Taken from Ford et al. (1994). Data from 33
families, each containing at least 4 individuals with ovarian or breast cancer diagnosed before
age 60, and each having a posterior probability of linkage to BRCA1 of at least 90%.
The pink curve represents estimations of the overall penetrance of BRCA1 obtained by maximizing the LOD score with respect to different penetrance functions. This is equivalent to maximizing the likelihood of the marker data, conditional on all the disease phenotype data and allows the penetrance to be estimated free of bias due to ascertainment of families on the basis of multiple affected individuals.
Age-specific frequency rates of ovarian cancer following breast cancer (yellow curve) were estimated from the observed number of cases and person-years of follow-up in those women with breast cancer diagnosed before age 60.