Proportion of families from set 1 testing positive for pathogenic mutations in BRCA1/2 with an overall estimate of the combined frequency
| BRCA1 mutations | BRCA2 mutations | Both tested* | One gene tested | Combined estimated†| |
|---|---|---|---|---|---|
| *This assumes that a sample testing positive for one gene will be negative for the other; †this calculation assumes that the detection rate in untested samples for each gene will be similar; this could not be calculated for MBC and FBC/ovary and therefore a final % determined. | |||||
| FBC, female breast cancer; FBC/ovary, proven ovarian cancer with breast cancer in first degree relative or second degree through father or double primary breast/ovary; FBC <36, isolated female breast cancers diagnosed at <36 years of age; 1+ ovary, one ovarian cancer+at least two breast cancers at <60 years of age; 2, breast cancers at <50 years of age; 2+ ovary, at least two ovarian cancers; 3, breast cancer at <60 years of age; 4+, breast cancer at <60 years of age. | |||||
| 4+ FBC | 8/61 (13%) | 15/64 (23%) | 23/50 (46%) | 25 | 26/75 (35%) |
| 3 FBC | 4/51 (10%) | 4/33 (12%) | 8/33 (24%) | 18 | 10/51 (20%) |
| 2 FBC | 1/26 (4%) | 3/21 (15%) | 4/21 (20%) | 5 | 4/26 (15%) |
| 2+ ovary | 32/60 (54%) | 7/25 (28%) | 39/56 (70%) | 4 | 40/60 (67%) |
| 1+ ovary | 34/120 (28%) | 9/50 (18%) | 43/84 (51%) | 36 | 50/120 (42%) |
| MBC | 1/1 | 13/36 (36%) | 14/14 | 22 | ?/36 |
| FBC/ovary | 4/20 (18%) | 0/5 | 4/9 | 11 | ?/20 |
| FBC <36 | 0/84 | 1/84 (1%) | 1/84 | 0 | 1/84 |
| Total | 84/422 (20%) | 54/318 (17%) | 138/351 (39%) | 121 | 138+/472 (29%+) |