BRCA1 and breast cancer: A BRCA1 mutation was found in 18.4 % (14 of 76) women diagnosed with BC at or under the age of 40 compared to 11.2 % (14 of 124) of women diagnosed at a later age (Table 3); a BRCA2 mutation was found in 4 % (3 of 76) women diagnosed with BC at or under the age of 40 compared to 6.5 % (8 of 124) of women diagnosed at a later age (Table 4).