Concerning the sum effect of truncating DNA-repair variants on the risk of breast cancer among BRCA1 mutation carriers, our results are suggesting an increase in the breast cancer risk for the BRCA1 mutation carriers who carry additional truncating DNA-repair variants (OR: 3.1; 95% CI 0.92 to 11.5; p-value = 0.07). The gene discussed is BRCA1; the disease is breast carcinoma.