www.cancergenetics.ie

BRCA1 and BRCA2

Risks associated with inherited alterations in BRCA1 or BRCA2

BRCA1 and BRCA2 are two examples of genes that works to prevent cancer by correcting specific types of  DNA damage.  Inherited alterations in either of these two genes greatly increase the risk of cancer; particularly cancer of the ovary, breast and prostate. Rarely, other cancers, such as melanoma, pancreatic, or other cancers, have also been reported in individuals with BRCA1 or BRCA2 gene alterations.  

risks.png

The exact risk of cancer in an individual with an inherited BRCA gene alteration depends on a number of different features, including:

  1. Gender

  2. Age

    • BRCA gene alterations are not associated with risks of cancer in childhood years

    • Most cancers in women with BRCA alterations are diagnosed after the age of 30

    • Most cancers in men with BRCA alterations are diagnosed after the age of 40

  3. Gene in which alteration is identified

    • BRCA1 -v- BRCA2

  4. Specific Genetic alteration

    • Alteration Type

    • Where alteration is located in the gene

  5. Family History

    • Number and type of cancers in the family

    • Age of onset of cancer in the family

  6. Other Genetic Risk Factors

    • other inherited risk factors

  7. Environmental Factors

    • Examples include use of Hormone Replacement Therapy, contraception

  8. Lifestyle Factors

    • e.g. alcohol consumption, weight, family planning

  9. Other factors (unknown)

Carriers of BRCA1/BRCA2 alterations 

If a woman is found to have inherited an alteration in BRCA1 or BRCA2, there are steps she can take to minimise your likelihood of developing cancer of the breast or ovary. If a man is found to have inherited an alteration in either of these genes, he may also be at risk of developing male breast cancer or prostate cancer, and may, in turn, pass the alteration on to his own children.

How are BRCA gene alterations inherited?

We each have two copies of each of these genes, one of which we inherit from our mother, and the other from our father. 

If you have inherited a BRCA gene alteration, each of your children (male or female) and each of your siblings (male or female) have a 50% (1 in 2) risk of inheriting the same alteration, as the video here below explains.