Cystic fibrosis is a common inherited condition. Cystic fibrosis is a genetic disorder in which internal bodily secretions become thick and sticky, and hinder the function of certain organs, such as the lungs and digestive system.

The condition is caused by a faulty gene that controls the movement of salt and water in and out of cells in the body. When cystic fibrosis occurs, too much salt and not enough water passes into the cells and turns the body's secretions, which normally act as a lubricant, into a thick mucus. This mucus then clogs up the body's tubes, ducts and passageways, and makes them ineffective (not work properly) and prone to infection.

The faulty gene that causes cystic fibrosis is recessive, which means that two separate genes, one from each parent, are needed to inherit it. It is possible to carry the disease and not suffer from it. If two people who are both carriers have a baby, there is a 25% chance that the child will have cystic fibrosis.

Symptoms of cystic fibrosis include recurrent chest infections and poor growth, and the condition can also result in related health problems such as diabetes and infertility.

There is no cure for cystic fibrosis, but much research has been done on the faulty gene since it was identified, which continues today. There are also many treatments and therapies that can make the condition easier to live with.