Phenocopies in breast cancer 1 (BRCA1) families: implications for genetic counselling

Abstract

In the process of counselling women from families with a known breast cancer 1 (BRCA1) mutation, we often encounter healthy women who are found to have a negative test. This is usually a source of great relief for the woman, and traditionally the genetic counsellor or physician offers the opinion that the residual risk is low—that is, approximately that of women in the general population. In Canada and the USA, the risk to the population is approximately 8% to age 75 years, and in Poland it is about 5%. In a recent paper from the UK, Smith and colleagues suggest that the residual risk is, in fact, much greater than this. They estimate that the risk of breast cancer …