Table 3

Frequency of BRCA1 and BRCA2 mutation carriers according to the criteria by which they were ascertained

Criteria*Total cases† (No)BRCA1 No (%)BRCA2 No (%)BRCA1 or BRCA2 No (%)
*For details of each inclusion criterion description refer to table 1.
†Each proband could be ascertained by more than one criterion, therefore, the categories are not mutually exclusive.
‡ Below age ⩽35 for breast and ⩽60 for ovarian cancer cases.
§Above age 35 for breast and 60 for ovarian cancer cases.
1 One first degree relative1499 (6.0)4 (2.7)13 (8.7)
    1a One younger first degree relative‡314 (12.9)2 (6.5)6 (19.4)
    1b One older first degree relative§1185 (4.2)2 (1.7)7 (5.9)
2 Two second degree relatives413 (7.3)4 (9.8)7 (17.1)
3 Proband diagnosis at age ⩽ 35535 (9.4)2 (3.8)7 (13.2)
4 Second or third degree relatives with diagnosis age restriction466 (13.0)3 (6.5)9 (19.6)
5 and 6 Male proband or male relative80 (0)0 (0)0 (0)
7 Multiple primary tumours362 (5.6)5 (13.9)7 (19.4)
8 and 9 Relative with multiple primary tumours161 (6.3)1 (6.3)2 (12.5)
10 Three first degree relatives with cancer694 (5.8)3 (4.4)7 (10.1)
11 Ashkenazi Jewish background434 (9.3)4 (9.3)8 (18.6)