ABSTRACT
The discovery and complete sequencing of BRCA1 and BRCA2 (1-3) and the subsequent clinical application of genetic testing for these genes have generated a series of questions
of research and clinical importance. For example, what is the mutation spectrum of these
genes? Are the cancer susceptibility mutations found in these genes gain of function
mutations? Are they loss of function mutations? Are their effects dominant negative?
How many different mutations are there in the population? How many different kinds of
mutations are there in breast cancer families? These questions were important for basic
biological understanding and because of their implications for therapeutic and diagnostic
uses of the genetic data.
