Although c.904_916del allele’s frequency in familial cohort is lower than the frequency of BRCA1 and BRCA2 mutations, which collectively explain 20% of the Finnish breast and ovarian cancer families [25,26], in unselected cases the combined frequency of different BRCA1/2 mutations (1.8%) [27] is roughly the same as observed for this single MCPH1 mutation. This evidence concerns the gene BRCA2 and ovarian cancer.