France
| | - Audrey Briand-Suleau
- Institut Cochin, INSERM U1016, CNRS UMR8104, Université Paris Cité, CARPEM, Paris, France; Fédération de Génétique et Médecine Génomique, DMU BioPhyGen, Assistance Publique-Hôpital Paris, Centre-Université Paris Cité, Hôpital Cochin, Paris, France
| | - Audrey Coustier
- Institut Cochin, INSERM U1016, CNRS UMR8104, Université Paris Cité, CARPEM, Paris, France
| | - Théodora Maillard
- Institut Cochin, INSERM U1016, CNRS UMR8104, Université Paris Cité, CARPEM, Paris, France
| | - Cécile Barbance
- Institut Cochin, INSERM U1016, CNRS UMR8104, Université Paris Cité, CARPEM, Paris, France
| | - Lucie Orhant
- Fédération de Génétique et Médecine Génomique, DMU BioPhyGen, Assistance Publique-Hôpital Paris, Centre-Université Paris Cité, Hôpital Cochin, Paris, France
| | - Nicolas Vaucouleur
- Fédération de Génétique et Médecine Génomique, DMU BioPhyGen, Assistance Publique-Hôpital Paris, Centre-Université Paris Cité, Hôpital Cochin, Paris, France
| | | | - Béatrice Parfait
- Institut Cochin, INSERM U1016, CNRS UMR8104, Université Paris Cité, CARPEM, Paris, France; Fédération de Génétique et Médecine Génomique, DMU BioPhyGen, Assistance Publique-Hôpital Paris, Centre-Université Paris Cité, Hôpital Cochin, Paris, France
| | - Pierre Wolkenstein
- Department of Dermatology, Hôpital Henri Mondor, Assistance Publique-Hôpital Paris, Créteil, France; INSERM, Clinical Investigation Center 1430, Referral Center of Neurofibromatosis, Hôpital Henri Mondor, Assistance Publique-Hôpital Paris, Faculté de Santé Paris Est Créteil, Créteil, France
| | - Michel Vidaud
- Institut Cochin, INSERM U1016, CNRS UMR8104, Université Paris Cité, CARPEM, Paris, France; Fédération de Génétique et Médecine Génomique, DMU BioPhyGen, Assistance Publique-Hôpital Paris, Centre-Université Paris Cité, Hôpital Cochin, Paris, France
| | - Dominique Vidaud
- Institut Cochin, INSERM U1016, CNRS UMR8104, Université Paris Cité, CARPEM, Paris, France; Fédération de Génétique et Médecine Génomique, DMU BioPhyGen, Assistance Publique-Hôpital Paris, Centre-Université Paris Cité, Hôpital Cochin, Paris, France
| | - Eric Pasmant
- Institut Cochin, INSERM U1016, CNRS UMR8104, Université Paris Cité, CARPEM, Paris, France; Fédération de Génétique et Médecine Génomique, DMU BioPhyGen, Assistance Publique-Hôpital Paris, Centre-Université Paris Cité, Hôpital Cochin, Paris, France.
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郑 婷, 朱 倍, 王 智, 李 青. [Gene therapy strategies and prospects for neurofibromatosis type 1]. ZHONGGUO XIU FU CHONG JIAN WAI KE ZA ZHI = ZHONGGUO XIUFU CHONGJIAN WAIKE ZAZHI = CHINESE JOURNAL OF REPARATIVE AND RECONSTRUCTIVE SURGERY 2024; 38:1-8. [PMID: 38225833 PMCID: PMC10796236 DOI: 10.7507/1002-1892.202309071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Revised: 11/20/2023] [Accepted: 11/22/2023] [Indexed: 01/17/2024]
Abstract
Objective To summarize the gene therapy strategies for neurofibromatosis type 1 (NF1) and related research progress. Methods The recent literature on gene therapy for NF1 at home and abroad was reviewed. The structure and function of the NF1 gene and its mutations were analyzed, and the current status as well as future prospects of the transgenic therapy and gene editing strategies were summarized. Results NF1 is an autosomal dominantly inherited tumor predisposition syndrome caused by mutations in the NF1 tumor suppressor gene, which impair the function of the neurofibromin and lead to the disease. It has complex clinical manifestations and is not yet curable. Gene therapy strategies for NF1 are still in the research and development stage. Existing studies on the transgenic therapy for NF1 have mainly focused on the construction and expression of the GTPase-activating protein-related domain in cells that lack of functional neurofibromin, confirming the feasibility of the transgenic therapy for NF1. Future research may focus on split adeno-associated virus (AAV) gene delivery, oversized AAV gene delivery, and the development of new vectors for targeted delivery of full-length NF1 cDNA. In addition, the gene editing tools of the new generation have great potential to treat monogenic genetic diseases such as NF1, but need to be further validated in terms of efficiency and safety. Conclusion Gene therapy, including both the transgenic therapy and gene editing, is expected to become an important new therapeutic approach for NF1 patients.
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Affiliation(s)
- 婷婷 郑
- 上海交通大学医学院附属第九人民医院整复外科(上海 200011)Department of Plastic and Reconstructive Surgery, Shanghai Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200011, P. R. China
- 上海交通大学医学院附属第九人民医院Ⅰ型神经纤维瘤病诊疗中心(上海 200011)Neurofibromatosis Type 1 Center, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200011, P. R. China
| | - 倍瑶 朱
- 上海交通大学医学院附属第九人民医院整复外科(上海 200011)Department of Plastic and Reconstructive Surgery, Shanghai Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200011, P. R. China
- 上海交通大学医学院附属第九人民医院Ⅰ型神经纤维瘤病诊疗中心(上海 200011)Neurofibromatosis Type 1 Center, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200011, P. R. China
| | - 智超 王
- 上海交通大学医学院附属第九人民医院整复外科(上海 200011)Department of Plastic and Reconstructive Surgery, Shanghai Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200011, P. R. China
- 上海交通大学医学院附属第九人民医院Ⅰ型神经纤维瘤病诊疗中心(上海 200011)Neurofibromatosis Type 1 Center, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200011, P. R. China
| | - 青峰 李
- 上海交通大学医学院附属第九人民医院整复外科(上海 200011)Department of Plastic and Reconstructive Surgery, Shanghai Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200011, P. R. China
- 上海交通大学医学院附属第九人民医院Ⅰ型神经纤维瘤病诊疗中心(上海 200011)Neurofibromatosis Type 1 Center, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200011, P. R. China
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Bildirici Y, Kocaaga A, Karademir-Arslan CN, Yimenicioglu S. Evaluation of Molecular and Clinical Findings in Children With Neurofibromatosis Type 1: Identification of 15 Novel Variants. Pediatr Neurol 2023; 149:69-74. [PMID: 37806041 DOI: 10.1016/j.pediatrneurol.2023.08.036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Revised: 08/25/2023] [Accepted: 08/26/2023] [Indexed: 10/10/2023]
Abstract
BACKGROUND Neurofibromatosis type 1 (NF1) is the most common neurocutaneous disease and is caused by mutations in the NF1 gene. The most common clinical features of NF1 are pigmentary abnormalities such as café-au-lait spots and inguinal or axillary freckling, cutaneous and plexiform neurofibromas, hamartomas of the iris, optic gliomas, and bone lesions. The aim of this retrospective study was to define the clinical and molecular characteristics of a pediatric sample of NF1, as well as the mutational spectrum and genotype-phenotype correlation. METHODS The study included 40 children with clinically suspected NF1. The patients were screened for NF1 mutations by DNA-based sequencing. In addition, all the patients were studied by multiplex ligation-dependent probe amplification (MLPA) to identify any duplications or deletions in NF1. The demographic, clinical, and genetic features of the children were characterized. RESULTS A total of 40 children with NF1 were included. Of those, 28 were female and 12 were male. The mean age was 8.91 years. An NF1 variant was discovered in 28 of 40 patients (70%). Among these mutations, intronic mutations were the most frequently detected mutations; 15 of these variants had not been previously reported. Only one patient had a whole NF1 gene deletion. CONCLUSIONS This study expands the spectrum of mutations in the NF1 gene. This study also showed that genetic screening using both next-generation sequencing and MLPA had a positive effect on diagnosis and genetic counseling in patients with suspected NF1.
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Affiliation(s)
- Yasar Bildirici
- Department of Pediatrics, Eskişehir City Hospital, Eskişehir, Turkey
| | - Ayca Kocaaga
- Department of Medical Genetics, Eskişehir City Hospital, Eskişehir, Turkey.
| | | | - Sevgi Yimenicioglu
- Department of Pediatric Neurology, Eskişehir City Hospital, Eskişehir, Turkey
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9
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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] [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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10
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Contribution of whole genome sequencing in the molecular diagnosis of mosaic partial deletion of the NF1 gene in neurofibromatosis type 1. Hum Genet 2023; 142:1-9. [PMID: 35941319 DOI: 10.1007/s00439-022-02476-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2022] [Accepted: 07/19/2022] [Indexed: 01/18/2023]
Abstract
Neurofibromatosis type 1 (NF1) is an autosomal dominant disease with complete penetrance but highly variable expressivity. In most patients, Next Generation Sequencing (NGS) technologies allow the identification of a loss-of-function pathogenic variant in the NF1 gene, a negative regulator of the RAS-MAPK pathway. We describe the 5-year diagnosis wandering of a patient with a clear NF1 clinical diagnosis, but no molecular diagnosis using standard molecular technologies. The patient presented with a typical NF1 phenotype but NF1 targeted NGS, NF1 transcript analysis, MLPA, and array comparative genomic hybridization failed to reveal a genetic aberration. After 5 years of unsuccessful investigations, trio WGS finally identified a de novo mosaic (VAF ~ 14%) 24.6 kb germline deletion encompassing the promoter and first exon of NF1. This case report illustrates the relevance of WGS to detect structural variants including copy number variants that would be missed by alternative approaches. The identification of the causal pathogenic variant allowed a tailored genetic counseling with a targeted non-invasive prenatal diagnosis by detecting the deletion in plasmatic cell-free DNA from the proband's pregnant partner. This report clearly highlights the need to make WGS a clinically accessible test, offering a tremendous opportunity to identify a molecular diagnosis for otherwise unsolved cases.
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11
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Drabent P, Fraitag S. Malignant Superficial Mesenchymal Tumors in Children. Cancers (Basel) 2022; 14:cancers14092160. [PMID: 35565289 PMCID: PMC9104419 DOI: 10.3390/cancers14092160] [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: 03/19/2022] [Revised: 04/12/2022] [Accepted: 04/22/2022] [Indexed: 11/16/2022] Open
Abstract
Malignant superficial mesenchymal tumors are a very diverse group of neoplasms with few clinical and radiological discriminatory factors. Hence, some of these cancers are rarely suspected based on clinical and radiological grounds, others may be easily misdiagnosed, and the histological analysis of a biopsy or resection is central in the diagnostic process. In children, the age at presentation is a major element of the differential diagnosis. Some tumors have a very distinct epidemiology, while others may be seen at any age. More recently, the advances in molecular biology have greatly improved the diagnosis of mesenchymal tumors and new entities are still being described. In the present review, we provide an overview of the diversity of malignant superficial mesenchymal tumors in children, including new and/or rare entities. We discuss the important diagnostic features, be they clinical, histological, or molecular. Special attention was given to the genetic features of these tumors, particularly when they were helpful for the diagnosis or treatment.
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Affiliation(s)
- Philippe Drabent
- Department of Pathology, Necker-Enfants Malades Hospital, APHP, 75015 Paris, France;
- Faculté de Médecine, Université de Paris, 75005 Paris, France
| | - Sylvie Fraitag
- Department of Pathology, Necker-Enfants Malades Hospital, APHP, 75015 Paris, France;
- Faculté de Médecine, Université de Paris, 75005 Paris, France
- Correspondence:
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12
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Kehrer-Sawatzki H, Bäzner U, Krämer J, Lewerenz J, Pfeiffer C. Das NF1-Mikrodeletions-Syndrom: Die frühzeitige genetische Diagnose erleichtert den Umgang mit einer klinisch definierten Erkrankung. J Dtsch Dermatol Ges 2022; 20:273-278. [PMID: 35304941 DOI: 10.1111/ddg.14707_g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Accepted: 11/29/2021] [Indexed: 12/01/2022]
Abstract
Neurofibromatose Typ-1 (NF1) ist ein Genodermatose, die häufig in der Dermatologie behandelt wird. Bei vielen Patienten mit NF1 wird die Diagnose aufgrund klinischer Merkmale erstellt wie Café-au-Lait-Flecken, Freckling und plexiformen Neurofibromen, die schon während der frühen Kindheit auftreten können. Später im Leben sind oft kutane Neurofibrome weitere wichtige diagnostische Merkmale. Die NF1 ist durch ausgeprägte klinische Variabilität und eine breite Heterogenität der NF1-Genmutationen charakterisiert, was Genotyp/Phänotyp-Korrelationen erschwert. Wichtige Ausnahmen sind NF1-Mikrodeletionen, die bei 5-11 % aller NF1-Patienten auftreten. Patienten mit NF1-Mikrodeletionen zeigen häufig spezifische Merkmale wie Gesichtsdysmorphien und sind von großer Statur. Zudem sind früh auftretende kutane und subkutane Neurofibrome, schwere Entwicklungsverzögerungen in multiplen Bereichen sowie kognitive Einschränkungen pathognomonisch für das NF1-Mikrodeletions-Syndrom. Darüber hinaus sind NF1-Mikrodeletionen mit einem Risiko für maligne periphere Nervenscheidentumoren assoziiert, das etwa zweifach höher ist als bei intragenischen NF1-Mutationen. Die schweren klinischen Manifestationen bei Patienten mit NF1-Mikrodeletionen machen eine frühe multidisziplinäre klinische Betreuung und häufige Tumor-Überwachung der Patienten notwendig. Wenn bei einem Patienten Red-Flag-Symptome für das NF1-Mikrodeletions-Syndrom auftreten, ist eine frühzeitige genetische Untersuchung notwendig, um eine NF1-Mikrodeletion zu bestätigen oder auszuschließen.
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Affiliation(s)
| | - Ute Bäzner
- Klinik für Neurochirurgie, Bezirkskrankenhaus Günzburg, und Klinik für Neurochirurgie, Universitätsklinikum Ulm
| | - Johannes Krämer
- Klinik für Kinder- und Jugendmedizin, Sektion Sozialpädiatrisches Zentrum und Pädiatrische Neurologie/Stoffwechsel, Universitätsklinikum Ulm
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13
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Kehrer-Sawatzki H, Bäzner U, Krämer J, Lewerenz J, Pfeiffer C. The NF1 microdeletion syndrome: early genetic diagnosis facilitates the management of a clinically defined disease. J Dtsch Dermatol Ges 2022; 20:273-277. [PMID: 35246941 DOI: 10.1111/ddg.14707] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Accepted: 11/29/2021] [Indexed: 11/30/2022]
Abstract
Neurofibromatosis type-1 (NF1) is a genodermatosis frequently encountered in general dermatology. In many patients, the diagnosis of NF1 is made clinically based on the presence of café-au-lait macules and skinfold freckling, as well as plexiform neurofibromas detectable during early childhood. Later in life, cutaneous neurofibromas often represent important diagnostic features. NF1 is characterized by extreme clinical variability and a broad heterogeneity of NF1 gene mutations which impede genotype/phenotype correlations. Notable exceptions are NF1 microdeletions observed in 5-11 % of all NF1 patients. Patients with NF1 microdeletions frequently exhibit facial dysmorphic features and a tall stature as rather specific clinical signs. Furthermore, cutaneous and subcutaneous neurofibromas present at an early age, severe global developmental delay and cognitive disability are pathognomonic for the "NF1 microdeletion syndrome". Importantly, NF1 microdeletions are associated with an approximately twofold higher risk for malignant peripheral nerve sheath tumors than intragenic NF1 gene mutations. The severe clinical manifestations of patients with NF1 microdeletions require early multidisciplinary clinical care and frequent tumor surveillance. Therefore, when red flag features for the "NF1 microdeletion syndrome" are present in a patient, genetic testing is necessary to confirm or exclude an NF1 microdeletion.
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Affiliation(s)
| | - Ute Bäzner
- Department of Neurosurgery, Ulm University Medical Center, Günzburg, Germany
| | - Johannes Krämer
- Department of Pediatrics and Adolescent Medicine, Ulm University Medical Center, Ulm, Germany
| | - Jan Lewerenz
- Department of Neurology, Ulm University Medical Center, Ulm, Germany
| | - Christiane Pfeiffer
- Department of Dermatology and Allergology, Ulm University Medical Center, Ulm, Germany
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14
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Mo J, Moye SL, McKay RM, Le LQ. Neurofibromin and suppression of tumorigenesis: beyond the GAP. Oncogene 2022; 41:1235-1251. [PMID: 35066574 PMCID: PMC9063229 DOI: 10.1038/s41388-021-02156-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Revised: 12/01/2021] [Accepted: 12/13/2021] [Indexed: 12/15/2022]
Abstract
Neurofibromatosis type 1 (NF1) is an autosomal dominant genetic disease and one of the most common inherited tumor predisposition syndromes, affecting 1 in 3000 individuals worldwide. The NF1 gene encodes neurofibromin, a large protein with RAS GTP-ase activating (RAS-GAP) activity, and loss of NF1 results in increased RAS signaling. Neurofibromin contains many other domains, and there is considerable evidence that these domains play a role in some manifestations of NF1. Investigating the role of these domains as well as the various signaling pathways that neurofibromin regulates and interacts with will provide a better understanding of how neurofibromin acts to suppress tumor development and potentially open new therapeutic avenues. In this review, we discuss what is known about the structure of neurofibromin, its interactions with other proteins and signaling pathways, its role in development and differentiation, and its function as a tumor suppressor. Finally, we discuss the latest research on potential therapeutics for neurofibromin-deficient neoplasms.
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Affiliation(s)
- Juan Mo
- Department of Dermatology, University of Texas Southwestern Medical Center at Dallas, Dallas, TX 75390-9069, USA
| | - Stefanie L. Moye
- Department of Dermatology, University of Texas Southwestern Medical Center at Dallas, Dallas, TX 75390-9069, USA
| | - Renee M. McKay
- Department of Dermatology, University of Texas Southwestern Medical Center at Dallas, Dallas, TX 75390-9069, USA
| | - Lu Q. Le
- Department of Dermatology, University of Texas Southwestern Medical Center at Dallas, Dallas, TX 75390-9069, USA,Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center at Dallas, Dallas, TX 75390-9069, USA,UTSW Comprehensive Neurofibromatosis Clinic, University of Texas Southwestern Medical Center at Dallas, Dallas, TX 75390-9069, USA,Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center at Dallas, Dallas, TX 75390-9069, USA,O’Donnell Brain Institute, University of Texas Southwestern Medical Center at Dallas, Dallas, TX 75390-9069, USA,Correspondence and requests for materials should be addressed to Lu Q. Le.
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15
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Kehrer-Sawatzki H, Wahlländer U, Cooper DN, Mautner VF. Atypical NF1 Microdeletions: Challenges and Opportunities for Genotype/Phenotype Correlations in Patients with Large NF1 Deletions. Genes (Basel) 2021; 12:genes12101639. [PMID: 34681033 PMCID: PMC8535936 DOI: 10.3390/genes12101639] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Revised: 09/30/2021] [Accepted: 10/14/2021] [Indexed: 11/16/2022] Open
Abstract
Patients with neurofibromatosis type 1 (NF1) and type 1 NF1 deletions often exhibit more severe clinical manifestations than patients with intragenic NF1 gene mutations, including facial dysmorphic features, overgrowth, severe global developmental delay, severe autistic symptoms and considerably reduced cognitive abilities, all of which are detectable from a very young age. Type 1 NF1 deletions encompass 1.4 Mb and are associated with the loss of 14 protein-coding genes, including NF1 and SUZ12. Atypical NF1 deletions, which do not encompass all 14 protein-coding genes located within the type 1 NF1 deletion region, have the potential to contribute to the delineation of the genotype/phenotype relationship in patients with NF1 microdeletions. Here, we review all atypical NF1 deletions reported to date as well as the clinical phenotype observed in the patients concerned. We compare these findings with those of a newly identified atypical NF1 deletion of 698 kb which, in addition to the NF1 gene, includes five genes located centromeric to NF1. The atypical NF1 deletion in this patient does not include the SUZ12 gene but does encompass CRLF3. Comparative analysis of such atypical NF1 deletions suggests that SUZ12 hemizygosity is likely to contribute significantly to the reduced cognitive abilities, severe global developmental delay and facial dysmorphisms observed in patients with type 1 NF1 deletions.
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Affiliation(s)
- Hildegard Kehrer-Sawatzki
- Institute of Human Genetics, University of Ulm, 89081 Ulm, Germany
- Correspondence: ; Tel.: +49-731-500-65421
| | - Ute Wahlländer
- Kliniken des Bezirks Oberbayern (KBO), Children Clinical Center Munich, 81377 Munich, Germany;
| | - David N. Cooper
- Institute of Medical Genetics, Cardiff University, Heath Park, Cardiff CF14 4XN, UK;
| | - Victor-Felix Mautner
- Department of Neurology, University Hospital Hamburg Eppendorf, 20246 Hamburg, Germany;
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16
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Kehrer-Sawatzki H, Cooper DN. Classification of NF1 microdeletions and its importance for establishing genotype/phenotype correlations in patients with NF1 microdeletions. Hum Genet 2021; 140:1635-1649. [PMID: 34535841 PMCID: PMC8553723 DOI: 10.1007/s00439-021-02363-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Accepted: 09/01/2021] [Indexed: 01/12/2023]
Abstract
An estimated 5–11% of patients with neurofibromatosis type-1 (NF1) harbour large deletions encompassing the NF1 gene and flanking regions. These NF1 microdeletions are subclassified into type 1, 2, 3 and atypical deletions which are distinguishable from each other by their extent and by the number of genes included within the deletion regions as well as the frequency of mosaicism with normal cells. Most common are type-1 NF1 deletions which encompass 1.4-Mb and 14 protein-coding genes. Type-1 deletions are frequently associated with overgrowth, global developmental delay, cognitive disability and dysmorphic facial features which are uncommon in patients with intragenic pathogenic NF1 gene variants. Further, patients with type-1 NF1 deletions frequently exhibit high numbers of neurofibromas and have an increased risk of malignant peripheral nerve sheath tumours. Genes located within the type-1 NF1 microdeletion interval and co-deleted with NF1 are likely to act as modifiers responsible for the severe disease phenotype in patients with NF1 microdeletions, thereby causing the NF1 microdeletion syndrome. Genotype/phenotype correlations in patients with NF1 microdeletions of different lengths are important to identify such modifier genes. However, these correlations are critically dependent upon the accurate characterization of the deletions in terms of their extent. In this review, we outline the utility as well as the shortcomings of multiplex ligation-dependent probe amplification (MLPA) to classify the different types of NF1 microdeletion and indicate the importance of high-resolution microarray analysis for correct classification, a necessary precondition to identify those genes responsible for the NF1 microdeletion syndrome.
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Affiliation(s)
| | - David N Cooper
- Institute of Medical Genetics, Cardiff University, Heath Park, Cardiff, CF14 4XN, UK
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