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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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