Everyone has BRCA1 (BReast Cancer 1) and BRCA2 (BReast Cancer 2) genes, which we inherit from our parents. They are tumour suppressor genes which prevent cells from growing and dividing too rapidly. Having a fault in one of these genes can increase the risk of a number of different cancers.
What are BRCA gene faults?
Our genes are like instruction manuals that tell the cells in our bodies how to work, grow and appear. A person has two copies of a gene, one inherited from each parent. Sometimes inherited genes have small changes which are known as a genetic fault. A fault in the BRCA gene can cause cells to become abnormal and grow in an uncontrolled way.
A BRCA1 or BRCA2 genetic fault is not a guarantee that you will develop cancer, but it does increase your risk of being diagnosed with breast cancer, ovarian cancer, pancreatic cancer and prostate cancer.
If a man or woman has a BRCA genetic fault, they have a 50% (one in two) chance of passing it on to their children, and one genetic fault is enough to increase the risk of some cancers.
How common are BRCA gene faults?
Anyone can have BRCA genetic faults; however, they are found to be higher amongst people from certain backgrounds including people with Ashkenazi and Sephardi Jewish heritage. In the general population, around 1 in every 200 people are BRCA1 or BRCA2 gene fault carriers. 1 in 40 Ashkenazi Jews and 1 in 140 Sephardi Jews heritage carry the faulty BRCA gene.
Why is the Ashkenazi and Sephardi Jewish population at higher risk?
Over 90% of the BRCA faults found in the Jewish community are one of three “founder faults”. Researchers have tried to trace the origins of these specific faults. One theory is that the original faults occurred around the time of a genetic “bottleneck” around 500-600 years ago, when the population reduced down to as few as 350 people. This was followed by a large expansion in the population which caused the current high frequency of the faults in the Jewish population.
BRCA1 and BRCA2 cancer risk
Having a fault in either the BRCA1 or BRCA2 genes can increase a person’s risk of breast cancer, melanoma (skin) cancer, ovarian cancer, prostate cancer and pancreatic cancer. Although rare, it is possible to inherit more than one genetic BRCA fault – the cancer risk in these cases is calculated using the highest risk for that cancer type.
|Type of cancer||Lifetime risk in general population||BRCA1 gene fault lifetime risk (up to age 80)||BRCA2 gene fault lifetime risk (up to age 80)|
|Breast cancer in men||1%||0.4% (0.1 - 1.5%)||4% (2 - 8%)|
|Breast cancer in women||15%||72% (65 - 79%)||69% (61 - 77%)|
|Melanoma||2 - 3%||1 - 2%||3 - 5%|
|Ovarian cancer||2%||44% (36 - 53%)||17% (11 - 25%)|
|Pancreatic cancer||2%||Up to 3% (1 - 5%)||Up to 3% (1 - 5%)|
|Prostate cancer||18%||17% (8 - 26%)||27% (21 - 35%)|
* Lifetime risk is the risk of developing cancer over the course of an individuals lifetime (from birth to age 80).
If you test negative for a BRCA fault you will know that you haven’t inherited that fault and the increased risk that goes along with it. Your risk of being diagnosed with cancers associated with BRCA will be the same as the general population.
The only way to know if you have a BRCA gene fault is to have a genetic test.
NHS genetic testing programme
NHS England is offering free BRCA gene testing for anyone living in England with one or more Jewish grandparent, of any type of Jewish heritage (Ashkenazi, Sephardi or Mizrahi). The testing programme is for all Jewish people irrespective of their personal or family history if cancer. A similar programme is already in Israel.
For more information visit www.jewishbrca.org or call the genetic counselling helpline on 0203 437 6001.
What are the advantages of genetic testing?
The advantages of having a genetic test are around understanding the things you and your family can do to reduce the risk of developing cancer. If you test positive for a genetic fault there may be a number of risk-reducing options could be available to you: you can make changes to your lifestyle, undergo regular screening, take risk-reducing medicine, have risk-reducing surgery, and there are options you can take if you are planning to start a family.
Reviewed: Feb 2023
Next review: Feb 2024