Despite intensive research, genetic linkage analysis, genome-wide association studies (GWAS) and most recently next generation sequencing (NGS) exome studies have failed to identify other common high penetrance breast cancer susceptibility genes, like BRCA1 and BRCA2, and it is now generally accepted that no single high penetrance gene is likely to account for a larger fraction of the remaining familial aggregation [4-9]. Here, BRCA1 is linked to breast carcinoma.