Within the Ashkenazi Jewish (Eastern European) community, gene faults within the two breast cancer susceptibility genes (BRCA1 and BRCA2) occur more commonly then in the general population.

In Ashkenazi Jewish women there are two specific mutations in BRCA1 gene and one mutation in the BRCA2 gene that occur. About 1 in 50 Jewish women have one of these three specific mutations that increase their risk of breast and ovarian cancer. If an individual from an Ashkenazi Jewish background has a family history of breast, ovarian or colorectal cancer that does not meet the WMFACS referral guidelines they should still be referred for assessment.

Genetic testing is also possible in a family where there are no surviving affected relatives or DNA stored because the specificity of the three gene faults means that it is possible to look at an unaffected individual's blood for the common Ashkenazi Jewish gene faults.