The 10 and 20-year cumulative risk of contralateral breast cancer was 32.3% (95% CI 24.0–42.6) and 56.6% (95% CI 44.8–69.1) for BRCA1, 20.7 (95% CI 13.0–32.1) and 45.3% (95% CI 31.4–61.9) for BRCA2 and 53.1% (29.6–80.6) and 82.4% (95% CI 49.9–98.8) for TP53 carriers. The gene discussed is BRCA1; the disease is breast carcinoma.