In the news

It is now thought that mutations in the BRCA1 and BRCA2 genes may account for only about 20% of the familial aggregation of breast cancer before the age of 55. Cui et al report the results of a study on three-generation Australian families affected by early-onset breast cancer that suggests there may be another dominantly inherited risk factor in addition to BRCA1/2 mutations, and also a recessively inherited risk [Cui, J. et al (2001) Am J Hum Genet 68, 420-431 (Abstract)]. They estimate that about 1/250 women may have the recessively inherited risk, and that it gives them an 85% chance of developing breast cancer by the age of 50 years, with disease virtually certain by the age of 60 years. In comparison, about 1/350 women are estimated to have a dominantly inherited risk (including BRCA1/2 mutations).

Comment: Some previous studies have failed to find evidence for a recessively inherited risk in early onset breast cancer. Cui et al suggest that the design of their study, which used women with early-onset breast cancer as probands, and included their aunts and grandmothers, might have enhanced their ability to detect a recessively inherited risk. The challenge now will be to find the gene(s) involved.