Women with a faulty version of the BRIP1 gene are twice as likely to develop breast cancer, according to research by scientists at the Institute of Cancer Research published in the journal Nature Genetics. Flaws in the gene increase the risk of breast cancer from one in 12 to one in six by the time a woman is 70 years old.

About 30,000 women in the UK, or about 0.1% of the total, carry the defective version of the BRIP1 gene, which is believed to account for about 100 cases of breast cancer each year. But scientists believe faults in dozens of other genes are also likely to increase the risk.