The BRCA1 gene was identified in the 1990s on chromosome 17 as a breast and ovarian cancer risk gene (Hall 1990, Ford 1994, Miki 1994, Thompson 2002, Chen 2006, Mavadatt 2013). Deleterious germline mutations in BRCA1 have also been associated with an increased risk of pancreatic cancer (Iqbal 2012) and prostate cancer (Leongamornlert 2012).
Affected Phenotypes Included in Penetrance Model
Breast Cancer (male and female)
Note: For the likelihood ratio calculation in this model, prostate cancer and pancreatic cancer are not counted as affected.
Coding the Pedigree
Code affected individuals in column 5 of the Excel or plain text file used to build your pedigree.
- Code “2” (affected) for individuals with breast or ovarian.
- Code “1” (unaffected) for individuals who have not had those cancers. Individuals who have only had prostate cancer and/or pancreatic cancer should be coded as “1.”
- Code “0” for individuals with uncertain or unknown affected status.
More information on formatting pedigrees can be found here.
Penetrance classes for BRCA1
Penetrance is gender-specific.
|Age Range||Homozygous Normal||Heterozygous||Homozygous Normal||Heterozygous|
- Hall JM, Lee MK, Newman B, Morrow JE, Anderson LA, Huey B, King MC. Linkage of early-onset familial breast cancer to chromosome 17q21. Science. 1990, 250(4988): 1684-1689. doi: 10.1126/science.2270482. PMID:2270482
- Ford D, et al. Risks of cancer in BRCA1-mutation carriers. Breast Cancer Linkage Consortium. Lancet. 1994, 343:692. PMID: 7907678
- Miki Y, et al. A strong candidate for the breast and ovarian cancer susceptibility gene BRCA1. Science. 1994, 266:66. PMID: 7545954
- Thompson D, et al. The breast cancer linkage consortium. Cancer incidence in BRCA1 mutation carriers. J Natl Cancer Inst. 2002, 94:1358. PMID: 12237281
- Chen S, et al. Characterization of BRCA1 and BRCA2 mutations in a large United States sample. J Clin Oncol. 2006, 24:863. PMID: 16484695
- Mavaddat, N, et al. Cancer risks for BRCA1 and BRCA2 mutation carriers: results from prospective analysis of EMBRACE. J Natl Cancer Inst. 2013, 105:812. PMID: 23628597
- Iqbal J, et al. The incidence of pancreatic cancer in BRCA1 and BRCA2 mutation carriers. Br J Cancer. 2012, 107:2005. PMID: 23099806
- Leongamornlert D, et al. Germline BRCA1 mutations increase prostate cancer risk. Br J Cancer. 2012, 106:1697. PMID: 22516946