We’ve all been affected by cancer, so it’s perfectly normal to be concerned about the risk it poses to us and our family. We’re aware of the faulty genes that can run in families and that raise the risk of certain cancers, such as BRCA1 – the so-called ‘Jolie gene’, after actor Angelina Jolie – and its close cousin, BRCA2, for breast cancer. But just how common are they – and how do you
