title: Identification and comprehensive characterization of large genomic rearrangements in the BRCA1 and BRCA2 genes.
abstract: Large genomic rearrangements are estimated to account for approximately 5-10% of all disease-causing mutations in BRCA1 and BRCA2 genes in patients with hereditary breast and ovarian cancer syndrome (HBOC). We use MRC-Holland Multiplex Ligation-dependent Probe Amplification (MLPA) to screen for such rearrangements in patients with HBOC and as a first step in our genetic testing workflow. The technique was applied to a set of 310 independent patients and detected eight different copy number alterations, corresponding to 2.6% of the studied samples. MLPA was also found to identify point mutations located in probe sequences. As commercial MLPA tests are not suitable for determining the specific breakpoints or for defining the exact extent of rearrangements, we applied a set of different complementary techniques to characterize these genetic alterations with greater precision. Long-range PCR amplification, RNA analysis, SNP-array chips, non-commercial MLPA probes, and FISH analysis were used to fully define the extent and mechanism of each alteration. In BRCA1, six rearrangements were characterized: deletion of E22, duplication of E9-E24, deletion of E16-E23, deletion of E1-E13, deletion of E1-E2 and duplication of E1-E2. In BRCA2, we studied a deletion of E15-E16 and a deletion of E1-E24. To the best of our knowledge, this is the most comprehensive study of the nature and underlying molecular causes of these mutational events in the BRCA1/2 genes.
authors.affiliation: Programa de Diagnòstic Molecular de Càncer Hereditari, Laboratori de Recerca Translacional, Institut Català d'Oncologia-IDIBELL, Hospital Duran i Reynals, Hospitalet de Llobregat, Gran Via s/n, km 2.7, L'Hospitalet de Llobregat, 08907 Barcelona, Spain.
authors.forename: Jesús
authors.initials: J
authors.lastname: del Valle
authors.forename: Lídia
authors.initials: L
authors.lastname: Feliubadaló
authors.forename: Marga
authors.initials: M
authors.lastname: Nadal
authors.forename: Alex
authors.initials: A
authors.lastname: Teulé
authors.forename: Rosa
authors.initials: R
authors.lastname: Miró
authors.forename: Raquel
authors.initials: R
authors.lastname: Cuesta
authors.forename: Eva
authors.initials: E
authors.lastname: Tornero
authors.forename: Mireia
authors.initials: M
authors.lastname: Menéndez
authors.forename: Esther
authors.initials: E
authors.lastname: Darder
authors.forename: Joan
authors.initials: J
authors.lastname: Brunet
authors.forename: Gabriel
authors.initials: G
authors.lastname: Capellà
authors.forename: Ignacio
authors.initials: I
authors.lastname: Blanco
authors.forename: Conxi
authors.initials: C
authors.lastname: Lázaro
mesh_terms: D000328:Adult; D001483:Base Sequence; D001943:Breast Neoplasms / Q000235:genetics*; D005260:Female; D015321:Gene Rearrangement; D019398:Genes, BRCA1; D024522:Genes, BRCA2; D020022:Genetic Predisposition to Disease; D015894:Genome, Human; D006801:Humans; D008297:Male; D008875:Middle Aged; D008969:Molecular Sequence Data; D010051:Ovarian Neoplasms / Q000235:genetics*; D010375:Pedigree; D017354:Point Mutation; D016133:Polymerase Chain Reaction; D020641:Polymorphism, Single Nucleotide; D012689:Sequence Homology, Nucleic Acid