Proportion of unaffected first-degree relatives of mutation carriers testing negative for the family mutation depending on age
| Age at testing (years) | Testing positive | Testing negative | Proportion negative (%) | Assumed proportion negative (%) |
|---|---|---|---|---|
| The table does not include 17 unaffected female first-degree relatives who tested positive (or were obligate carriers) but had a daughter with breast or ovarian cancer who also tested positive. | ||||
| 18–39 | 75 | 62 | 45 | 50 |
| 40–59 | 51 | 73 | 59 | 60 |
| ⩾60 | 4 | 26 | 87 | 90 |
| Total | 130 | 161 | ||