BRCA mutations are rare – affecting about 1 in 400 people. However, individuals of Ashkenazi Jewish decent have about a 1 in 40 chance of having a BRCA mutation. Close to 1 million people in the United States are estimated to have a BRCA mutation, but less than 10 percent are aware that they have a mutation that increases their risk for cancer. That’s why genetic counseling is very important.