[BRCA2 Mutation Profile in a Proband with Hereditary Breast and Ovarian Cancer-Two Germline Pathogenic Variants Aligned in the Cis Position].

We report the first Japanese case of hereditary breast and ovarian cancer(HBOC)carrying 2 germline pathogenic variants (GPVs)in the BRCA2 gene. Genetic testing of the BRCA1 and BRCA2 genes was performed in a young woman with HBOC and 2 GPVs were identified in the BRCA2 gene. Since simultaneous GPVs in both parental alleles(ie, trans)in the BRCA2 gene is diagnostic of Fanconi anemia, which is characterized by bone marrow dysfunction and susceptibility to malignancy, we genetically tested her relatives. The same variants were revealed, and both variants were located in the cis position. For patients with multiple GPVs in the BRCA2 gene, we should consider genetic testing of the relatives to confirm whether the variants are located in the cis or trans position under appropriate genetic counseling.