The BRCA1 mutation is a frameshift mutation located at codon 1756 of exon 20: 5382 ins C. This mutation has been previously described in Ashkenazi Jews and is clearly associated with an increased risk of breast cancer.17 The woman with this mutation in the present study developed breast cancer at 33 years of age and she has a first-degree relative with breast cancer. The gene discussed is BRCA1; the disease is breast carcinoma.