title: Characterization of an Italian founder mutation in the RING-finger domain of BRCA1.
abstract: The identification of founder mutations in cancer predisposing genes is important to improve risk assessment in geographically defined populations, since it may provide specific targets resulting in cost-effective genetic testing. Here, we report the characterization of the BRCA1 c.190T>C (p.Cys64Arg) mutation, mapped to the RING-finger domain coding region, that we detected in 43 hereditary breast/ovarian cancer (HBOC) families, for the large part originating from the province of Bergamo (Northern Italy). Haplotype analysis was performed in 21 families, and led to the identification of a shared haplotype extending over three BRCA1-associated marker loci (0.4 cM). Using the DMLE+2.2 software program and regional population demographic data, we were able to estimate the age of the mutation to vary between 3,100 and 3,350 years old. Functional characterization of the mutation was carried out at both transcript and protein level. Reverse transcriptase-PCR analysis on lymphoblastoid cells revealed expression of full length mRNA from the mutant allele. A green fluorescent protein (GFP)-fragment reassembly assay showed that the p.Cys64Arg substitution prevents the binding of the BRCA1 protein to the interacting protein BARD1, in a similar way as proven deleterious mutations in the RING-domain. Overall, 55 of 83 (66%) female mutation carriers had a diagnosis of breast and/or ovarian cancer. Our observations indicate that the BRCA1 c.190T>C is a pathogenic founder mutation present in the Italian population. Further analyses will evaluate whether screening for this mutation can be suggested as an effective strategy for the rapid identification of at-risk individuals in the Bergamo area.
authors: Unit of Molecular Bases of Genetic Risk and Genetic Testing, Department of Preventive and Predictive Medicine, Fondazione IRCCS Istituto Nazionale dei Tumori (INT), c/o Amadeolab, Milano, Italy.
authors: Laura
authors: L
authors: Caleca
authors: Department of Biomedical, Experimental and Clinical Sciences, University of Florence, Florence, Italy ; FiorGen Foundation for Pharmacogenomics, Sesto Fiorentino, Italy.
authors: Anna Laura
authors: AL
authors: Putignano
authors: Unit of Molecular Bases of Genetic Risk and Genetic Testing, Department of Preventive and Predictive Medicine, Fondazione IRCCS Istituto Nazionale dei Tumori (INT), c/o Amadeolab, Milano, Italy.
authors: Mara
authors: M
authors: Colombo
authors: Department of Biomedical, Experimental and Clinical Sciences, University of Florence, Florence, Italy.
authors: Caterina
authors: C
authors: Congregati
authors: Department of Chemistry and Department of Biochemistry, The Ohio State University, Columbus, Ohio, United States of America.
authors: Mohosin
authors: M
authors: Sarkar
authors: Department of Chemistry and Department of Biochemistry, The Ohio State University, Columbus, Ohio, United States of America.
authors: Thomas J
authors: TJ
authors: Magliery
authors: Unit of Molecular Bases of Genetic Risk and Genetic Testing, Department of Preventive and Predictive Medicine, Fondazione IRCCS Istituto Nazionale dei Tumori (INT), c/o Amadeolab, Milano, Italy.
authors: Carla B
authors: CB
authors: Ripamonti
authors: Unit of Molecular Bases of Genetic Risk and Genetic Testing, Department of Preventive and Predictive Medicine, Fondazione IRCCS Istituto Nazionale dei Tumori (INT), c/o Amadeolab, Milano, Italy.
authors: Claudia
authors: C
authors: Foglia
authors: Unit of Medical Genetics, Department of Preventive and Predictive Medicine, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy.
authors: Bernard
authors: B
authors: Peissel
authors: Unit of Medical Genetics, Department of Preventive and Predictive Medicine, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy.
authors: Daniela
authors: D
authors: Zaffaroni
authors: Unit of Medical Genetics, Department of Preventive and Predictive Medicine, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy.
authors: Siranoush
authors: S
authors: Manoukian
authors: Unit of Medical Oncology, Azienda Ospedaliera Papa Giovanni XXIII, Bergamo, Italy.
authors: Carlo
authors: C
authors: Tondini
authors: Division of Cancer Prevention and Genetics, Istituto Europeo di Oncologia, Milan, Italy.
authors: Monica
authors: M
authors: Barile
authors: COGENTECH-Cancer Genetic Testing Laboratory, Milan, Italy ; Fondazione Istituto FIRC di Oncologia Molecolare, Milan, Italy.
authors: Valeria
authors: V
authors: Pensotti
authors: COGENTECH-Cancer Genetic Testing Laboratory, Milan, Italy ; Department of Experimental Oncology, Istituto Europeo di Oncologia, Milan, Italy.
authors: Loris
authors: L
authors: Bernard
authors: Department of Biomedical, Experimental and Clinical Sciences, University of Florence, Florence, Italy.
authors: Laura
authors: L
authors: Papi
authors: Unit of Molecular Bases of Genetic Risk and Genetic Testing, Department of Preventive and Predictive Medicine, Fondazione IRCCS Istituto Nazionale dei Tumori (INT), c/o Amadeolab, Milano, Italy.
authors: Paolo
authors: P
authors: Radice
mesh_terms: D000328:Adult; D000367:Age Factors; D019313:BRCA1 Protein / Q000737:chemistry* / Q000235:genetics*; D001943:Breast Neoplasms / Q000235:genetics / Q000473:pathology; D020090:Chromosome Segregation / Q000235:genetics; D005091:Exons / Q000235:genetics; D005190:Family; D005260:Female; D018703:Founder Effect; D015972:Gene Expression Regulation, Neoplastic; D020022:Genetic Predisposition to Disease; D005843:Geography; D049452:Green Fluorescent Proteins / Q000378:metabolism; D006239:Haplotypes / Q000235:genetics; D006801:Humans; D007558:Italy; D008875:Middle Aged; D009154:Mutation / Q000235:genetics*; D059645:Mutation Rate; D010051:Ovarian Neoplasms / Q000235:genetics / Q000473:pathology; D011485:Protein Binding; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D054829:RING Finger Domains; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D025521:Tumor Suppressor Proteins / Q000378:metabolism; D044767:Ubiquitin-Protein Ligases / Q000378:metabolism
chemical_list: D019313:BRCA1 Protein; D020033:Protein Isoforms; D012333:RNA, Messenger; D025521:Tumor Suppressor Proteins; D049452:Green Fluorescent Proteins; C102449:BARD1 protein, human; D044767:Ubiquitin-Protein Ligases