Germline BRCA2 Pathogenic Variant in Primary Breast Cancer of a Down Syndrome Individual

A 35-year-old woman with Down syndrome was diagnosed with invasive ductal carcinoma of the breast and subsequently found to carry a BRCA2 pathogenic variant after developing metastases 23 months post-mastectomy. Despite treatment with olaparib (PARP inhibitor), the patient developed progressive metastatic disease and died 59 months after initial diagnosis, highlighting the intersection of Down syndrome, BRCA-related cancer risk, and treatment response in this rare clinical scenario.