The Scots and Northern Irish are genetically distinct from elsewhere in the UK, with a different legacy of inherited cancers than in England and Wales.
Women from Scotland and Northern Ireland with breast cancer in their families have inherited a distinct cluster of genetic mutations
The study, published in the British Journal of Cancer (BJC Vol. 88:8), found women from Scotland and Northern Ireland with breast cancer in their families have inherited a distinct cluster of genetic mutations, including one that may have been brought over by the Vikings. Inheriting damaged versions of two key genes - called BRCA1 and BRCA2 - causes around three per cent of breast cancers, many ovarian cancers and several other types of cancer.
Scientists also found evidence that specific genetic faults in the Scottish population have a different effect on cancer risk than others. They found that faults in the first two thirds of the BRCA1 gene gave women a significantly higher risk of ovarian cancer than faults in the final third, while damage in the central portion of BRCA2 also conveyed a high risk of the disease. This information should allow doctors to carefully tailor the advice they give to individual women.
Women who inherit a damaged BRCA1 gene have a 60-85 per cent chance of developing breast cancer at some stage in their lives and a 20-40 per cent chance of developing ovarian cancer. For BRCA2, the risks are 40-60 per cent and 10-20 per cent respectively.
Studies of cancer genetics in Scotland are particularly accurate, because the Scottish Cancer Registry is recognised as one of the best in the world.