Dataset Information
From a variant of unknown significance to pathogenic: Reclassification of a large novel duplication in BRCA2 by high-throughput sequencing.
Ontology highlight
ABSTRACT: Background
Germline mutations in BRCA1/2 significantly contribute to hereditary breast and/or ovarian cancer. Here, we report a novel BRCA2 duplication of exons 22-24 in a female patient with bilateral breast cancer at age 35 and 44. The duplicated region was initially detected by gene panel sequencing and multiplex ligation-dependent probe amplification. However, the location and orientation of the duplicated region was unknown. Therefore, it was initially classified as a variant of unknown significance.Methods
The spatial directional characterization of the BRCA2 duplication was achieved by targeted enrichment of the whole-genomic BRCA2 locus including exons and introns, and subsequent high-throughput sequencing. Subsequently, bioinformatics tools and a breakpoint-spanning PCR were used for identification of location and orientation of the duplication.Results
The duplicated region was arranged in tandem and direct orientation (Chr13(GRCh37):g.32951579_32960394dup; NM_000059.3 c.8754 + 651_9256+6112dup p.(Ala3088Phefs*3)). It is predicted to result in a frameshift and a premature stop codon likely triggering nonsense-mediated mRNA decay. Consequently, it is regarded as pathogenic.Conclusion
This case study demonstrates that a comprehensive characterization of a structural variant by breakpoint assessment is crucial for its correct classification. Therefore, sequencing strategies including non-coding regions might be necessary to identify cancer predispositions in affected families.
SUBMITTER: van Luttikhuizen JL
PROVIDER: S-EPMC7506983 | biostudies-literature | 2020 Sep
REPOSITORIES: biostudies-literature
Publications
From a variant of unknown significance to pathogenic: Reclassification of a large novel duplication in BRCA2 by high-throughput sequencing.
Molecular genetics & genomic medicine 20191113 9
<h4>Background</h4>Germline mutations in BRCA1/2 significantly contribute to hereditary breast and/or ovarian cancer. Here, we report a novel BRCA2 duplication of exons 22-24 in a female patient with bilateral breast cancer at age 35 and 44. The duplicated region was initially detected by gene panel sequencing and multiplex ligation-dependent probe amplification. However, the location and orientation of the duplicated region was unknown. Therefore, it was initially classified as a variant of unk ...[more]