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Bettinaglio P, Tritto V, Paterra R, Eoli M, Riva P. Expression analysis of NF1-mutated alleles in a rare compound heterozygous spinal NF1 patient by digital PCR. Ann Hum Genet 2024; 88:183-193. [PMID: 38018226 DOI: 10.1111/ahg.12540] [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: 05/08/2023] [Revised: 11/03/2023] [Accepted: 11/06/2023] [Indexed: 11/30/2023]
Abstract
BACKGROUD Neurofibromatosis type 1 (NF1) is a heterogeneous neurocutaneous disorder. Spinal neurofibromatosis (SNF) is a distinct clinical entity of NF1, characterized by bilateral neurofibromas involving all spinal nerve roots. Although both forms are caused by intragenic heterozygous variants of NF1, missense variants have been associated with SNF, according to a dominant inheritance model causing haploinsufficiency. Most patients carry pathogenic variants in one of the NF1 alleles; nevertheless, patients with both NF1-mutated copies have been described. Interestingly, all NF1 variants carried by the known SNF compound heterozygotes were missense/splicing variants or in-frame insertion-deletions. AIMS To investigate whether there is a differential expression of NF1 variant alleles in an NF1 compound heterozygous SNF patient possibly contributing to clinical phenotype. MATERIALS & METHODS We performed an allele-specific expression study, by chip-based digital PCR, in an SNF family carrying two NF1 missense variants. We evaluated the expression levels of the two NF1-mutated alleles both carried by the compound heterozygous SNF patient and his relatives. RESULTS Both alleles were expressed at comparable levels in the patient and hyper-expressed compared to the wild-type alleles of healthy controls. DISCUSSION Here we provide new insights into expression studies of NF1-mutated transcripts suggesting that a novel pathogenetic mechanism, caused by gain-of-function variants, could be associated with SNF. CONCLUSIONS Further studies should be performed in larger cohorts, opening new perspectives in the NF1 pathogenesis comprehension.
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Affiliation(s)
- Paola Bettinaglio
- Department of Medical Biotechnology and Translational Medicine (BIOMETRA), University of Milan, Segrate, Italy
| | - Viviana Tritto
- Department of Medical Biotechnology and Translational Medicine (BIOMETRA), University of Milan, Segrate, Italy
| | - Rosina Paterra
- Molecular Neuroncology Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milano, Italy
| | - Marica Eoli
- Molecular Neuroncology Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milano, Italy
| | - Paola Riva
- Department of Medical Biotechnology and Translational Medicine (BIOMETRA), University of Milan, Segrate, Italy
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Paterra R, Bettinaglio P, Borghi A, Mangano E, Tritto V, Cesaretti C, Schettino C, Bordoni R, Santoro C, Avignone S, Moscatelli M, Melone MAB, Saletti V, Piluso G, Natacci F, Riva P, Eoli M. A Translational Approach to Spinal Neurofibromatosis: Clinical and Molecular Insights from a Wide Italian Cohort. Cancers (Basel) 2022; 15:cancers15010059. [PMID: 36612057 PMCID: PMC9817775 DOI: 10.3390/cancers15010059] [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: 11/04/2022] [Revised: 12/07/2022] [Accepted: 12/12/2022] [Indexed: 12/24/2022] Open
Abstract
Spinal neurofibromatosis (SNF), a phenotypic subclass of neurofibromatosis 1 (NF1), is characterized by bilateral neurofibromas involving all spinal roots. In order to deepen the understanding of SNF’s clinical and genetic features, we identified 81 patients with SNF, 55 from unrelated families, and 26 belonging to 19 families with at least 1 member affected by SNF, and 106 NF1 patients aged >30 years without spinal tumors. A comprehensive NF1 mutation screening was performed using NGS panels, including NF1 and several RAS pathway genes. The main features of the SNF subjects were a higher number of internal neurofibromas (p < 0.001), nerve root swelling (p < 0.001), and subcutaneous neurofibromas (p = 0.03), while hyperpigmentation signs were significantly less frequent compared with the classical NF1-affected cohorts (p = 0.012). Fifteen patients underwent neurosurgical intervention. The histological findings revealed neurofibromas in 13 patients and ganglioneuromas in 2 patients. Phenotypic variability within SNF families was observed. The proportion of missense mutations was higher in the SNF cases than in the classical NF1 group (21.40% vs. 7.5%, p = 0.007), conferring an odds ratio (OR) of 3.34 (CI = 1.33−10.78). Two unrelated familial SNF cases harbored in trans double NF1 mutations that seemed to have a subclinical worsening effect on the clinical phenotype. Our study, with the largest series of SNF patients reported to date, better defines the clinical and genetic features of SNF, which could improve the management and genetic counseling of NF1.
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Affiliation(s)
- Rosina Paterra
- Molecular Neuroncology Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta, 20122 Milano, Italy
| | - Paola Bettinaglio
- Department of Medical Biotechnology and Translational Medicine (BIOMETRA), University of Milan, Segrate, 20122 Milan, Italy
| | - Arianna Borghi
- Molecular Neuroncology Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta, 20122 Milano, Italy
| | - Eleonora Mangano
- Institute of Biomedical Technologies (ITB) National Research Center (CNR), ITB-CNR, Segrate, 20122 Milan, Italy
| | - Viviana Tritto
- Department of Medical Biotechnology and Translational Medicine (BIOMETRA), University of Milan, Segrate, 20122 Milan, Italy
| | - Claudia Cesaretti
- Medical Genetics Unit, Woman-Child-Newborn Department, Fondazione IRCCS Ca’ Granda-Ospedale Maggiore Policlinico, 20122 Milano, Italy
| | - Carla Schettino
- Department of Advanced Medical and Surgical Sciences, 2nd Division of Neurology, Center for Rare Diseases and InterUniversity Center for Research in Neurosciences, University of Campania “Luigi Vanvitelli”, 81100 Naples, Italy
| | - Roberta Bordoni
- Institute of Biomedical Technologies (ITB) National Research Center (CNR), ITB-CNR, Segrate, 20122 Milan, Italy
| | - Claudia Santoro
- Neurofibromatosis Referral Center, Department of Woman, Child and of General and Specialized Surgery, and Clinic of Child and Adolescent Neuropsychiatry, Department of Mental Health, Physical and Preventive Medicine, University of Campania “Luigi Vanvitelli”, 81100 Naples, Italy
| | - Sabrina Avignone
- Neuroradiology Department, Fondazione IRCCS Ca’ Granda-Ospedale Maggiore Policlinico, 20122 Milano, Italy
| | - Marco Moscatelli
- Neuroradiology Department, Fondazione IRCCS Istituto Neurologico Carlo Besta, 20133 Milano, Italy
| | - Mariarosa Anna Beatrice Melone
- Department of Advanced Medical and Surgical Sciences, 2nd Division of Neurology, Center for Rare Diseases and InterUniversity Center for Research in Neurosciences, University of Campania “Luigi Vanvitelli”, 81100 Naples, Italy
- Sbarro Institute for Cancer Research and Molecular Medicine, Center for Biotechnology, Temple University, Philadelphia, PA 19122, USA
| | - Veronica Saletti
- Developmental Neurology Unit, Mariani Foundation Center for Complex Disabilities, Fondazione IRCCS Istituto Neurologico Carlo Besta, 20133 Milan, Italy
| | - Giulio Piluso
- Department of Precision Medicine, Università degli Studi della Campania “Luigi Vanvitelli”, 81100 Naples, Italy
| | - Federica Natacci
- Medical Genetics Unit, Woman-Child-Newborn Department, Fondazione IRCCS Ca’ Granda-Ospedale Maggiore Policlinico, 20122 Milano, Italy
| | - Paola Riva
- Department of Medical Biotechnology and Translational Medicine (BIOMETRA), University of Milan, Segrate, 20122 Milan, Italy
- Correspondence: (P.R.); (M.E.); Tel.: +39-02-503130462 (P.R.); +39-02-23942285 (M.E.)
| | - Marica Eoli
- Molecular Neuroncology Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta, 20122 Milano, Italy
- Correspondence: (P.R.); (M.E.); Tel.: +39-02-503130462 (P.R.); +39-02-23942285 (M.E.)
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Trevisson E, Morbidoni V, Forzan M, Daolio C, Fumini V, Parrozzani R, Cassina M, Midena E, Salviati L, Clementi M. The Arg1038Gly missense variant in the NF1 gene causes a mild phenotype without neurofibromas. Mol Genet Genomic Med 2019; 7:e616. [PMID: 30843352 PMCID: PMC6503065 DOI: 10.1002/mgg3.616] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Revised: 01/16/2019] [Accepted: 02/11/2019] [Indexed: 01/08/2023] Open
Abstract
Background Neurofibromatosis type 1 (NF1) is an autosomal dominant condition caused by inactivating mutations of the NF1 gene. The wide allelic heterogeneity of this condition, with more than 3,000 pathogenic variants reported so far, is paralleled by its high clinical variability, which is observed even within the same family. The definition of genotype–phenotype correlations has been hampered by the complexity of the NF1 gene and, although a few exceptions have been recognized, the clinical course remains unpredictable in most patients. Methods Sequencing of NF1 in patients with cafè‐au‐lait spots identified the c.3112A>G variant. RNA analysis and a minigene assay were employed to investigate splicing. Results Here we report a novel genotype–phenotype correlation in NF1: the identification of the missense variant NM_000267.3:c.3112A>G p.(Arg1038Gly) in seven individuals from two unrelated families with a mild phenotype. All the patients manifest cafè‐au‐lait spots without neurofibromas or other NF1–associated complications, and Noonan syndrome features in most cases. The missense variant was not previously reported in available databases, segregates with the phenotype and involves a highly conserved residue. Both a minigene assay and patient's RNA analysis excluded an effect on splicing. Conclusion Our data support the correlation of the p.Arg1038Gly missense substitution with the cutaneous phenotype without neurofibromas or other complications. This finding may have relevant implications for patients and genetic counseling, but also to get insights into the function of neurofibromin.
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Affiliation(s)
- Eva Trevisson
- Department of Women's and Children's Health, Clinical Genetics Unit, University of Padova, Padova, Italy.,Laboratorio di Genetica Clinica ed Epidemiologica, Istituto di Ricerca Pediatrica, IRP, Padova, Italy
| | - Valeria Morbidoni
- Department of Women's and Children's Health, Clinical Genetics Unit, University of Padova, Padova, Italy.,Laboratorio di Genetica Clinica ed Epidemiologica, Istituto di Ricerca Pediatrica, IRP, Padova, Italy
| | - Monica Forzan
- Department of Women's and Children's Health, Clinical Genetics Unit, University of Padova, Padova, Italy.,Laboratorio di Genetica Clinica ed Epidemiologica, Istituto di Ricerca Pediatrica, IRP, Padova, Italy
| | | | - Valentina Fumini
- Department of Women's and Children's Health, Clinical Genetics Unit, University of Padova, Padova, Italy
| | | | - Matteo Cassina
- Department of Women's and Children's Health, Clinical Genetics Unit, University of Padova, Padova, Italy
| | - Edoardo Midena
- Department of Neurosciences, University of Padova, Padova, Italy.,IRCCS-Fondazione Bietti, Rome, Italy
| | - Leonardo Salviati
- Department of Women's and Children's Health, Clinical Genetics Unit, University of Padova, Padova, Italy.,Laboratorio di Genetica Clinica ed Epidemiologica, Istituto di Ricerca Pediatrica, IRP, Padova, Italy
| | - Maurizio Clementi
- Department of Women's and Children's Health, Clinical Genetics Unit, University of Padova, Padova, Italy.,Laboratorio di Genetica Clinica ed Epidemiologica, Istituto di Ricerca Pediatrica, IRP, Padova, Italy
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Ruggieri M, Polizzi A, Spalice A, Salpietro V, Caltabiano R, D'Orazi V, Pavone P, Pirrone C, Magro G, Platania N, Cavallaro S, Muglia M, Nicita F. The natural history of spinal neurofibromatosis: a critical review of clinical and genetic features. Clin Genet 2015; 87:401-10. [PMID: 25211147 DOI: 10.1111/cge.12498] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2013] [Revised: 09/08/2014] [Accepted: 09/08/2014] [Indexed: 11/28/2022]
Abstract
Spinal neurofibromatosis (SNF) is a related form of neurofibromatosis 1 (NF1), characterized by bilateral neurofibromas (histologically proven) of all spinal roots (and, eventually, of all the major peripheral nerve branches) with or without other manifestations of classical NF1. By rigorous application of these criteria to the 98 SNF cases published, we developed: (i) a cohort of 49 SNF patients (21 males and 28 females; aged 4-74 years]: 9 SNF families (21/49), 1 mixed SNF/NF1 family (1/49) and 27 of 49 sporadic SNF patients (including 5 unpublished patients in this report); and (ii) a group of 49 non-SNF patients including: (a) 32 patients with neurofibromas of multiple but not all spinal roots (MNFSR): 4 mixed SNF/MNFSR families (6/32); (b) 14 patients with NF1 manifestations without spinal neurofibromas, belonging to SNF (8/49) or MNFSR families (6/32); (c) 3 patients with neurofibromas in one spinal root. In addition to reduced incidence of café-au-lait spots (67% in SNF vs 56% in MNFSR), other NF1 manifestations were less frequent in either cohort. Molecular testing showed common NF1 gene abnormalities in both groups. The risk of developing SNF vs NF1 was increased for missense mutations [p = 0.0001; odds ratio (OR) = 6.16; confidence interval (CI) = 3.14-13.11], which were more frequent in SNF vs MNFSR (p = 0.0271).
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Affiliation(s)
- M Ruggieri
- Department of Educational Sciences, Chair of Paediatrics, Catania, Italy; Centre for Neurocutaneous Disorders, University of Catania, Catania, Italy
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Wong YC, Ho PC, Tse WL, Chow LTC, Wong CWY. Malignant schwannoma of the radial nerve with unusual presentation: a case report. ACTA ACUST UNITED AC 2014; 19:95-7. [PMID: 24641748 DOI: 10.1142/s0218810414720022] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Malignant schwannoma (MPNST) is a rare tumor. Many of these cases occur in patients with neurofibromatosis type I (NF-1) and they usually present as a mass lesion which rapidly increase in size with or without neurological symptoms. Here we present an unusual case of MPNST along the radial nerve in which the patient has no underlying neurofibromatosis type I.
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Affiliation(s)
- Yu Chung Wong
- Department of Orthopaedics and Traumatology, Prince of Wales Hospital, Hong Kong, China
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Spinal neurofibromatosis in a family with classical neurofibromatosis type 1 and a novel NF1 gene mutation. J Clin Neurosci 2014; 21:328-30. [DOI: 10.1016/j.jocn.2013.01.026] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2012] [Accepted: 01/27/2013] [Indexed: 11/22/2022]
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Pascual-Castroviejo I, Pascual-Pascual SI, Viaño J, Velazquez-Fragua R, López-Gutierrez JC. Bilateral spinal neurofibromas in patients with neurofibromatosis 1. Brain Dev 2012; 34:563-9. [PMID: 21999966 DOI: 10.1016/j.braindev.2011.09.011] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/18/2011] [Revised: 09/19/2011] [Accepted: 09/20/2011] [Indexed: 11/26/2022]
Abstract
Neurofibromatosis 1 (NF1) is a neurocutaneous syndrome that can be inherited as autosomal dominant or may appear due to a de novo mutation. We present 8 patients (5 M and 3 F) with sporadic or non-familial spinal neurofibromatosis 1 (non-FSNF1) associated with bilateral spinal neurofibromas involving all of the paraspinal nerves. To our knowledge, this is the first series of such association described in the literature. Their ages ranged from 6 months to 20 years (average 9.8 years) at the time of radiological diagnosis. This presentation appears to be earlier than in familial spinal neurofibromas in NF1 (FSNF1). Predisposition to malignancy probably is greater in the non-FSNF1 type. MRI studies were performed routinely in all patients with NF1 and these were complemented with MRI enhanced with gadolinium and repeated at different ages in cases with paraspinal tumors. Coronal views provided the best evidence for the presence of neurofibromas in every spinal nerve. The size of the tumors and the clinical complications increased with advancing age in most patients. Giant plexiform tumors were often seen in the cervico-thoracic region. Malignant peripheral nerve sheath tumors (MPNST) were found in one patient with a sciatic tumor and another patient died suddenly at home without necropsy or pathological study. Voluminous paraspinal neurofibromas can be at risk for malignancy. More frequent neuroimaging studies may be necessary for an earlier detection. Early surgical treatment to anticipate the occurrence of MPNST during surveillance could be an option. Bilateral spinal neurofibromas are found in both patients who inherited the NF1 and in those due to de novo mutations.
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