Germline mutations in the BRCA1 and BRCA2 genes result in a high increased lifetime risk of developing breast and ovarian cancer and, to a lesser extent, other types of cancer such as prostate cancer, pancreatic cancer and melanoma.
BRCA1 and BRCA2 related susceptibility to breast and ovarian cancer (also known as hereditary cancer and ovarian syndrome) is inherited in an autosomal dominant manner. Most individuals with a BRCA1 or BRCA2 pathogenic variant have inherited it from a parent. Because of incomplete penetrance, variable age of cancer, early death or cancer risk reduction from medical treatment, the parent may be affected or unaffected. De novo (i.e. not inherited) mutations in BRCA1 and BRCA2 have been rarely reported.
The reported lifetime risk for developing cancer in individuals with a pathogenic variant in BRCA1 or BRCA2 is as follows: 40%-80% for breast cancer; 11%-40% for ovarian cancer; 1%-10% for male breast cancer; up to 39% for prostate cancer; 1%-7% for pancreatic cancer. Individuals with BRCA2 pathogenic variants may also be at an increased risk for melanoma.