title: A diagnostic genetic test for the physical mapping of germline rearrangements in the susceptibility breast cancer genes BRCA1 and BRCA2.
abstract: The BRCA1 and BRCA2 genes are involved in breast and ovarian cancer susceptibility. About 2 to 4% of breast cancer patients with positive family history, negative for point mutations, can be expected to carry large rearrangements in one of these two genes. We developed a novel diagnostic genetic test for the physical mapping of large rearrangements, based on molecular combing (MC), a FISH-based technique for direct visualization of single DNA molecules at high resolution. We designed specific Genomic Morse Codes (GMCs), covering the exons, the noncoding regions, and large genomic portions flanking both genes. We validated our approach by testing 10 index cases with positive family history of breast cancer and 50 negative controls. Large rearrangements, corresponding to deletions and duplications with sizes ranging from 3 to 40 kb, were detected and characterized on both genes, including four novel mutations. The nature of all the identified mutations was confirmed by high-resolution array comparative genomic hybridization (aCGH) and breakpoints characterized by sequencing. The developed GMCs allowed to localize several tandem repeat duplications on both genes. We propose the developed genetic test as a valuable tool to screen large rearrangements in BRCA1 and BRCA2 to be combined in clinical settings with an assay capable of detecting small mutations.
authors.affiliation: Genomic Vision, 80–84 rue des Meuniers,Bagneux, Paris, France.
authors.forename: Kevin
authors.initials: K
authors.lastname: Cheeseman
authors.forename: Etienne
authors.initials: E
authors.lastname: Rouleau
authors.forename: Anne
authors.initials: A
authors.lastname: Vannier
authors.forename: Aurélie
authors.initials: A
authors.lastname: Thomas
authors.forename: Adrien
authors.initials: A
authors.lastname: Briaux
authors.forename: Cedrick
authors.initials: C
authors.lastname: Lefol
authors.forename: Pierre
authors.initials: P
authors.lastname: Walrafen
authors.forename: Aaron
authors.initials: A
authors.lastname: Bensimon
authors.forename: Rosette
authors.initials: R
authors.lastname: Lidereau
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Conseiller
authors.forename: Maurizio
authors.initials: M
authors.lastname: Ceppi
mesh_terms: D001943:Breast Neoplasms / Q000175:diagnosis / Q000235:genetics; D055088:Early Detection of Cancer; D005091:Exons; D005260:Female; D019398:Genes, BRCA1; D024522:Genes, BRCA2; D005820:Genetic Testing / Q000379:methods*; D018095:Germ-Line Mutation; D006801:Humans; D010051:Ovarian Neoplasms / Q000175:diagnosis / Q000235:genetics; D020161:Physical Chromosome Mapping / Q000379:methods*; D015203:Reproducibility of Results; D014178:Translocation, Genetic