Table 1

Description of the study population

BC, breast cancer
*For specific mutations see table 2.
†At the initiation of the study, the carrier status was known in 31 of the participating subjects. During the study all included subjects wanted to have a predictive genetic BRCA test, so that in the end we knew the carrier status of all participating subjects.
‡These statistics do not represent the actual cancer incidence, as only living individuals are included in this study. The BRCA1 mutation was carried by 36% of the subjects, BRCA2 by 46%, and 18% did not carry the familial BRCA1/2 mutation and were considered to be sporadic cancers. Of the subjects with ovarian cancer, 75% carried a BRCA1 mutation, and 25% a BRCA2 mutation. The only subject with breast and ovarian cancer carried a BRCA2 mutation. Of the subjects without breast or ovarian cancer, 19% carried a BRCA1 mutation, 19% had a BRCA2 mutation, and 62% did not carry a BRCA1/2 mutation.
Number of participating families/subjects14/107
Minimum/maximum age of the subjects21 years/83 years
Relationship to the proband1st−4th degree (largest group 1st–3rd)
Families with a BRCA1/BRCA2 mutation*7/7
No. of carriers of a BRCA1/BRCA2 mutation†23/22
No. of non-carriers of a BRCA1/2 mutation†62
Percentage of subjects with:
    no breast or ovarian cancer ‡85.9%
    breast cancer‡10.3% (1.7% bilateral BC)
    ovarian cancer‡3.7%
    breast and ovarian cancer‡0.9%