A hereditary ovarian cancer family with rare pathogenic splicing mutation: Implications for variant interpretation

The BRCA1/2 gene is important for assessing the risk of familial/hereditary ovarian cancer (OC). This case is a patient with OC, and two of her immediate family members are cancer patients. We sequenced the coding and splicing regions of 42 OC susceptibility genes, and found a rare pathogenic splicing mutation BRCA1:c.132C > T (p.cys44 =) in 2 patients. Although the mutation is synonymous, software prediction and functional verification have shown that it affects alternative splicing and leads to frameshift mutations (c.131_134del). Chromosome microarray analysis of the tissue samples revealed the presence of a BRCA1 gene deletion with a fragment size of 1.42 Mb and an HRD score of 71. In addition, the proband showed a sensitive response to platinum treatment. This case suggests the clinical significance of OC susceptibility genes sequencing and HRD scoring in screening hereditary OC families.