BRCA1 and BRCA2 Pathogenic Variant: Risk Numbers, Surveillance, and Next Steps
A pathogenic BRCA1 variant means 65–72% lifetime breast cancer risk. Here’s what the classification means, what surveillance looks like, and who else in your family should be tested.
Category: Research · By GenomeNarrator Team · · 8 min read
BRCA1 and BRCA2 are two of the most studied genes in medicine. They produce proteins that help repair damaged DNA, and when they carry a pathogenic variant, cells can accumulate errors that lead to cancer. Getting a result that flags one of these genes raises important questions. This is what you actually need to know.
What BRCA1 and BRCA2 do
Both genes act as guardians of the genome. They produce proteins involved in homologous recombination, a process that fixes breaks in double-stranded DNA. When a pathogenic variant disrupts this function, DNA damage accumulates, and the risk of cancer, particularly breast and ovarian cancer, increases significantly.
Not all variants are equal
This is the most important thing most people miss. Variants in BRCA1 and BRCA2 fall into three categories.
Pathogenic or likely pathogenic variants have strong evidence that they disrupt the gene's function and meaningfully raise cancer risk. These are the findings that require clinical action.
Variants of uncertain significance (VUS) are detected but their clinical impact is unclear. A VUS is not a positive result; it means the science has not yet determined what the variant does. Most VUS findings require no action and are re-evaluated as more data emerges.
Benign variants are changes in the DNA that have no effect on protein function and are not associated with increased risk.
What a pathogenic BRCA1 variant means for cancer risk
For women carrying a pathogenic BRCA1 variant, the estimated lifetime risk of breast cancer is approximately 65–72%, compared to roughly 12% in the general population. The lifetime risk of ovarian cancer is approximately 39–46%, compared to about 1–2% in the general population.
For women with a pathogenic BRCA2 variant, breast cancer lifetime risk is approximately 45–69%, and ovarian cancer risk is approximately 11–17%. BRCA2 also raises the risk of pancreatic cancer and, for men, prostate cancer.
A variant is not a diagnosis
A pathogenic BRCA variant is not a diagnosis of cancer. It is a substantially elevated risk that, with the right surveillance and preventive strategy, can be managed effectively. The medical community has well-established protocols for carriers.
Standard care for BRCA1/2 carriers includes enhanced breast cancer surveillance starting at age 25–30 (annual MRI alongside mammography), risk-reducing salpingo-oophorectomy typically recommended between ages 35–40 for BRCA1 carriers after childbearing, and discussion of risk-reducing mastectomy based on personal risk tolerance and family history.
The limits of consumer genetic testing
Consumer genome files from 23andMe and AncestryDNA use SNP arrays: chips that test for hundreds of thousands of known variants. They do not sequence the entire BRCA1 and BRCA2 genes. This means a clean result on a consumer test does not rule out a BRCA variant. Comprehensive clinical BRCA testing requires full gene sequencing ordered by a clinician.
If GenomeNarrator flagged a BRCA1 or BRCA2 variant from your consumer genome file, that finding should be confirmed with clinical-grade diagnostic testing before any medical decisions are made.
Family implications
Pathogenic BRCA1/2 variants are inherited. First-degree relatives (parents, siblings, children) each have a 50% chance of carrying the same variant. A positive finding in one family member triggers cascade testing recommendations for the rest of the family.
What to do next
If you have a flagged BRCA1 or BRCA2 variant, the most important next step is a referral to a genetic counselor. They can explain what the finding means in the context of your specific variant, your family history, and your clinical situation, and help you navigate the surveillance and prevention options that are right for you.
This report is not a clinical diagnosis. Always consult a qualified healthcare provider before making any medical decisions based on genetic findings.
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