BRCA1 and Cowden disease: 20.2% (93/460) were assessed to also have features suggestive of alternative hereditary cancer syndromes, most commonly Lynch Syndrome (65, 69.9%), Li Fraumeni (11, 11.8%) and Cowden Syndrome (11, 11.8%) which have overlapping phenotypes with BRCA1/2 hereditary breast cancer syndrome.