🧬 NHS & WHO sourced

Breast Cancer Genes, BRCA and Family History

About 5–10% of breast cancers are caused by an inherited gene fault — most often BRCA1 or BRCA2. What you need to know about genetic testing and risk management.

Reviewed against NHS & WHO guidelines Last reviewed: January 2025 For educational purposes — not medical advice
✓ 5–10% of breast cancers are caused by an inherited gene mutation
✓ BRCA1 mutation carriers have up to 80% lifetime breast cancer risk
✓ BRCA2 mutation carriers have up to 60% lifetime risk
✓ Prophylactic mastectomy reduces risk by up to 97% for high-risk carriers

BRCA1 and BRCA2

BRCA1 and BRCA2 are tumour suppressor genes — they normally help prevent abnormal cell growth. A faulty (mutated) copy significantly raises lifetime cancer risk. BRCA1 mutation: lifetime breast cancer risk of approximately 65–80%. BRCA2 mutation: approximately 45–60% lifetime risk. Both also raise ovarian cancer risk.

Other gene mutations

PALB2, TP53, PTEN, CDH1 and RAD51C/D are other genes associated with raised breast cancer risk. Gene testing panels now routinely check multiple genes simultaneously.

Who should consider genetic testing?

The NHS offers genetic testing if you have a significant family history. Indicators include:

  • Three or more relatives with breast or ovarian cancer on the same side of the family
  • Two relatives with breast cancer, at least one diagnosed under 50
  • A male relative with breast cancer
  • A known BRCA mutation in a family member
  • A personal diagnosis of breast cancer under 40
  • Ashkenazi Jewish heritage with any family history of breast or ovarian cancer

What happens with genetic counselling?

A genetic counsellor explains what testing involves, what results might mean for you and your family, and helps you decide whether to proceed. Testing usually involves a blood sample. Results can take several weeks. Counselling is provided both before and after testing.

Options for BRCA mutation carriers

  • Enhanced surveillance: Annual MRI and/or mammogram from age 30
  • Preventive drug therapy: Tamoxifen or anastrozole to reduce risk
  • Risk-reducing surgery: Bilateral prophylactic mastectomy (reduces risk by up to 97%) and/or salpingo-oophorectomy (removal of ovaries and fallopian tubes, recommended after childbearing is complete)

Frequently asked questions

Should I get a BRCA gene test? +
NHS genetic testing is offered if you have a significant family history of breast or ovarian cancer — for example, multiple relatives affected, a relative diagnosed under 50, or a known BRCA mutation in the family. Speak to your GP if you are concerned. A genetic counsellor will explain what testing involves, what the results might mean, and help you decide whether to proceed.
What is the BRCA gene mutation? +
BRCA1 and BRCA2 are tumour suppressor genes. A faulty (mutated) copy significantly raises lifetime breast cancer risk. A BRCA1 mutation carries a lifetime risk of around 65–80%; BRCA2 around 45–60%. Both also raise ovarian cancer risk. Faulty BRCA genes are inherited and can be passed on to children of either sex.
What are the options for BRCA mutation carriers? +
Options include enhanced surveillance (annual MRI and/or mammogram from age 30), preventive drug therapy (tamoxifen or anastrozole to reduce risk), and risk-reducing surgery (bilateral prophylactic mastectomy, which reduces lifetime risk by up to 97%). The right approach depends on individual circumstances and is discussed with a specialist genetics team.

Clinical sources

  • NHS — www.nhs.uk
  • World Health Organization — www.who.int

This content is for educational purposes and does not constitute medical advice. Always consult a qualified healthcare professional for personal medical guidance.

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