My son has this condition and I am running this marathon for him and all the other people who suffer. Cystic fibrosis (CF) is a life-limiting genetic condition affecting more than 10,000 people across the UK. It affects the lungs and digestive system and can cause chronic infections and reduced lung function. Currently, half of those with CF will not live past age 41.The Cystic Fibrosis Trust is fighting for a brighter future for people with CF and their families by funding cutting-edge research, driving up standards of care and supporting people with the condition and their loved ones every step of the way.