Two mutations of BRCA2 gene at exon and splicing site in a woman who underwent oncogenetic counseling

Background: Although most BRCA sequence variants are clearly deleterious and unequivocally pathogenetic, several are still classified as variants of unknown significance. Patients and methods: We followed families undergoing oncogenetic counseling from risk identification to risk definition by genetic testing and risk management. Results: We identified two germline mutations in the BRCA2 gene in a woman with breast and ovarian cancer. One sequence alteration was 859/G > A in exon 7 (V211I). The other second sequence alteration (IVS13-2A > T) affected the splicing site in intron 13. The latter alteration is not yet listed in the Breast Cancer Information Core database. RT-PCR resulted in transcription of a sequence lacking exon 7 and a subsequent anomalous stop codon in exon 9 thereby confirming altered messenger RNA (mRNA) maturation. Amplification of the mutation in intron 13 resulted in transcription of a sequence lacking exon 14 and an anomalous stop codon in exon 15 thereby confirming altered mRNA maturation. Both mutations led to a truncated BRCA2 protein in its carboxy-terminal region. Conclusion: The two BRCA2 mutations identified affect mRNA splicing fidelity and play a pathogenetic role in breast and ovarian cancer.