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Background: Alterations in BRCA1 gene are responsible for the majority of hereditary breast and/or ovarian cancers. However, the frequency of detected germline mutations is lower than expected by linkage analysis. Standard PCR-based screening methods are mainly used for detecting mutations, but the large genomic rearrangements are commonly overlooked. The purpose of this study was to confirm and characterize a novel deletion identified in BRCA1 gene which has not yet been reported to date., Methods: Multiplex ligation-dependent probe amplification was used to analyze BRCA1 rearrangements in 255 unrelated index patients with familial breast and/or ovarian cancer negative for BRCA1/BRCA2 mutations studied in Program of Genetic Counselling on Cancer of Valencia Community (Spain). The breakpoints of detected novel rearrangement were characterized by sequencing., Results and Discussion: Five different rearrangements in the BRCA1 gene were identified in five unrelated index patients out of the 225 (2%). We found four large genomic rearrangements already described consisting in a 1A/1B and 2 deletion; deletion of exons 5-7; deletion of exons 8-13; exon 20 deletion. Additionally, we found the novel g.8097_22733del14637 deletion that encompasses exons 3-5. This deletion affects the RING domain of the BRCA1 protein and it is suggestive of having a negative impact on its function., Conclusion: The new mutation here reported broadens the mutational spectrum of large rearrangements. Furthermore, the five large rearrangements found in patients non-carriers of BRCA1/BRCA2 mutations reinforce the need of studying BRCA1 large genomic rearrangements in genetic counselling programs.

It is well established that mutations in BRCA1 and BRCA2 genes significantly increase the risk of breast and ovarian cancer. We here report 23 novel genetic variants of the BRCA1 and BRCA2 genes found in 349 cancer-prone unrelated families from Eastern Spain detected during the first 2 years of performance of the Program of Genetic Counseling of Valencia Community. Mutational screening was performed by pre-screening the heteroduplex formed in the PCR products obtained amplifying BRCA1 and BRCA2 genes by conformation sensitive electrophoresis. We detected 10 deletereous mutations, four in BRCA1 (three frame-shift (FS) and one nonsense mutation (NS)) and six in BRCA2 (four FS and one NS mutation). Moreover, we detected 13 unclassified variants, four in BRCA1 (one missense (MS), two synonymous (SYN) and one intronic (I) variant) and nine in BRCA2 (six MS, one SYN and two I). The relevance of the novel mutations is discussed. Our contribution broadens the BRCA1/2 world mutational spectra.

Background and Objective: The objective of the present study was to investigate the mutational spectrum of BRCA1 and BRCA2 in the Valencian Community, comparing this spectrum with that reported in Spain. We also analyze the association of the mutations with the family history of the selected families., Patients and Method: We analyzed the mutations in the BRCA1 and BRCA2 in 147 families with history of breast and/or ovarian cancer. The detection was based on the amplification of in frame and flanking regions of BRCA1 and BRCA2 genes by polymerase chain reaction, detection of the heteroduplex formed by conformation-sensitive gel electrophoresis and their characterization by sequencing., Results: We identified 24 different pathogenic mutations in 50 out of the 147 families (34.0%; 23 in BRCA1 and 27 in BRCA2). The higher incidence of pathogenic mutations was observed in families with breast and ovarian cancer or with more than 3 cases of breast cancer. The most frequent mutations in BRCA1 were the c.187_188delAG, c.2080delA and the c.3889_3890delAG, whereas for BRCA2 the mutations with higher prevalence was observed for c.9254_9258delATCAT and the c.9204delCATCAGATTTATAT. We detected 5 pathogenic mutations (p.Y1429X in BRCA1 and c.1835insT, c.5025delT, c.6722delT and p.Q3156X in BRCA2) not reported in the Breast Cancer Information Core Database. Among them, the BRCA2 mutations c.1835insT and c.5025delT were recurrent and seemed to be characteristic of the population the Valencian Community., Conclusions: We detected pathogenic mutations in BRCA1 and BRCA2 genes in 34.0% of the families studied. The mutations c.1835insT and c.5025delT were 2 new recurrent pathogenic mutations in BRCA2 that seemed to be characteristic of the population of the Valencian Community. The study reports 5 new pathogenic mutations to the world spectrum of BRCA1 and BRCA2 mutations and other 5 mutations to the Spanish spectrum.