What are genes and genetic mutations?

Genes make up our DNA, which is found in almost every cell in our body. They act like blueprints and contain the information that enables our bodies to grow and function correctly. Genes are inherited, you received half of yours from each parent, and any biological children you may have would have inherited half of their genes from you. Sometimes there are changes or alterations on a gene that can increase your risk of certain cancers.

Here we explain what you need to know about genes and genetic mutations.

What are gene alterations / mutations?

Sometimes the information in a gene can become altered (sometimes called mutated), and this change causes it to not work as it should.

There are a number of reasons for a gene becoming altered. This can be simply through chance, or because of environmental factors, such as exposure to certain substances, or lifestyle factors, such as obesity or smoking.

Are all gene alterations passed on to children?

A gene alteration does not always pass down to children, if it is a hereditary alteration, there is a 50% chance that a child may inherit it, whether they are female or male. A test is needed to check whether the alteration has passed down or not.

What gene alterations are known to be linked to gynaecological cancers?

There are two key types of genes, that if altered, can increase your risk of a gynae cancer. Alterations on the BRCA1 or 2 gene are known to increase your risk of ovarian cancer, as well as breast, prostate (for men) and pancreatic cancer.

Lynch Syndrome is another genetic alteration linked to gynae cancers, it increases the risk of womb cancer, as well as bowel cancer.

Does having a gene alteration mean you need to look out for cancer symptoms?

If you have been tested and told that you have a gene alteration that puts you at an increased risk of cancer, it may mean that you need to be more vigilant of symptoms. You can read more about ovarian cancer symptoms here, and womb cancer symptoms here.

It could also mean that you may be able to access some forms of cancer prevention on the NHS, such as regular surveillance or risk-reduction surgery. Visit our page on ovarian cancer, breast cancer, and Lynch Syndrome for more information.

What do BRCA genes do?

Everyone has BRCA1 and BRCA2 genes. They are known as tumour suppressor genes as they play a role in protecting us from cancer. They do this by helping to prevent the cells in our bodies from growing and dividing out of control. If there is a significant alteration in either of the BRCA1 or BRCA2 genes, they may lose the ability to protect us from a cancer developing.

What is the risk a BRCA gene alteration will result in a cancer developing?

*Estimated lifetime risk (up to age 70) for people with BRCA1/2 alterations (mutations). Source: Royal Marsden Beginner’s Guide to BRCA1 and BRCA2

How common are BRCA gene alterations?

Around 1 in every 200-300 people in the general population will have a BRCA gene alteration. In some populations, they are more frequent, people of Ashkenazi Jewish descent, for example, have around a 1 in 40 chance of carrying a BRCA gene alteration.

What is your risk of a cancer developing if you have Lynch Syndrome?

Here is a table with the cancer risk associated with Lynch Syndrome.

If you are found to have Lynch Syndrome you may be offered a hysterectomy to prevent the risk of womb cancer or regular hysterscopies to try and detect any womb cancer in the earliest stages. You may also be offered regular colonoscopies to pick up any bowel cancer at the earliest stages. You can read more about Lynch Syndrome here.