Characteristics of the participants
| Population controls | Family-based cases | Family-based cases: subset* | |
| n | 3474 | 3918 | 1968 |
| Families | 3492 | 1602 | |
| Relatives per family included | |||
| 1 | 3474 | 3099 | 1263 |
| 2 | 0 | 364 | 309 |
| 3 | 0 | 25 | 25 |
| 4 | 0 | 4 | 3 |
| Study | |||
| ABCS | 1563 | 904 | 82 |
| HEBON | 0 | 2248 | 1671 |
| ORIGO | 987 | 0 | 0 |
| RBCS | 924 | 766 | 215 |
| Array | |||
| GSA | 1781 | 1781 | |
| iCOGS | 2388 | 1680 | 163 |
| OncoArray | 1086 | 457 | 24 |
| Age | |||
| Mean | 45.6 | 45.1 | 46.8 |
| Range | 18–93 | 21–91 | 21–91 |
| First breast cancer | |||
| Invasive | NA | 3575 | 1630 |
| In situ | NA | 312 | 308 |
| Unknown | NA | 31 | 30 |
| ER status | |||
| Positive | NA | 1755 | 927 |
| Negative | NA | 488 | 213 |
| Unknown | NA | 1675 | 828 |
| Second breast tumour (n) | NA | 719 | 327 |
| Age | |||
| Mean | NA | 52.6 | 52.9 |
| Range | NA | 26–80 | 26–79 |
| Unknown | NA | 130 | 29 |
| Invasiveness | |||
| Invasive | NA | 460 | 220 |
| In situ | NA | 116 | 77 |
| Unknown | NA | 144 | 30 |
| ER status | |||
| Positive | NA | 290 | 153 |
| Negative | NA | 49 | 21 |
| Unknown | NA | 380 | 153 |
| Gene panel results | |||
| All | 2584 | 2586 | 1586 |
| No PV | 2537 | 2369 | 1463 |
| CHEK2 PV | 31 | 167 | 98 |
| ATM PV | 9 | 39 | 18 |
| CHEK2+ATM PV | 0 | 2 | 1 |
| PALB2 PV† | 7 | 10 | 6 |
| Standardised PRS313 (SD) | |||
| Overall BC | 0 (1.03) | 0.71 (0.96) | 0.64 (0.88) |
| ER+ BC | 0 (1.03) | 0.72 (0.97) | 0.65 (0.88) |
| ER− BC | 0 (1.01) | 0.45 (0.94) | 0.29 (0.85) |
| BOADICEAFH | |||
| Mean (SD) | 0 (0.99) | 0.55 (0.39) | 0.69 (0.35) |
| Affected FDR | |||
| 0 | NA | 1125 | |
| 1 | NA | 1454 | |
| 2 | NA | 555 | |
| >2 | NA | 176 | |
| Affected SDR | |||
| 0 | NA | 1360 | |
| 1 | NA | 1086 | |
| 2 | NA | 583 | |
| >2 | NA | 281 | |
| Unknown | NA | 615 | |
*Cases included in the association analyses which were not part of the development data set for the PRS313 as described in Mavaddat et al. 5
†Excluding variants in the last exon of PALB2 to make it uniform for all 2586 cases.
ABCS, Amsterdam Breast Cancer Study; BC, breast cancer; BOADICEAFH, polygenic load calculated in the Breast and Ovarian Analysis of Disease Incidence and Carrier Estimation Algorithm; ER, Estrogen Receptor; FDR, first-degree relatives; GSA, Global Screening Array; HEBON, Hereditary Breast and Ovarian cancer study in the Netherlands; n, number of individuals; NA, Not Applicable; ORIGO, Oorsprong van borstkanker integraal onderzocht; PRS, Polygenic Risk Score; PV, pathogenic variant; RBCS, Rotterdam Breast Cancer Study; SDR, second-degree relatives.